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['Singh, J.', 'Hauser, C.', 'Chalker, P.R.', 'Sutcliffe, C.J.'] | 2021-09-29T20:25:24Z | 2021-09-29T20:25:24Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88214', 'http://dx.doi.org/10.26153/tsw/15155'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['adaptive slicing algorithm', 'Digital Light Processing', 'micro chemical reactors', 'layer based manufacturing'] | Customised Layer Deposition for Chemical Reactor Applications | Conference paper | https://repositories.lib.utexas.edu//bitstreams/92bf59fc-5ac2-4671-a284-5eeab058c9e6/download | University of Texas at Austin | This paper discusses the development and application of an adaptive slicing algorithm for
use with Digital Light Processing (DLP) for the manufacture of micro chemical reactors. Micro
reactors have highly complex constructions and DLP has a proven ability to deliver features at
the micro level with high accuracy. However, DLP fails to provide a truly smooth profiled
surface finish which could influence fluid flow through entrance and exit apertures and along
snaking micro channels. Ensuring smooth surfaces will minimise energy losses in the fluid flow
path. Generally, layer based manufacturing techniques incur a trade off between build time and
resolution. The algorithms used in this study attempt to mitigate this to some degree by
calculating locations where high resolution is required through surface profiling techniques and
adjusts the layer thickness accordingly. It is proposed that this adaptive layering technique may
improve surface roughness and reduce friction related energy losses along micro channels within
chemical reactor applications. | null | null | null | null | null | null |
['Jones, J.', 'Jones, C.L.', 'Wimpenny, D.I.'] | 2021-09-29T17:48:21Z | 2021-09-29T17:48:21Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88200', 'http://dx.doi.org/10.26153/tsw/15141'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['customised rapid manufactured parts', 'Custom-Fit project', 'CAD packages', 'European Commission'] | Customised Rapid Manufactured Parts: Technology and Case Studies from the Custom-Fit Project | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c457cd0c-623f-4f4d-ae8e-af9f52db675e/download | null | The design and manufacture of individually customised products is generally restricted to
bespoke clothing or footwear for very wealthy customers. The aim of the Custom-Fit project was
to develop a fast, flexible and economically viable route for the manufacture of individually
customised parts. These products not only provide improved comfort levels but also provide
better functional performance, including enhanced safety for the user. This 4.5 year, European
Commission subsidised €16 million project, supported by the EU, involving 30 partners across
the breadth of the Europe finished in early 2009. This paper will showcase the technology
developed: CAD packages which automate the design process and three new rapid
manufacturing methods. It will also include case studies on a range of customised products,
including customised Motorcycles helmets. The case studies not only demonstrate the
performance benefits of individual customisation but also show the potential for new approaches
to product design. More information at www.Custom-Fit.org. | null | null | null | null | null | null |
['Sturm, L.D.', 'Williams, C.B.', 'Camelio, J.A.', 'White, J.', 'Parker, R.'] | 2021-10-18T20:40:06Z | 2021-10-18T20:40:06Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89238 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'cyber-physical attacks'] | Cyber-Physical Vulnerabilities in Additive Manufacturing Systems | Conference paper | https://repositories.lib.utexas.edu//bitstreams/56503a7b-0693-4a53-8532-01a1e489b7bf/download | University of Texas at Austin | One of the key advantages of additive manufacturing (AM) is its digital thread, which allows
for rapid communication, iteration, and sharing of a design model and its corresponding physical
representation. While this enables a more efficient design process, it also presents opportunities
for cyber-attacks to impact the physical word. In this paper the authors examine potential attack
vectors along the Additive Manufacturing process chain. Specifically, the effects of cyber-physical attacks, and potential means for detecting them, are explored. Based on the results of
this study, recommendations are presented for preventing and detecting cyber-physical attacks on
AM processes. | null | null | null | null | null | null |
['BenAzouz, Aymen', "O'Connor, Richard", 'Vasquez, Mercedes', 'Brabazon, Dermot', 'Paull, Brett'] | 2021-09-30T13:19:46Z | 2021-09-30T13:19:46Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88230', 'http://dx.doi.org/10.26153/tsw/15171'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['mutli-layered fabrication', 'microfluidic chips', 'cyclic olefin copolymer', 'COC chips', 'xurographic processing', 'laser processing'] | Cyclic Olefin Copolymer Strip Processing for Freedom Fabrication of Multi-Layered Microfluidic Sensing Systems | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cc7054de-9be5-4834-bb0f-f69c20ac7239/download | University of Texas at Austin | Researchers have developed techniques for multi-layered fabrication of microfluidic chips which
allow for increased scope of channel geometries and associated improved sensing capabilities. In
these techniques, slits have been fabricated in thin layers of polymer or glass, typically of a
couple of hundred micrometers thick. These layers are then bonded to each other using adhesives,
hot embossing or a combination of bonding methods. This paper presents a new fast freeform
methodology for 3D channel geometries to be fabricated in COC chips using laser and
xurographic processing for slit formation and cyclohexane promoted bonding for multi-layer
joining at room temperature. | null | null | null | null | null | null |
['Fang, Wei', 'Siang Ngooi, Chan', 'Gong, Haiqing'] | 2018-12-07T16:05:22Z | 2018-12-07T16:05:22Z | 1997 | Mechanical Engineering | doi:10.15781/T2N58D62B | http://hdl.handle.net/2152/71441 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['CAD', '3D objects'] | A data format providing side wall orientation and adaptive slicing for use in stepless rapid prototyping | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1141909a-e385-47f0-a50f-f468de587896/download | null | Current Rapid Prototyping systems mainly use 2D layers building techniques that result
in the 'staircase' effect on slanted surface. A new method has been developed to eliminate the
'staircase' effect and to improve the surface quality by extending the 2D layers to 3D layers
building. In this approach, a new data format, Layer Transfer Interface (LTI), is introduced to
generate layers having slanted side wall. It provides a faster slicing algorithm and accurate
reconstruction of 3D objects. This format is independent of any particular RP machines.
Furthermore, adaptive slicing has been achieved using this format and implemented on a fiveaxis
milling RP system. | null | null | null | null | null | null |
['Perišić, Milica', 'Milenković, Dimitrije', 'Lu, Yan', 'Jones, Albert', 'Ivezić, Nenad', 'Kulvatunyou, Boonserm'] | 2021-12-07T17:59:01Z | 2021-12-07T17:59:01Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90738', 'http://dx.doi.org/10.26153/tsw/17657'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['data integration framework', 'data integration', 'data management', 'additive manufacturing'] | A Data Integration Framework for Additive Manufacturing Big Data Management | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e5faba3e-06ae-4390-8d14-fab302bbc210/download | University of Texas at Austin | Large amounts of data are generated throughout the entire, AM, part-development lifecycle. Data
are generated by various functions within process monitoring, material characterization,
equipment status, and part qualification. Hence, data integration and management are critical in
streamlining, accelerating, certifying, and deploying these functions. However, achieving that
integration and management has several challenges because AM data embodies the four
characteristics of Big Data - volume, velocity, variety, and veracity. This paper proposes an AM
framework as a foundation for addressing those challenges. In the framework, AM data are
streamed, curated, and configured automatically for real-time analysis and batch processing, which
increases the effectiveness of archiving and querying that data. The framework also includes a
description of the associated AM metadata, which links the various data types and improves
browsing, discovering, and analyzing that data. Finally, the framework can be used to derive
requirements for standards that enable data sharing. | null | null | null | null | null | null |
['Baldwin, Martha', 'Meisel, Nicholas A.', 'McComb, Christopher'] | 2023-03-01T17:17:53Z | 2023-03-01T17:17:53Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117549', 'http://dx.doi.org/10.26153/tsw/44429'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | Lattice Structure | A Data-Driven Approach for Multi-Lattice Transitions | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1559df14-4360-4ce7-ba10-fa5906044501/download | null | Additive manufacturing is advantageous for producing lightweight components while
maintaining function and form. This ability has been bolstered by the introduction of unit lattice
cells and the gradation of those cells. In cases where loading varies throughout a part, it may be
necessary to use multiple lattice cell types, also known as multi-lattice structures. In such
structures, abrupt transitions between geometries may cause stress concentrations, making the
boundary a primary failure point; thus, transition regions should be created between each lattice
cell type. Although computational approaches have been proposed, smooth transition regions are
still difficult to intuit and design, especially between lattices of drastically different geometries.
This work demonstrates and assesses a method for using variational autoencoders to automate the
creation of transitional lattice cells. In particular, the work focuses on identifying the relationships
that exist within the latent space produced by the variational autoencoder. Through computational
experimentation, it was found that the smoothness of transition regions was higher when the
endpoints were located closer together in the latent space. | null | null | null | null | null | null |
['Sammons, P.M.', 'Bristow, D.A.', 'Landers, R.G.'] | 2021-10-21T18:34:54Z | 2021-10-21T18:34:54Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89422 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['Laser Metal Deposition', 'layer-to-layer stability', 'stability criterion', 'process planning', 'process control'] | DC-Gain Layer-to-Layer Stability Criterion in Laser Metal Deposition Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0e97acf2-7c1f-48b8-87f2-0014c39f7b91/download | University of Texas at Austin | In Laser Metal Deposition (LMD), a blown powder metal additive manufacturing
process, functional metal parts are fabricated in a layer-by-layer fashion. In addition to the inlayer dynamics, which describe how the process evolves within a given layer, the additive-fabrication property of LMD creates a second set of dynamics which describe how the process
evolves from layer-to-layer. While these dynamics, termed layer-to-layer dynamics, are coupled
with both the in-layer dynamics and the process operating conditions, they are not widely
considered in the modeling, process planning, or process control of LMD operations. Because of
this, seemingly valid choices for process parameters can lead to part failure – a phenomenon
commonly encountered when undergoing the laborious procedure of tuning a new LMD process.
Here, a layer-to-layer stability condition for LMD fabrications is given, based on the shape of the
powder catchment efficiency function, which provides insight into the layer-to-layer evolution of
LMD processes and can be useful in process planning and control. The stability criterion is
evaluated for various operating points, allowing stable and unstable operating regions to be
identified. Simulation results are presented showing both stable and unstable layer-to-layer
LMD fabrications. The simulated behavior successfully predicts the results seen in both stable
and unstable experimental depositions. | null | null | null | null | null | null |
['Liu, X.', 'Mileo, A.'] | 2021-12-01T22:53:57Z | 2021-12-01T22:53:57Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90645', 'http://dx.doi.org/10.26153/tsw/17564'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['deep learning', 'defect detection', 'titanium alloys', 'additive manufacturing'] | A Deep Learning Approach to Defect Detection in Additive Manufacturing of Titanium Alloys | Conference paper | https://repositories.lib.utexas.edu//bitstreams/419fef57-4807-438c-98c9-f0d15ad29714/download | University of Texas at Austin | In Additive Manufacturing (AM) of titanium alloys, the formation of defects in parts is typically related
to the stability of the melt pool. With increased instability and size of the melt pool comes an increase in the level
of emissions generated as the laser processes the material. Recent developments with in-situ monitoring and
process control allows the collection of large amounts of data during the printing process. This includes data about
emissions, which are made available as 2D representations in the form of colour images. However, it is still a
manual process to inspect these 2D representations to identify defects, which hinders scalability. Given recent
advances in Deep Learning for computer vision and the availability of large amounts of data collected from in-situ monitoring, our approach leverages Deep Learning techniques for characterizing abnormal emissions to
automatically identify defects during the printing process. One of the challenges to apply deep learning in AM is
the lack of proper labelled data for training the models. In this paper, we tackle this challenge by proposing an
approach that uses transfer learning and fine-tuning on a pre-trained Convolutional Neural Network (CNN) model
called VGG 16 to successfully train the deep model with a small labelled dataset. Results show good classification
accuracy on the emission images obtained from the in-situ monitoring system, and improvements in classification
of defects on a public industrial benchmark datasets named DAGM (Deutsche Arbeitsgemeinschaft für
Mustererkennung e.V., German chapter of the IAPR). | null | null | null | null | null | null |
['Khalid-Rafi, H.', 'Karthik, N.V.', 'Starr, Thomas L.', 'Stucker, Brent E.'] | 2021-10-06T20:03:38Z | 2021-10-06T20:03:38Z | 8/16/12 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88428', 'http://dx.doi.org/10.26153/tsw/15365'] | eng | 2012 International Solid Freeform Fabrication Symposium | Open | ['EBM parts', 'electron beam melting', 'defect formation', 'horizontal orientation'] | Defect Formation in EBM Parts Built in Horizontal Orientation | Conference paper | https://repositories.lib.utexas.edu//bitstreams/55f49f73-c39b-4543-a36c-092ae884df2b/download | University of Texas at Austin | EBM built parts in a horizontal orientation, particularly with bottom curved surfaces, are prone
to variations in dimensional accuracy and defect formation. These defects likely occur due to the
nature of the supports utilized and the build strategy. To understand the effect of support
structures and scan direction on these defects, a series of cylindrical parts were built using
different diameters, support structures and scan strategies. The as-built samples were
mechanically tested and sample cross sections were analyzed. Pore formation and balling effects
were observed in the lower section of some samples. The study looks at the effects of supports,
geometry and scan strategy on the minimization of these defects and improving the dimensional
accuracy of horizontally built samples. | null | null | null | null | null | null |
['Gong, Haijun', 'Rafi, Khalid', 'Karthik, N.V.', 'Starr, Thomas', 'Stucker, Brent'] | 2021-10-11T20:31:29Z | 2021-10-11T20:31:29Z | 8/16/13 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88632', 'http://dx.doi.org/10.26153/tsw/15566'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['Selective Laser Melting', 'Electron Beam Melting', 'defects', 'morphology', 'process parameters', 'porosity'] | Defect Morphology in Ti-6Al-4V Parts Fabricated by Selective Laser Melting and Electron Beam Melting | Conference paper | https://repositories.lib.utexas.edu//bitstreams/82fe1e59-cfd1-4332-98f1-cb3fa6db8f46/download | University of Texas at Austin | In order to investigate the morphology of defects present in Selective Laser Melting (SLM)
and Electron Beam Melting (EBM) processes, Ti-6Al-4V specimens were fabricated with varying
porosity using non-optimum processing parameters. Defective specimens were sectioned and
polished for microscopy. Image processing was adopted for statistically analyzing the
characteristics of defects, such as distribution of defect area and dimensional proportion of each
defect. It is found that defect morphology is influenced by process parameters as a result of a
variation in the melt pool. Image processing of a cross-section could be a feasible way for
calculating porosity of specimens. | null | null | null | null | null | null |
['Gaja, Haythem', 'Liou, Frank'] | 2021-11-04T18:22:03Z | 2021-11-04T18:22:03Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/89997', 'http://dx.doi.org/10.26153/16918'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['laser metal deposition', 'acoustic emission', 'deposition defects', 'clustering analysis'] | Defects Classification of Laser Metal Deposition Using Acoustic Emission Sensor | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0d207cb7-0176-4e12-b0f5-e49dadd95378/download | University of Texas at Austin | Laser metal deposition (LMD) is an advanced additive manufacturing (AM) process used
to build or repair metal parts layer by layer for a range of different applications. Any presence of
deposition defects in the part produced causes change in the mechanical properties and might
cause failure to the part. In this work, defects monitoring system was proposed to detect and
classify defects in real time using an acoustic emission (AE) sensor and an unsupervised pattern
recognition analysis. Time domain and frequency domain, and relevant descriptors were used in
the classification process to improve the characterization and the discrimination of the defects
sources. The methodology was found to be efficient in distinguishing two types of signals that
represent two kinds of defects. A cluster analysis of AE data is achieved and the resulting
clusters correlated with the defects sources during laser metal deposition. | null | null | null | null | null | null |
['Li, Anyi', 'Liu, Jia', 'Shao, Shuai', 'Shamsaei, Nima'] | 2023-02-09T15:46:21Z | 2023-02-09T15:46:21Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117436', 'http://dx.doi.org/10.26153/tsw/44317'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | ['Laser beam powder bed fusion', 'X-ray CT', 'Hierarchical graph convolutional network', 'Defects classification'] | Defects Classification via Hierarchical Graph Convolutional Network in L-PBF Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3d7305a2-e91c-4144-b5be-00a0496491e6/download | null | Three typical types of defects, i.e., keyholes, lack of fusion (LoF), and gas-entrapped pores
(GEP), characterized by various features (e.g., volume, surface area, etc.), are generated under
different process parameters of laser beam powder bed fusion (L-PBF) processes in additive
manufacturing (AM). The different types of defects deteriorate the mechanical performance of L-
PBF components, such as fatigue life, to a different extent. However, there is a lack of recognized
approaches to classify the defects automatically and accurately in L-PBF components. This work
presents a novel hierarchical graph convolutional network (H-GCN) to classify different types of
defects by a cascading GCN structure with a low-level feature (e.g., defect features) layer and a
high-level feature (e.g., process parameters) layer. Such an H-GCN not only leverages the multi-
level information from process parameters and defect features to classify the defects but also
explores the impact of process parameters on defect types and features. The H-GCN is evaluated
through a case study with X-ray computed tomography (CT) L-PBF defect datasets and compared
with several machine learning methods. H-GCN exhibits an outstanding classification
performance with an F1-score of 1.000 and reveals the potential effect of process parameters on
three types of defects. | null | null | null | null | null | null |
['Soar, R.C.', 'Dickens, P.M.'] | 2018-11-30T16:43:08Z | 2018-11-30T16:43:08Z | 1997 | Mechanical Engineering | doi:10.15781/T2B56DQ7X | http://hdl.handle.net/2152/70598 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['Laminated Tooling', 'Rapid Prototyping'] | Deflection and the Prevention of Ingress within Laminated Tooling for Pressure Die-Casting | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e86ee249-ccaf-47b3-a584-7f1d5128a6f7/download | null | Wrthin the context ofrapid tooling, we are currently assessing the fundamental limitations
oflaminated tooling for pressure die-casting (PDC) applications. The use ofindividual laminates
to form a die-cast tool presents it own problems, namely the prevention of excessive deflection
that may lead to the ingress of pressurised molten aluminium between laminates. Ultimate
solutions lie with bonding and clamping techniques of which work is already underway. This
paper describes an initial study to establish the fundamental laminated die behaviour in extreme
die-casting environments. | null | null | null | null | null | null |
['Crane, N.B.', 'Lusk, C.P.', 'Nussbaum, J.', 'Consuegra Reyes, Y.'] | 2021-10-07T17:50:42Z | 2021-10-07T17:50:42Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88494', 'http://dx.doi.org/10.26153/tsw/15428'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'post processing', 'deformation', 'planar manufacturing', '3D printing'] | Deformation Post-Processing of Additive Manufacturing Components | Conference paper | https://repositories.lib.utexas.edu//bitstreams/69655cf5-e12e-4623-8dc9-b9514a5d4c79/download | University of Texas at Austin | Parts produced by additive manufacturing (AM) often require post processing to improve
surface finish and mechanical properties. However, little attention has been given to including
deformation in the post processing. Deformation post-processing can address some part size,
manufacturing cost, and geometry limitations of 3D printing. Additionally, it could be used to
create 3D surfaces using planar manufacturing processes (such as printed circuit board
manufacturing). The challenge of deformation post-processing is the design of the correct
fabrication state to produce the desired final state and the accurate deformation of the parts to the
desired final state. This paper demonstrates the geometric capability, potential applications, and
methods for accurately and repeatedly deforming the initial geometry to the desired
configuration using features in the parts. | null | null | null | null | null | null |
['Lipkowitz, Gabriel', 'Desimone, Joseph M.'] | 2024-03-26T16:59:34Z | 2024-03-26T16:59:34Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124373', 'https://doi.org/10.26153/tsw/50981'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['resin', '3D printing', 'paraflow', 'fluid dynamics', 'additive manufacturing'] | Demonstrating Paraflow: Interactive fluid dynamics simulation with real-time visualization for augmented resin 3D printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7a959257-8c13-4222-952f-b96ba4ff2846/download | University of Texas at Austin | While resin 3D printers are seeing growing adoption in both manufacturing and personal
fabrication settings, detecting print failures in real time remains challenging. Object-detection
neural networks have shown benefits in a variety of extrusion-based 3D printing methods. Here,
we extend such work to resin printing using a physics-informed machine learning data generation
pipeline. Our approach leverages our models of the fluid dynamics of the printing process at
every slice, in order to synthetically generate a library of print defects. We show such an
approach is capable of providing data sufficiently resembling real-world failures to fine-tune a
pre-trained custom defect detection neural network that can alert users of failure in real-time.
Finally, to allow novice users to take advantage of our simulation platform, we integrate our tool
into an interactive augmented reality interface, which displays simulation predictions to provide
guidance on design and machine parameters prior to printing. | null | null | null | null | null | null |
['Berzins, M.', 'Childs, T.H.C', 'Dalgarno, K.W.', 'Ryder, G.R.', 'Stein, G.'] | 2018-10-10T16:00:28Z | 2018-10-10T16:00:28Z | 1995 | Mechanical Engineering | doi:10.15781/T2DB7W864 | http://hdl.handle.net/2152/68759 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['Thermal distortions', 'polycarbonate parts', 'selective laser sintering'] | Densification and Distortion in Selective Laser Sintering of Polycarbonate | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d314871a-f26b-4a3e-b9ef-2ec5d11d5c6c/download | null | The creation of a 3D numerical model for real part accuracy simulations is the goal of
this work. An improvement of a first attempt to predict densification, which used a
classical moving heat source calculation and a viscous sintering model, is reported: it
includes a numerical thermal calculation with thermal properties allowed to vary with
temperature. A study of polycarbonate part 'curl' distortion is also reported. The
development of curl at part edges and with part thickness is followed. Mechanical and
thermal reasons are sought as to why the distortion is concentrated at edges. | null | null | null | null | null | null |
['Rao, T. Srinvasa', 'Bourell, D.L.', 'Marcus, H.L.'] | 2018-11-08T15:10:15Z | 2018-11-08T15:10:15Z | 1995 | Mechanical Engineering | doi:10.15781/T2C53FM37 | http://hdl.handle.net/2152/69884 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['SFF', 'SLS', 'hot isostatic pressing'] | Densification Behavior of SLS Processed Al2O3/Al Composite | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f3584cbb-034f-4987-820b-9feca7ab9b48/download | null | Production of structurally sound parts by any rapid prototype technique is essential, because
fully functional features are necessary where application testing is required. In the present work,
a powder blend of A1203/AI (3:1 by weight) was mixed with ammonium dihydrogen phosphate
and subjected to selective laser sintering (SLS) using a C02 laser. An attempt has been made
to increase the powder bed density by introducing vibration to the part cylinder. These SLS
processed preforms were then subj ected to a secondary heat treatment in a hydrogen
atmosphere and to hot isostatic pressing. Densification behavior of these Al20 3/Al composite
preforms is discussed. | null | null | null | null | null | null |
['Beaman, Joseph Jr.', 'Agarwala, Mukesh K.', 'Bourell, David L.'] | 2018-09-26T20:05:29Z | 2018-09-26T20:05:29Z | 1994 | Mechanical Engineering | doi:10.15781/T2NV99W1V | http://hdl.handle.net/2152/68592 | eng | 1994 International Solid Freeform Fabrication Symposium | Open | ['metal matrix alloy', 'selective laser sintering', 'three-dimensional fully functional parts'] | Densification of Selective Laser Sintered Metal Part by Hot Isostatic Pressing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e60d4c4b-d83b-487c-a6e5-ecce1f5ba728/download | null | Metal matrix alloy composite parts were made from powders by Selective Laser Sintering (SLS).
In this study, partially dense (60%-80%) metal parts made by SLS were densified to full density
(>98%) by hot isostatic pressing (HIPping) without any loss of shape. HIPping was done by
vacuum sealing SLS samples in glass capsules. HIPping parameters, such as, temperature,
pressure, and time, were studied with respect to density, linear shrinkage, and microstructures.
Anisotropy in linear shrinkage was correlated to the SLS processing parameters. Densification
resulting from HIPping was correlated to microstructures and theoretical HIP densification maps.
A detailed analysis of such maps is presented. | null | null | null | null | null | null |
['Raghavan, S.', 'Nai, Mui Ling Sharon', 'Wang, Pan', 'Sin, Wai Jack', 'Li, Tao', 'Wei, Jun'] | 2021-10-27T21:41:14Z | 2021-10-27T21:41:14Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89623 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['heat treatment', 'microstructure', 'tensile property', 'Ti-6Al-4V', 'electron beam melting'] | Dependence of Microstructure and Mechanical Properties on Heat Treat Cycles of Electron Beam Melted Ti-6Al-4V | Conference paper | https://repositories.lib.utexas.edu//bitstreams/11093d6e-1eb2-418c-af8e-eff9902a36fd/download | University of Texas at Austin | The EBM Ti-6Al-4V alloy has generally superior mechanical properties, owing to finely
spaced α−β laths which give a good combination of strength and ductility. The grain structures in
the as-printed structures are long columnar which can give rise to anisotropic mechanical
properties. Moreover the non-uniformity in microstructure can also arise from part geometry
where the thin features have propensity to form martensite phase. Heat treatment provides a
viable solution to modify the microstructure and to tailor to the properties as desired. A wide
range of heat treatment experiments were performed, followed by microstructure and tensile
property analyses. It was observed that the microstructure and the tensile properties significantly
changed depending on the heat treat cycle performed. Tensile properties of solution treated air-cool plus aged samples yielded globular equiaxed grains with fine α−β lath structure, which were
found to be the best among the different heat treated samples and better than ASTM F1472
specifications. | null | null | null | null | null | null |
['Lammers, S.', 'Koers, T.', 'Magyar, B.', 'Zimmer, D.', 'Lieneke, T.'] | 2024-03-26T17:01:23Z | 2024-03-26T17:01:23Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124374', 'https://doi.org/10.26153/tsw/50982'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['technical drawings', 'support structures', 'ISO 128-3', 'additive manufacturing'] | DEPICTION OF SUPPORT STRUCTURES IN TECHNICAL DRAWINGS | Conference paper | https://repositories.lib.utexas.edu//bitstreams/08a37fcd-265a-4b5e-969d-839d63238c69/download | University of Texas at Austin | To ensure uniform documentation of support structure information, a concept is presented that enables a
standardized depiction of support structures in technical drawings based on ISO 128-3. To this end, requirements
for a uniform depiction are defined and a procedure for drawing entry is presented. The drawing entry should
contain all production-relevant support structure information. The standardized documentation of support
structure information in technical drawings is intended to ensure a simple, clear and safe exchange of information
between business units or different companies along the value chain. As a result a possible drawing entry of
support structures was developed. To distinguish between different support structure types, a standardized
depiction of geometrical information in a specification field is shown. The specification field gives a detailed
description of the support structure type, the geometry as well as the connection to the part and the building
platform. Also uncommon support types like lattice structures or CAD based support structures can be
implemented. To ensure the usability the depiction is editable and extendable. | null | null | null | null | null | null |
['Watson, Nathan D.', 'Von Lockette, Paris'] | 2021-11-10T22:26:46Z | 2021-11-10T22:26:46Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90192', 'http://dx.doi.org/10.26153/tsw/17113'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['deposition controlled', 'magnetic alignment', 'iron-PLA composites', 'fused filament fabrication'] | Deposition Controlled Magnetic Alignment in Iron-PLA Composites | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7ee2debe-a602-431b-a74f-ccf897349e54/download | University of Texas at Austin | By manipulating the print plane, infill direction, and geometry of Fused Filament
Fabricated (FFF) iron-PLA composite parts, the alignment of their magnetic axes can be
influenced. FFF printing allows control of deposition direction, which affects the arrangement of
the iron within the composite part in ways that induce preferred magnetic orientation, the so-called easy axis. Qualitative results show the direction of deposition of the composite iron-PLA
filament has significant effects on the response of the printed parts to an external magnetic field.
Results further show that across different geometries, the easy axis of a printed part can be
prescribed by setting the print plane and infill direction parallel to the desired
orientation. Expected part geometry effects, along with the print plane and infill
influences, suggest the phenomenon can be modeled using multi-scale demagnetizing field
theories to print magneto-sensitive devices that can perform localized, controlled actuation in a
uniform magnetic field. | null | null | null | null | null | null |
['Janaki Ram, G.D.', 'Yang, Y.', 'Stucker, B. E.'] | 2020-03-10T16:08:16Z | 2020-03-10T16:08:16Z | 9/5/07 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80220', 'http://dx.doi.org/10.26153/tsw/7239'] | eng | 2007 International Solid Freeform Fabrication Symposium | Open | Laser Engineered Net Shaping | Deposition of Ti/TiC Composite Coatings on Implant Structures Using Laser Engineered Net Shaping | Conference paper | https://repositories.lib.utexas.edu//bitstreams/70acce11-de53-4b48-84e3-4097c4ee4603/download | null | A new method of depositing hard and wear resistant composite coatings on metal-onmetal bearing surfaces of titanium implant structures is proposed and demonstrated. The method
consists of depositing a Ti/TiC composite coating (~ 2.5 mm thick) on titanium implant bearing
surfaces using Laser Engineered Net Shaping (LENS®). Defect-free composite coatings were
successfully produced at various amounts of the reinforcing TiC phase with excellent interfacial
characteristics using a mixture of commercially pure Ti and TiC powders. The coatings consisted
of a mixture of coarser unmelted/partially melted (UMC) TiC particles and finer, discreet
resolidified (RSC) TiC particles uniformly distributed in the titanium matrix. The amounts of
UMC and RSC were found to increase with increasing TiC content of the original powder
mixture. The coatings exhibited a high level of hardness, which increased with increasing TiC
content of the original powder mixture. Fractographic studies indicated that the coatings, even at
60 vol.% TiC, do not fail in a brittle manner. Various aspects of LENS® deposition of Ti/TiC
composite coatings are addressed and a preliminary understanding of structure-property-fracture
correlations is presented. The current work shows that the proposed approach to deposit
composite coatings using laser-based metal deposition processes is highly-effective, which can
be readily utilized on a commercial basis for manufacture of high-performance implants. | null | null | null | null | null | null |
['Lee, Y.L.', 'Tompkins, J.V.', 'Sanchez, J.M.', 'Marcus, H.L.'] | 2018-11-08T15:42:35Z | 2018-11-08T15:42:35Z | 1995 | Mechanical Engineering | doi:10.15781/T2B56DQ4G | http://hdl.handle.net/2152/69892 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['SALD', 'CVD systems', 'TMS pressure'] | Deposition Rates of Silicon Carbide by Selected Area Laser Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/34350d68-771a-489a-a463-47287ed831da/download | null | The deposition rates using pure tetramethylsilane (TMS) as precursor are calculated numerically
for a ~od .grown by th~ .Selected Area Laser Dep?sition J?rocess. In particular, the dependence of
the kinettcs of deposItion on pressure of TMS IS examIned. The conditions for which volcano
d~pos~tion pr?files occur are also investigated. The results show that deposition rate increases
wIth IncreasIng pressure and then becomes saturated. In addition, adsorption-desorption
phenomena, rather than effects ofreactants depletion, are responsible for the volcano deposition
profile observed experimentally | null | null | null | null | null | null |
['Gaja, Haythem', 'Liou, Frank'] | 2021-10-19T21:16:54Z | 2021-10-19T21:16:54Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89340 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['depth of cut detection', 'acoustic emission', 'artificial neural network'] | Depth of Cut Monitoring for Hybrid Manufacturing Using Acoustic Emission Sensor | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fe3c04e9-702c-45f5-b549-f6d775d3b70a/download | University of Texas at Austin | Laser Metal Deposition LMD is a hybrid manufacturing process consist of a laser
deposition system combined with a 5-axis CNC milling system. During laser deposition many
parameters and their interaction affect the dimensional accuracy of the part produced, powder flow
rate, laser power and travel speed are some of these parameters. Sensing the acoustic emission
during milling marching gives feedback information regarding depth of metal being cut subsequent
part dimensions, if an error in dimensions is found certain actions, such as remaching, close loop
control, or laser remelting can be carried out to correct it. Thus a reliable hybrid manufacturing
management system requires that a depth-of-cut detection system be integrated with the milling
machine architecture. This work establishes, first a methodology to detect an acoustic emission
signal, so that the acoustic emission characteristics of the milling could be analyzed. Second, it
sought to relate these acoustic data to machining parameters to detect depth-of-cut. | null | null | null | null | null | null |
['Pallari, J.H.P.', 'Dalgarno, K.W.', 'Munguia, J.', 'Muraru, L.', 'Peeraer, L.', 'Telfer, S.', 'Woodburn, J.'] | 2021-10-01T00:21:14Z | 2021-10-01T00:21:14Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88307', 'http://dx.doi.org/10.26153/tsw/15248'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['foot orthoses', 'ankle-foot orthoses', 'additive fabrication', 'additive fabrication technology'] | Design and Additive Fabrication of Foot and Ankle-Foot Orthoses | Conference paper | https://repositories.lib.utexas.edu//bitstreams/95434e2e-169f-422f-bafb-7dc4cea77e8d/download | University of Texas at Austin | Foot and ankle-foot orthoses are prescribed in order to promote mobility through supporting
and/or realigning the lower leg and alleviating pain in the foot in different parts of the gait
cycle. This paper will outline new approaches to the design and manufacture of personalised
foot and ankle-foot orthoses (FO and AFO) using additive fabrication technology. The
research is addressing the need for specific software design tools for orthosis design which
enable their properties to be locally tailored within a mass customisation framework.
Structure/material testing to support that activity is also being undertaken and will be
described. | null | null | null | null | null | null |
['Mulholland, T.', 'Felber, R.', 'Rudolph, N.'] | 2021-11-08T22:44:43Z | 2021-11-08T22:44:43Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90061', 'http://dx.doi.org/10.26153/tsw/16982'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['3D printing', 'FFF', 'thermal conductivity', 'additive manufacturing'] | Design and Additive Manufacturing of a Composite Crossflow Heat Exchanger | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cc8cc501-be97-4707-b926-3179e27683e3/download | University of Texas at Austin | Additive manufacturing (AM) with composite materials reveals new possibilities for
direct manufacturing of end-use products, breaking the paradigm of 3D printing as only a
prototyping or pre-production technique that has been the norm for many AM technologies. A
crossflow air-to-water heat exchanger (HX) was designed for manufacturing via fused filament
fabrication (FFF). Design iterations improved the manufacturability, considering issues such as
geometric fidelity, watertightness, print time, support material, and manufacturing cost. Carbon
fiber fillers enhanced the thermal conductivity of the base polyamide resin, allowing for thermal
HX performance comparable to conventional aluminum finned tube heat exchangers. The
anisotropic thermal conductivity impacts the heat exchanger performance. The design and
manufacturing challenges reveal additional routes to continued performance gains as the HX is
scaled up to an 8 kilowatt product. | null | null | null | null | null | null |
['Mohammed, Mazher Iqbal', 'Fay, Pearse'] | 2021-11-09T20:57:16Z | 2021-11-09T20:57:16Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90163', 'http://dx.doi.org/10.26153/tsw/17084'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['splint', '3D printing', 'CAD', 'patient specific', 'FFF', 'polymer', 'orthotic'] | Design and Additive Manufacturing of a Patient Specific Polymer Thumb Splint Concept | Conference paper | https://repositories.lib.utexas.edu//bitstreams/5e22cffa-852e-40b6-8911-95f7cf998882/download | University of Texas at Austin | Traditionally, upper limb splints often fall short of being optimal with respect fit and patient
expectations, resulting in a lack of use and no treatment of the underlying condition. In this study we
address several current limitations and examine the feasibility of using 3D optical scanning, Computer
Aided Design (CAD) and low cost 3D printing as a tool to create more ergonomic and efficacious splints
for patients suffering from compromised musculature or trauma of the thumb. Optical scanning allows
for a non-invasive and rapid means to reproduce the surface topology of a person’s hand and this data
was used as the template for the device design. We explore the use of CAD to create a more
aesthetically pleasing and functional splint, enhancing both comfort and potential moisture release.
Finally, we demonstrate that low cost polymer printing can allow for rapid design evaluation and
production of a final, usable device. | null | null | null | null | null | null |
['Yaple, Jordan', 'Noe, Cameron', 'Alenezi, Abdulmajeed', 'Phelan, Patrick', 'Bhate, Dhruv'] | 2023-02-10T13:59:34Z | 2023-02-10T13:59:34Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117448', 'http://dx.doi.org/10.26153/tsw/44329'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | Additive manufacturing | Design and Additive Manufacturing of Bio-Inspired Copper Heat Sinks for Microelectronics Cooling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/502b78b4-f695-4ddd-9f7c-70bb0bb5961c/download | null | The heat sink is a key component in thermal management of microelectronics and is
traditionally designed with arrays of pins or fins. In this work, a bio-inspired approach to designing
heat sinks was evaluated. A process was first developed on a 100W Laser Powder Bed Fusion
(LPBF) system for the copper alloy CuNi2SiCr, which was found to have a tenfold deficit in
thermal conductivity relative to commercially pure Copper. This process was then used to fabricate
four heat sinks: two replicates of commercial heat sink designs, and two leveraging bio-inspired
design approaches with the aim of increasing the available surface area per unit volume. The four
designs were tested on a microelectronics package placed on a hot plate and their performance
compared against commercially available heat sinks. The results demonstrated that despite their
poor thermal conductivity, the bio-inspired heat sinks had equivalent performance to the
commercial heat sinks. | null | null | null | null | null | null |
['Carbonell, R.M.', 'Crawford, R.H.'] | 2023-04-05T17:15:41Z | 2023-04-05T17:15:41Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117781', 'http://dx.doi.org/10.26153/tsw/44660'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | gait | Design and Analysis of a Topology Optimized Transtibial Prosthetic Socket Using Combined Static Gait Analysis | Conference paper | https://repositories.lib.utexas.edu//bitstreams/682d029d-e429-47da-9a47-0941931bb2b7/download | null | This paper presents the design and analysis of an optimized transtibial prosthetic socket
developed using the ground structure method of topology optimization (GSM). The socket wall
between the distal 25% of the original socket and a proximal brim is replaced with an optimized
truss geometry and a thin wall (1 mm). Separate trusses are developed for the loading conditions
of three critical stances: heel strike, vertical (standing), and toe-off. The truss models are combined
with critical components to create the final design. The proposed socket is 81.58% of the original
socket volume and is designed for manufacturing using Selective Laser Sintering (SLS) and nylon-
12. The socket design is analyzed, with the material properties for sintered nylon-12, at 10%
increments between heel strike and toe-off to determine the viability of both the socket and the
corresponding methodology. Simulation results indicate that the design exceeds requirements for
all tested stances. | null | null | null | null | null | null |
['Faustini, Mario', 'Crawford, Richard', 'Neptune, Richard R.', 'Rogers, William', 'Gitter, Andrew', 'Bosker, Gordon'] | 2019-11-21T17:50:57Z | 2019-11-21T17:50:57Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78544', 'http://dx.doi.org/10.26153/tsw/5600'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | Duraform/SLS | Design and Analysis of Orthogonally Compliant Features for DuraForm/SLS Manufactured Plates | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4a99d8f4-a95a-49c5-9828-60022a0363d3/download | null | In many applications of parts manufactured by Solid Freeform Fabrication (SFF), compliance is
an important factor. In order to achieve given deformation goals with optimal shape, the design
of compliant mechanisms and elements fabricated with SFF techniques must take into account
the particular constraints and boundary conditions of the target application as well as the specific
material properties of the part. The present work focuses on the design and evaluation of
compliant features for a geometrically constrained thin-wall part subject to loads normal to its
tangent plane. Such features would need to be embedded in the object. The manufacture of
prosthetic sockets for lower-limb amputees is the specific application presented, where greater
compliance is needed at sites in contact with pressure sensitive tissues. Sample parts were
fabricated by selective laser sintering, and the material used was Duraform. | The authors gratefully acknowledge financial support for this work from the VA Rehabilitation
Research and Development Service. | null | null | null | null | null |
['Meisel, Nicholas A.', 'Williams, Christopher B.'] | 2021-10-12T19:01:48Z | 2021-10-12T19:01:48Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88722', 'http://dx.doi.org/10.26153/tsw/15656'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['3D printing', 'material extrusion', 'vending machine', 'informal learning'] | Design and Assessment of an AM Vending Machine for Student Use | Conference paper | https://repositories.lib.utexas.edu//bitstreams/754ef7e2-e036-42b3-945d-a5632745e709/download | University of Texas at Austin | Due to prohibitive costs, access to Additive Manufacturing (AM) technologies at academic
institutions tends to be limited to upper-level courses that feature significant project-based
coursework, such as capstone design. However, with the decreasing cost of desktop-scale AM
technology, there is potential to improve student access to such technologies throughout a
student’s undergraduate career, and thus provide more opportunities for AM education. In this
poster, the authors present the design and implementation of an AM “vending machine” that is
powered by desktop-scale extrusion-based AM systems. The resulting machine allows for
unrestricted student use of AM equipment, and thus provides ample opportunity for informal
learning regarding AM. The results of a formal assessment of student use of the machine are
presented. | null | null | null | null | null | null |
['Yang, L.', 'Harrysson, O.', 'West, H. II', 'Cormier, D.'] | 2021-10-05T13:38:43Z | 2021-10-05T13:38:43Z | 8/17/11 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88369', 'http://dx.doi.org/10.26153/tsw/15308'] | eng | 2011 International Solid Freeform Fabrication Symposium | Open | ['electron beam melting', 'auxetic structures', 'Ti6Al4V', 'copper'] | Design and Characterization of Orthotropic Re-Entrant Auxetic Structures Made via EBM Using Ti6Al4V and Pure Copper | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0b0f48ff-c5e6-4f88-8fec-9b282bc660b9/download | University of Texas at Austin | An orthotropic 3D re-entrant honeycomb structure that exhibits a negative Poisson’s ratio
was designed and fabricated via the electron beam melting (EBM) process. The modeling work
established the relationships between various structural parameters and the mechanical properties
of the auxetic structures. Compressive tests were performed on the re-entrant honeycomb
samples made with Ti6Al4V as well as pure copper. Results of the strength, modulus and energy
absorption for the two materials were compared with the theoretical models in order to verify the
theoretical predictions. | null | null | null | null | null | null |
['Grossman, James', 'Parad, Warren', 'Lipson, Hod'] | 2021-09-28T18:51:33Z | 2021-09-28T18:51:33Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88152', 'http://dx.doi.org/10.26153/tsw/15093'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['freeform fabricator', 'six degree of freedom', 'fabrication design', 'fabrication construction'] | Design and Construction of a 6-DoF Fabrication Platform | Conference paper | https://repositories.lib.utexas.edu//bitstreams/137e1018-cf28-4d29-b51d-3cee6479bb08/download | University of Texas at Austin | This research demonstrates a working freeform fabricator with a six degree of freedom printhead capable of additive fabrication onto existing structures. A parallel actuation mechanism was
developed with stationary motors. Kinematic simulations of the printer’s motion were used to
analyze and optimize the design. The components of the printer are described, including the
control system and print head mechanism. A working fabricator was then constructed and tested.
An additive three dimensional structure is demonstrated and the accuracy and reliability of the
printer is analyzed. | null | null | null | null | null | null |
['Daruwala, Darius P.', 'Johnson, Christopher M.', 'Jacobsen, Donald R.'] | 2018-11-29T20:22:35Z | 2018-11-29T20:22:35Z | 1997 | Mechanical Engineering | doi:10.15781/T21834N7T | http://hdl.handle.net/2152/70339 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['endoscopic', 'Tomography'] | The Design and Construction of a Medical System to Optimize the Endoscopic Ultrasound Procedure | Conference paper | https://repositories.lib.utexas.edu//bitstreams/5ae3b8c5-8946-445e-8254-6ddf47cd7b42/download | null | This project involved the use ofrapid prototyping to produce a model of a section ofthe
gastrointestinal (GI) tract which could be used for practice ofthe Endoscopic Ultrasound (EUS)
procedure.
Computed Tomography (CT) scans were obtained from Dr. Donald Jacobsen, Assistant
Professor ofRadiology at the Medical College ofWisconsin in Milwaukee. Apart from the final
testing, the entire project was performed at the Milwaukee School ofEngineering's Rapid
Prototyping Center. To convert the CT scans into files that are compatible with the rapid
prototyping machines, a software developed by Materialise, N.V., was used. The rapid prototype
models were used as master patterns for molds so that a polyurethane material with similar
properties to human tissue could be used for actual simulation. Finally, these polyurethane
models were placed in an enclosure and surrounded by a gelatin to simulate fatty abdominal
tissue. The system was tested at Froedtert Memorial Lutheran Hospital under the supervision of
Dr. Anthony Bohorfoush in conjunction with the Medical Physics Department ofthe Medical
College ofWisconsin. | null | null | null | null | null | null |
['Wagner, Grady W.', 'Bass, Lindsey B.', 'Rau, Daniel A.', 'Ziv, Scott B.', 'Wolf, Mitchell S.', 'Wolf, David L.', 'Meenakshisundaram, Viswanath', 'Williams, Christopher B.'] | 2021-11-04T18:44:55Z | 2021-11-04T18:44:55Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90001', 'http://dx.doi.org/10.26153/16922'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['multi-tool additive manufacturing', 'additive manufacturing', 'design and development'] | Design and Development of a Multi-Tool Additive Manufacturing System | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ae712bef-de1d-43ba-b687-780ca0af3476/download | University of Texas at Austin | Additive manufacturing (AM) makes complex parts with a single class of material. Each
AM technology encompasses specific techniques and requires diverse components to selectively
form each layer, which has segregated AM research by respective technologies. Multimaterial
AM exists, but it is the same class of material with the same deposition tool. To fully benefit
from AM, researchers must explore the combination of multiple AM modalities and materials
such that a multifunctional part may be fabricated using strengths of multiple
technologies. While the methods for fabricating each layer differ, all of the AM technologies
share the fundamental layer-based approach. By recognizing this universal similarity coupled
with the desire to make multifunctional parts, a single system has been created to combine five
different AM modalities. In this paper, the authors discuss the design and development of a
multi-tool AM system that includes binder jetting, material jetting, vat photopolymerization,
paste extrusion, and filament extrusion. Examples of multifunctional, multimaterial parts
fabricated by multiple AM processes in a single integrated process are demonstrated. | null | null | null | null | null | null |
['Chen, T.', 'Mueller, J.', 'Shea, K.'] | 2021-11-01T21:04:58Z | 2021-11-01T21:04:58Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89751 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['bistable unit actuators', 'Von Mises Truss', 'bistability', 'material stiffness', 'multi-material additive manufacturing', 'additive manufacturing'] | Design and Fabrication of a Bistable Unit Actuator with Multi-Material Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/81c616cc-c0b0-48f4-872f-27f896fa7156/download | University of Texas at Austin | Bistable systems have two stable equilibrium states around which they can be perturbed.
Bistability in a mechanical system requires large deformation, which is commonly accommodated
by means of springs or soft joints. In this paper, the authors leverage the ability of advanced
Additive Manufacturing (AM) technology that enables printing of materials of varying stiffness
values to design and fabricate monolithic bistable unit actuators that maximize the stroke length.
A Von Mises Truss (VMT) based bistable structure utilizing snap-through buckling behavior is
designed and fabricated. By varying the material stiffness and length of the joints, the authors
are able to adjust the activation forces while keeping the geometry constant. 56 specimens are
fabricated and tested in tension and compression. Numerical simulation models are constructed
and the results are found to correlate well with experimental data. The required activation force
can be increased with a decrease in joint length or an increase in joint material stiffness. | null | null | null | null | null | null |
['Gervasi, Vito R.', 'Stahl, Douglas C.'] | 2020-02-20T18:42:26Z | 2020-02-20T18:42:26Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80039', 'http://dx.doi.org/10.26153/tsw/7061'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Solid Freeform Fabrication | Design and Fabrication of Components with Optimized Lattice Microstructures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/57ce3517-e9c4-4e67-855e-07d4f38ddae2/download | null | The design and fabrication of components with optimized lattice microstructures is a new
approach to creating lightweight high-performance objects. This paper introduces a unique and
complete integration of design and fabrication leading to the creation of structural components
with complex composite microstructures. Rather than a solid cast component with optimized
outer shape this new approach leads to a component with an inner skeleton or microstructure
maximizing one or more properties such as the stiffness-to-weight ratio. Three dimensional
gradient materials are a natural outcome of this approach. An introduction to the design
optimization and hybrid fabrication approach will be provided in addition to research progress
and challenges through Spring 2004. | null | null | null | null | null | null |
['Sun, C.N.', 'Choy, S.Y.', 'Leong, K.F.', 'Wei, J.'] | 2021-11-01T22:28:47Z | 2021-11-01T22:28:47Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89783 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['functionally graded components', 'gradient lattice strucutres', 'unit cells', 'selective laser melting'] | Design and Fabrication of Functionally Graded Components by Selective Laser Melting | Conference paper | https://repositories.lib.utexas.edu//bitstreams/da42230d-b853-4c98-8cf5-cdedf0436122/download | University of Texas at Austin | The control of structure formation of additive manufacturing simplifies the fabrication of functionally
graded components (FGC), which changes in the physical properties can be achieved via structural design. In
this research, selective laser melting (SLM) technology was used to fabricate structures with gradient lattice
designs. The structure was varied in strut thickness continuously and linearly in single direction for cubic and
honeycomb unit cells. Results showed that the complex design was successfully built and achieved nearly full-dense strut. Compression test results showed that the stress-strain curves of both cubic and honeycomb lattice
structures oscillate with multiple peak loads, suggesting ductile characteristics. However, lattice structures with
graded thickness tend to oscillate upward as the strut diameter increases. | null | null | null | null | null | null |
['Chen, Xueyang', 'Yan, Lei', 'Newkirk, Joe', 'Liou, Frank'] | 2021-11-02T14:05:52Z | 2021-11-02T14:05:52Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89807 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['functionally graded material', 'laser metal deposition', 'crack-free', 'titanium', 'γ-TiAl', 'TiAl'] | Design and Fabrication of Functionally Graded Material from Ti to γ-TiAl by Laser Metal Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ba36dd0c-1e8d-4ad9-a8ce-9906142632a3/download | University of Texas at Austin | Functionally graded material (FGM) is one kind of advanced material characterized by a
gradual change in properties as the position varies. The spatial variation of compositional and
microstructure over volume is aimed to control corresponding functional properties. In this
research, when 100% γ-TiAl was directly deposited on pure Ti substrate, cracks were formed
within the γ-TiAl layer. Then a six-layer crack-free functionally graded material of Ti/TiAl was
designed and fabricated by laser metal deposition (LMD) method, with composition changing from
pure Ti on one side to 100% γ-TiAl on the other side. The fabricated FGM was characterized for
material properties by a variety of techniques. The chemical compositions, microstructure, phases,
and hardness of the composite were characterized by Scanning Electronic Microscope (SEM),
Optical Microscope (OM), Energy Dispersive X-ray Spectroscopy (EDS), and hardness testing.
The microstructure and chemical compositions in different layers were studied. | null | null | null | null | null | null |
['Maheshwaraa, Uma', 'Tradd, Catherine', 'Bourell, David', 'Seepersad, Carolyn Conner'] | 2020-03-05T19:17:01Z | 2020-03-05T19:17:01Z | 2006 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80144', 'http://dx.doi.org/10.26153/tsw/7165'] | eng | 2006 International Solid Freeform Fabrication Symposium | Open | Solid Freeform Fabrication | Design and Freeform Fabrication of Deployable Structures with Lattice Skins | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e91e0586-e0a6-4955-9c78-72a97a8bc4d9/download | null | Frontier environments—such as battlefields, hostile territories, remote locations, or outer
space—drive the need for lightweight, deployable structures that can be stored in a compact
configuration and deployed quickly and easily in the field. We introduce the concept of lattice
skins to enable the design, solid freeform fabrication (SFF), and deployment of customizable
structures with nearly arbitrary surface profile and lightweight multi-functionality. Using
Duraform FLEX® material in a selective laser sintering machine, large deployable structures are
fabricated in a nominal build chamber by either virtually collapsing them into a condensed form
or decomposing them into smaller parts. Before fabrication, lattice sub-skins are added
strategically beneath the surface of the part. The lattices provide elastic energy for folding and
deploying the structure or constrain expansion upon application of internal air pressure. Nearly
arbitrary surface profiles are achievable and internal space is preserved for subsequent usage. In
this paper, we present the results of a set of experimental and computational models that are
designed to provide proof of concept for lattice skins as a deployment mechanism in SFF and to
demonstrate the effect of lattice structure on deployed shape. | null | null | null | null | null | null |
['Yeung, Ho', 'Hutchinson, Keely', 'Lin, Dong'] | 2021-12-07T18:05:42Z | 2021-12-07T18:05:42Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90741', 'http://dx.doi.org/10.26153/tsw/17660'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['testbed control software', 'testbed', 'laser powder bed fusion', 'National Institute of Standards and Technology'] | Design and Implementation of Laser Powder Bed Fusion Additive Manufacturing Testbed Control Software | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ee547614-48d8-465e-9736-b66549830ca6/download | University of Texas at Austin | The National Institute of Standards and Technology developed a facility titled the Additive
Manufacturing Metrology Testbed to advance the research in laser powder bed fusion (LPBF)
processes. The testbed adopted an open control architecture which allows full access to all key
process parameters. Although LPBF control is a very important topic, very little literature can be
found on how this is implemented. This paper reviews the testbed control software design and
implementation. Scan path planning, galvo motion control, and laser power control are detailed
with select highlights. Comparison with commercial machine control software is made, and recent
experiments utilizing the advanced features of the testbed control software are also discussed. | null | null | null | null | null | null |
['Abdullah, J. Laeng aka Jamaluddin', 'Liou, Frank', 'Mohamad Ibrahim, M.N.', 'Wan Muhammad, W.M.'] | 2019-09-25T16:19:48Z | 2019-09-25T16:19:48Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76002', 'http://dx.doi.org/10.26153/tsw/3101'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Deposition | Design and Integration of a Laser-Based Materials Deposition System | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bed4ba6e-c79c-4579-b98e-b74a09543b6b/download | null | This paper aims to demonstrate the design process of an integrated five-axis Laser-Based Material Deposition (LBMD) system for rapid prototyping application. Several design evaluation methods are selected and applied to the design of the system. A three-dimensional graphical simulation software package was used as a decision making aid and as an analysis tool
in the design process. Hardware integration of a five-axis computer numerical controlled (CNC) vertical milling machine, a 2.5 KW Nd:YAG laser and a linear table is discussed. A brief introduction to the system software and control architecture is also summarized. Some important design issues and considerations specific to Laser Based Material Deposition process are suggested. | null | null | null | null | null | null |
['Jayashankar, Dhileep Kumar', 'Devarajan, Aarthi', 'Dong, Guoying', 'Rosen, David'] | 2021-12-06T21:46:36Z | 2021-12-06T21:46:36Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90683', 'http://dx.doi.org/10.26153/tsw/17602'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['UAV wing', 'topology optimization', 'fiber reinforced composites', 'material extrusion', 'design for additive manufacturing'] | Design and Manufacture of a Continuous Fiber-Reinforced 3D Printed Unmanned Aerial Vehicle Win | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e2918b6c-f663-4fa3-b284-85f9f777b10b/download | University of Texas at Austin | The Markforged Mark Two 3D printer is capable of printing various orientations of
continuous fiber reinforcement. An initial study of how the orientation of the fiber influences the
strength characteristics (tensile and flexural properties) was conducted. Four combinations of
carbon fiber reinforcement orientations were tested, specifically unidirectional, isotropic,
concentric and a combination of isotropic and concentric, with the Markforged Onyx matrix
material. The results will aid in designing a wing with the optimum fiber configuration that will
give the desired mechanical properties based on the forces acting on the wing. Design for Additive
Manufacturing (DfAM) concepts and tools will be used to design and manufacture a large UAV
wing. Topology optimization, based on a CFD computed pressure distribution, was used to
determine geometric regions where carbon fiber reinforcement could be best utilized. From there,
a honeycomb structure was designed to ensure stiffness and light weight based on desired densities.
A wing section was fabricated using the Mark Two printer to identify the capabilities and
limitations of the system in realizing the design objectives. | null | null | null | null | null | null |
['Ilardo, Ryan', 'Williams, Christopher B.'] | 2021-09-29T20:10:14Z | 2021-09-29T20:10:14Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88209', 'http://dx.doi.org/10.26153/tsw/15150'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['Fused Deposition Modeling', 'intake manifold', 'formula SAE'] | Design and Manufacture of a Formula SAE Intake System Using Fused Deposition Modeling and Fiber-Reinforced Composite Materials | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f91454b9-1b3a-418c-b11f-eb1ce6c51c6c/download | University of Texas at Austin | In this paper, the authors discuss the design and manufacture of an intake system for a 600cc Formula
SAE engine. Specifically, Fused Deposition Modeling is used to create an intake system (consisting of a
plenum, plenum elbow, and cylinder runners) that is then later covered in layers of carbon fiber composite
fabric through vacuum bagging. As a result of this approach, the geometry of the intake system has been
redesigned to result in reduced weight (due to lower material density and lack of welds, hose clamps, and
silicon couples), improved charge distribution, and increased torque through a wide RPM range when
compared to its traditionally-manufactured aluminum counterpart. | null | null | null | null | null | null |
['Burhan, Danny', 'Crawford, Richard'] | 2020-02-20T18:27:19Z | 2020-02-20T18:27:19Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80035', 'http://dx.doi.org/10.26153/tsw/7057'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Selective Laser Sintering | Design and Manufacture of an Attachment Fitting for Transtibial Prosthetic Sockets Using Selective Laser Sintering | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a61e61f4-66a4-4531-9b94-b34b28086c2e/download | null | The focus of this work is using selective laser sintering to manufacture transtibial
prosthetics sockets with compliant features to relieve contact pressure in sensitive areas. Each of
these sockets requires an integrated attachment fitting to connect to the pylon and foot using
standard hardware. Several design concepts of an attachment fitting are presented and
compared. The design concepts were tested using a tensile test machine and analyzed using
ground reaction force data to ensure a structurally sound connection. The resulting design
employs standard hardware while maintaining the integrity of the connection for a normal gait
cycle. | null | null | null | null | null | null |
['Horn, Timothy J.', 'Harrysson, Ola L.A.', 'Little, Jeffrey P.', 'West, Harvey A. Jr', 'Marcellin-Little, Denis J.'] | 2021-10-01T00:31:43Z | 2021-10-01T00:31:43Z | 9/23/10 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88310', 'http://dx.doi.org/10.26153/tsw/15251'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['orthopedic implants', 'cadaveric bone specimens', 'direct metal freeform fabrication', 'bone analog models'] | Design and Manufacturing of Bone Analog Models for the Mechanical Evaluation of Custom Medical Implants | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e47b668b-9ec8-49dc-9b3b-3a2031a7840e/download | null | The performance of orthopedic implants is often evaluated using cadaveric bone
specimens. The high inter-specimen variability of cadaveric bone properties requires large
sample sizes to obtain statistical significance. With recent focus on custom implants
manufactured using direct metal freeform fabrication techniques, the need for a customized bone
analog model is recognized. Data for bone geometry and internal structure were obtained from
computed-tomography imaging. Traditional rapid prototyping techniques are then used to
generate the rapid tooling from which composite bones that mimic the properties of the real bone
can be duplicated. This work focused on the manufacturing process of bone analog models. | null | null | null | null | null | null |
['VanHorn, Austin', 'Zhou, Wenchao'] | 2021-10-19T21:24:55Z | 2021-10-19T21:24:55Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89341 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['inkjet deposition', 'high temperature microheater', 'microheater', 'thermal inkjet', 'design', 'optimization'] | Design and Optimization of a High Temperature Microheater for Inkjet Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7dfe7257-84f8-4dc4-a9be-1b2c9a47db2d/download | University of Texas at Austin | Inkjet deposition has become a promising additive manufacturing technique due to its fast
printing speed, scalability, wide choice of materials, and compatibility for multi-material
printing. Among many different inkjet techniques, thermal inkjet, led by Hewlett-Packard and
Canon, is the most successful inkjet technique that uses a microheater to produce a pressure
pulse for ejecting droplets by vaporizing the ink materials in a timespan of microseconds.
Thermal inkjet has been widely adopted in many commercial 3D inkjet printers (e.g., 3D
Systems ProJet X60 series) due to its low cost, high resolution, and easy operation. However, the
viscosity of the printable materials has been limited to less than 40cP due to insufficient energy
provided inside the nozzle to overcome the viscous dissipation of energy. This paper presents a
study on the design and optimization of a high temperature microheater with a target heating
temperature of more than 600˚C (compared to ~300 ˚C for current printhead) to increase the
energy supply to the nozzle. The benefits are fourfold: 1) higher temperature will lead to faster
vaporization of ink and thus higher jetting frequency and print speed; 2) higher temperature will
make it possible for jetting materials with higher boiling points; 3) higher temperature will
reduce the viscosity of the ink and thus the viscous dissipation of energy; 4) higher energy
supply will increase the magnitude of the pressure pulse for printing more viscous materials. In
this paper, a high temperature microheater was designed with the following objectives: to reduce
thermal stress in heaters, and to minimize uneven heat distribution. A literature survey was first
conducted on design, fabrication, and operation of thin-film resistive microheaters. A
multiphysics numerical model was then developed to simulate electrical, thermal, and
mechanical responses of the microheater. The model was validated by comparison to
experimental data and existing models obtained from literature. With proper parameterization of
the design geometry, the geometry of the microheater is optimized using a particle swarm
optimization method. Results show the optimized high temperature microheater successfully
operates at temperatures in excess of 600˚C. The design optimization enabled better
characteristics for even heat distribution and minimizing stress. The design approach can serve as
a fundamental means of design optimization for microheaters. | null | null | null | null | null | null |
['Sinha, Swapnil', 'Rieger, Kelsey', 'Knochel, Aaron D.', 'Meisel, Nicholas A.'] | 2021-11-08T23:08:50Z | 2021-11-08T23:08:50Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90072', 'http://dx.doi.org/10.26153/tsw/16993'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['deployable mobile makerspace', 'design', 'evaluation', 'additive manufacturing education', 'additive manufacturing', 'STEAM', 'education'] | Design and Preliminary Evaluation of a Deployable Mobile Makerspace for Informal Additive Manufacturing Education | Conference paper | https://repositories.lib.utexas.edu//bitstreams/5539075a-62ac-4410-8948-372e80c9c25c/download | University of Texas at Austin | Additive Manufacturing (AM) has played an integral part in the growth of makerspaces as
democratization of manufacturing continues to evolve. AM has also shown potential in enabling
the successful amalgamation of art (A) with science, technology, engineering, and math (STEM)
disciplines, giving new possibilities to STEAM subjects and its implementation. This paper
presents the conceptual design and development of a deployable, mobile makerspace curriculum
focused on AM education for a diverse range of participant backgrounds, ages, and locations. The
aim is to identify effective means of informal learning to broaden participation and increase
engagement with STEAM subjects through the context of AM. The curriculum is envisioned as
“material-to-form,” offering separate modules that present opportunities for self-directed learning
through all the stages of design, material use, and manufacturing associated with AM. Pilot studies
of the curriculum were performed to identify potential changes to improve the effectiveness of the
mobile makerspace. | null | null | null | null | null | null |
['Handler, Evan', 'Sterling, Amanda', 'Pegues, Jonathan', 'Ozdes, Huseyin', 'Masoomi, Mohammad', 'Shamsaei, Nima', 'Thompson, Scott M.'] | 2021-11-08T22:42:55Z | 2021-11-08T22:42:55Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90060', 'http://dx.doi.org/10.26153/tsw/16981'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['powder bed fusion', 'heat transfer equipment', 'heat exchangers', 'additive manufacturing'] | Design and Process Considerations for Effective Additive Manufacturing of Heat Exchangers | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a05b4e06-f8d8-4e1a-a07e-98211909d5bc/download | University of Texas at Austin | This paper provides some insights into using powder bed fusion (PBF) techniques for
additively manufacturing heat transfer equipment (HTE), such as heat pipes and heat sinks.
Background information is provided on the operating principles of PBF and the subsequent
features of parts fabricated via PBF. Examples of heat transfer equipment produced using PBF
are discussed. Some benefits and challenges associated in using PBF for generating effective
heat transfer equipment are summarized. | null | null | null | null | null | null |
['Kubalak, Joseph R.', 'Mansfield, Craig D.', 'Pesek, Taylor H.', 'Snow, Zachary K.', 'Cottiss, Edward B.', 'Ebeling-Koning, Oliver D.', 'Price, Matthew G.', 'Traverso, Mark H.', 'Tichnell, L. David', 'Williams, Christopher B.', 'Wicks, Alfred L.'] | 2021-10-28T19:30:49Z | 2021-10-28T19:30:49Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89676 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['material extrusion', 'additive manufacturing', '3D printing', 'industrial robot', 'out of plane deposition'] | Design and Realization of a 6 Degree of Freedom Robotic Extrusion Platform | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e50a5111-44bd-4052-b88b-554a6e7af3cb/download | University of Texas at Austin | The layer-wise deposition of Additive Manufacturing (AM) processes allows for significant
freedom in the design of product geometry; however, the use of 3-axis deposition tools results
in layer interfaces that reduce material properties in the build direction. Adding additional
degrees-of-freedom (DOF) to the AM tool could remove this limitation by enabling out of
plane material deposition. For example, multi-DOF tool paths could align material extrusion
with a part's stress contours to circumvent inter-layer delamination. As a step towards this
goal, the authors designed, fabricated, and tested an AM extrusion system that leverages a
6-DOF robotic arm. In this paper, the authors detail the realization of this system including
the design of a high-temperature filament extruder, kinematics and tool path generation,
and user interface. The performance of the system is evaluated through layered deposition
of ABS thermoplastic. | null | null | null | null | null | null |
['Velu, Rajkumar', 'Vaheed, Nahaad', 'Raspall, Felix'] | 2021-11-10T21:39:10Z | 2021-11-10T21:39:10Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90184', 'http://dx.doi.org/10.26153/tsw/17105'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['molds', 'design', 'fabrication', 'production workflow', 'fiber placement', 'composites', '3D printing'] | Design and Robotic Fabrication of 3D Printed Moulds for Composites | Conference paper | https://repositories.lib.utexas.edu//bitstreams/af3ab220-3a4a-4a1e-9bd8-39c27a58c006/download | University of Texas at Austin | 3D printing technologies have a direct impact on manufacturing the composite structures and in
particularly fabrication of molds. Molds produced through additive manufacturing methods would
greatly improve product features. The material selection and process conditions involved for
producing mold tooling, mainly towards Automated fiber placement (AFP) work cells. In this
study, the main objective is to improve the design and fabrication of composite parts through
complex molds as well as to assess and improve the production workflow through the development
of an effective design environment for the existing fiber placement operation. A robotic arm will
be used to hold the print surface and to follow a pre-programmed print path with a stationary
extruder to fabricate the mold tooling. This paper will present a review on the selection process for
mold materials and the initial experimental work carried out to investigate required properties of
3D printed molds. | null | null | null | null | null | null |
['Felber, R.A.', 'Rudolph, N.', 'Nellis, G.F.'] | 2021-11-01T21:55:55Z | 2021-11-01T21:55:55Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89770 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['material extrusion', 'conductive fillers', 'air-cooled heat exchangers', '3D printing', 'design', 'simulation'] | Design and Simulation of 3D Printed Air-Cooled Heat Exchangers | Conference paper | https://repositories.lib.utexas.edu//bitstreams/23a96a01-1152-4322-b5c4-e3366d7e7411/download | University of Texas at Austin | The use of material extrusion with conductive fillers is explored for air-cooled heat
exchangers. A general overview of the manufacturing tasks, design criteria, printability
constraints, and modeling techniques is given, along with experimental data from prototype
testing. The first sub-scale prototype design is an air-water crossflow heat exchanger designed to
transfer around 100 Watts. It was printed with unfilled conventional ABS and the air channels
designed with an array of round pin fins to enhance heat transfer. The prototype was also CT-scanned for inspection of the printed pin fin shapes. | null | null | null | null | null | null |
['Bales, Brenin', 'Walker, Roo', 'Pokkalla, Deepak', 'Kim, Seokpum', 'Kunc, Vlastimil', 'Duty, Chad'] | 2023-01-27T14:10:24Z | 2023-01-27T14:10:24Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117335', 'http://dx.doi.org/10.26153/tsw/44216'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | z-pinning | Design and Use of a Penetrating Deposition Nozzle for Z-Pinning Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a05372c9-76ca-4207-ac92-062ef2295e03/download | null | Fused Filament Fabrication (FFF) involves depositing material layer-by-layer to create a
three-dimensional object. This method often demonstrates high mechanical anisotropy in the
printed structure, leading to a drop in the material strength of the part when comparing structures
along the deposition plane (X/Y-Axis) versus across layers in the build direction (Z-Axis). Initial
efforts to improve anisotropy led to the development of the Z-Pinning process, where continuous
pins are deposited across layers in the Z-Axis. Z-pinning has demonstrated significant gains in
toughness and inter-layer strength, particularly in fiber-reinforced materials. However, this
process can also create flaws in the structure that increase in severity and frequency as the pins
grow in length and diameter. To mitigate this, a penetrating nozzle has been developed that
extends a fine-tipped extrusion nozzle deep into the pin cavity and simultaneously extrudes
material as it retracts. This study investigates the printability of the penetrating nozzle for simple
geometries and evaluates the resulting Z-pinning mesostructure. As a result of this study, the
prototype penetrating nozzle design was analyzed and built. Through a pressure driven flow
analysis it was determined that filament will flow through the penetrating nozzle as the system
pressure drop of 9.3 Mpa is less then the minimum critical pressure of 12.07 Mpa. Additionally,
it was after a transient thermal simulation, it was found that after a pause of 15 seconds the
system can resume printing with no drop in heat at nozzle exit. This means the additional length
of the penetrating nozzle, will not cause any clogs during any pauses in filament flow. | null | null | null | null | null | null |
['Hiller, Jonathan D.', 'Lipson, Hod'] | 2021-09-28T19:55:01Z | 2021-09-28T19:55:01Z | 9/18/09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88166', 'http://dx.doi.org/10.26153/tsw/15107'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['multi-material printing', 'autonomous design', 'freeform shapes', '3D non-uniform structures', '3D compliant actuators'] | Design Automation for Multi-Material Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f966abd6-519e-4f0b-aef0-34f83c956f67/download | University of Texas at Austin | The advent of multi-material freeform fabrication technologies has exponentially
increased the mechanical design space available to engineers. The feature-based
paradigm of traditional CAD software is insufficient to take advantage of the
freedom of internal material distribution and gradients. Here we present a flexible
evolutionary design algorithm for 3D multi-material structures that fully utilizes
this expanded design space. The material distribution is optimized subject to high
level functional constraints, or simple constraints such as maximizing stiffness per
weight. The algorithm is inherently capable of shape optimization, or can simply
optimize material distribution within a given geometry. We demonstrate
autonomous design of freeform shapes, 3D non-uniform structures, and 3D
compliant actuators. | null | null | null | null | null | null |
['Lambert, Phillip M.', 'Campaigne, Earl A. III', 'Williams, Christopher B.'] | 2021-10-07T15:38:19Z | 2021-10-07T15:38:19Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88484', 'http://dx.doi.org/10.26153/tsw/15418'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['mask projection', 'microstereolithography', 'stereolithography', 'vat polymerization', 'morphological matrix', 'functional decomposition', 'system design', 'system analysis', 'literature review'] | Design Considerations for Mask Projection Microstereolithography Systems | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3d3c81d3-5bed-4bdc-bd62-2d97530f702f/download | University of Texas at Austin | Mask projection microstereolithography (MPµSL) uses a dynamic mask and focusing optics
to digitally pattern UV light and selectively cure entire layers of photopolymer resin. These
systems have been shown to be capable of creating parts with features smaller than 10µm. In this
paper, the authors analyze existing MPµSL systems using functional decomposition. Within the
context of a morphological matrix, these systems’ design embodiment decisions are compared
and the resulting performance tradeoffs are quantified. These embodiment decisions include the
dynamic mask, UV light source, projection orientation, and supporting optics. The aim of this
work is to provide a design guide for the realization of future MPµSL systems. | null | null | null | null | null | null |
['Speirs, M.', 'Pyka, G.', 'Kruth, J.-P.', 'Luyten, J.', 'Schrooten, J.', 'Wevers, M.', 'Van Humbeeck, J.'] | 2021-10-18T21:17:38Z | 2021-10-18T21:17:38Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89248 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['selective laser melting', 'biomedical scaffolds', 'TiAl6V4', 'node modification', 'design modification'] | Design Enhancement of Biomedical Scaffolds Made By Selective Laser Melting | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d7576252-57a7-492b-8801-3025554a2b79/download | University of Texas at Austin | Selective laser melting (SLM) is increasingly used to fabricate biomedical scaffolds.
However, the intrinsic specifications of the process such as laser spot size, layer thickness,
and particle size limit the production accuracy, altering the geometrical characteristics and
mechanical properties of the scaffolds. This work attempts to assess and improve the
mechanical properties of TiAl6V4 biomedical scaffolds by eliminating/modifying the sharp
and thin nodes (as the main source of stress concentrations and lowering the mechanical
properties). This is carried out through a gradual increase of the beam (strut) thickness around
the nodes where corresponding struts meet. The compression performance of these scaffolds
was assessed and compared to common examples (unaltered struts) and to scaffolds designed
with thicker struts in the centre of the beams (demonstrating the largest contrast). The findings
prove that the thickening of the nodal points improves the strain distribution while maintains
the mechanical properties at an identical solid volume fraction. This can be used to improve
the scaffold design by a gradual strut thickness (in a comparable volume fraction) for an
improved bio-mechanical performance. | null | null | null | null | null | null |
['Williams, Christopher B.', 'Seepersad, Carolyn Conner'] | 2021-10-05T15:43:21Z | 2021-10-05T15:43:21Z | 2012 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88395', 'http://dx.doi.org/10.26153/tsw/15334'] | eng | 2012 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'engineering education', 'design education'] | Design for Additive Manufacturing Curriculum: A Problem- and Project-Based Approach | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8f43b5e7-c71c-4f0d-925a-976b266ad044/download | University of Texas at Austin | Additive manufacturing education is of key importance because unfamiliarity with AM
technologies is one of the barriers to its widespread adoption. In this paper, the authors describe
their efforts to address this need via an undergraduate/graduate course in Additive
Manufacturing. Their courses, offered at the University of Texas at Austin and Virginia Tech,
cover the science of AM as well as principles of “design for additive manufacturing.” The
courses use both problem-based and project-based pedagogies to present students with
opportunities to gain hands-on experience with the technologies of AM. Examples of project
activities are presented along with student feedback. | null | null | null | null | null | null |
['Pareek, Shrey', 'Sharma, Vaibhav', 'Rai, Rahul'] | 2021-10-13T21:07:50Z | 2021-10-13T21:07:50Z | 2014 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88785', 'http://dx.doi.org/10.26153/tsw/15719'] | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['kinematic pairs', 'fused deposition modeling', '3D printing', 'additive manufacturing', 'revolute pair', 'prismatic pair', 'cylindrical pair'] | Design for Additive Manufacturing of Kinematic Pairs | Conference paper | https://repositories.lib.utexas.edu//bitstreams/092e7eee-db56-4bae-9428-cf4feccac5a3/download | University of Texas at Austin | While additive manufacturing processes are better suited for fabrication of parts with complex
geometries, they face serious challenges whilst fabricating parts that require relative motion with
respect to each other. The primary challenge in additive manufacturing of mechanisms is
preventing the mating parts from bonding with each other during the fabrication process. In this
paper the authors investigate design and additive fabrication of kinematic pairs that can move
relative to each other. The paper outlines fabrication of kinematic pairs based on optimal
clearance value for three basic lower order kinematic pairs, viz. revolute pair, prismatic pair, and
cylindrical pair. Using empirical testing functional relationships between extractive force and
clearance, and between moment and clearance have been developed. These functional
relationships can be used by users to fabricate kinematic pairs using FDM based 3D printing
processes. The efficacy of the proposed approach is demonstrated on 3D printed kinematic pairs
and experimental validation studies. | null | null | null | null | null | null |
Rosen, David W. | 2020-03-10T14:20:28Z | 2020-03-10T14:20:28Z | 2007 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80208', 'http://dx.doi.org/10.26153/tsw/7227'] | eng | 2007 International Solid Freeform Fabrication Symposium | Open | Additive Manufacturing | Design for Additive Manufacturing: A Method to Explore Unexplored Regions of the Design Space | Conference paper | https://repositories.lib.utexas.edu//bitstreams/161728ed-4841-4cb1-9c3e-1774854e7fb6/download | null | Additive Manufacturing (AM) technologies enable the fabrication of parts and devices that
are geometrically complex, have graded material compositions, and can be customized. To take
advantage of these capabilities, it is important to assist designers in exploring unexplored regions
of design spaces. We present a Design for Additive Manufacturing (DFAM) method that
encompasses conceptual design, process selection, later design stages, and design for
manufacturing. The method is based on the process-structure-property-behavior model that is
common in the materials design literature. A prototype CAD system is presented that embodies
the method. Manufacturable ELements (MELs) are proposed as an intermediate representation
for supporting the manufacturing related aspects of the method. Examples of cellular materials
are used to illustrate the DFAM method. | null | null | null | null | null | null |
['Meisel, Nicholas A.', 'Williams, Christopher B.'] | 2021-10-13T21:30:27Z | 2021-10-13T21:30:27Z | 2014 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88786', 'http://dx.doi.org/10.26153/tsw/15720'] | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Design for Additive Manufacturing (DfAM)', 'PolyJet', '3D printing', 'multiple materials', 'material jetting'] | Design for Additive Manufacturing: An Investigation of Key Manufacturing Considerations in Multi-Material PolyJet 3D Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/643201f1-7a1e-43be-b06f-ed82cee02bf1/download | University of Texas at Austin | The PolyJet material jetting process is uniquely qualified to create complex, multi-material structures.
However, there is currently a lack of understanding and characterization regarding important
manufacturing considerations to guide designers in their use of the PolyJet process. This paper
investigates key considerations necessary to ensure that proposed designs are manufacturable and that
part properties are appropriate for the intended use. Considerations included in this paper include 1)
minimum manufacturable feature size, 2) removal of support material from channels, 3) survivability of
small features during water jet cleaning, and 4) the maximum self-supporting angle of printed parts in the
absence of support material. The result of this work is an understanding of which geometric and process
variables affect these manufacturing considerations. This understanding is crucial for the creation of a set
of Design for Additive Manufacturing (DfAM) guidelines to help designers create ideal, manufacturable
parts with less iteration and provide constraints for insertion into automated design processes such as
topology optimization. | null | null | null | null | null | null |
['Kim, Samyeon', 'Tang, Yunlong', 'Rosen, David W.'] | 2021-11-16T15:33:23Z | 2021-11-16T15:33:23Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90315', 'http://dx.doi.org/10.26153/tsw/17236'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['design for additive manufacturing', 'designers', 'part consolidation', 'part identification', 'lifecycle', 'additive manufacturing'] | Design for Additive Manufacturing: Simplification of Product Architecture by Part Consolidation for the Lifecycle | Conference paper | https://repositories.lib.utexas.edu//bitstreams/99ecbe19-7841-444d-9b9e-a2cdcdd83b67/download | University of Texas at Austin | Additive manufacturing (AM) can support the fabrication of the complex design and generate new
design opportunities for improving products. To identify and leverage these opportunities, design studies in early
product design stages are required. Since part consolidation is one of AM design potentials in conceptual and
embodiment design stages, this study proposes a design method to reconceptualize existing product design in
the context of part consolidation. Function requirements and physical relations between existing parts are
used to investigate AM design potential and identify candidates for consolidation. After identification of
consolidation candidates, function sharing between parts and modules is checked because they have high
possibilities to be consolidated if they share the same functions. Furthermore, AM design potential is identified
to help designers add value in part design. In order to support designers, it is required to link AM design
potential to the part candidates in order to explore AM design benefits. A case study with motorcycles is
performed to demonstrate the proposed method. The AM design potential for the case study contains the
lifecycle considerations related to fuel savings due to lightweight, and simplified and less expensive assembly
operations due to simplified product architecture by part consolidation. | null | null | null | null | null | null |
['Yang, L.', 'Harrysson, O.L.A.', 'Cormier, D.', 'West, H.', 'Zhang, S.', 'Gong, H.', 'Stucker, B.'] | 2021-11-01T21:37:45Z | 2021-11-01T21:37:45Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89762 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['lightweight structure', 'additive manufacturing', 'cellular structure', 'unit cell', 'design'] | Design for Additively Manufactured Lightweight Structure: A Perspective | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c810ea68-8ab4-413d-a9ec-5064ab1a050f/download | University of Texas at Austin | The design of lightweight structures realized via additive manufacturing has been drawing
considerable amount of attentions in academia and industries for a wide range of
applications. However, various challenges remain for AM lightweight structures to be
reliably used for these applications. For example, despite extensive advancement with
geometric design, there still lacks adequate understanding with the process-material
property relationship of AM lightweight structures. In addition, a more integrated design
approach must also be adopted in order to take non-uniform material design into
consideration. In our works, a design approach based on unit cell cellular structure was
taken in the attempt to establish a comprehensive design methodology for lightweight
structures. Analytical cellular models were established to provide computationally efficient
property estimation, and various design factors such as size effect, stress concentration and
joint angle effect were also investigated in order to provide additional design guidelines.
In addition, it was also found that the geometry and microstructure of the cellular structures
are dependent on both the process setup and the feature dimensions, which strongly support
the argument to establish a multi-scale hierarchical cellular design tool. | null | null | null | null | null | null |
['Palomino, Donald', 'McClelland, Ryan', 'Grau, Mike', 'Watkins, Ryan', 'Li, Bingbing'] | 2024-03-27T03:44:25Z | 2024-03-27T03:44:25Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124473', 'https://doi.org/10.26153/tsw/51081'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['metal additive manufacturing', 'generative design', 'internal lattice structure'] | DESIGN FOR INTERNAL LATTICE STRUCTURES WITH APPLICATION IN ADDITIVE MANUFACTURING | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a17e7382-7a18-4580-861d-089f5d5de06c/download | University of Texas at Austin | Internal lattice structures have the potential to significantly reduce the mass of an existing metal
component, which is a desirable characteristic in the aerospace and automobile industries.
However, there are still uncertainties on whether or not internal lattice structures can outperform
a solid version of the same mass. Additionally, internal lattice structures can only be produced
via additive manufacturing methods, bringing more challenges to resolve. To determine the
viability of internal lattice structures, a study will be performed to compare its performance with
solid, hollow, and mass penalty designs of equivalent masses using Autodesk Fusion 360. A
performance baseline will be established by running multiple simulations on simple geometries
to obtain the maximum displacement, first four modes, and first buckling mode. A generative
design part, better known within NASA Goddard Space Flight Center as A15, will undergo the
same simulations and have its results analyzed to determine feasibility. | null | null | null | null | null | null |
['Jahnke, U.', 'Koch, R.', 'Oppermann, A.T.'] | 2021-11-08T21:31:31Z | 2021-11-08T21:31:31Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90046', 'http://dx.doi.org/10.26153/tsw/16967'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['product piracy', 'design for protection', 'protective measures', 'product development', 'additive manufacturing'] | Design for Protection: Systematic Approach to Prevent Product Piracy During Product Development Using AM | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e66a82cd-50c6-48b5-8fd5-1ec3a0409ed3/download | University of Texas at Austin | Although infringements of intellectual properties in terms of product piracy are growing
for years and threaten investments in research and development most companies still rely on
legal measures like property rights. A more preventive effect to protect against counterfeits can
be achieved using technical measures complicating reverse engineering, improving traceability
and assuring data protection. Additive Manufacturing can contribute a lot to the effectivity and
efficiency of those technical measures but presently they are often unconsidered during product
development. To support decision makers and designers through all the steps of a product
development process an integrated systematic approach has been developed. Protective
measures using AM are allocated to specific process steps and responsible persons in charge so
that the result is a guideline for “design for protection”. The main idea is to help developing
piracy-robust products for that the return of investment is not threatened by counterfeits and its
economical impacts. | null | null | null | null | null | null |
Rosen, David W. | 2021-12-01T21:16:35Z | 2021-12-01T21:16:35Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90615', 'http://dx.doi.org/10.26153/tsw/17534'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['design for additive manufacturing', 'manufacturing process chain', 'process chain map'] | Design for the Additive Manufacturing Process Chain | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bcb70654-7a12-411f-932b-7743d07fe4d9/download | University of Texas at Austin | Post-processing operations are required for most additive manufacturing (AM) processes. For production
parts, consideration of these post-processing operations during design is critical to achieve design
requirements. For both metal and polymer parts, the sequence of steps in the process chain can be extensive.
A design framework called the Process Chain Map (PCM) is introduced in this paper that explicitly relates
design requirements for the part to each step in the AM process chain. This PCM visually shows the role
of each step in the process chain and facilitates communication among design and manufacturing personnel.
Software implementation of the PCM enables generation of system-level problem formulations of
multidisciplinary design optimization problems. An example of a metal AM part demonstrates the PCM
and the formulation of such a design problem. | null | null | null | null | null | null |
Meisel, Nicholas | 2024-03-27T16:08:38Z | 2024-03-27T16:08:38Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124502', 'https://doi.org/10.26153/tsw/51110'] | en | 2022 International Solid Freeform Fabrication Symposium | Open | ['problem-based learning', 'design for additive manufacturing', 'DfAM'] | DESIGN FOR(E!) ADDITIVE MANUFACTURING: IN SEARCH OF A COMPREHENSIVE DESIGN CHALLENGE SUITABLE ACROSS AM EDUCATION | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ca1242ac-8a34-4f3d-ba5e-6842edeeea7c/download | University of Texas at Austin | Modern engineering design education relies heavily on the concept of problem-based learning
(PBL). Driven by the constructivist theory of education, PBL enables students to build
knowledge organically, rather than through rote memorization. As such, design for additive
manufacturing (DfAM) education also tends to emphasize the use of PBL to encourage student
learning. Unfortunately, dedicated DfAM education is still nascent. The result is a wide range of
educators leveraging an equally wide, and often unproven, range of design challenges to support
DfAM PBL. Because of this, there is the possibility that a chosen design challenge will not
represent AM as a true end-use manufacturing process nor promote a design space that can
benefit from the full consideration of all opportunistic and restrictive DfAM concepts. In this
paper, the author discusses the creation and implementation of a comprehensive design challenge
that is suitable across the range of AM education. Specifically, the author proposes the use of a
golf putter DfAM design challenge. This concept draws from lessons learned over years of
DfAM instruction at undergraduate and graduate levels and is based in the need for three key
aspects for a successful DfAM challenge in education: (1) clarity, (2) applicability, and (3)
demonstrability. | null | null | null | null | null | null |
['Lammers, S.', 'Tominski, J.', 'Magerkohl, S.', 'Künneke, T.', 'Lieneke, T.', 'Zimmer, D.'] | 2021-11-09T19:11:35Z | 2021-11-09T19:11:35Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90132', 'http://dx.doi.org/10.26153/tsw/17053'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['design guidelines', 'software algorithm', 'design check', 'robust production', 'additive manufacturing'] | Design Guidelines for a Software-Supported Adaptation of Additively Manufactured Components with Regard to a Robust Production | Conference paper | https://repositories.lib.utexas.edu//bitstreams/35eb7f98-3cc9-4426-a406-f4d8b43b21cc/download | University of Texas at Austin | The design of additively manufactured components requires a rethinking in the design
process. This is inhibited by a lack of knowledge about additive manufacturing technologies.
For this reason, a large number of design guidelines have been developed in recent years. In
their present form the design guidelines are not suitable for processing in a software algorithm,
since the guidelines have a certain redundancy and partly influence each other. This paper
describes several steps to consolidate the existing guidelines and to prepare them in a way that
they can be used in a software algorithm for a design check. Therefore, existing guidelines are
collected, prioritized and quantified with regard to their relevance for a robust production. To
quantify the guidelines, test specimens are developed, produced and evaluated in order to obtain
a limit value for the geometric properties. With these limit values, quantifiable design
guidelines can be applied to designers and software tools. | null | null | null | null | null | null |
['Hassani, Vahid', 'Rosen, David W.', 'Goh, Ethan', 'Sarwan, Sufiyan', 'Doetzer, Florian'] | 2021-11-30T20:25:10Z | 2021-11-30T20:25:10Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90536', 'http://dx.doi.org/10.26153/tsw/17455'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['fiber-reinforced composites', 'additive manufacturing', 'synergies', 'design method'] | A Design Method to Exploit Synergies Between Fiber-Reinforce Composites and Additive Manufactured Processes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f753b450-9bd2-4a07-b805-38011bb929d8/download | University of Texas at Austin | This paper proposes a design method for devices composed of long fiber-reinforced composites
(FRC) and additive manufactured (AM) parts. Both FRC and AM processes have similar application
characteristics: suitable for small production volumes, additive in nature, and capable of being highly
automated. On the other hand, the classes have distinct characteristics. FRC components tend to be large
and of simple shapes, while AM components tend to be small with highly complex geometry. Their
combination has the potential for significant synergies, while mitigating their individual limitations. A
decision guide is proposed, in the form of a series of questions, to guide the designer to determine if their
application is a good candidate for FRC+AM. The decision guide is reformulated into a proposed design
process that guides the designer to advantageously benefit from AM and FRC characteristics. The tools
are illustrated with an example of a composite pressure vessel with integrated pressure reducer. | null | null | null | null | null | null |
['Singh, Prabhjot', 'Moon, Yong-Mo', 'Dutta, Debasish', 'Kota, Sridhar'] | 2019-11-20T16:37:51Z | 2019-11-20T16:37:51Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78477', 'http://dx.doi.org/10.26153/tsw/5562'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | Multi-Directional | Design of a Customized Multi-Directional Layered Deposition System Based on Part Geometry | Conference paper | https://repositories.lib.utexas.edu//bitstreams/2fd149b1-01b4-4d7b-b7b2-681c51c9f8dd/download | null | Multi-Direction Layered Deposition (MDLD) reduces the need for supports by depositing
on a part along multiple directions. This requires the design of a new mechanism to reorient the part, such that the deposition head can approach from different orientations.
We present a customized compliant parallel kinematic machine design configured to
deposit a set of part geometries. Relationships between the process planning for the
MDLD of a part geometry and considerations in the design of the customized machine
mechanism are illustrated. MDLD process planning is based on progressive part
decomposition and kinematic machine design uses dual number algebra and screw
theory. | null | null | null | null | null | null |
['Chang, Yu-Chuen', 'Crawford, Richard H.'] | 2021-11-04T14:53:59Z | 2021-11-04T14:53:59Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89976 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['desktop wire-feed prototyping machine', 'desktop prototyping machine', 'wire processing', 'wire melting', 'additive manufacturing'] | Design of a Desktop Wire-Feed Prototyping Machine | Conference paper | https://repositories.lib.utexas.edu//bitstreams/614dc808-7fc8-44f1-87ec-7ea4666cb8dc/download | University of Texas at Austin | Much additive manufacturing research focuses on systems suitable for industrial
applications, especially research on metal processing. Our research aims to design a desktop-scale
prototyping machine to process metal wire. Possible applications for this research include various
wire structures, such as wire sculptures.
The wire joining technology is the most important subsystem of the envisioned layer-based
process. In this research, three concepts are proposed and analyzed according to the power required
to fully melt the wire. The selected approach uses a wire bender to create the desired geometry of
the product, and a pulse TIG welder to join the metal wire to retain the shape. Experiments were
conducted to evaluate the joining strength of pulse TIG welds to verify the joining efficiency of
the method. The experimental results indicate that filler metal is required to produce acceptable
welding strength. A conceptual CAD model of the complete system is presented. | null | null | null | null | null | null |
['Wang, Hongqing Vincent', 'Johnston, Scott R.', 'Rosen, David W.'] | 2020-02-27T20:27:17Z | 2020-02-27T20:27:17Z | 9/14/06 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80101', 'http://dx.doi.org/10.26153/tsw/7122'] | eng | 2006 International Solid Freeform Fabrication Symposium | Open | Unit Truss | Design of a Graded Cellular Structure for an Acetabular Hip Replacement Component | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a2a30b2a-ee83-4610-b12b-6c2947bee12f/download | null | The state-of-the-art porous coatings become more and more popular in uncemented prostheses
to make bone grow into implants for biological fixation. In this paper, graded cellular structures are
proposed for uncemented prostheses to enhance stability on implant-bone interfaces. As an example
study, the authors develop a new acetabular implant with gradient porosity for hip replacement. A
gradient porous acetabular component with cellular structure could match the bone’s elasticity.
Material is adaptively distributed from high porosity at the bone-implant interface to solid metal at the
joint’s articulating surface. The new acetabular prosthesis would replace metal-on-polyethylene
bearing with metal-on-metal bearing for less wear. The design problem of acetabular component is
formulated and a requirement list is elaborated. A detailed design of the prosthesis with a graded
cellular structure is presented. The design concept is validated with a comparison to the existing
products according to the design requirements. | null | null | null | null | null | null |
['McWilliams, John', 'Hysinger, Christopher', 'Beaman, J.J.'] | 2018-04-19T17:03:27Z | 2018-04-19T17:03:27Z | 1992 | Mechanical Engineering | doi:10.15781/T26H4D72P | http://hdl.handle.net/2152/64384 | eng | 1992 International Solid Freeform Fabrication Symposium | Open | ['Department of Mechanical Engineering', 'HTW', 'process chamber'] | Design of a High Temperature Process Chamber for the Selective Laser Sintering Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7d0ae54d-962a-482d-af0c-9ceab1392361/download | null | null | null | null | null | null | null | null |
['Das, Suman', 'McWilliam, John', 'Wu, Benny', 'Beaman, J.J.'] | 2018-04-17T16:48:36Z | 2018-04-17T16:48:36Z | 1991 | Mechanical Engineering | doi:10.15781/T2SN01N0P | http://hdl.handle.net/2152/64332 | eng | 1991 International Solid Freeform Fabrication Symposium | Open | ['Department of Mechanical Engineering', 'Selective Layer Sintering', 'SLS', 'High temperature workstation', 'HTW'] | Design of a High Temperature Workstation for the Selective Laser Sintering Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ee46c425-aadf-49c8-b7d5-d5145a69a808/download | null | null | null | null | null | null | null | null |
['Das, Suman', 'Santosa, James'] | 2019-10-09T16:31:35Z | 2019-10-09T16:31:35Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76159', 'http://dx.doi.org/10.26153/tsw/3248'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Deposition | Design of a Micro-Hopper Array for Multi-Material Powder Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6f6f7961-e8e9-43be-85db-c113e6f4a0f5/download | null | We present a concept for creating patterned beds of multi-material powder particles using
an array of small-scale hoppers. Using this technique, we propose that to place fine particles of
multiple fluidized powders discretely in a thin layer as opposed to depositing an entire powder
layer of uniform composition using a roller device or doctor blade. Processing and consolidation
of multiple, patterned powders can enable fabrication of composite objects with spatially varying
structural and multifunctional characteristics. Although theory on the design of small-scale
hoppers is lacking, our design for a hopper, its valving, and its particle delivery system are
guided by background theory for large hoppers. A hopper array configuration is proposed, and a
calculation for deposition time is presented. Delivery of powder was achieved on a prototype
hopper. Experimentally measured mass flow rates were used to justify the use of this hopper with
SLS and to guide further design improvements. | null | null | null | null | null | null |
['Roy, Nilabh K.', 'Foong, Chee S.', 'Cullinan, Michael A.'] | 2021-10-28T20:20:24Z | 2021-10-28T20:20:24Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89689 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['microscale selective laser sintering', 'µ-SLS', 'feature-size resolution'] | Design of a Micro-scale Selective Laser Sintering System | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1d6c1ec2-2ee9-40bb-adb9-dd6e4676d104/download | University of Texas at Austin | Micro and nanoscale additive manufacturing methods employing metals and ceramics have
many promising applications in the aerospace, medical device, and electronics industries.
However, the present state of art metal additive manufacturing tools have feature-size
resolutions of greater than 100 µm, which is too large to precisely control the geometrical
and dimensional aspects of the parts they produce. The weakness is particularly profound
in application of additive manufacturing to the fabrication of fine pitch interconnects in the
packaging and assembly of integrated circuits. A new microscale selective laser sintering
(µ-SLS) is being developed in this research to improve the minimum feature-size resolution
of metal additively manufactured parts by up to two orders of magnitude, while still
maintaining the throughput of traditional additive manufacturing processes. This paper
presents a detailed design of the sub-assemblies of the µ-SLS system including innovative
design features such as the use of (1) ultra-fast lasers, (2) a micro-mirror based optical
system, (3) nanoscale particles, (4) a precision spreader mechanism, (5) long-range
precision XY nano-positioner and (6) a global positioner. | null | null | null | null | null | null |
['Thissell, W.Richards', 'Tompkins, James', 'Marcus, Harris L.'] | 2018-04-10T17:05:44Z | 2018-04-10T17:05:44Z | 1990 | Mechanical Engineering | doi:10.15781/T2C24R501 | http://hdl.handle.net/2152/64237 | eng | 1990 International Solid Freeform Fabrication Symposium | Open | ['Department of Mechanical Engineering', 'Center for Materials Science and Engineering', 'SFF', 'CAD', 'Computer aided designs'] | Design of a Solid Freeform Fabrication Diamond Reactor | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a7627b3f-d701-44d5-8bf6-2e6347946644/download | null | Solid Freeform Fabrication (SFF) has progressed from the visualization aided
stage of computer aided designs (CAD) to rapid prototyping of structural parts.
Among the promising techniques for producing structural prototypes is the technology
ofchemical vapor deposition (CVD) ofpolycrystalline diamond. This paper
discusses the thermodynamic and kinetic theories that suggest that structural
diamond may be rapidly deposited at rates approaching 1 mmJhr from the vapor
phase at metastable thermodynamic conditions. The design of a reactor that will
produce structural diamond prototypes is discussed. This reactor combines downstream
microwave plasma enhanced chemical vapor deposition (DMWPECVD)
with a scanned CO2 laser that locally heats the substrate to diamond deposition
temperatures. The input:Fases are H2, 02' CH4, and Ar. The operating pressure range
of the reactor is 1 x 10- to 7 x 102 Torr. The reactor is designed for in situ determination
of deposit thickness while deposition occurs as well as having the capacity
of fitting on an existing resonance enhanced multiphoton ionization time of flight
mass spectroscopy (REMPITOFMS) apparatus that will allow for plasma diagnostics
immediately above the heated substrate. Plasma diagnostics will be
employed to determine the active metastable species that results in diamond
deposition so that optimization can be made ofthe operating parameters to maximize
diamond selectivity and deposition rate. | null | null | null | null | null | null |
['Martina, Filomeno', 'Williams, Stewart W.', 'Colegrove, Paul'] | 2021-10-11T22:07:00Z | 2021-10-11T22:07:00Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88661', 'http://dx.doi.org/10.26153/tsw/15595'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['wire + arc additive manufacturing', 'pulsed tungsten inert gas', 'process parameters', 'deposition parameters', 'Ti-6Al-4V'] | Design of an Empirical Process Model and Algorithm for the Tungsten Inert Gas Wire+Arc Additive Manufacture of Ti-6Al-4V Components | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6ba5f47c-89e4-4ffb-a3a5-c778128ce1f9/download | University of Texas at Austin | In the wire+arc additive manufacture process parameters can be varied to achieve a wide range
of deposit widths, as well as layer heights. Pulsed Tungsten Inert Gas was chosen as the deposition
process. A working envelope was developed, which ensures unfeasible parameters combinations
are excluded from the algorithm. Thanks to an extensive use of a statistically designed experiment,
it was possible to produce process equations through linear regression, for both wall width and
layer height. These equations are extremely useful for automating the process and reducing the
buy-to-fly ratio. For a given layer height process parameters can be selected to achieve the required
layer width while maximising productivity. | null | null | null | null | null | null |
['Yang, Li', 'Harrysson, Ola', 'Cormier, Denis', 'West, Harvey', 'Park, Chun', 'Peters, Kara'] | 2021-10-12T18:20:39Z | 2021-10-12T18:20:39Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88713', 'http://dx.doi.org/10.26153/tsw/15647'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['auxetic sandwich structures', 'cellular sandwich structures', 'auxetic cores', 'structural applications', 'electron beam melting', 'selective laser sintering'] | Design of Auxetic Sandwich Panels for Structural Applications | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e0de36c8-4cf8-4afb-a8cf-f657519d149b/download | University of Texas at Austin | Based on an analytical modeling analysis, a sandwich structure with a 3D re-entrant
auxetic core was designed. Auxetic samples were produced by electron beam melting (EBM) and
selective laser sintering (SLS), and compared to other regular cellular sandwich structures
through various experiments. It was shown that sandwich structures with pre-designed auxetic
cores could exhibit significantly improved mechanical properties such as bending compliance
and energy absorption, which are critical to many structural applications. This work
demonstrated an alternative of effectively designing 3D cellular structures, and also showed the
potential of this type of auxetic structure in applications via careful design. | null | null | null | null | null | null |
['Philip, Ravi', 'Sparks, Todd E.', 'Liou, Frank'] | 2020-03-09T13:34:31Z | 2020-03-09T13:34:31Z | 8/27/07 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80174', 'http://dx.doi.org/10.26153/tsw/7193'] | eng | 2007 International Solid Freeform Fabrication Symposium | Open | Laser Deposition | Design of Embedded Resistance Heating Element Using Rapid Manufacturing Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a2e20fbe-bfd3-49f5-bf92-29f3c6c6922b/download | null | null | null | null | null | null | null | null |
['Wallace, T. A.', 'Bey, K. S.', 'Taminger, K.M.B.', 'Hafley, R. A.'] | 2020-02-12T15:23:25Z | 2020-02-12T15:23:25Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/79936', 'http://dx.doi.org/10.26153/tsw/6962'] | null | 2004 International Solid Freeform Fabrication Symposium | Open | Microstructure | A Design of Experiments Approach Defining the Relationships Between Processing and Microstructure for Ti-6Al-4V | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8bff84f5-af99-4bfc-90e0-edb7eb493d78/download | null | null | null | null | null | null | null | null |
['Quintana, Rolando', 'Puebla, Karina', 'Wicker, Ryan'] | 2020-03-09T15:29:14Z | 2020-03-09T15:29:14Z | 8/21/07 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80199', 'http://dx.doi.org/10.26153/tsw/7218'] | eng | 2007 International Solid Freeform Fabrication Symposium | Open | rapid prototyping | Design of Experiments Approach for Statistical Classification of Stereolithography Manufacturing Build Parameters: Effects of Build Orientation on Mechanical Properties for ASTM D-638 Type I Tensile Test Specimens of DSM Somos® 11120 Resin | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b9d2b3fe-0760-4bf0-91a9-28aa772da300/download | null | A statistical design of experiments (DOE) approach was used to determine if specific build
orientation parameters impacted mechanical strength of fabricated parts. A single platform (10-
inch by 10 inch cross-section) on the 3D Systems Viper si2 machine was designed to hold 18,
ASTM D-638 Type I samples built in six different orientations (called Location) with three
samples built for each location. The DOE tested four factors: Location, Position, Axis, and
Layout. Each sample within a Location was labeled as Positions 1, 2, or 3 depending on the
distance from the center of the platform with Position 1 being the closest to the center. Samples
were fabricated parallel with the x-axis, y-axis, or 45o
to both axes (called Axis 1, 2, and 3,
respectively) and were fabricated either flat or on an edge relative to the x-y plane (called Layout
1 and 2, respectively). The results from the statistical analyses showed that Axis, Location, and
Position had no significant effect on UTS or E. However, Layout (or whether a sample was built
flat or on an edge) was shown to have a statistically significant effect on UTS and E (at a 95%
level of confidence). This result was not expected since a comparison of the average UTS for
each Layout showed only a 1.2% difference (6966 psi versus 7050 psi for samples built flat and
on an edge, respectively). Because of the small differences in means for UTS, the statistical
differences between Layout most likely would not have been identified without performing the
DOE. Furthermore, Layout was the only factor that tested different orientations of build layers
(or layer-to-layer interfaces) with respect to the sample part, and thus, it appears that the
orientation of the build layer with respect to the fabricated part has a significant effect on the
resulting mechanical properties. This study represents one of many to follow that is using
statistical analyses to identify and classify important fabrication parameters on mechanical
properties for layer manufactured parts. Although stereolithography is the focus of this work, the
techniques developed here can be applied to any layered manufacturing technology. | null | null | null | null | null | null |
['Jorapur, Nikhil', 'West, Robert', 'Williams, Christopher B.', 'Druschitz, Alan'] | 2021-11-01T21:02:08Z | 2021-11-01T21:02:08Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89750 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['tensegrity behavior', 'fiber-reinforced cellular structures', 'cellular structures', 'sand molds', '3D printing'] | Design of Fiber-Reinforced Cellular Structures with Tensegrity Behavior Manufactured Using 3D Printed Sand Molds | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4744a3fb-ee79-4a9e-b5d6-66a80287712c/download | University of Texas at Austin | Tensegrity structures provide a high stiffness to mass ratio since all the comprising
elements are either in compression or tension. However, they have limited applications since
fabrication of such structures is challenging due to their complexity and mainly requires manual
assembly of components. The authors look to Additive Manufacturing (AM) as a means to
introduce tensegrity behavior in cellular structures to enhance structural performance. Specifically,
octet cellular structures are created by casting aluminum into 3D-printed sand molds embedded
with continuous wires. In this paper, the authors describe design and analysis of octet cellular
structures that feature high strength fibers held in continuous tension. Finite element analysis of 4-
point bending test is used to evaluate the effectiveness of embedded fibers. Also, the presence of
tensegrity behavior was evaluated using this analysis and testing. The structure with tensegrity
behavior was found to be 30 % stronger. The simulation and experimental results were shown to
match within 6 % error in the elastic region. | null | null | null | null | null | null |
['Modica, F.', 'Stöckli, F.R.', 'Shea, K.'] | 2021-10-21T19:57:24Z | 2021-10-21T19:57:24Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89436 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['fused deposition modeling', 'walking robots', 'passive dynamic walkers', 'additive manufacturing'] | Design of Passive Dynamic Walking Robots for Additive Manufacture | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3a5eec83-109b-497e-889a-8f67ef3a252a/download | University of Texas at Austin | Ongoing research in the direction of printable, non-assembly mechatronic systems give
rise to the need for multi-material printing, including electronics. However, there are robotic
systems that do not use electronic components and still exhibit complex dynamic behavior. Such
passive dynamic systems have the potential to save energy and component cost in the field of
robotics compared to actuated systems. Ongoing research in computational design synthesis of
passive dynamic systems aims at automatically generating robotic configurations based on a
given task. However, an automated design-to-fabrication process also requires a flexible
fabrication method. Towards the goal of printing functional, non-assembly passive dynamic
robots using Fused Deposition Modeling (FDM), this paper explores designing and fabricating
passive walking robots and all necessary components using single material FDM. Two
configurations of passive dynamic walkers are re-designed and fabricated in this paper. For one
of them all components are printed in one job and only little assembly after printing is needed.
However, the gait cycle of the second configuration is much more sensitive to small parametric
changes and therefore more flexible prototyping is needed in order to allow adjusting of the robot
after printing. Moreover, FDM printed robotic joints with sufficient smoothness and axial
stiffness are required and a variety of different joint assemblies are designed and tested for the
robot prototypes. Even though the most stable gait for the second robot is achieved using a metal
bearing instead of the FDM printed ones, this is not necessary for the first robot example. The
approach to prototyping with FDM presented in this paper allows achieving functionality through
design iteration without incurring significant cost. To arrive at feasible solutions, a modular
design approach allows to combine different joints, legs, feet and balancing weights and the
connection points of the different elements are adjustable after printing, which makes it possible
to shift the center of gravity and other variables of the robot. | null | null | null | null | null | null |
['Kumar, Vikas', 'Manogharan, Guhaprasanna', 'Cormier, Denis R.'] | 2021-09-29T18:14:23Z | 2021-09-29T18:14:23Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88206', 'http://dx.doi.org/10.26153/tsw/15147'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['powder based metal', 'additive manufacturing', 'heat exchangers', 'catalyst support structures', 'hexagonal periodic cellular structures', 'cellular structure orientation'] | Design of Periodic Cellular Structures for Heat Exchanger Applications | Conference paper | https://repositories.lib.utexas.edu//bitstreams/9542a938-17c1-4d27-b638-a2eaf02c2548/download | University of Texas at Austin | Powder based metal additive manufacturing processes generally produce parts with a textured
surface. Although surface roughness is undesirable in most cases, it can be advantageous for
applications such as heat exchangers or catalyst support structures. While stochastic metal foams
have been used for these applications, it is not possible to tailor the foam geometry to the
application. SFF techniques permit designers to use different cell geometries and orientations to
achieve specific performance objectives. More specifically, the unit cell type and size, ligament
size, and cell orientation have a considerable influence on surface area, volume, density and fluid
flow behavior of the lattice structure. This paper illustrates the effect of the orientation of
hexagonal periodic cellular structures on heat transfer and pressure drop. Finite element analysis
of air flowing through the hot hexagonal periodic cellular structures shows the effect of
orientation on heat transfer and pressure drop. The analysis indicates that the ideal orientation is
dependent on the specific application. | null | null | null | null | null | null |
['Wei, Chongyi', 'Smith, Douglas E.'] | 2024-03-27T03:46:26Z | 2024-03-27T03:46:26Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124474', 'https://doi.org/10.26153/tsw/51082'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['triply periodic minimal surface', 'lattice structures', 'additive manufacturing'] | Design of Spatially Varying Orientation Lattice Structures Using Triply Periodic Minimal Surfaces | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7205fec3-59d5-4a7e-8cc7-ddb7077748fa/download | University of Texas at Austin | Interest continues to grow for lattice structures produced by additive manufacturing
methods that are described by triply periodic minimal surface (TPMS). Tunable parameters that
define the TPMS provide unique design flexibility where prior research has focused on designing
hybrid or functionally graded TPMS structures. In this paper, a new strategy is proposed to
include an orientation angle and volume fraction of each lattice cell simultaneously when
defining structures derived from TPMS. The algorithm iteratively solves an underlying partial
differential equation with the finite difference method to obtain a smooth, continuous lattice
structure with a spatially varying orientation angle. The resulting lattice structure can be
combined with other types of TPMS models using Gaussian radial basis and distance functions
to achieve multi-TPMS lattice designs. The spatially varying lattice structures can also take the
advantage of the directional effective modulus of TPMS to improve the strength the performance
of lattice design. | null | null | null | null | null | null |
['McDowell, Christopher S.', 'Boomer, Mark C.'] | 2018-11-14T17:47:00Z | 2018-11-14T17:47:00Z | 1996 | Mechanical Engineering | doi:10.15781/T2V980B5V | http://hdl.handle.net/2152/70249 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['stereolithography', 'Investment casting', 'SL pattern generation'] | Design of Stereolithography Trees for Use in the Investment Casting of Stereolithography Patterns | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cbd342ee-c9e4-4ff6-8b21-3809d0f1db30/download | null | null | null | null | null | null | null | null |
['Gao, Feng', 'Koresawa, Hiroshi', 'Narahara, Hiroyuki', 'Suzuki, Hiroshi'] | 2019-10-30T16:51:25Z | 2019-10-30T16:51:25Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78191', 'http://dx.doi.org/10.26153/tsw/5280'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Thermal Environment | Design of Thermal Environment in Plastic Injection Mold Based on Evaluation of Resin Cooling Uniformity | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0f4bccce-4aff-47be-9bd2-0dc88563191d/download | null | Thermal state in plastic injection molds greatly influences the molding quality of products. This paper discusses the optimum design of thermal environment in the molds by observing and estimating the cooling uniformity of resin. Numerical analysis based on unsteady heat transfer is conducted to confirm the utility of the proposed evaluation method, and case studies show the comparison results of resin deformations under different cooling systems conditions and the improved designs. | null | null | null | null | null | null |
['Fitzpatrick, Angus', 'Mohammed, Mazher', 'Collins, Paul', 'Gibson, Ian'] | 2021-11-08T21:08:04Z | 2021-11-08T21:08:04Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90041', 'http://dx.doi.org/10.26153/tsw/16962'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['patient specific', 'design', '3D printing', 'orthosis', 'optimisation'] | Design Optimisation of a Thermoplastic Splint | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6f470aba-2bcb-4c06-819a-5f06c87061ab/download | University of Texas at Austin | Following partial hand amputation, a post-surgery orthosis is required to hold the
remaining ligaments and appendages of the patient in a fixed position to aid recovery. This
type of orthosis is traditionally handmade and fabricated using laborious and qualitative
techniques, which would benefit from the enhancements offered by modern 3D technologies.
This study investigated the use of optical laser scanning, Computer Aided Design (CAD) and
Material Extrusion (ME) additive manufacturing to manufacture a polymeric splint for use in
post-surgical hand amputation. To examine the efficacy of our techniques, we take an existing
splint from a patient and use this as the template data for production. We found this approach
to be a highly effective means of rapidly reproducing the major surface contours of the orthosis
while allowing for the introduction of advanced design features for improved aesthetics,
alongside reduced material consumption. Our demonstrated techniques resulted in a more
lightweight and lower cost device, while the design and manufacturing elements afford greater
flexibility for orthosis customisation. Ultimately, this approach provides an optimized and
complete methodology for orthosis production. | null | null | null | null | null | null |
['Chahine, Gilbert', 'Atharifar, Hosein', 'Smith, Pauline', 'Kovacevic, Radovan'] | 2021-09-29T17:34:51Z | 2021-09-29T17:34:51Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88197', 'http://dx.doi.org/10.26153/tsw/15138'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['finite element analysis', 'dental implants', 'design optimization', 'Electron Beam Melting'] | Design Optimization of a Customized Dental Implant Manufactured via Electron Beam Melting® | Conference paper | https://repositories.lib.utexas.edu//bitstreams/79a0b434-bfcf-470b-b4fe-12a861a5acec/download | University of Texas at Austin | Finite Element Analysis (FEA) is a commonly used tool to evaluate biomechanics of traditional dental implants.
Biomechanics help predict bone response and implant retention which strongly affects the longevity of the
implant. The current research utilizes an analogues approach with FEA, to evaluate the biomechanics of a
customized dental implant design built by Electron Beam Melting®, and to contribute towards the implant’s
design optimization. The analysis consists of three distinct simulation models. The first model is established in
order to get an insight of the biomechanics produced by a biting force of 400 N on a second human molar in the
mandible, its corresponding superposed mate and the surrounding biomaterial. In the second model, the lower
jaw molar is replaced by a Ti-6Al-4V customized dental implant with a solid surface at the root. In the third
model, the customized dental implant has a modified outer-layer at the root with adjustable elasticity. By using a
deterministic optimization technique in the FEA, an elasticity of the modified layer can be selected in a manner
to minimize stress shielding from occurring. | null | null | null | null | null | null |
['Panesar, A.', 'Brackett, D.', 'Ashcroft, I.', 'Wildman, R.', 'Hague, R.'] | 2021-10-18T21:50:09Z | 2021-10-18T21:50:09Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89261 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Additive Manufacturing', 'Topology Optimization', '3D printing', 'multifuctional parts', 'design optimization'] | Design Optimization Strategy for Multifunctional 3D Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/76e40d5f-cd12-4494-8a17-65e7978b2568/download | University of Texas at Austin | An optimization based design methodology for the additive manufacture of multifunctional parts (for example, a structure with embedded electronic/electrical systems and
associated conductive paths) is presented. This work introduces a coupled optimization strategy
where Topology Optimization (TO) is combined with an automated placement and routing
approach that enables determination of an efficient internal system configuration. This permits
the effect of the incorporation of the internal system on the structural response of the part to be
taken into account and therefore enables the overall optimization of the structure-system unit. An
example test case is included in the paper to evaluate the optimization strategy and demonstrate
the methods effectiveness. The capability of this method allows the exploitation of the
manufacturing capability under development within the Additive Manufacturing (AM)
community to produce 3D internal systems within complex structures. | null | null | null | null | null | null |
['Gibson, I.', 'Goenka, G.', 'Narasimhan, R.', 'Bhat, N.'] | 2021-09-30T20:10:54Z | 2021-09-30T20:10:54Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88293', 'http://dx.doi.org/10.26153/tsw/15234'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['Rapid Prototyping', 'Additive Manufacturing', 'layer-based fabrication', 'AM constraints', 'AM technology', 'design rules'] | Design Rules for Additive Manufacture | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6feb6d2d-2efe-4be0-903f-33fb9d04b0a9/download | University of Texas at Austin | As Rapid Prototyping (RP) has evolved to become Additive Manufacture (AM) it has become
possible to exploit the effects of the layer-based approach to fabrication so that parts can become
easier to build and with greater functionality. Initially parts made in a manner that could not be
manufactured further using conventional processes were considered merely as a novelty to RP
machine users rather than of any wider benefit. With improvements in the technology and
increasing demand for more complex geometry products, AM is coming into its own. As a result,
we are now able to manufacture parts that have interlocking features, overlapping and
mechanistic properties as well as us not having to worry about constraints like draft angles and
overhanging features.
However, this does not mean we can completely ignore manufacturing constraints. More that we
have to concern ourselves with a different set of constraints. AM technologies are limited
according to the following (1): -
Speed of build
Accuracy
Surface geometry
Tolerances
Wall thickness and feature size
Material properties
Range of materials
These have always been an issue; it’s just that now improvements have now gotten to the stage
where parts are acceptable for final application. We must therefore concern ourselves with a new
set of design rules that allow us to understand how the technology can be best applied to the
advantage of the creator of the new products... | null | null | null | null | null | null |
['Kelly, S.', 'Paterson, A.M.J.', 'Bibb, R.J.'] | 2021-11-09T20:55:12Z | 2021-11-09T20:55:12Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90162', 'http://dx.doi.org/10.26153/tsw/17083'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'wrist splints', 'finite element analysis', 'design of experiments'] | Design Rules for Additively Manufactured Wrist Splints Created Using Design of Experiment Methods | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b9a249b9-e4ff-433f-b2be-b09447d54bde/download | University of Texas at Austin | Research has shown that wrist splints can be made using Additive
Manufacturing (AM) with a similar or greater performance than splints created using
traditional manufacturing methods. By using AM, many of the problems associated with
traditional splinting such as poor aesthetics and poor ventilation could be mitigated.
However, work to date typically reviews splints with singular pattern designs (e.g. Voronoi
patterns), which have structural and safety implications if similar but untested patterns are
created. Using Design of Experiments (DOE) design rules were to enable clinicians to
confidently design splints alongside their patients.
Design rules were created by investigating variables of cut out patterns using DOE
methods. Finite Element Analysis (FEA) of various combinations of cut out variables was
conducted. | null | null | null | null | null | null |
['Jee, H.', 'Lu, Y.', 'Witherell, P.'] | 2021-10-21T19:33:40Z | 2021-10-21T19:33:40Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89430 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['design rules', 'modularity', 'additive manufacturing'] | Design Rules with Modularity for Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/9884ccbb-0d78-418d-b07f-1e0ad4576d77/download | University of Texas at Austin | Design rules for additive manufacturing (AM) can help ensure manufacturability, which can be
viewed as compatibility between designs and the fabrication processes that produce those designs.
Additionally, such rules frequently provide direct guidelines or constraints for designing AMdestined parts. Here, we present design rules as sets of modular components and associated
formalisms. Independent of context, these representations can be more easily interpreted and
efficiently implemented. Given context, components are specialized to represent process-specific
parameters for different AM builds and processes. This method of specialization enables designers
to reconfigure design rules, rather than create new rules from scratch, thus preserving fundamental
AM principles while supporting customization and explicit representation. | null | null | null | null | null | null |
['Wang, Hongqing Vincent', 'Williams, Chris', 'David W., Rosen'] | 2020-03-02T15:16:11Z | 2020-03-02T15:16:11Z | 2006 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80130', 'http://dx.doi.org/10.26153/tsw/7151'] | eng | 2006 International Solid Freeform Fabrication Symposium | Open | Mesoscopic Cellular Structure | Design Synthesis of Adaptive Mesoscopic Cellular Structures with Unit Truss Approach and Particle Swarm Optimization Algorithm | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c269ce7a-a4d2-4246-9d01-14e2c7525b83/download | null | Cellular material structures have been engineered at the mesoscopic scale for high performance
and multifunctional capabilities. However, the design of adaptive cellular structures - structures with
cellular configurations, sizes, and shapes designed for a specific geometric and loading context - has
not been sufficiently investigated. In this paper, the authors present a design synthesis method with the
use of unit truss approach and particle swarm optimization algorithm to design adaptive cellular
structures. A critical review is presented to show the pros and cons of the new design synthesis method
and an existing homogenization method. The research extends the application of additive
manufacturing in the design of new materials for high performances and benefits its long-term growth. | null | null | null | null | null | null |
['Lane, B.', 'Mekhontsev, S.', 'Grantham, S.', 'Vlasea, M.L.', 'Whiting, J.', 'Yeung, H.', 'Fox, J.', 'Zarobila, C.', 'Neira, J.', 'McGlauflin, M.', 'Hanssen, L.', 'Moylan, S.', 'Donmez, A.', 'Rice, J.'] | 2021-10-28T15:24:16Z | 2021-10-28T15:24:16Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89662 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing metrology testbed', 'AMMT', 'National Institute Standards and Technology', 'NIST', 'system design', 'system construction'] | Design, Developments, and Results from the NIST Additive Manufacturing Metrology Testbed (AMMT) | Conference paper | https://repositories.lib.utexas.edu//bitstreams/114e208f-21a4-47be-81ac-155b507367f4/download | University of Texas at Austin | The National Institute of Standards and Technology (NIST) is developing a facility titled
the Additive Manufacturing Metrology Testbed that will enable advanced research into
monitoring, controls, process development, and temperature measurement for laser powder bed
fusion additive manufacturing and similar processes. This system provides an open control
architecture as well as a plethora of sensor systems and calibration sources that are primarily
radiance-based and aligned co-axially with the laser beam and focused on the laser interaction
zone. This paper briefly reviews the system requirements, and details the current progress of the
facility design and construction. Mechanical, optical, and control systems designs are detailed
with select highlights that may be relevant to additive manufacturing researchers and system
developers. Recent experimental results from the prototype laser control and in-situ monitoring
system are also highlighted. | null | null | null | null | null | null |
['Kashdan, Lia', 'Seepersad, Carolyn', 'Haberman, Michael', 'Wilson, Preston S.'] | 2021-09-29T20:36:36Z | 2021-09-29T20:36:36Z | 2009-09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88218', 'http://dx.doi.org/10.26153/tsw/15159'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['constrained bistable structures', 'negative stiffness behavior', 'metamaterials', 'broadband imaging transducers', 'conventional manufacturing', 'selective laser sintering'] | Design, Fabrication and Evaluation of Negative Stiffness Elements | Conference paper | https://repositories.lib.utexas.edu//bitstreams/15a9fec0-ba01-4eda-abb5-9068ff4b7fe8/download | University of Texas at Austin | Recent research has shown that constrained bistable structures can display negative
stiffness behavior and provide extremal vibrational and acoustical absorptive capacity.
These bistable structures are therefore compelling candidates for constructing new
metamaterials for noise reduction, anechoic coatings, and backing materials for
broadband imaging transducers. To date, demonstrations of these capabilities have been
primarily theoretical, because the geometry of bistable elements is difficult to construct
and refine with conventional manufacturing methods and materials. The objective of this
research is to exploit the geometric design freedoms provided by selective laser sintering
(SLS) technology to design and construct constrained bistable structures with negative
stiffness behavior. The static and dynamic behaviors of resulting bistable structures are
experimentally investigated. Initial bistable designs and test results are presented in this
paper. | null | null | null | null | null | null |
['Alayavalli, Kaushik', 'Bourell, David L.'] | 2021-09-29T17:56:53Z | 2021-09-29T17:56:53Z | 9/15/09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88202', 'http://dx.doi.org/10.26153/tsw/15143'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['Direct Methanol Fuel Cells', 'clean energy', 'bipolar plate', 'graphite', 'indirect Selective Laser Sintering'] | Design, Fabrication and Testing of Graphite Bipolar Plates for Direct Methanol Fuel Cells | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a60b5d90-8bf7-4b09-97ca-41a34294034c/download | University of Texas at Austin | Direct Methanol Fuel Cells (DMFCs) are clean energy devices that convert chemical energy into
electrical energy. The bipolar plate component of the DMFC is required to be fluid impermeable
to prevent fuel leakage and electrically conductive to collect the electrons produced within the
cell. Graphite possesses the properties of high electrical conductivity, low weight and resistance
to corrosion that make it an attractive material for bipolar plates. However, the poor mechanical
properties of graphite lead to prohibitive machining costs. The indirect Selective Laser Sintering
(SLS) process, involving the laser sintering of graphite powders mixed with a phenolic resin
binder, offers the advantage of complex part production and testing of prototype bipolar plates in
short times. The current research deals with the production of bipolar plates for DMFC's by
utilizing indirect SLS followed by post processing steps. | null | null | null | null | null | null |
['Geating, J.T.', 'Wiese, M.C.', 'Osborn, M.F.'] | 2021-11-08T21:18:09Z | 2021-11-08T21:18:09Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90044', 'http://dx.doi.org/10.26153/tsw/16965'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['3D printing', 'additive manufacturing', 'metal parts', 'quadruped robot', 'quadruped body', 'hydraulic manifold', 'mechanical interface', 'core structure', 'design', 'fabrication', 'qualification'] | Design, Fabrication, and Qualification of a 3D Printed Metal Quadruped Body: Combination Hydraulic Manifold, Structure and Mechanical Interface | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c709eaf8-d9c2-4ee8-ae86-0c5d5e65d2d5/download | University of Texas at Austin | Additive manufacturing allows designers to make complex, efficient parts that are not
achievable through conventional manufacturing techniques. Efficiencies are achieved by
combining structural members, component interfaces, and hydraulic power distribution elements
while eliminating redundant structural mass and volume. This paper documents the design,
fabrication, inspection and testing of complex additively manufactured metal components. Parts
utilizing AlSi10Mg aluminum alloy combine the roles of hydraulic manifold, mechanical
interface, and core structure for a meso-scale quadruped robot. These parts allow Naval Research
Laboratory (NRL) engineers to design and construct a highly capable quadruped robot that is
both dynamic and lightweight. Metal parts were designed with computer aided design (CAD)
and constructed using powder-bed direct laser metal sintering (DLMS). High-pressure hydraulic
lines with internal fluid passageways were printed into the body assembly seamlessly creating a
complex hydraulic manifold. After fabrication, a rigorous program involving post-processing,
inspection, and destructive and non-destructive testing was performed to validate the design and
manufacturing methods. The manifold has been approved for use and integrated on the
quadruped, awaiting system level testing. | null | null | null | null | null | null |
['Peng, Hao', 'Gao, Feng', 'Hu, Wenjing'] | 2021-11-30T22:05:54Z | 2021-11-30T22:05:54Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90564', 'http://dx.doi.org/10.26153/tsw/17483'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['triply periodic minimal surface', 'additive manufacturing', 'heat exchanger', 'lattice structure'] | Design, Modeling and Characterization on Triply Periodic Minimal Surface Heat Exchangers with Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cee91e29-4578-4d2a-b49d-893c5bb562e3/download | University of Texas at Austin | Next-generation power plants will generate heated fluids at significantly higher
temperatures than current-generation power plants, which challenges the state-of-the-art heat
exchanger design. In this study triply periodic minimal surfaces were combined with additive
manufacturing for next-generation heat exchanger design. Triply periodic minimal surfaces
separate three-dimensional space into two interpenetrating channels, creating high surface area to
volume ratios and low hydrodynamic resistance. Parametric design of triply periodic minimal
surface heat exchanger is straightforward because they are governed by simple implicit functions
with parameters such as periodic length and offset parameter. In this study a design workflow was
developed to streamline the design of triply periodic minimal surface heat exchangers and a
numerical model was developed to optimize triply periodic minimal surface heat exchanger design
for optimal performance. Finally, the optimized triply periodic minimal surface heat exchanger
was printed with EOS M290 DMLS machine and the performance was tested by experiment. | null | null | null | null | null | null |