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['Muraru, L.', 'Pallari, J.', 'Creylman, V.', 'Vander Sloten, J.', 'Peeraer, L.'] | 2021-10-01T00:18:32Z | 2021-10-01T00:18:32Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88306', 'http://dx.doi.org/10.26153/tsw/15247'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['Selective Laser Sintering', 'ankle-foot orthoses', 'customized', 'computer-aided design', 'Nylon-12', 'finite element models'] | SLS Nylon 12 Characterization Through Tensile Testing and Digital Image Correlation for Finite Element Modeling of Food and Ankle-Foot Orthoses | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3b704dbb-40e1-42f0-9cc4-8b18c72aeabe/download | University of Texas at Austin | Selective Laser Sintering has been recently proposed as a feasible engineering technique
for manufacturing of customized ankle-foot orthoses (AFOs). Development of
computer-aided design (CAD) models and virtual evaluation of the orthotic devices are
important steps in the engineering design process. This paper will describe a method for
accurate characterization of SLS Nylon 12 mechanical properties to be implemented in
the finite element models (FEM) of AFOs. Elastic mechanical properties were
determined for principal and perpendicular building directions. | null | null | null | null | null | null |
['Choren, J.', 'Gervasi, V.', 'Herman, T.', 'Kamara, S.', 'Mitchell, J.'] | 2019-10-09T16:00:16Z | 2019-10-09T16:00:16Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76145', 'http://dx.doi.org/10.26153/tsw/3234'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Powder | SLS Powder Life Study | Conference paper | https://repositories.lib.utexas.edu//bitstreams/777e258a-c7db-4ad7-894a-0e3217fde152/download | null | Producing acceptable models on the Selective Laser Sintering (SLS) machine involves
adjusting machine parameters relative to powder age. Typically, a fraction of the powder is used
and the remainder of the unused powder is recycled. After 5-7 recycles, this method leads to a
powder inventory with inconsistent characteristics. The goal of this study was to apply a new
recycling program to extend powder life, reduce powder inventory, and improve part quality.
This study looks at various material properties of processed powder over its lifetime, including:
surface quality, toughness, impact strength, elastic modulus, tensile strength, and shrinkage. A
new approach to powder recycling and machine parameter adjustment will be recommended. | null | null | null | null | null | null |
['Jepson, L.', 'Beaman, J. J.', 'Bourell, D. L.', 'Wood, K. L.'] | 2018-11-28T19:35:53Z | 2018-11-28T19:35:53Z | 1997 | Mechanical Engineering | doi:10.15781/T2TQ5S07J | http://hdl.handle.net/2152/70327 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['SLS process', 'powder delivery', 'Selective Laser Sintering'] | SLS Processing of Functionally Gradient Materials | Conference paper | https://repositories.lib.utexas.edu//bitstreams/75923433-2750-4aa4-aea0-22014dc6587a/download | null | A developing SLS process, known as Multiple Material Selective Laser Sintering,
will allow the material composition of a component to be varied in a controlled
manner. This process could allow the fabrication of functionally gradient materials
(FGMs) in which a blended interface exists. Two potential applications of FGMs are
the reduction of thermal stresses in metal/ceramic joints and the matching of
material properties to functional requirements. A tungsten carbide/cobalt system has
been examined in which the ceramic/metal ratio has been varied in an attempt to
control the hardness/fracture resistance _ratio. An FGM powder bed was manually
fabricated using a discrete banding technique. Results of traditional SLS processing
of this powder bed are presented. | null | null | null | null | null | null |
['Cheng, J.', 'Lao, S.', 'Nguyen, K.', 'Ho, W.', 'Cummings, A.', 'Koo, J.'] | 2020-02-20T20:58:27Z | 2020-02-20T20:58:27Z | 2005 | Mechanical Engineering | null | https://hdl.handle.net/2152/80052 | eng | 2005 International Solid Freeform Fabrication Symposium | Open | Selective Laser Sintering | SLS Processing Studies of Nylon 11 Nanocomposites | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c41a4e2b-0cea-4e81-9ab6-28c985413c74/download | null | Selective Laser Sintering (SLS) is widely used for rapid prototyping/manufacturing of
nylon 11 and nylon 12 parts. This processing technique has not been explored for
nylon nanocomposites. This study investigates the technicalities of processing nylon
11-clay and nylon-carbon nanofiber nanocomposites with SLS. Microstructural
analyses of the SLS powders and parts were conducted under SEM. Results suggest
that SLS processing is possible with the new nylon 11 nanocomposites. Yet the SLS
parts built have inferior properties relative to those of injection molding, suggesting
that more fine tuning for the processing is required. | null | null | null | null | null | null |
['Forderhase, Paul', 'McAlea, Kevin', 'Michalewicz, Mary', 'Ganninger, Mark', 'Firestone, Kent'] | 2018-09-26T20:52:25Z | 2018-09-26T20:52:25Z | 1994 | Mechanical Engineering | doi:10.15781/T2WD3QM05 | http://hdl.handle.net/2152/68596 | eng | 1994 International Solid Freeform Fabrication Symposium | Open | ['Rapid prototyping', 'Compression molded', 'SLS Nylon Processing'] | SLSTM Prototypes From Nylon | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d3d8d786-b644-41a4-ad92-c793eec64557/download | null | Many rapid prototypmg materials and processes produce parts which have relatively low
stiffness, strength, and ductility. While such parts are useful for visualization, they have limited value
where functional features are necessary or where application testing is required. In order to satisfy these
more demanding requirements, rapid prototyping materials which offer part performance representative of
molded plastics are required.
DTM has developed and commercialized nylon-based materials (LN-4010 and LNF-5000) for the
SLS process which produce strong, durable parts without the use of constraint or support structures. In
order to produce dimensionally accurate SLS nylon parts, careful control of the thermal environment is
required during the entire process cycle. In this paper, the thermal control elements necessary to achieve
this goal are described. Background information concerning SLS nylon part performance and material
process behavior is also provided. | null | null | null | null | null | null |
['Cima, M.J.', 'Oilveira, M.', 'Wang, H.R.', 'Sachs, E.', 'Holman, R.'] | 2019-10-10T17:28:11Z | 2019-10-10T17:28:11Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76177', 'http://dx.doi.org/10.26153/tsw/3266'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Ceramic | Slurry-Based 3DP and Fine Ceramic Components | Conference paper | https://repositories.lib.utexas.edu//bitstreams/53cb9f52-829f-4da2-aa92-838014c95dd2/download | null | Slurry-based 3DPTM (S-3DPÔ) is a solid freeform fabrication technique developed at MIT for
production of fine ceramic components with complex geometries and fired densities in excess of
99% of theoretical density. Current research involves identification of the factors controlling
minimum feature size in S-3DPTM. The ink-jet printed binder droplet size is the primary factor
controlling the minimum feature dimension when deposited on the powder layers. For a given
droplet size, however, a balance between spreading of the binder solution on the surface of the S3DPTM powderbed and infiltration determine the feature size, while interactions between the
polymeric binder and the powder surface (polymer adsorption) control the minimum feature
cross-section. Droplet-on-demand printing of the binder solution has been introduced to improve
resolution, decreasing the minimum feature width from 300 mm to less than 150 mm. | null | null | null | null | null | null |
['Erhard, P.', 'Volk, W.', 'Guenther, D.'] | 2024-03-27T03:15:57Z | 2024-03-27T03:15:57Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124460', 'https://doi.org/10.26153/tsw/51068'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['slurry-based binder jetting', '3D printing', 'foundry', 'casting cores', 'ceramics'] | SLURRY-BASED BINDER JETTING OF CERAMIC CASTING CORES | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8b7f36fa-3fd0-4f65-a0bd-46741a2dcf2f/download | University of Texas at Austin | The production of complex sand cores to represent internal contours in castings is typically
achieved by powder-based binder jetting. However, a trade-off between the load-bearing capacity
during casting and the subsequent removability from the cast part leads to design limitations.
Slurry-based binder jetting allows the processing of fine powders and the economical production
of sinterable ceramic cores. Its performance, potential, and challenges are presented in the context
of the foundry process chain. As drying affects material properties and process efficiency, detailed
investigations are carried out to control the properties via drying. Average roughness depths of 1.2
µm and flexural strengths of 25 MPa were achieved using aqueous quartz slurry and appropriate
process parameters. By incorporating predetermined breaking lines into the internal geometry of
hollow casting core structures, the stress generated during the solidification of the cast metal
induces decoring. A promising process chain is outlined for producing efficient, close-contour
coolings in high-performance castings and digital code tags for part tracking in foundries. | null | null | null | null | null | null |
['Meyers, Sebastian', 'Feys, Quinten', 'Yang, Shoufeng', 'Vleugels, Jef', 'Kruth, Jean-Pierre'] | 2021-11-09T21:07:14Z | 2021-11-09T21:07:14Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90168', 'http://dx.doi.org/10.26153/tsw/17089'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['alumina', 'additive manufacturing', 'laser sintering', 'powder metallurgy'] | Slurry-Based Laser Sintering of Alumina Ceramics | Conference paper | https://repositories.lib.utexas.edu//bitstreams/071f5cea-eaa8-44f1-a971-c3e2677da54b/download | University of Texas at Austin | In this work, a slurry-based laser sintering process is investigated. Laser sintering allows
for a broad palette of materials to be used. Since the binder content is only about 16 vol% with
respect to the ceramic powder load, the debinding process is faster and less susceptible to crack
formation and part warping compared to lithography-based manufacturing. The alumina slurry,
used as a starting material for laser sintering, was optimized by adjusting the dispersant content to
reach a minimum viscosity. After debinding and furnace sintering, multi-layer alumina parts with
densities up to 97% were obtained. | null | null | null | null | null | null |
['Hossain, Mohammad Shojib', 'Gonzalez, Jose A.', 'Martinez Hernandez, Ricardo', 'Morton, Philip', 'Mireles, Jorge', 'Choudhuri, Ahsan', 'Lin, Yirong', 'Wicker, Ryan B.'] | 2021-11-08T21:25:57Z | 2021-11-08T21:25:57Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90045', 'http://dx.doi.org/10.26153/tsw/16966'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['smart parts', 'powder bed fusion', 'additive manufacturing', 'fabrication process'] | Small Parts Fabrication Using Powder Bed Fusion Additive Manufacturing Technologies | Conference paper | https://repositories.lib.utexas.edu//bitstreams/686d9665-e09f-4c49-a65c-22a8c250e3dd/download | University of Texas at Austin | Metallic components with embedded sensors or smart parts can be a beneficial tool for
monitoring harsh environments in the energy, biomedical, automotive, and aerospace industries.
Smart parts maintain structural integrity with added functionality of sensing temperature, pressure,
and structural health. A non-intrusive placement of a sensor in metallic components was
developed using powder bed fusion additive manufacturing (AM). A paused build procedure was
used to fabricate a proof of concept, a cylindrical shaped smart part using both electron beam
melting (EBM) and selective laser melting (SLM) technologies. This paper focuses on the
fabrication process and characterization of the smart part. A functional complex shaped energy
system component, a smart injector was fabricated to demonstrate the applicability in harsh
environments. The pressure and temperature sensing capabilities were tested using compressive
cyclic loading and hot fire testing in a combustion chamber testing. A maximum sensing response
of 3V was obtained for EBM fabricated smart part while applying compressive load. An image
analysis based part positioning method was demonstrated for EBM technology that can be
employed in other AM technologies to alleviate or completely remove misalignment in a paused
build fabrication process. | null | null | null | null | null | null |
['Alghamdi, F.', 'Verma, D.', 'Haghshenas, M.'] | 2021-11-10T23:02:47Z | 2021-11-10T23:02:47Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90203', 'http://dx.doi.org/10.26153/tsw/17124'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['small-scale property', 'microstructural assessment', 'depth-sensing', 'depth-sensing indentation', 'aluminum alloy', 'additive manufacturing'] | Small-Scale Characterization of Additively Manufactured Aluminum Alloys Through Depth-Sensing Identification | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4def42bb-5ffb-4ba0-bae7-b71849a3fad8/download | University of Texas at Austin | Selective laser melting (SLM) can be considered as a suitable additive manufacturing
method for printing complex-in-shape aluminum components. However, to adopt the SLM for
mass production of aluminum components for automotive and aerospace applications, one needs
to fully understand the correlations between the SLM parameters, produced microstructure, and
local mechanical properties of the printed parts. In this paper, along with microstructural
assessments (optical and scanning electron microscopy), small-scale properties of two additively
manufactured aluminum alloys, AlSi10Mg and A205.0, were examined using an instrumented
(depth-sensing) indentation testing technique. An instrumented indentation testing approach is a
semi-destructive, reliable and convenient method which enables us to study the variations and
distributions of the mechanical properties (i.e. hardness) as a function of distance from the build
plate. The variations in properties are then compared in AlSi10Mg and A205.0 alloys and are
correlated to the generated microstructures in the printed alloys. | null | null | null | null | null | null |
['Haghshenas, M.', 'Totuk, O.', 'Masoomi, M.', 'Thompson, S.M.', 'Shamsaei, N.'] | 2021-11-02T14:02:55Z | 2021-11-02T14:02:55Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89806 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['Ti-6Al-4V', 'additive manufacturing', 'mechanical properties', 'nanoindentation', 'microstructure'] | Small-Scale Mechanical Properties of Additively Manufactured Ti-6Al-4V | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4925d796-0a72-41c8-af60-5a67de084dd4/download | University of Texas at Austin | This article aims at studying microstructure and nano/micro-scale mechanical responses of Ti-6Al-4V fabricated using a Laser-based Powder Bed Fusion (L-PBF) method. To this end, an
instrumented depth-sensing nanoindentation system has been used to assess hardness, Young’s
modulus, strain rate sensitivity and rate dependent plastic deformation of the alloy at different
build Orientations (in the Z-plane and X-plane) at ambient temperature. Indentation tests were
conducted at constant proportional loading rate of 15 mN/s in a depth-controlled (hind=2000 nm)
testing regime. The Microstructure characterizations were performed using optical and scanning
electron microscopy to assess the correlations to the mechanical properties achieved by the
nanoindentation testing to better establish structure-property relationships for L-PBF Ti-6Al-4V.
It is expected that the fine microstructure, developed by fast solidification during the L-PBF
process, to directly contribute to the nanoindentation measurements at different strain rates. | null | null | null | null | null | null |
['Liu, Renwei', 'Wang, Zhiyuan', 'Zhang, Yunlu', 'Sparks, Todd', 'Liou, Frank'] | 2021-10-28T14:40:42Z | 2021-10-28T14:40:42Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89653 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['laser metal deposition', 'toolpath generation', 'additive manufacturing'] | A Smooth Toolpath Generation Method for Laser Metal Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/885b1f5f-e05c-485b-9e1e-6a536dfb954b/download | University of Texas at Austin | Laser metal deposition (LMD), also known as direct metal deposition (DMD) or laser engineered
net shaping (LENS), which uses a laser beam to form a melt pool on a metallic substrate, into
which powder or wire is fed. The conventional contour and zigzag toolpath pattern for LMD are
discontinuous at turn points or corner points. The discontinuous toolpath causes uneven
deposition, which brings height variation and porosity problems. This paper aims to develop a
smooth toolpath generation method for LMD to improve the deposition quality. A parametric
curve equation based on trigonometric functions is derived and built. It can be used for arbitrary
smooth connections or transitions in toolpath planning and provide constant feedrate for
deposition. The proposed method was applied to a patch deposition experiment and a component
repair experiment with Ti-6Al-4V powder. The experimental results show that the smooth
toolpath can noticeably improve the dimensional accuracy and surface roughness and reduce
porosity. | null | null | null | null | null | null |
['Carvalho, C.', 'Landers, R.', 'Mülhaupt, R.'] | 2020-02-17T15:31:33Z | 2020-02-17T15:31:33Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80011', 'http://dx.doi.org/10.26153/tsw/7036'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | polymer melts | Soft and Hard Implant Fabrication Using 3D-Bioplotting TM | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1ac082af-da0f-4f8f-b010-8115f85d6bd0/download | null | At the Freiburger Materialforschungszentrum we have developed a new process (3DBioplotting
TM) that permits most kind of polymers and biopolymers to be used in 3D scaffold
design, including hydrogels (e.g. collagen, agar), polymer melts (e.g. PLLA, PGA, PCl) and twocomponent systems (e.g. chitosan, fibrin). Cells can be incorporated within the construction
process, making this an ideal Rapid Prototyping technique for Organ Printing. Tailor-made
biodegradable soft or hard scaffolds can so be fabricated in a short time using individual
computer-tomography data from the patient. In-vitro tests showed promising results and in-vivo
experiments are now under observation. | null | null | null | null | null | null |
['Elkins, Kurt', 'Nordby, Howard', 'Janak, Christopher', 'Gray IV, Robert W.', 'Helge Bohn, Jan', 'Baird, Donald G.'] | 2018-12-05T20:29:54Z | 2018-12-05T20:29:54Z | 1997 | Mechanical Engineering | doi:10.15781/T2833NJ55 | http://hdl.handle.net/2152/71413 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['aircrewoxygen', 'STPE'] | Soft Elastomers for Fused Deposition Modeling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ac34d988-7e22-4a30-8ce9-b1269f630e98/download | null | This paper describes an ongoing effort towards extending the capabilities of the fused deposition
modeling (FDM) process to soft thermoplastic elastomers (STPEs). Two thermoplastic
elastomers with hardness of 72 and 78 Shore A, respectively, have been processed into 0.070"
(1.78 mm) filament stock for use in the FDM 1600 rapid prototyping system. The FDM 1600
liquifier subsystem has been modified to accommodate the reduced column strength ofthe STPE
filament stock. Sample STPE parts have been fabricated with ABS material support structures. | null | null | null | null | null | null |
['Lee, Cheol H.', 'Gaffney, Thomas M.', 'Thomas, Charles L.'] | 2018-11-09T16:54:22Z | 2018-11-09T16:54:22Z | 1996 | Mechanical Engineering | doi:10.15781/T21J97T4W | http://hdl.handle.net/2152/69938 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['SCA', 'SLA', 'LOM'] | Soft Tooling for Low Production Manufacturing of Large Structures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fbe8ddd2-a7f0-4632-8ebf-d99a80cca425/download | null | A new technique for building large prototypes from layered substrate relies on a higher
order construction algorithm to produce accurate prototypes from thick layers. The process is
capable ofproducing a 4' by 8' by 20' object in less than two days. Using this technique to
produce molds instead ofparts allows construction oflarge castings and composite structures.
Example parts include composite airfoils, a 19 foot canoe, and a custom fairing for a racing car. | null | null | null | null | null | null |
['Ensz, M. T.', 'Griffith, M. L.', 'Harrwell, L. D.'] | 2019-02-22T20:02:53Z | 2019-02-22T20:02:53Z | 1998 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/73470', 'http://dx.doi.org/10.26153/tsw/620'] | eng | 1998 International Solid Freeform Fabrication Symposium | Open | ['LENS', 'CAD'] | Software Development for Laser Engineered Net Shaping | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1c220cb6-82e6-47da-be66-47c1d0334e44/download | null | Laser Engineered Net Shaping, also known as LENSTM, is an advanced manufacturing technique used to
fabricate near-net shaped, fully dense metal components directly from computer solid models without the
use oftraditional machining processes. The LENSTM process uses a high powered laser to create a molten
pool into which powdered metal is injected and solidified. Like many SFF techniques, LENSTM parts are
made through a layer additive process. In the current system, for any given layer, the laser is held
stationary, while the part and its associated substrate is moved, allowing for the each layer's geometry to
be formed. Individual layers are generated by tracing out the desired border, followed by filling in the
remaining volume. Recent research into LENSTM has highlighted the sensitivity ofthe processes to
multiple software controllable parameters such as substrate travel velocity, border representation, and fill
patterns. This research is aimed at determining optimal border outlines and fill patterns for LENSTM and
at developing the associated software necessary for automating the creation ofthe desired motion control. | null | null | null | null | null | null |
Dreher, Stefan | 2019-10-18T16:32:56Z | 2019-10-18T16:32:56Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76253', 'http://dx.doi.org/10.26153/tsw/3342'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Configuration | Software for the Interactive Configuration of RP Based Process Chains | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f020c17e-b59f-4de2-83ef-5ceb19ebc3b5/download | null | In product development, time is one of the most critical factors. By introducing Rapid Prototyping methods, development time can be reduced dramatically. But the required characteristics of the generated prototypes become more and more complex. As a result, a great variety of Rapid Prototyping devices and services have emerged on the market. The product developer may be highly satisfied with the wide range of new potentials, tools and methods but who will give an orientation about the most suitable process chain to fulfill his demands? To solve the problem, a new software is being developed at the Fraunhofer Institute IPK in Berlin, the iViP-RPSelector. In a first step, the software tracks a record of the demands to the prototype. These values can be inserted manually, but there is an interface as well connecting the RPSelector to CAD and PDM systems to obtain the design parameters without user interaction. The RPSelector then calculates a completer RP based process chain, which may comprise a layer wise creation, some post processing, a copying process and several finishing processes. | null | null | null | null | null | null |
['Crawford, Richard H.', 'Beaman, J.J.', 'Das, Suman'] | 2018-04-12T18:06:49Z | 2018-04-12T18:06:49Z | 1991 | Mechanical Engineering | doi:10.15781/T2KD1R309 | http://hdl.handle.net/2152/64277 | eng | 1991 International Solid Freeform Fabrication Symposium | Open | ['Department of Mechanical Engineering', 'Solid Freeform Fabrication', 'SFF', 'SLS'] | Software Testbed for Selective Laser Sintering | Conference paper | https://repositories.lib.utexas.edu//bitstreams/754a413e-1c5e-43c8-8a74-ab4538c34c9a/download | null | Computer software plays an important role in the implementation of Solid Freeform
Fabrication (SFF) technologies. This paper describes a software testbed for processing
part geometry for a particular SFF technology, selective laser sintering (SLS), that is built
around the separation of the slicing and rasterization operations to accommodate geometric
information from a variety of sources. The paper also discusses the process control
software being developed for a new high-temperat rkstation for SLS of metal
powders. This program features a high-resolution data rmat, the ability to interpolate
to achieve a desired resolution, and a menu-driven user interface with graphical feedback
and process simulation capabilities. | null | null | null | null | null | null |
['Stuffle, Kevin', 'Mulligan, Anthony', 'Calvert, Paul', 'Lombardi, John'] | 2018-05-03T16:53:19Z | 2018-05-03T16:53:19Z | 1993 | Mechanical Engineering | doi:10.15781/T2WM14B4S | http://hdl.handle.net/2152/65038 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['CAD systems', 'photocurable polymers'] | Solid Freebody Forming of Ceramics from Polymerizable Slurry | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ea27bc59-0ef0-482c-afd8-2bc03fb5d61e/download | null | In solid free body forming a component is described by a CAD system as a series
of slices. The slices are deposited as a sequence of layers which are.cured or solidified
by a moving head such that a three dimensional part is built up. Systems have been
developed based on photocurable polymers, solidifying polymer melts, laser fused
powder layers, polymer-bound powders and others. | null | null | null | null | null | null |
['Bourell, D.L.', 'Beaman, J.J.', 'Marcus, H.L.', 'Barlow, J.W.'] | 2018-04-10T16:01:44Z | 2018-04-10T16:01:44Z | 1990 | Mechanical Engineering | doi:10.15781/T2W08X029 | http://hdl.handle.net/2152/64233 | eng | 1990 International Solid Freeform Fabrication Symposium | Open | ['Solid Freeform Fabrication', 'SFF', 'The Center for Materials Science and Engineering', 'Mechanical Engineering Department', 'Chemical Engineering Department', 'The University of Texas at Austin'] | Solid Freeform Fabrication An Advanced Manufacturing Approach | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6bafd42a-d410-451b-81d2-13aeda96733c/download | null | null | null | Solid freeform fabrication (SFF) is the production of freeform solid objects directly from a
computer model without part-specific tooling or human intervention. SFF has been realized in the
last ten years through the merging of several previously distinct technologies: computer science,
mechanical design, controls, high-energy beam technology and materials science and engineering.
Their combination has produced over a relatively short time..frame numerous SFF methods. The
value of SFF to the commercial sector is usually articulated in terms of reduced time to market
(prototyping), low production "one-of-a-kind" parts and patterns for casting. The purpose of this
introductory paper is to describe briefly some of the approaches to SFF as a background for the
articles included in this proceedings. | null | ['Bourell, D.L.', 'Beaman, J.J.', 'Marcus, H.L.', 'Barlow, J.W.'] | null | null |
Boudreaux, J.C. | 2019-10-23T15:22:12Z | 2019-10-23T15:22:12Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76760', 'http://dx.doi.org/10.26153/tsw/3849'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Parametric | Solid Freeform Fabrication and Parametric Engineering | Conference paper | https://repositories.lib.utexas.edu//bitstreams/998b9b8d-3042-4ac8-a7b3-4b41b968aea1/download | null | Solid freeform fabrication (SFF) is based on a part-centric process model: create a solid model of the
part, form planar slices, and fabricate the part by producing all of the polyhedra by any of several methods. A class
of applications is emerging which will pull SFF from the part-centric model to a new paradigm in which parts are
seen as components of interactive networks. This is precisely the context for which parametric engineering has been
proposed. In this paper, a computational framework will be developed that consists of a finitary topological
representation of parts as 3-manifolds and representation of the evaluative context by means of a symbolic
environment. Parametric engineering is interpreted as a controlled evaluation of parameters within the context of
the symbolic environment. | null | null | null | null | null | null |
Watkins, K. G. | 2019-12-05T17:08:33Z | 2019-12-05T17:08:33Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78648', 'http://dx.doi.org/10.26153/tsw/5704'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Interface | Solid Freeform Fabrication and the Interface with Direct Write | Conference paper | https://repositories.lib.utexas.edu//bitstreams/44195a61-b63e-4750-8dc7-eb5685a5107f/download | null | An overview is given of research activity in solid freeform fabrication (SFF) in England’s
Northwest, concentrating on work in the Laser Group at University of Liverpool (including the
Lairdside Laser Engineering Centre) and at the Laser Processing Research Centre at UMIST.
This work is placed in the context of the strategy for science in the Northwest and its aims in
developing and supporting industrial capability, showing that laser based approaches, including
SFF, are regarded as key enabling technologies. The account also includes a consideration of the
interface between SFF and other “Direct Write” technologies and outlines the recent
development of Direct Write initiatives in the UK. | null | null | null | null | null | null |
['Wang, Wanshan', 'Wu, Wenzheng', 'Yu, Tianbiao', 'Qin, Xingjun', 'Chen, Yadong', 'Rosen, David W.'] | 2021-10-01T00:59:28Z | 2021-10-01T00:59:28Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88312', 'http://dx.doi.org/10.26153/tsw/15253'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['Solid Freeform Fabrication', 'mandible reconstruction', 'computer aided design'] | Solid Freeform Fabrication Assisting Free Fibula Flap for the Reconstructive Surgery of Mandibular Defects | Conference paper | https://repositories.lib.utexas.edu//bitstreams/051ba1ff-fec5-4eca-8477-aed8a4fb6abc/download | null | The usage of RP models can shorten the operation time for reconstructive surgery of mandible
defects using the free fibula flap technique and can improve the accuracy of mandible
reconstruction. This paper reports on a case study of reconstructive surgery on a patient with a
mandibular defect caused by a tumor. A customized mandible rapid prototype model was
manufactured from the patient’s CT data and was used to simulate the reconstructive surgery
procedure. A customized titanium plate was shaped using the mandible RP model as a pattern
before surgery. The usage of a mandible RP model reduced the operation time by 1.5-2.5 hours
and the shape precision of the reconstructed mandible was improved. The customized titanium
plate was consistent with the mandible anatomy. | null | null | null | null | null | null |
['Harrison, Shay', 'Crocker, James E.', 'Manzur, Tariq', 'Marcus, Harris L.'] | 2018-11-14T18:02:28Z | 2018-11-14T18:02:28Z | 1996 | Mechanical Engineering | doi:10.15781/T26H4D94J | http://hdl.handle.net/2152/70254 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['SALD', 'SFF', 'Chemical Vapor Deposition'] | Solid Freeform Fabrication at The University of Connecticut | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b57b2fcb-e9c6-471d-a6d5-e2f5297fe45d/download | null | Gas phase solid freeform fabrication research at The University of Connecticut focuses
on two main procedures, Selective Area Laser Deposition (SALD) and Selective Area Laser
Deposition Vapor Infiltration (SALDVI). A SFF research laboratory is under construction at
UCONN, with two new operation systems. These systems possess temperature control, data
acquisition capabilities, in-situ video monitoring, and the ability to fabricate SALDVI parts up
to four inches wide by four inches long. The procurement of a harmonic generating Nd:YAG six
watt laser, capable of producing output at 532, 355, and 266 nanometer wavelengths, as well as a
coupled effort with the Photonics Center at the University providing laser diodes at a variety of
wavelengths, presents the opportunity to explore interactions involved in gas reactions driven by
lasers. Investigations of material systems will include ceramic carbides, nitrides, and their
composites, as well as metals. | null | null | null | null | null | null |
['Wang, Huijun', 'Jiang, Wenhui', 'Valant, Michael', 'Kovacevic, Radovan'] | 2019-11-20T16:43:57Z | 2019-11-20T16:43:57Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78480', 'http://dx.doi.org/10.26153/tsw/5565'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | Micro-Plasma | Solid Freeform Fabrication Based on Micro-Plasma Powder Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/295ee298-1d4a-4fda-b8ae-58ba7a4b5dd6/download | null | This paper presents a solid freeform fabrication (SFF) technique based on micro-plasma powder
deposition (MPPD). The relationship between the geometric features of the deposited layers and
the welding parameters is investigated. The arc length is controlled through the monitoring of the
arc voltage. The result of building parts with functionally graded components by the MPPD
process is shown as well. The microstructure and the properties of the deposited layers are
analyzed. The experimental results show that the MPPD process is a promising welding-based
solid freeform fabrication technology. | null | null | null | null | null | null |
['Kumar, Ashok V.', 'Dutta, Anirban', 'Fay, James E.'] | 2019-11-15T15:57:55Z | 2019-11-15T15:57:55Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78417', 'http://dx.doi.org/10.26153/tsw/5504'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | Electrographic | Solid Freeform Fabrication by Electrographic Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/11dff1e3-a7fa-4289-8fb6-be90580aa838/download | null | A solid freeform fabrication technique is described where powder is deposited layer by layer using electrophotographic printing. In this process, powder is picked up and deposited using a charged photoconducting surface and deposited on a build platform. The paper describes a test bed that was designed and constructed to study the application of electrophotography to solid freeform fabrication. It can precisely deposit powder in the desired shape on each layer. The electric field required to transfer the powder on to the platform (or onto previously printed layers) was studied. A polymer toner powder was used to build small components by fusing each layer of printer powder using a hot compaction plate. | Funding for this research from NSF grand number DMI-9875445 and ONR grant N00014-98-1-0694 is gratefully acknowledged. | null | null | null | null | null |
['Zong, G.S.', 'Carnes, R.', 'Wheat, H.G.', 'Marcus, H.L.'] | 2018-04-10T18:08:43Z | 2018-04-10T18:08:43Z | 1990 | Mechanical Engineering | doi:10.15781/T2KK94V9T | http://hdl.handle.net/2152/64243 | eng | 1990 International Solid Freeform Fabrication Symposium | Open | ['Center for Materials Science and Engineering', 'Laser Chemical vapor deposition', 'SFF', 'SEM', 'Raman microprobe'] | Solid Freeform Fabrication by Selective Area Laser Deposition | Conference paper | https://repositories.lib.utexas.edu//bitstreams/30d66043-1a3b-44be-82fe-7608412c2758/download | null | Laser chemical vapor deposition is capable of selective area deposition of thin fums at high
spatial resolution, and in the present work this advantage was used to perform solid
freeform fabrication (SFF). The pyrolytic selective area laser deposition of carbon is
studied as a function of the scanning speed, the laser power, and the diameter of the focal
spot on the substrate, at different pressures of the acetylene precursor in a gas phase SFF
system. Carbon rods and rings have been made. SEM and Raman microprobe were used to
characterize the deposits. | null | null | null | null | null | null |
['Wang, Jiwen', 'Shaw, Leon L.', 'Xu, Anping', 'Cameron, Thomas B.'] | 2020-02-20T18:35:37Z | 2020-02-20T18:35:37Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80037', 'http://dx.doi.org/10.26153/tsw/7059'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Solid Freeform Fabrication | Solid Freeform Fabrication of Artificial Human Teeth | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8c9f2fd6-3974-418d-b8fc-015425da755e/download | null | In this paper, we describe a solid freeform fabrication procedure for human dental
restoration via porcelain slurry micro-extrusion. Based on submicron-sized dental porcelain
powder obtained via ball milling process, a porcelain slurry formulation has been developed. The
formulation developed allows the porcelain slurry to show a pseudoplastic behavior and
moderate viscosity, which permits the slurry to re-shape to form a near rectangular cross section.
A well-controlled cross-section geometry of the extrudate is important for micro-extrusion to
obtain uniform 2-D planes and for the addition of the sequential layers to form a 3-D object.
Human teeth are restored by this method directly from CAD digital models. After sintering,
shrinkage of the artificial teeth is uniform in all directions. Microstructure of the sintered teeth is
identical to that made via traditional dental restoration processes. | null | null | null | null | null | null |
['Shanjani, Yaser', 'Toyserkani, Ehsan', 'Pilliar, Robert'] | 2021-09-23T22:55:29Z | 2021-09-23T22:55:29Z | 9/10/08 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88048', 'http://dx.doi.org/10.26153/tsw/14989'] | eng | 2008 International Solid Freeform Fabrication Symposium | Open | ['solid freeform fabrication', 'dual-porous structure scaffolds', '3D-printing', 'calcium polyphosphate', 'polyvinyl alcohol'] | Solid Freeform Fabrication of Calcium Polyphosphate Dual-Porous Structure Osteochondral Scaffold | Conference paper | https://repositories.lib.utexas.edu//bitstreams/83fdeb5c-c591-4c9e-9c1e-1601901733aa/download | null | In this work the solid freeform fabrication (SFF) of dual-porous structure scaffolds using the
3D-printing method is investigated. The structure, including a cartilage substrate and a bone
scaffold with different porosities and pore sizes, provide a suitable facility for repairing the
osteochondral tissues in the implanted site. Calcium polyphosphate (CPP), with distinct particle
sizes for each portion, was utilized as the biomaterial. Polyvinyl alcohol (PVA), as a
biocompatible polymer was also used as a binder to adhere the CPP particles upon injecting of a
solvent through the 3D-printing process. The prototyped parts are finally post-processed in the
controlled furnace to obtain the required bio-mechanical properties. The biomechanical
properties of the fabricated samples are also characterized by the X-ray diffraction (XRD),
scanning electron microscopy (SEM), and density analysis. | null | null | null | null | null | null |
['Sindelar, R.', 'Buhler, P.', 'Niebling, F.', 'Otto, A.', 'Greil, P.'] | 2019-10-22T18:22:19Z | 2019-10-22T18:22:19Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76335', 'http://dx.doi.org/10.26153/tsw/3424'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Ceramic | Solid Freeform Fabrication of Ceramic Parts from Filler Loaded Preceramic Polymers | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bd337b1e-91c9-4050-b306-f52dce55e005/download | null | Manufacturing of ceramic parts was achieved by selective laser treatment of a
preceramic polymer (polysiloxane) loaded with ceramic filler powder (alumina). Thin layers
of polymer/filler powder mixture were sequentially cured with a CO2-laser (λ=10.6 µm)
thereby generating the geometrical shape of the part. Subsequently, the cured thermoset part
was annealed in nitrogen atmosphere at 600 to 1000 °C to convert the compact into a Si-OC/Al2O3 micro-composite material. Dimensional changes upon pyrolysis (∆l/l0 ≈ 3 %) can be
controlled by adjusting the polymer-to-filler ratio and the heat treatment conditions. The new
process is called Selective Laser Curing (SLC). | Financial support of Fonds der Chemischen Industrie and Deutsche
Forschungsgemeinschaft is gratefully acknowledged. | null | null | null | null | null |
['Griffin, Curtis', 'Daufenbach, JoDee', 'McMillin, Scott'] | 2018-09-26T18:38:54Z | 2018-09-26T18:38:54Z | 1994 | Mechanical Engineering | doi:10.15781/T2ZC7SD22 | http://hdl.handle.net/2152/68582 | null | 1994 International Solid Freeform Fabrication Symposium | Open | ['Laminated Object Manufacturing', 'Lone Peak Engineering', 'CAD'] | Solid Freeform Fabrication of Functional Ceramic Components Using a Laminated Object Manufacturing Technique | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0a635fc6-ef1c-4157-b9a5-909db91d4127/download | null | Lone Peak Engineering (LPE) has demonstrated the feasibility ofusing solid freeform
fabrication to prepare advanced structural ceramics using a laminated object manufacturing (LOM)
technique. High purity, high density alumina ceramic components were successfully made using the LOM
process. The properties oft he laminated object manufactured (LOMed) components were very
similar to the physical and mechanical properties of alumina ceramics that were prepared by a
conventional pressing process. The LOMed ceramics were also very similar in properties to
commercially available alumina ceramics. | null | null | null | null | English | null |
['Rodrigues, S. J.', 'Chartoff, R. P.', 'Klosterman, D. A.', 'Agarwala, M.', 'Hecht, N.'] | 2019-06-13T14:01:24Z | 2019-06-13T14:01:24Z | 2000 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/74940', 'http://dx.doi.org/10.26153/tsw/2052'] | eng | 2000 International Solid Freeform Fabrication Symposium | Open | ['silicon nitride', 'LOM', 'ceramics'] | Solid Freeform Fabrication of Functional Silicon Nitride Ceramics by Laminated Object Manufacturing 1 | Conference paper | https://repositories.lib.utexas.edu//bitstreams/df35d4b8-5609-45e8-b842-bb0178385c99/download | null | The processing of silicon nitride (Si3N4) structural ceramics by Laminated Object
Manufacturing (LOM) using ceramic tape preforms was investigated. The key processing stages
involved green shape formation (which used the LOM process), followed by the burnout of all
organics, and final densification by pressureless sintering. Two material systems were
considered. These were a) monolithic Si3N4 and b) a preceramic polymer infiltrated Si3N4. The
raw materials for the process were tape preforms of Si3N4, which were fabricated by standard
tape casting techniques.
Mechanical property data obtained for the LOM processed Si3N4 showed high strength and
fracture toughness values. The room temperature and high temperature (1260 o
C) flexural
strengths were in the range of 700-900 MPa and 360-400 MPa, respectively. The fracture
toughness averaged from 5.5-7.5 MPa.m1/2. These strength and fracture toughness values are
comparable to those reported for conventionally prepared Si3N4 ceramics. Thus, this research
demonstrated that the LOM technique is a viable method for preparing functional Si3N4 ceramics
with good physical and mechanical properties. | null | null | null | null | null | null |
['Birmingham, B.R.', 'Marcus, H.L.'] | 2018-05-03T19:54:05Z | 2018-05-03T19:54:05Z | 1993 | Mechanical Engineering | doi:10.15781/T2CF9JQ5T | http://hdl.handle.net/2152/65073 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['Center for Materials Science and Engineering', 'Selective Laser Reaction Sintering', 'SLRS'] | Solid Freeform Fabrication of Silicon Carbide Shapes by Selective Laser Reaction Sintering (SLRS) | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a946f4f9-d76e-4dcf-884d-be3b8a6aa88a/download | null | This paper describes an investigation ofthe production ofsilicon carbide shapes by
Selective Laser Reaction Sintering (SLRS). One type ofSLRS process, which combines
laser sintering of silicon with acetylene decomposition, is briefly outlined, and the
mechanisms important to the process are discussed. A series oftest shapes are made at
different acetylene pressures to determine pressure effects on conversion to silicon
carbide. X-ray diffraction spectroscopy is used for bulk analysis ofthe shapes, and Auger
electron spectroscopy is used for surface analysis. The results indicate that acetylene
pressure does have a strong effect on silicon conversion to silicon carbide, and SLRS can
be used successfully to make silicon carbide shapes. | null | null | null | null | null | null |
['Marcus, H.L.', 'Birmingham, B.R.'] | 2018-11-08T15:21:39Z | 2018-11-08T15:21:39Z | 1995 | Mechanical Engineering | doi:10.15781/T23N2106M | http://hdl.handle.net/2152/69886 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['SLRS', 'ceramic materials', 'sintering'] | Solid Freeform Fabrication of Silicon Nitride Shapes by Selective Laser Reaction Sintering (SLRS) | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0babd20e-fb32-4f2d-a7c0-16a4be646f1a/download | null | SelectiveLaser ReactionSinteringis a variation ofselective laser sintering (SLS) that incorporates
anjn~situreaction underthe·scannedbeamtofabricate shapes from materials not directly accessible by
traditional SLS. Thispaperclescribesaninvestigation into the production of silicon nitride (Si3N4) shapes
by lasersinteringsiliconpowderinanammonia (NH3) atmosphere. The effect of gas pressure and the
importance of gas/laserinteractionsarediscussed. Single and multiple layer shapes are fabricated. The
material is analyzed by x~ray diffraction spectroscopy (XRDS) for phase content and scanning electron
microscopy (SEM) for macrostructure. Data is presented that demonstrates conversion rates from silicon to
silicon nitride on the order of 85%. | null | null | null | null | null | null |
['Lipton, Jeffrey Ian', 'Tow, Adam Perry', 'Burbank, Istavan', 'Vazquez, Andre', 'Lipson, Hod'] | 2021-10-18T20:55:44Z | 2021-10-18T20:55:44Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89243 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Solid Freeform Fabrication', 'soft tissue simulators', 'hypodermic needle stick', 'injection force', 'medical training', 'surgical planning'] | Solid Freeform Fabrication of Soft Tissue Simulators for Needle Injection | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fc45fa48-d324-409d-aae9-70f202e21548/download | University of Texas at Austin | Medical training and surgical planning are becoming important applications for Solid Freeform Fabrication
(SFF). To date, the vast majority of these training applications have relied on the production of stiff
materials to replicate bones. Others have used soft materials to replicate soft tissues without regard for
replicating the mechanical properties of the tissues. Varying the Young’s Modulus of a printed object using
various propriety materials and processes, we were able to replicate the injection force profile of a sharp
hypodermic needle stick using blunted needles safer for training usage. The composite structures and needle
pairs have a puncture force of 2.8 Newtons at a depth of 9 - 15mm, within the reported range for human
skin. This will provide a safer training alternative in the use of hypodermic needles without the need for
training on humans or animals. | null | null | null | null | null | null |
['Lobovsky, Maxim', 'Lobovsky, Alexander', 'Behi, Mohammad', 'Lipson, Hod'] | 2020-03-10T17:34:55Z | 2020-03-10T17:34:55Z | 2008 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80235', 'http://dx.doi.org/10.26153/tsw/7254'] | eng | 2008 International Solid Freeform Fabrication Symposium | Open | Selective Laser Sintering | Solid Freeform Fabrication of Stainless Steel Using Fab@Home | Conference paper | https://repositories.lib.utexas.edu//bitstreams/dc6fecb3-5df6-4fe5-84ef-c21d3e29bf6f/download | null | Metal or ceramic parts can be solid freeform fabricated (SFF) using powdered material
processing techniques. A slurry of the powdered material is deposited in a layer-by-layer
fashion, and then sintered. We demonstrate this process using a 17-4 PH stainless steel slurry
deposited via robotically controlled syringe in the low-cost Fab@Home rapid prototyper.
Completed parts had densities as high as 90% volume fraction and tensile strength as high as
35% of the pure solid. Details of the process as well as a number of samples of different
geometries are shown. | null | null | null | null | null | null |
['Luo, J.', 'Gilbert, L.J.', 'Qu, C.', 'Morrow, B.', 'Bristow, D.A.', 'Landers, R.G.', 'Goldstein, J.', 'Urbas, A.', 'Kinzel, E.C.'] | 2021-10-19T18:07:19Z | 2021-10-19T18:07:19Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89313 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Additive Manufacturing', 'fused quartz', 'filament fed process', 'glass filaments', 'Solid Freeform Fabrication'] | Solid Freeform Fabrication of Transparent Fused Quartz Using a Filament Fed Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b78a81b8-0c6d-4c73-9ae3-fce59b142771/download | University of Texas at Austin | Glass is a critical material for many scientific and engineering applications including
optics, communications, electronics, and hermetic seals. Despite this technological relevance,
there has been minimal research toward Additive Manufacturing (AM) of glass, particularly
optically transparent glass. Additive Manufacturing of transparent glass offers potential
advantages for lower processing costs for small production volumes, increased design freedom,
and the ability to locally vary the optical properties of the part. Compared to common soda lime
glass, fused quartz is better for AM since it has lower thermal expansion and higher index
homogeneity. This paper presents a study of additive manufacturing of transparent fused quartz
by a filament fed process. A CW CO2 laser (10.6 µm) is used to melt glass filaments layer by
layer. The laser couples to phononic modes in the glass and is well absorbed. The beam and melt
pool are stationary while the work piece is scanned using a standard lab motion
system. Representative parts are built to explore the effects of variable laser power on the
properties of printed fused quartz. During printing the incandescent emission from the melt pool
is measured using a spectrometer. This permits process monitoring and identifies potential
chemical changes in the glass during printing. After deposition, the printed parts are polished and
the transmission measured to calculate the absorption/scattering coefficient. Finally, a low-order
thermal analysis is presented and correlated to experimental results, including an energy balance
and finite volume analysis using Fluent. These results suggest that optical quality fused quartz
parts with low absorption and high index of refraction uniformity may be printed using the
filament-fed process. | null | null | null | null | null | null |
['Crockett, R.S.', 'Gervasi, V.R.'] | 2019-02-19T20:32:31Z | 2019-02-19T20:32:31Z | 1998 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/73446', 'http://dx.doi.org/10.26153/tsw/598'] | eng | 1998 International Solid Freeform Fabrication Symposium | Open | ['SFF', 'stereolithography'] | Solid Freeform Fabrication Research In Engineering Education | Conference paper | https://repositories.lib.utexas.edu//bitstreams/98cea85e-458a-480d-8188-d9eba885d02f/download | null | Because Solid Freeform Fabrication (SFF) has an extremely wide range of potential applications,
crossing traditional engineering and science boundaries, it is a technology that lends itself to
multi-disciplinary activities and projects. SFF is an ideal mechanism to present scientific
concepts including materials science and mechanics, as well as larger-scope engineering topics
such as agile manufacturing. At Milwaukee School of Engineering (MSOE), we are using SFF
technologies as a means to teach engineering concepts to undergraduate students through multidisciplinary research.
MSOE was awarded a five-year grant under the NSF Research Experiences for Undergraduates
Program (EEC-9619715) to facilitate student exploration in the field of Solid Freeform
Fabrication. Sixty undergraduates will participate in summer and academic year programs by the
year 2001. Eighteen students from around the country have participated in the program to date,
bringing with them a diverse background of university experience, skill level, and interests.
Working closely with a faculty advisor possessing expertise in a particular research area, they
have performed research on Solid Freeform Fabrication applications in the biomedical,
aerospace, architectural, manufacturing, and electronics industries.
Some ofthe keys to the success of this program include:
• Hands-on access to Solid Freeform Fabrication equipment through the facilities
ofthe MSOE Rapid Prototyping Center (SLA 250, LOM 2030, and FDM 1650).
• Close partnerships of the students with faculty and industry mentors in
specialized areas of expertise.
• Teaming with other educational institutions.
• Significant cross-pollination between projects; faculty from diverse
departments.
• Encouraging students to publish and present results at national conferences and symposia. | null | null | null | null | null | null |
Marcus, Harris L. | 2021-10-12T19:22:43Z | 2021-10-12T19:22:43Z | 2014 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88724', 'http://dx.doi.org/10.26153/tsw/15658'] | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Solid Freeform Fabrication', 'Solid Freeform Fabrication Symposium', 'Austin'] | Solid Freeform Fabrication Symposium, An Overview | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4499367b-2f34-4ab2-8b62-2715b292c718/download | University of Texas at Austin | null | null | This paper provides a brief overview of the annual Solid Freeform Fabrication Symposium as of 2014. | null | null | null | null |
Beaman, Joseph J. | 2019-10-18T17:09:28Z | 2019-10-18T17:09:28Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76265', 'http://dx.doi.org/10.26153/tsw/3354'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Fabrication | Solid Freeform Fabrication: An Historical Perspective | Conference paper | https://repositories.lib.utexas.edu//bitstreams/10f15bee-4273-4a94-9bb9-b0e9d2bcd819/download | null | null | null | null | null | null | null | null |
['Kumar, Vinod', 'Dutta, Debasish'] | 2018-12-07T16:02:42Z | 2018-12-07T16:02:42Z | 1997 | Mechanical Engineering | doi:10.15781/T2RX9405P | http://hdl.handle.net/2152/71440 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['CAD', 'SFF'] | Solid Model Creation for Materially Graded Objects | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bee6046c-e100-4ecc-bad8-d3a67d392484/download | null | Materially graded objects are objects composed of different constituent materials and could
exhibit continuously varying composition and/or microstructure [1][2]. Such continuous changes
results in gradation in their properties and distinguish them from objects made of conventional
composites. They are also known as heterogeneous objects, functionally graded/gradient materials
(FGM) and multi-material objects/structures [1]. In this paper, we use the terms "materially
graded objects" and "heterogeneous objects" interchangeably. Recently, heterogeneous objects
have found use in several engineering applications. The fabrication process that has shown potential
to manufacture heterogeneous objects is called Solid Freeform Fabrication (SFF), also known
as Layered Manufacturing (LM) [3][4]. SFF is a material deposition process in which the material
deposition can be controlled to vary the material composition throughout an object, thus fabricating
a materially graded object.
All SFF technologies are computer-based and require the CAD model ofthe object to be manufactured.
However, current CAD systems are capable of representing only the geometry/topology
information. Therefore, heterogeneous objects are fabricated using SFF by manually feeding
the material information along with the geometry data. This is a cumbersome process and leads to
the under-utilization ofthe SFF process. An assessment of existing representations for SFF is presented
in [5] highlighting the need for CAD models which represent material information along
with the geometry data of the object. | null | null | null | null | null | null |
['Baumgardner, Owen', 'Blake, Paul'] | 2018-04-12T17:23:16Z | 2018-04-12T17:23:16Z | 1990 | Mechanical Engineering | doi:10.15781/T2BV7BC3Z | http://hdl.handle.net/2152/64270 | eng | 1990 International Solid Freeform Fabrication Symposium | Open | ['Texas Instruments Incorporated', 'defense systems', 'electronics group', 'SLA'] | Solid Modeling and Stereolithography as a Solid Freeform Fabrication Technique at Texas Instruments Incorporated | Conference paper | https://repositories.lib.utexas.edu//bitstreams/85290cdf-a0db-4891-9a75-afc4d1420b11/download | null | Over the past 25 years, the CAE/CAD/CAM industry has developed technological advances that
have provided industrial users the ability to increase productivity and decrease the cycle time necessary
for product development. These technologies include basic wireframe and surface design, specializedapplication
software packages, finite element analysis, numerical control, solid modeling, and rapid
prototyping.
Each of these technologies plays a significant role in industry today. The Defense Systems & Electronics
Group of Texas Instruments currently uses these technologies in the mechanical design engineering
process. This paper discusses the two specific technologies of solid modeling and rapid prototyping
(specifically stereolithography), including their advantages, benefits, and practical applications within the
Texas Instruments Defense Systems & Electronics Group. This paper also discusses the use of
stereolithography (SLA) rapid~prototype parts within the solid-mold investment~casting process. | null | null | null | null | null | null |
Partanen, Jouni P. | 2018-11-14T19:51:48Z | 2018-11-14T19:51:48Z | 1996 | Mechanical Engineering | doi:10.15781/T2X34NB7Q | http://hdl.handle.net/2152/70259 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['CAD', 'stereolithography', 'protoyping'] | Solid State Lasers for Stereolithography | Conference paper | https://repositories.lib.utexas.edu//bitstreams/aedf9b8a-8fba-47f7-a4dd-ee911546c64e/download | null | Stereolithography is a Rapid Prototyping & Manufacturing (RP&M) technique which is
used to produce 3 dimensional plastic parts directly out computer files generated by CAD.
Stereolithography systems use ultraviolet lasers to solidify liquid resin into the desired form as
defined by the CAD file. In recent years, solid state laser technology has reached the point where
it can be applied to stereolithography (SL). Frequency tripling of the powerful lines of diode
pumped NdlYAG, Nd/YV04, and Nd/YLF lasers results in wavelengths of 355 nm (YAG,
YV04), 351 nm (YLF), and 349 nm (YLF). All these lines are applicable for SL. Commercial
diode pumped lasers with tens or even hundreds milliwatts in the ultraviolet are already
available. Efficient frequency tripling of the Nd/YAG, Nd/YV04 , or Nd/YLF lasers requires
pulsed operation. The pulse repetition rates at maximum average power are typically between 1
and 30 kHz. This talk describes the issues relating to the applications of pulsed all solid state
lasers in SL. | null | null | null | null | null | null |
['DuPont, J.N.', 'Nawrocki, J.G.', 'Griffith, M.L.'] | 2019-10-18T14:39:51Z | 2019-10-18T14:39:51Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76226', 'http://dx.doi.org/10.26153/tsw/3315'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Net Shaping | Solidification Modeling and Microstructural Characterization of Alloy IN718 Deposited by Laser Engineered Net Shaping | Conference paper | https://repositories.lib.utexas.edu//bitstreams/16245963-6821-4260-8f9e-c57e1dcb6285/download | null | Alloy IN718 deposited by the LENS process was characterized using light optical, and
scanning and transmission electron microscopy techniques. The as-solidified microstructure
contained primary γ−austenite cells with intercellular NbC and Laves phases. Underlying layer
microstructures were not altered by the thermal cycles of subsequent passes. Dendrite tip
modeling calculations provided a reasonable estimate of cell core compositions measured
experimentally by analytical electron microscopy techniques and were used to demonstrate that
dendrite tip undercooling was not significant under the deposition conditions employed.
Preliminary guidelines on solidification conditions required to suppress microsegregation during
LENS deposition of IN718 are provided from the modeling results. A solute redistribution model
was employed, which accurately described the solidification reaction sequence and resultant
phases present in the final microstructure. | null | null | null | null | null | null |
['Ramos Grez, Jorge A.', 'Bourell, David L.'] | 2020-02-13T19:05:13Z | 2020-02-13T19:05:13Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/79960', 'http://dx.doi.org/10.26153/tsw/6985'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Solidification Morphology Analysis | Solidification Morphology Analysis of SLM of Cu Powder | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f4850a50-70d3-404a-8a9b-9053c4b3ba8f/download | null | The solidification morphology analysis of fine Cu powder melted by a raster
scanned energy beam from a focused Nd:YAG laser is presented here. The powder was
processed inside of sealed chamber where it was subjected to a high vacuum cycle. The
laser fusion process consisted raster scanning a narrow rectangular pattern with a high
density of scanning lines, the chamber was purged with inert gas during the process. Up
to a 3.3 mm/s laser travel speed and maximum laser power level of 240 W were used to
melt a 2 mm thick bed of loose powder. The resulting solidified ingots were separated
into categories based on their shape integrity. Metallographic analysis by means of
optical microscopy and scanning electron microscopy was performed on the cross section
and longitudinal section of the ingots with homogeneous surface and complete shape
integrity. Characterization revealed an elongated columnar grain structure with a grain
orientation along the direction of the laser travel direction, some degree of porosity was
observed too in some of the specimens. It was observed that grains diameter ranged from
10 to 100 µm and contained a two phase eutectic microstructure of copper and it oxides.
Oxygen content was accounted from a 5.5 up to 8.1 atomic percent, a small percentage of
chlorine was present, too. A 2 to 8 percent variation in the Vickers microhardness values
were found between the different specimens when measured along the longitudinal
section. These HV values corresponded to approximate 20-25% cold rolled oxygen free
copper (80-90 HV). The ingots thus produced suggest that a multilayer structure from Cu
powder could be build by the SLM process having sufficiently adequate compositional,
microstructure and mechanical properties for functional applications. | null | null | null | null | null | null |
['Shimono, Yusuke', 'Oba, Mototeru', 'Nomoto, Sukeharu'] | 2021-11-11T16:50:06Z | 2021-11-11T16:50:06Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90246', 'http://dx.doi.org/10.26153/tsw/17167'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['multi-phase field method', 'thermal analysis', 'soldification', 'microstructure', 'titanium alloys', 'direct energy deposition'] | Solidification Simulation of Direct Energy Deposition Process by Multi-Phase Field Method Coupled with Thermal Analysis | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a72fecc6-07d2-47fc-8b2c-64decd64b75a/download | University of Texas at Austin | The multi-phase field method coupled with the thermodynamics database of calculation of phase diagrams
has been successfully applied to simulation of solidification microstructure evolutions in engineering casting
processes. As multi-phase field method is based on the local (quasi-)equilibrium assumption in solidification
theory [1], applying this method to solidification of additive manufacturing processes is not studied enough
because of extremely large cooling rate and temperature gradient conditions. On the other hand, some researchers
have reported experimental observations of the columnar-to-equiaxed transition in the solidification of the
additive manufacturing processes including the direct energy deposition. They suggest that the local
(quasi-)equilibrium assumption can be applied to solidification of additive manufacturing processes [2]. In this
study, solidification microstructures of titanium alloys in direct energy deposition are calculated by multi-phase
field method. Temperature distributions obtained by thermal analyses using finite element method are adapted to
multi-phase field method. The microstructure evolution of columnar-to-equiaxed transition is confirmed. The
results are summarized in a solidification map for direct energy deposition process conditions. | null | null | null | null | null | null |
['Mtikela*, I.', 'Dolenc, A.'] | 2018-05-03T18:12:33Z | 2018-05-03T18:12:33Z | 1993 | Mechanical Engineering | doi:10.15781/T2GB1Z108 | http://hdl.handle.net/2152/65049 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['CAD systems', '3D Models', 'Rapid Prototyping Techniques', 'RPT'] | Some Efficient Procedures for Correcting Triangulated Models | Conference paper | https://repositories.lib.utexas.edu//bitstreams/70f8b4a6-0971-44a0-8e41-f4c6abdd7de4/download | null | This paper describes methods for handling efficiently a large class of problems encountered when
dealing with 3D models represented by a collection of triangles in STL format. In spite of its drawbacks,
the STL format has become a de facto industrial standard for transferring models to manufacturing
processes generally known as Rapid Prototyping Techniques (RPT) or Solid Freeform Fabrication (SF2).
As the accuracy and size of the workspace of such processes increases, so does the size of the models one
wishes to manufacture. Therefore, the efficiency of application programs is an important consideration.
Previous published work has focused on the problem of eliminating gaps in triangulated models. In
addition to efficiency, this paper descrihes methods for dealing with other problems such as overlapping
triangles and intersecting triangles. The algorithms have been implemented and tested in industry. The
underlying data structures hased on adaptive space subdivision also allow the development of other
efficient tools such as slicing. | null | null | null | null | null | null |
['Fischer, M.', 'Schöppner, V.'] | 2021-10-11T22:52:41Z | 2021-10-11T22:52:41Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88675', 'http://dx.doi.org/10.26153/tsw/15609'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['Fused Deposition Modeling', 'Ultem*9085', 'surface-smoothing', 'high-energy finishing'] | Some Investigations Regarding the Surface Treatment of Ultem*9085 Parts Manufactured with Fused Deposition Modeling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e12b0b1a-3964-49c1-9b97-b6e3b0aad8c6/download | University of Texas at Austin | Fused Deposition Modeling (FDM) parts are typically subject to process-related rough or
wavy surfaces, with stair-stepping effects whenever the parts produced have sloped or rounded
part geometries; however, the level of optical quality frequently required demands that parts
feature a smooth surface. In this paper, the results of a high-energy finishing process, which uses
a disc finishing unit and is designed for parts manufactured with the material Ultem*9085, are
presented. The analysis discusses the surface-smoothing effect of various finishing materials with
varying geometries, as well as the effect of finishing time and speed. Additionally, the efficiency
of the surface treatment has been analyzed specifically at corners, edges and in cavities. | null | null | null | null | null | null |
['Norazman, Farhana', 'Smith, Patrick', 'Hopkinson, Neil'] | 2021-10-28T21:34:04Z | 2021-10-28T21:34:04Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89704 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['spectral irradiance', 'sintering lamps', 'infrared lamps', 'high speed sintering'] | Spectral Analysis of Infrared Lamps for Use in the High Speed Sintering Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/86c4b0a9-b334-468a-8bef-03fe3802f5c5/download | University of Texas at Austin | High Speed Sintering (HSS) is an additive manufacturing (AM) process that utilizes a
combination of inkjet printing and infrared heating to create three dimensional objects from
polymer powder. The interaction between the ink, sintering lamp and powder is pivotal in
promoting the optimum sintering behavior required to ensure the high dimensional accuracy
and strength of parts. This paper investigates the relationship between the spectral irradiance
of sintering lamps and the mechanical properties of high speed sintered parts. Nylon-12 parts
were manufactured using two different infrared lamps. Ultimate tensile strength, Young’s
modulus and elongation at break of the manufactured parts were determined. Densities of parts
were calculated while porosities were measured using micro-computed tomography.
Irradiances of the IR lamps were measured and their spectra analyzed. Results show that the
parts manufactured using the high irradiance lamp had better tensile properties, and lower
density and porosity compared to the low irradiance lamp. | null | null | null | null | null | null |
['Kamilis, D.', 'Lee, S.', 'Desjardins, J.', 'Polydorides, N.'] | 2021-11-16T16:28:00Z | 2021-11-16T16:28:00Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90335', 'http://dx.doi.org/10.26153/tsw/17256'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['discrete tomography', 'spectral X-ray CT', 'non-destructive testing'] | Spectral X-ray CT for Fast NDT Using Discrete Tomography | Conference paper | https://repositories.lib.utexas.edu//bitstreams/50fbbf0c-6ac8-4079-bd4d-5d939b289cb7/download | University of Texas at Austin | We present progress in fast, high-resolution imaging, material classification, and fault detection using
hyperspectral X-ray measurements. Classical X-ray CT approaches rely on data from many projection
angles, resulting in long acquisition and reconstruction times. Additionally, conventional CT cannot
distinguish between materials with similar densities. However, in additive manufacturing, the majority of
materials used are known a priori. This knowledge allows to vastly reduce the data collected and increase
the accuracy of fault detection. In this context, we propose an imaging method for non-destructive testing
of materials based on the combination of spectral X-ray CT and discrete tomography. We explore the
use of spectral X-ray attenuation models and measurements to recover the characteristic functions of
materials in heterogeneous media with piece-wise uniform composition. We show by means of numerical
simulation that using spectral measurements from a small number of angles, our approach can alleviate
the typical deterioration of spatial resolution and the appearance of streaking artifacts. | null | null | null | null | null | null |
['Hauser, C.', 'Sutcliffe, C.', 'Egan, M.', 'Fox, P.'] | 2020-02-20T19:08:28Z | 2020-02-20T19:08:28Z | 2005 | Mechanical Engineering | null | https://hdl.handle.net/2152/80040 | eng | 2005 International Solid Freeform Fabrication Symposium | Open | Spiral growth manufacturing | Spiral Growth Manufacturing (SGM) – A Continuous Additive Manufacturing Technology for Processing Metal Powder by Selective Laser Melting | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4da2dda0-6b58-43b1-b3b3-38b105a88f4e/download | null | Spiral growth manufacturing is a new innovative powder based rapid manufacturing
technique. The innovation exists in the methodology in which powder layers are deposited.
Unlike other pre-placed powder systems, the deposited layers move relative to the location at
which they are processed. This is made possible by a rotating build drum into which powder is
deposited, in spiralled layers, from a stationary hopper. With this configuration powder can be
continuously deposited and levelled and simultaneously processed, eliminating delays in the
build cycle. Stainless steel and cobalt-chrome powder is selectively melted using a 100W flash
lamp pumped Nd:YAG laser. This paper reports on factors affecting build rate and on build
strategies for creating a number of axis-symmetric thin and thick walled cylinders. Experimental
results suggest that build rate for thin walled structures bonded to a substrate will ultimately be
governed by tangential movements of the powder particles when frictional forces are not
sufficient to accelerate the particles along a curved path, provided that enough laser power is
available for melting. Even melt pool balling, which is evident when melting one layer at high
speeds, diminishes in multiple layer builds due to re-melting and infilling. | null | null | null | null | null | null |
['Ghayad, Ibrahim M.', 'Geiss, Erik', 'Crocker, James E.', 'Marcus, Harris L.'] | 2019-10-09T16:36:43Z | 2019-10-09T16:36:43Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76161', 'http://dx.doi.org/10.26153/tsw/3250'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | Ceramics | Spot Joining of Si3N4 and SIC Ceramics using Selective Area Laser Deposition (SALD) Technique | Conference paper | https://repositories.lib.utexas.edu//bitstreams/88df9f10-6f57-4206-bcf3-bdd5abcc2f8b/download | null | null | null | null | null | null | null | null |
['Fussell, P.S.', 'Kirchner, H.O.K.', 'Prinz, F.B.'] | 2018-09-26T20:14:09Z | 2018-09-26T20:14:09Z | 1994 | Mechanical Engineering | doi:10.15781/T2J38M29S | http://hdl.handle.net/2152/68593 | eng | 1994 International Solid Freeform Fabrication Symposium | Open | ['thermal spray deposition', 'stereolithography', 'rapid tooling'] | Sprayed Metal Shells for Tooling: Improving the Mechanical Properties | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1c85d4ff-37d5-4a20-9cf2-4c86ff567be7/download | null | Tbis work describes methods to improve the quality of the metal resulting from thermal spray deposition,
including both the mechanical and metallurgical behavior. The engineering context is the
production of sprayed metal shells suitable for tooling applications. The sprayed metal shells are
mechanically dominated by interparticle interfaces; the particles are largely mechanically interlocked
with very little metallurgical bonding. Based on these observations, improvements are
made to these interfaces, and the measure of the improvement is shown in mechanical tests. | null | null | null | null | null | null |
['Bayazitoglu, Kaya J.', 'Cassoli, Matthew', 'Beaman, Joseph J.', 'Kovar, Desiderio'] | 2024-03-26T21:54:59Z | 2024-03-26T21:54:59Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124428', 'https://doi.org/10.26153/tsw/51036'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['selective laser flash sintering', 'aluminum', 'alumina powder', 'additive manufacturing'] | Spreading and Packing of Alumina Powder Using a Displacement-controlled Roller in SLFS | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0acfcae7-4f12-41e0-b100-45e3c4055da1/download | University of Texas at Austin | Selective laser flash sintering (SLFS) is a powder bed fusion process that enables direct
additive manufacturing of ceramics. Similar to other powder bed fusion processes, the density of
the ceramic powder bed impacts attainable density of the final part. Experiments were conducted
using a spray-dried alumina powder that was spread and then packed using a displacementlimited roller. The spreadability of the powder was visually assessed. The microstructure of the
resulting compacted powder was compared to a traditional method of pressing ceramic powder
into a pellet using a die and hydraulic press. Packed regions were sintered to final density and
compared in a scanning electron microscope to samples hydraulically pressed at known pressure
to evaluate the efficacy of a roller-based packing process. | null | null | null | null | null | null |
['Vaughan, D.M.', 'Nycz, A.', 'Noakes, M.W.', 'Masuo, C.'] | 2021-11-17T23:47:07Z | 2021-11-17T23:47:07Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90359', 'http://dx.doi.org/10.26153/tsw/17280'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['process development', 'process parameters', 'process characteristics', 'stainless steel 410', 'wire-arc deposition'] | SS410 Process Development and Characterization | Conference paper | https://repositories.lib.utexas.edu//bitstreams/396d9bfc-c08b-4eaf-a0cc-27d688a70ee0/download | University of Texas at Austin | Wire-fed stainless-steel additive manufacturing provides the potential for an
alternative to traditional stainless-steel tool making processes. 410 stainless steel
provides the necessary hardness for long term tool use and its corrosion resistances
negates the need for post processing of non-critical faces. 410 has unique
characteristics that require different design and welding parameters from other
materials. This paper will look at the parameters and characteristics to expect when
using wire-arc deposition for 410 stainless steel. Individual weld beads and simple
geometric features were printed using the mBAAM wire-arc system at ORNL to
determine effective wire-arc parameters for SS410. Once parameters were chosen,
additional features were printed to determine the geometric characteristics of printed
SS410 as well as compare the differences between designed geometries and printed
geometries. These results allow for the formulation of smarter design rules when
designing parts for SS410 additive manufacturing. | null | null | null | null | null | null |
['Sojiphan, K.', 'Sriraman, M.R.', 'Babu, S.S.'] | 2021-09-30T15:18:12Z | 2021-09-30T15:18:12Z | 9/23/10 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88262', 'http://dx.doi.org/10.26153/tsw/15203'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['Very High Power Ultrasonic Additive Manufacturing', 'microstructural stability', 'aluminum parts'] | Stability of Microstructure in Al3003 Builds Made by Very High Power Ultrasonic Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/eadb8eaa-58e3-4dc9-8f9d-e0bc50f16d18/download | University of Texas at Austin | Very High Power Ultrasonic Additive Manufacturing (VHP-UAM) system was used to
produce aluminum parts from 150 µm thick Al3003-H18 foils. The build was processed at 36 μm
vibration amplitude, 8 kN normal load, and 35.6 mm/s weld speed at 20 kHz frequency. Almost
100% linear weld density was achieved. A deformation-interaction volume of ~20 μm was
observed below the bonded interface. The microstructural stability including grain boundary
structures, and crystallographic orientations was evaluated after annealing these samples at
343oC for 2 hours and 450oC for 2 hours. After heat treatment, small grains persisted at the
interfaces with sluggish grain growth kinetics. In contrast, normal grain growth kinetics was
observed in the middle of the foils. Possible mechanisms for such phenomena are discussed. | null | null | null | null | null | null |
['Williams, G.T.', "O'Brien, J.F.", 'Mezghani, A.', 'Eachus, M.J.', 'Meisel, N.A.', 'McComb, C.C.'] | 2021-11-18T16:57:18Z | 2021-11-18T16:57:18Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90427', 'http://dx.doi.org/10.26153/tsw/17348'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['mesostructure patterns', 'mesostructure', 'additive manufacturing', 'standardized framework'] | A Standardized Framework for Communicating and Modeling Parametrically Defined Mesostructure Patterns | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bb4b366e-8253-4212-995c-c9e0e699fafe/download | University of Texas at Austin | Intricate mesostructures in additive manufacturing (AM) designs can offer enhanced strength-to-weight performance. However, complex mesostructures can also hinder designers, often
resulting in unpalatably large digital files that are difficult to modify. Similarly, existing methods
for defining and representing complex mesostructures are highly variable, which further increases
the challenge in realizing such structures for AM. To address these gaps, we propose a standardized
framework for designing and representing mesostructured components tailored to AM. Our
method uses a parametric language to describe complex patterns, defined by a combination of
macrostructural, mesostructural, and vector field information. We show how various
mesostructures, ranging from simple rectilinear patterns to complex, vector field-driven cellular
cutouts can be represented using few parameters (unit cell dimensions, orientation, and spacing).
Our proposed framework has the potential to significantly reduce file size, while its extensible
nature enables it to be expanded in the future. | null | null | null | null | null | null |
['Joy, Ranjit', 'Wu, Sung-Heng', 'Tariq, Usman', 'Mahmood, Muhammad Arif', 'Isanaka, Sriram Praneeth', 'Malik, Asad Waqar', 'Liou, Frank'] | 2024-03-26T22:48:05Z | 2024-03-26T22:48:05Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124430', 'https://doi.org/10.26153/tsw/51038'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['secure distributed digital factory', 'additive manufacturing', 'subtractive manufacturing', 'challenges with distributed digital factory', 'scalability and interoperability'] | State-of-the-art Cyber-enabled Physical and Digital Systems Deployed in Distributed Digital Factory Using Additive and Subtractive Manufacturing Systems: Open, Scalable, and Secure Framework | Conference paper | https://repositories.lib.utexas.edu//bitstreams/573f88d1-f450-4a5d-91c5-aacc0571ce0f/download | University of Texas at Austin | A distributed digital factory (DDF) integrates physical and digital systems, leveraging additive
manufacturing (AM) and subtractive manufacturing (SM), to enable the dispersed production of components.
Existing work focuses on digital twins, AM and SM systems, and some security aspects. Nevertheless, a holistic
view of integrating devices with dynamic provisions to invoke digital twins has limited supporting research. This
paper will detail cyber-physical and digital systems deployed in DDFs. The components of cyber systems,
including AM & SM equipment, sensors, communication protocols, and monitoring software, are covered.
Challenges associated with the design and deployment of DDFs, such as security, scalability, and interoperability,
are detailed. The assessment emphasizes an open framework for DDF development, allowing system integration
from vendors & participants across diverse locations and capabilities. The article also examines the significance
of a scalable and secure framework for the implementation of DDFs, which ensures the dependability and
availability of on-demand manufacturing. | null | null | null | null | null | null |
['Mulka, Nicholas', 'Goyal, Tarun', 'Jariwala, Amit', 'Rosen, David'] | 2021-12-07T18:43:16Z | 2021-12-07T18:43:16Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90753', 'http://dx.doi.org/10.26153/tsw/17672'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['top-down stereolithography', 'support structure', 'static liquid', 'support liquid'] | Static Liquid Interface to Reduce Support Structure Necessity in Top-Down Stereolithography | Conference paper | https://repositories.lib.utexas.edu//bitstreams/62bbbf89-12d0-45b3-9820-b99f6120c4c5/download | University of Texas at Austin | Stereolithography (SLA) 3D printing is a vat photopolymerization additive
manufacturing process that utilizes photocurable resin, which requires sacrificial supporting
structures on part overhangs, increasing material waste and post-processing time. This study
details a novel process for conducting top-down SLA 3D printing from a thin resin layer located
above a static immiscible supporting fluid, which reduces or eliminates the need for solid
supports. The support fluid prevents deflection from buoyant and gravitational forces on thin
overhangs from anchored parts due to minute density differences between the supporting fluid
and cured resin, while reducing the volume of resin necessary to print compared to traditional
top-down SLA. Using this process, we have experimentally demonstrated printed geometry with
overhangs of up to 90 degrees. Additionally, necessary material properties of both fluids and
process parameters of the system have been identified for the system’s feasibility and broader
adaptation. | null | null | null | null | null | null |
['Smith, Tyler', 'Copenhaver, Katie', 'Lamm, Meghan', 'Brackett, James', 'Kumar, Vipin', 'Hershey, Christopher', 'Joslin, Chase', 'Lindahl, John', 'Tobin, Jim', 'Rodriguez, Brittany A.', 'Kunc, Vlastimil', 'Hassen, Ahmed'] | 2024-03-26T22:50:23Z | 2024-03-26T22:50:23Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124433', 'https://doi.org/10.26153/tsw/51041'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'nozzle', 'short fiber', 'extrusion'] | Static Mixing Nozzles for Long and Short Fiber Additive Extrusion Processes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c06cb946-b938-45ed-9486-4bccae347ced/download | University of Texas at Austin | Additive manufacturing is conventionally used to create structures by extruding plastic or
metal layer by layer. In the case of polymer processes, fibers are typically added to increase stiffness and
reduce warping during building. The length of the fiber exiting the nozzle can impact the overall
mechanical properties of the structure. Using long fiber pellets can increase the starting length of the
pellets to help increase the average fiber length coming out from the extruder. However, extruded long
fiber materials tend to have low fiber alignment and high porosity leading to poor mechanical properties.
By blending long fiber and short fiber resins using a static mixing nozzle, consolidated beads can be
created to produce more stable and solid structures while adding a fixed amount of long fiber into the
extruded bead to increase mechanical performance. | null | null | null | null | null | null |
['Witt, Gerd', 'Sehrt, Jan T.'] | 2021-09-30T15:39:47Z | 2021-09-30T15:39:47Z | 9/23/10 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88266', 'http://dx.doi.org/10.26153/tsw/15207'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['beam melted parts', 'static strength', 'material properties', 'surface finish'] | Static Strength Analysis of Beam Melted Parts Dependent on Various Elements | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d4dbe516-cb01-4161-a086-006e6447b9d3/download | University of Texas at Austin | For the optimum design and correct use of beam melted parts extensive material
comprehension is necessary. For this reason this paper presents static strength analysis of beam
melted parts dependent on various influences such as manufacturing position and orientation,
exposure strategy and surface quality. It turned out that the anisotropic material properties can be
described by the transversal isotropy (2D) since the azimuth angle displays small dependence
especially in combination with the rotate scan strategy. In contrast to this the polar angle has the
biggest influence at all exposure strategies. Another great influence arises from the surface finish
- the better the surface finish the higher the static strength. The exposure strategies in turn have
the smallest effect on the static strength. | null | null | null | null | null | null |
['Murphy, J.', 'Lappo, K.', 'Wood, K.', 'Beaman, J.'] | 2019-10-30T16:36:44Z | 2019-10-30T16:36:44Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78188', 'http://dx.doi.org/10.26153/tsw/5277'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Surface Finishing | A Statistical Model of Laser Surface Finishing Using Design of Experiments and ANOVA | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1aef07b3-dbdf-47b7-8129-a6f267eca75a/download | null | In previous work, laser polishing indirect-SLS metal parts was achieved using a Nd:YAG
laser raster scanned at high speed. This work showed surface roughness could effectively
be reduced by means of shallow surface melting. Surface area roughness data, Ra, was
obtained by line profilometry measurements of the polished samples according to a
modified procedure based on the ASME standard for surface texture measurements. A
Design of Experiments (DOE) was conducted to better understand the effects of
processing parameters such as laser beam power, scan time, and scan line density on the
surface roughness. The DOE consisted of a multi-level test for each variable and included
one replicate. ANOVA was used to determine the significance of each variable and the
interactions between variables. Three reduced order models were derived, but large
variations in absorptivity in the experiment resulted in large errors and inaccurate models.
The data did show the average reduction in roughness over all the trails was about 20%,
however several trials resulted in roughness reductions of over 50%. Future work will
concentrate on reducing the absorptivity noise to produce more accurate models. | The Laboratory of Freeform Fabrication gratefully acknowledges the support of
the Office of Naval Research for funding the project ìSurface Engineering for SFF
Processesî, Grant Nº: N00014-00-1-0334. | null | null | null | null | null |
['Akande, S.O.', 'Dalgarno, K.W.', 'Munguia, J.', 'Pallari, J.'] | 2021-10-28T21:07:27Z | 2021-10-28T21:07:27Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89701 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['quality control', 'statistical process control', 'lasers', 'sintering', 'polymer', 'impact strength'] | Statistical Process Control Application to Polymer Based SLS process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8f326c7a-ce99-4b44-b653-172270feec82/download | University of Texas at Austin | The quality of selective laser sintering (SLS) made parts is known to be influenced by
process parameters and the quality of input material. In order to ensure consistency in part
quality, there is a need to monitor the quality of parts made using the SLS machines.
Benchmark specimens were designed and manufactured to track key quality characteristics of
strength, bending stiffness, density and dimensional accuracy of parts made in multiple
builds. Using data collected from the benchmark tests, correlation analysis and statistical
process control (SPC) charts were established. SPC was found to be a useful tool that can
provide SLS users with the mean of identifying possible changes in the process. Therefore, it
can be used for process monitoring in SLS process to ensure consistency in part quality for
long term production. | null | null | null | null | null | null |
Gervasi, Vito R. | 2018-11-28T21:30:43Z | 2018-11-28T21:30:43Z | 1997 | Mechanical Engineering | doi:10.15781/T2XG9FX1N | http://hdl.handle.net/2152/70334 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['SFF', 'SPC'] | Statistical Process Control For Solid Freeform Fabrication Processes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8e1db966-0f8b-4a18-a8cf-bffd6f961173/download | null | Statistical prpcess control (SPC) has not been widely used for solid freeform fabrication (SFF) pr~cesses, primarily due to the wide diversity ofgeometries in builds. In addition, typical parts created on SFF platforms are not ofsimple, nor easy-to- measure geometries, which fVrther complicates the application ofSPC. A study is currently in progress to establisq a method to apply SPC to SFF. Three SPC test parts were studied to determine the addedIbuild cost and accuracy improvement when SPC is applied to stereolithography. In this study, SPC was applied to X & Y shrinkage, and line-widthcompensation facto~s over a period oftime. IfSPC can be effectively applied, it will alert the operator to othe~seunnoticed system changes before valuable build-time is lost. | null | null | null | null | null | null |
['Fussell, P.S.', 'Weiss, L.E.'] | 2018-04-10T18:50:30Z | 2018-04-10T18:50:30Z | 1990 | Mechanical Engineering | doi:10.15781/T26970F5X | http://hdl.handle.net/2152/64246 | eng | 1990 International Solid Freeform Fabrication Symposium | Open | ['The Engineering Design Research Center', 'solid free form', 'SFF', 'SLA'] | Steel-Based Sprayed Metal Tooling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bc0618e3-8930-4de2-bec5-c3f1cf7b8ef4/download | null | A strategy for building sprayed steel tooling by arc spray deposition is discussed in this paper. Depositing steel is
crucial for moving sprayed metal toolingfrom prototype applications to superior prototype and production-quality
tooling. Tooling is fabricated by spraying onto S\lbStra~S that define the tooling shell shape. In particular, two
process issues are addressed: deposition of thick metal shells, and control of oxide content by atomization with inert
gases. | null | null | null | null | null | null |
['Himmer, T.', 'Nakagawa, T.', 'Noguchi, H.'] | 2018-12-05T17:34:04Z | 2018-12-05T17:34:04Z | 1997 | Mechanical Engineering | doi:10.15781/T2JM2424G | http://hdl.handle.net/2152/71402 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['Ceramics', 'superconductivity'] | Sterelithography of Ceramics | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a29ce521-740e-4546-b12a-cc413e5d1fa3/download | null | For studies of Stereolithography of Ceramics (SOC), a composite has been produced by
mixing ceramic powder with a photosensitive resin. To obtain high load of ceramics a
lamination preprocess was used. Then, the produced ceramic-binder films have been laminated
and selectively cured in a Stereolithography machine. After cleaning, the green bodies were
fired to burn out the binder and afterwards sintered to achieve full strength. | null | null | null | null | null | null |
['Liu, Renwei', 'Wang, Zhiyuan', 'Sparks, Todd', 'Liou, Frank'] | 2021-10-19T15:31:35Z | 2021-10-19T15:31:35Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89301 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['stereo vision', 'component repair process', 'titanium parts', 'Ti-6Al-4V', 'hybrid manufacturing'] | Stereo Vision Based Hybrid Manufacturing of Ti-6Al-4V in Component Repair Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8c78af47-8371-4118-b881-4c19635233fe/download | University of Texas at Austin | Parts or products from high performance metal are very expensive, partly due to the
processing complexities during manufacturing. Recent studies have indicated that hybrid
processes of additive manufacturing and machining process can be used to repair titanium parts,
thus extending the service life. In order to implement these methods automatically, it is necessary
to obtain the spatial geometry information of component with defects to generate the tool path.
The purpose of this paper is to summarize the research on hybrid manufacturing with stereo
vision function which can be applied to the component repair process. Stereo vision is adopted to
detect the location and the size of the defect area which is marked by color marker. And then
laser displacement sensor is applied to scan the defect area. Therefore, automated alignment,
reconstruction of the defect area and tool path planning could be implemented based on the
spatial geometry information. Finally, a Ti64 part repair experiment is done to verify the method.
This work provides an automatic method for repairing damaged parts by hybrid manufacturing. | null | null | null | null | null | null |
['Jayanthi, Suresh', 'Bokuf, Bronson', 'McConnel, Ronald', 'Speer, Robert J.', 'Fussell, Paul S.'] | 2018-11-30T16:14:09Z | 2018-11-30T16:14:09Z | 1997 | Mechanical Engineering | doi:10.15781/T2QF8K479 | http://hdl.handle.net/2152/70595 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['Stereolithography', 'rapid prototyping'] | Stereolithographic Injection Molds for Direct Tooling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f2dc9932-8ebb-4286-8cbf-a28302b2b1a2/download | null | The use of stereolithographic core and cavity sets in low volume injection molding is
experiencing steady growth. The use of plastic instead of metal molds raises several issues in
terms ofmold handling, material injection and process cycle requirements. This study focuses on
identifying and understanding these issues and optimizing them for low volume direct tooling
applications. Some experimental observations are presented using DuPont Somos® epoxy
photopolymers and representative mold geometries which identify the critical mold properties
that influence mold life and the injection molded part quality. | null | null | null | null | null | null |
['Pang, Dr. Thomas H.', 'Jacobs, Dr. Paul F.'] | 2018-05-03T18:29:06Z | 2018-05-03T18:29:06Z | 1993 | Mechanical Engineering | doi:10.15781/T2TM72J2B | http://hdl.handle.net/2152/65054 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['stereolithography', 'SL', 'RMS'] | StereoLithography 1993: QuickCast TM | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d18b28f9-bdba-4975-9ebd-609c533f72ae/download | null | Previously, StereoLithography (SL) generated solid patterns had limited success highly
accurate shell investment casting applications. The majority of the failures involved the cracking of
the ceramic investment casting shell. However, the recent invention of the QuickCast TM build-style
and the development of a new epoxy resin, XB 5170, led to an unprecedented level of success
the burnout process of SL patterns from investment casting shells. Unlike conventional
building techniques, QuickCast involves the building of SL patterns with essentially hollow
structures. When the low viscosity liquid epoxy resin is drained from the interior of the pattern,
voids are formed, allowing the cured resin to collapse inwards during the autoclave and burn-out
stages. This effectively prevents the shells from cracking as the result of outward thermal
expansion. 3D Systems formed QuickCast teams with three respected foundries to test shell
investment casting using SL patterns. A test part having relatively complex geometries a
Boeing 737 cargo door bracket) was selected. To date, this SL part has been successfully cast
aluminum, titanium, beryllium-copper, and stainless steel, with RMS surface finish as low as 1
micrometer, without any subsequent finishing operations. | null | null | null | null | null | null |
['Tang, Yanyan', 'Henderson, Clifford L.', 'Muzzy, John', 'Rosen, David W.'] | 2020-02-17T14:49:39Z | 2020-02-17T14:49:39Z | 9/1/04 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80001', 'http://dx.doi.org/10.26153/tsw/7026'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | complex stereolithography | Stereolithography Cure Process Modeling Using Acrylate Resin | Conference paper | https://repositories.lib.utexas.edu//bitstreams/163929cb-80e4-4039-9073-660d74e90737/download | null | In this paper, a complex stereolithography (SL) cure process model is presented that
incorporates transient thermal and chemical effects which influence final part shape and
properties. The model incorporates photopolymerization, mass diffusion, and heat transfer.
Material properties are characterized and a comprehensive kinetic model parameterized for a
model compound system. SL process simulations are performed using finite element methods
with the software package FEMLAB, and validated by the capability of predicting the fabricated
part dimensions. A degree of cure (DOC) threshold model is proposed which can predict the cure
line size within 15% error, comparing with 30% prediction error by the exposure threshold
model currently used in SL. Furthermore, through the sensitivity analysis conducted by the
process model presented here, the sensitive parameters are identified and the SL bath
temperature, photointiator absorptivity and concentration are found to be the most sensitive
factors that affect the SL fabrication results. The sensitive variables will be the focus of further
research meant to improve SL process speed and resolution. | null | null | null | null | null | null |
Pang, Thomas H. | 2018-05-03T16:25:07Z | 2018-05-03T16:25:07Z | 1993 | Mechanical Engineering | doi:10.15781/T2J960T1N | http://hdl.handle.net/2152/65033 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['stereolithography', 'SL', 'QuickCast', 'SLA', '3D systems'] | Stereolithography Epoxy Resin Development: Accuracy and Dimensional Stability | Conference paper | https://repositories.lib.utexas.edu//bitstreams/afff9dbe-e6c0-46dd-a437-fa9ccde78f6b/download | null | null | null | null | null | null | null | null |
Pang, Thomas H. | 2018-10-03T15:34:02Z | 2018-10-03T15:34:02Z | 1994 | Mechanical Engineering | doi:10.15781/T2S75745M | http://hdl.handle.net/2152/68648 | eng | 1994 International Solid Freeform Fabrication Symposium | Open | ['Stereolithography', '3D Systems', 'Dimensional stability'] | Stereolithography Epoxy Resins SL 5170 and SL 5180: Accuracy, Dimensional Stability, and Mechanical Properties | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a2d91019-aac3-4378-8bc0-05692cb21ef0/download | null | Stereolithography (SL) resins based on epoxy chemistry provide significantly improved overall
part accuracy, dimensional stability, and mechanical properties relative to the earlier acrylate SL resins.
In July, 1993, epoxy-based SL 5170 resin was introduced for use on the SLA-250 system. In March,
1994, the epoxy-based resin for the SLA-500 system, SL 5180, was also released. These epoxy resins
have minima11aser-cure and post-cure shrinkage, resulting in extremely low curl and distortion. Overall
dimensional accuracy has also improved. Standard User-Parts built in SL 5170 on the SLA-250, and
now, SL 5180 on the SLA-500, have recently achieved the highest level of dimensional accuracy from a
statistically significant number of measurements taken in the x, y, and z directions. Diagnostic test results
presented in this paper show that these epoxy-based resins are now capable of producing extremely flat
parts when required. SL parts built in these resins also exhibit superb dimensional stability in the lasercured
state, as demonstrated by the "Green" Creep Distortion diagnostic test. Dimensional stability in the
laser-cured state is critical, especially for SL parts having the characteristic quasi-hollow internal
structure, generated using the QuickCast™ build style. Creep results are presented in this paper.
Furthermore, the overall mechanical properties of these epoxy resins were measured according to the
ASTM standards for plastics. Tensile, flexural, and impact properties for the epoxy-based and acrylatebased
SL resins are presented in this paper. Mechanical properties ofthermoplastics, acrylic plastic
(PMMA) and medium impact polystyrene, are also presented for comparison. The data shows that the
mechanical properties of epoxy-based SL 5170 and SL 5180 are comparable to, or exceed those of acrylic
plastic and medium impact polystyrene.
For applications that require greater mechanical strengths than SL 5170 and SL 5180, metal
parts can be obtained using QuickCast. QuickCast, made possible with the development of these epoxybased
SL resins, is the key to successfully utilizing SL parts for shell investment casting applications, and
the generation of precision metal components directly from SL parts. Furthermore, when a "negative"
core and cavity pair of a part geometry is produced in metal using QuickCast, tooling is obtained.
Prototype, and eventually, production functional parts may then be ultimately injection molded in the
QuickCast tooling, using the desired engineering thermoplastic material. | null | null | null | null | null | null |
['Rahmati, Sadegh', 'Dickens, Philip'] | 2018-11-30T16:37:59Z | 2018-11-30T16:37:59Z | 1997 | Mechanical Engineering | doi:10.15781/T2FX74J2V | http://hdl.handle.net/2152/70597 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['SL', 'engineering environment'] | Stereolithography Injection Mould Tool Failure Analysis | Conference paper | https://repositories.lib.utexas.edu//bitstreams/25173bc8-39cd-4926-9797-23e7a9a157d9/download | null | Manufacturing technology does not always enjoy the traditional cost benefits of mass
production because large quantities may not be required. Separating low cost from
high volume requires new approaches to product and process design and technology.
Stereolithography tooling supports this concept by providing tools quickly during the
design process to prove out and select optimal new concepts. The SL tooling
technique is a first step in realising the near-term objectives such as conceptual
modelling and design verification, as well as the long-term objectives in production.
At the University ofNottingham development ofthe SL injection moulding tools has
taken place along two fronts. The first to provide material data for tool design under
extreme conditions of stress and temperature; and obtaining data from different tests
carried out on simple tools which resemble real situations (Rahmati 1997). The
second development is theoretical and analytical analysis of the simple tools during
the injection process. Both ofthe above developments have ultimately been directed
towards achieving the goal of successful SL injection mould tooling. The results of
such developments may help the industry to reduce the lead time and provide a faster
technique in a concurrent engineering environment.
The first experimental resuhs proved the capabilities of the technique and
demonstrated its advantages and weaknesses. In addition, the important parameters in
SL injection moulding such as injection pressure, injection speed, injection
temperature, freeze time, cycle time etc. were investigated. The results and
derivations may be used either as an instruction guide for industry users to design SL
injection tools, or to provide design information for particular conditions and to
predict tool failure. | null | null | null | null | null | null |
['Jackson, Ian', 'Xiao, Huinian', 'Ashtiani, Mansour', 'Berben, Luc'] | 2018-11-08T19:06:48Z | 2018-11-08T19:06:48Z | 1996 | Mechanical Engineering | doi:10.15781/T2959CT3R | http://hdl.handle.net/2152/69903 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['stereolithography', 'structures', 'model fabrication'] | Stereolithography Model in Presurgical Planning of Craniofacial Surgery | Conference paper | https://repositories.lib.utexas.edu//bitstreams/320c0488-6121-41d4-998a-ad8c694fc852/download | null | A rapid prototyping technique, which was originally used in mechanical engineering, has
found applications in medicine. Recently stereolithographic models have been used in
complex craniofacial surgeries for visualization, presurgical planning and implant design[ 1-
4]. There are some advantages ofmodel fabrication when preparing for surgery: more
accurate evaluation ofthe patient's condition/deformities, better informed consent for
surgery and better-fitting artificial body parts. This paper is a case report in which a
sterelithographic skull model was used in the presurgical planning of a complex
craniofacial tumor resection | null | null | null | null | null | null |
['Srisawadi, S.', 'Lapapong, S.', 'Dokkhan, S.', 'Wiroonpochit, P.'] | 2021-11-18T01:53:48Z | 2021-11-18T01:53:48Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90402', 'http://dx.doi.org/10.26153/tsw/17323'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['natural rubber latex', 'highly elastic parts', 'stereolithography', 'additive manufacturing'] | Stereolithography of Natural Rubber Latex, a Highly Elastic Material | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6c1f3d97-c8f5-4344-be29-5b4e2cf7b97c/download | University of Texas at Austin | Typically, natural rubber (NR) offers a wide range of applications because of its exceptional
mechanical properties, particularly elasticity. However, due to its unique mechanism of
vulcanization, 3D fabrication techniques with NR is still to be explored. Vulcanization is necessary
to form crosslinks between the NR chains and greatly improve its elasticity and tensile strength.
In this study, the pre-vulcanized NR latex was prepared for the stereolithography (SLA) process
to additively manufacture highly elastic parts. Process parameters were studied to investigate the
feasibility of the fabrication. The parameters include laser power, scan speed, and layer thickness.
This work demonstrates a promising 3D fabrication technique using the NR latex that achieves
mechanical properties and crosslink density comparable to those from the conventional processes. | null | null | null | null | null | null |
['Sager, Benay', 'Rosen, David'] | 2019-10-30T16:34:16Z | 2019-10-30T16:34:16Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78187', 'http://dx.doi.org/10.26153/tsw/5276'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Stererolithography | Stereolithography Process Resolution | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a2b70211-7d88-4d5a-8e57-ab99c6d5183f/download | null | To build smaller parts in StereoLithography (SL) and detect some build errors before
fabrication, a good understanding of process resolution is needed. A categorization of resolution
factors into process-inherent and software-induced categories is presented in the paper. Results
from several experiments testing different aspects of SL resolution illustrate the effects of these
factors. A method based on offsetting algorithms is presented to determine as-built part crosssections and aid detection of possible build errors. A method that will enhance build resolution
of SL parts is proposed. | null | null | null | null | null | null |
['Marutani, Yoji', 'Kamitani, Takayuki'] | 2018-11-14T17:48:49Z | 2018-11-14T17:48:49Z | 1996 | Mechanical Engineering | doi:10.15781/T2QJ78H94 | http://hdl.handle.net/2152/70250 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['Rapid prototyping', 'LOM', 'UV laser'] | Stereolithography System Using Multiple Spot Exposure | Conference paper | https://repositories.lib.utexas.edu//bitstreams/56ee007a-5c32-44a9-b756-ef9714557382/download | null | A new method ofmaking 3-D objects is proposed. A discharge lamp is used as a UV
light source, and to make the fabrication time shorter, multiple spots exposure using optical
fibers is employed. The light is distributed to some optical fibers. The output side of each fiber
is arrayed linearly and the emitted lights are focused on the surface ofthe photosensitive resin.
As the fiber array is raster-scanned, the light transmission of each fiber is controlled by the
optical shutter independently according to the pixel data at the corresponding position to be
irradiated. Small-sized stereo-lithography systems can be realized economically by this
method. | null | null | null | null | null | null |
['Catalanotto, A.M.', 'Ware, L.G.', 'Chagolla, J.A.', 'Suzuki, D.H.', 'Cordero, Z.C.'] | 2021-11-09T16:31:05Z | 2021-11-09T16:31:05Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90106', 'http://dx.doi.org/10.26153/tsw/17027'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['directionally solidified castings', 'shell molds', 'positives', '3D printing', 'stereolithography'] | Stereolithography-Based Manufacturing of Molds for Directionally Solidified Castings | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f67630f3-0446-44b1-b501-83ddd2e3c10e/download | University of Texas at Austin | Directionally solidified components, such as single crystal turbine blades, are
typically grown using shell molds prepared using a lost wax process that begins with injection-molded wax positives. These positives have complex designs, are manufactured in low volumes,
and are made using expensive tooling. Here we investigate the potential of replacing these
injection-molded positives with plastic patterns created using stereolithography. By using 3D
printing instead of injection molding to create the positives, we can dramatically reduce tooling
costs and leverage the freedom of design offered by 3D printing to create more intricate turbine
blade designs. While using 3D printed positives to create molds for shape castings was one of the
earliest examples of rapid prototyping of metallic components, the present work highlights the
potential of extending this approach to molds used for growing single crystal parts. | null | null | null | null | null | null |
['Palmer, J. A.', 'Davis, D. W.', 'Gallegos, P. L.', 'Yang, P.', 'Chavez, B. D.', 'Medina, F. R.', 'Wicker, R. B.'] | 2020-02-24T15:37:09Z | 2020-02-24T15:37:09Z | 8/3/05 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80084', 'http://dx.doi.org/10.26153/tsw/7105'] | eng | 2005 International Solid Freeform Fabrication Symposium | Open | stereolithography | Stereolithography: A Basis for Integrated Meso Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c32b5325-929d-49a0-a40f-ed6a99036a7b/download | null | null | null | null | null | null | null | null |
['Bzymek, Zbigniew M', 'Theis, Scott', 'Manzur, Tariq', 'Roychaudhuri, Chandra', 'Sun, Lianchao', 'L. Shaw, Leon'] | 2019-02-20T17:47:25Z | 2019-02-20T17:47:25Z | 1998 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/73458', 'http://dx.doi.org/10.26153/tsw/610'] | eng | 1998 International Solid Freeform Fabrication Symposium | Open | ['SFF', 'CAD'] | Stereometric Design for Desk-Top SFF Fabrication | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1deafcfc-b2a3-427e-8f2f-a5dcb92ce88e/download | null | Solid Freeform Fabrication (SFF) technologies refer to the fabrication of physical parts directly from
computer based solid models described by STL (Stereo Lithography) or VRML (Virtual Reality Modeling
Language) files generated by Computer-Aided Design (CAD) systems. Most of the SFF processes produce parts
by building them layer by layer using a row by row pattern, though it is possible to build the part using other
patterns. The SFF technology represents a challenge to designers who, in addition to making decisions
concerning optimum shape and functionality of the entire part, have'to take under consideration several other
manufacturing factors. These factors cover a wide range of technical issues such as Computer-Aided Design
model generation, part description and model slicing files, laser path files, precision of part design, rendering
patterns, manufacturing tolerances, thermal expansion and residual stress phenomena.
This paper investigates the effect of rendering patterns on the integrity, material characteristics and
mechanical properties of the parts prepared by a desk-top SFF device using diode lasers. Fe - Bronze (Cu - Sn)
premixed metal powders were used as the starting material. The particle size was about 100 /lm to 200 /lm.
Density, tensile strength and microstructure of the parts prepared using different rendering patterns were
characterized. The results were analyzed to seek optimal rendering patterns. It was noticed that the samples
were strong along the laser scanning direction, while they were weak perpendicular to the scanning direction.
These results suggest that the laser scanning patterns should be designed to minimize the warping and maximize
the strength of the part in the direction depending on the part's function. | null | null | null | null | null | null |
['Allanic, A.L.', 'Medard, C.', 'Schaeffer, P.'] | 2018-04-19T18:27:36Z | 2018-04-19T18:27:36Z | 1992 | Mechanical Engineering | doi:10.15781/T27D2QQ9K | http://hdl.handle.net/2152/64407 | eng | 1992 International Solid Freeform Fabrication Symposium | Open | ['Laser 3D', 'SPL', 'SS', 'SPL machines', 'CAD designs'] | Stereophotolithography: A Brand New Machinery | Conference paper | https://repositories.lib.utexas.edu//bitstreams/210593b2-96ad-4f37-872a-869486e10ee2/download | null | null | null | null | null | null | null | null |
['Perez, Mireya', 'Block, Michael', 'Espalin, David', 'Winker, Rob', 'Hoppe, Terry', 'Medina, Francisco', 'Wicker, Ryan'] | 2021-10-05T19:07:15Z | 2021-10-05T19:07:15Z | 8/15/12 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88411', 'http://dx.doi.org/10.26153/tsw/15350'] | eng | 2012 International Solid Freeform Fabrication Symposium | Open | ['Fused Deposition Modeling', 'medical devices', 'medical sterilization'] | Sterilization of FDM-Manufactured Parts | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0962f07d-a261-4a4e-96a3-c16d74916845/download | University of Texas at Austin | Fused Deposition Modeling (FDM) can be used to produce an array of medical devices;
however, for such devices to be practical, they must be manufactured using sterilizable materials.
Nine FDM materials were tested using four methods of sterilization: autoclave, ethylene oxide,
hydrogen peroxide, and gamma radiation. Sterility testing was performed by incubating the
samples in Tryptic Soy Broth for 14 days. The majority of the materials were sterilizable by all
four methods while deformations were caused by autoclaving. Results from this research will
allow medical staff to sterilize an FDM-manufactured device using a suitable method. | null | null | null | null | null | null |
['Hiller, Jonathan D.', 'Lipson, Hod'] | 2021-09-28T19:40:22Z | 2021-09-28T19:40:22Z | 9/15/09 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88165', 'http://dx.doi.org/10.26153/tsw/15106'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['additive fabrication technology', 'Additive Manufacturing File', 'STL 2.0', 'STL file format'] | STL 2.0: A Proposal for a Universal Multi-Material Additive Manufacturing File Format | Conference paper | https://repositories.lib.utexas.edu//bitstreams/157ede43-8378-4453-8b8f-ed031d6dbfd1/download | University of Texas at Austin | The de-facto standard STL file format has served the rapid prototyping
community for over two decades, but falls short with the advent of new
technological developments such as the ability to handle multiple and graded
materials, specify volumetric digital inkjet patterns and surface colors. We study a
variety of requirements for additive fabrication technologies and propose a new
compact XML-based file format. The new Additive Manufacturing File (AMF)
format allows the resolution-independent specification of geometry and material
properties. Regions may be defined geometrically either using a triangle mesh,
using functional representations, or through a voxel bitmap. Each region is
associated with a material, which may be defined as a base (single) material or
hierarchically by a combination of other materials, either functionally (enabling
smooth gradients) or voxel-wise (for arbitrary microstructure). Files can be self-contained or refer to external or online material libraries. With a simple
conversion, the AMF file format is both forward and backwards compatible with
the current standard STL format, and the flexibility of the XML structure enables
additional features to be adopted as needed by CAD programs and future additive
manufacturing processes. Code and examples are publicly available. | null | null | null | null | null | null |
['Qu, Xiuzhi', 'Stucker, Brent E.'] | 2019-10-18T15:09:05Z | 2019-10-18T15:09:05Z | 2001 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76233', 'http://dx.doi.org/10.26153/tsw/3322'] | eng | 2001 International Solid Freeform Fabrication Symposium | Open | STL-based | STL-based Finish Machining of Rapid Manufacturing Parts and Tools | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e48fd4f8-3411-4e26-991a-f60fcc2cccd1/download | null | Accuracy and surface quality problems when utilizing layered manufacturing
technologies have limited its use in tooling areas. Therefore, in some situations a CNC
machine is still necessary for finish machining of rapid manufactured parts and tools.
This paper presents a STL-based CNC machining technique for automating the finishing
of RP tools and parts to obtain CNC accuracies and surface finishes. Preprocess
operations, such as rotate and scale, are used to change the part orientation and
compensate for shrinkage in the whole process. An offset algorithm is developed to add
“skin” to the original STL file to make sure enough material is left for finish machining
after the rapid manufacturing process. The machining strategy of adaptive raster milling
of the surface, plus hole drilling and sharp edge contour machining, is proposed to finish
the RP parts and tools. Corresponding algorithms of adaptive tool path generation for
raster milling, automatic hole recognition and drilling tool path generation, and automatic
sharp edge detection and tool path generation are developed. Finally, a designed
benchmark is machined successfully by using the above mentioned machining strategies
and tool paths generated by developed software. | null | null | null | null | null | null |
['Johnston, Scott', 'Frame, Dustin', 'Storti, Duane', 'Anderson, Rhonda'] | 2020-02-12T15:33:30Z | 2020-02-12T15:33:30Z | 8/4/04 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/79939', 'http://dx.doi.org/10.26153/tsw/6965'] | null | 2004 International Solid Freeform Fabrication Symposium | Open | Strain Analysis | Strain Analysis of Initial Stage Sintering of 316L SS Three Dimensionally Printed (3DP TM) Components | Conference paper | https://repositories.lib.utexas.edu//bitstreams/9a85480f-0f75-4db2-a642-26b7ec1ab694/download | null | null | null | null | null | null | null | null |
['Charan, B.', 'Bagchi, A.', 'Ogale, A.A.', 'Renault, T.'] | 2018-05-03T19:45:16Z | 2018-05-03T19:45:16Z | 1993 | Mechanical Engineering | doi:10.15781/T2WD3QJ7N | http://hdl.handle.net/2152/65069 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['SLA', 'ADPU', 'SFF techniques', 'CAD', '3D CAD systems'] | Strategy for Composite Development in Rapid Prototyping | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e1b21618-cf87-4a87-acf5-c0e9160c9b22/download | null | The polymeric parts built with a stereolithography apparatus (SIA) have good dimensional
accuracy, but they cannot be used as functional prototypes because of their low mechanical
properties. This paper describes the concept of fabricating fiber composites by 3-D
photolithography. In this process, the strength and stiffness of parts are improved over
stereolithography by adding fiber reinforcement to the resin. An automated desktop
photolithography unit (ADPU) was designed and built in-house, to add continuous E-glass or
quartzfibers in situ to the photoresin. Thefirst composite parts made by 3-Dphotolithography are
presentedin this paper, thefeasibility ofcurvilinearaddition offibers is demonstrated, andstrategies
for selective reinforcement are discussed. | null | null | null | null | null | null |
['Amine, Tarak A.', 'Sparks, Todd E.', 'Liou, Frank'] | 2021-10-04T21:11:39Z | 2021-10-04T21:11:39Z | 8/17/11 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88347', 'http://dx.doi.org/10.26153/tsw/15286'] | eng | 2011 International Solid Freeform Fabrication Symposium | Open | ['rapid prototyping', 'laser deposition', 'milling process'] | A Strategy for Fabrication Complex Structures via a Hybrid Manufacturing Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/286e17eb-502d-4a5c-a52e-123545ca372a/download | University of Texas at Austin | The purpose of this paper is to introduce a strategy for fabricating complex structures via
a hybrid manufacturing process. The Laser Aided Manufacturing Process (LAMP) lab at
Missouri S&T has developed a hybrid process combining both a direct metal deposition process
and a five-axis CNC milling. Accessibility is a difficulty when finish machining internal
features. The concept is to pause the deposition process to finish machine an internal feature
while it is still visible is one possible solution to this issue. However, this must be done in a
manner that will not be spoiled when the deposition process continues. This paper discusses
processing strategy, tool selection, and experimental validation of a technique to build complex
structures via mid-process machining with an undercutting mill. | null | null | null | null | null | null |
['Tran, Hong-Chuong', 'Lo, Yu-Lung', 'Le, Trong-Nhan'] | 2021-11-18T17:43:09Z | 2021-11-18T17:43:09Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90443', 'http://dx.doi.org/10.26153/tsw/17364'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'selective laser melting', 'surrogate model'] | A Strategy to Determine the Optimal Parameters for Producing High Density Part in Selective Laser Melting Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6ab9290f-40df-4625-88f5-00534286940a/download | University of Texas at Austin | Finding the processing conditions which can produce high density components using Selective Laser
Melting (SLM) technique based on trial-and-error is costly and time consuming. With a given SLM machine
characteristics (e.g., laser power, scanning speed, laser spot size and laser type), powder material and powder
size distribution, the present study proposes an approach to reduce the time and cost in searching optimal
parameters for fabricating fully dense parts. The proposed method include several simulation models which are
powder bed simulation, Monte Carlo ray tracing simulation, Finite Element Heat Transfer simulation and
surrogate modeling. These simulation models are employed to find the viable processing parameters to produce
high density component. The experimental results show that the proposed methods results in a maximum
component density of 99.97%, an average component density of 99.89% and a maximum standard deviation of
0.03%. | null | null | null | null | null | null |
['Kolter, M.', 'Schleifenbaum, J.H.'] | 2024-03-27T16:07:00Z | 2024-03-27T16:07:00Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124501', 'https://doi.org/10.26153/tsw/51109'] | en | 2023 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'powder bed fusion', 'PBF-LB\\M', 'streaming'] | Streaming in Additive Manufacturing: Analyzing the Impact on the Powder Bed Fusion of Metals Process Chain | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1d3fff8f-3928-48eb-9b15-8edd73b133c3/download | University of Texas at Austin | Streaming is a popular concept in the music and movie industry and has helped solve problems related to
file distribution, storage capacity and intellectual property protection. In recent years, streaming has also become
a research topic for the manufacturing sector, e.g., to collect data for predictive maintenance, advanced machine
control concepts, or over-the-air updates. After initial studies have investigated the feasibility of streaming for
additive manufacturing technologies, the question how streaming will affect the process chain remains open. In
the music and movie industries, new business models and customer experiences have been created, leading to
billion-dollar businesses and the creation of companies such as Netflix and Spotify. By drawing parallels from
music and media to the AM industry this paper gives an overview of potential innovations fostered by streaming
in the domain of Additive Manufacturing (AM) such as file distribution and novel process control possibilities.
Furthermore, the impact of these innovations on the process chain is discussed by the example of Powder Bed
Fusion of Metals with Laser Beam (PBF-LB/M). | null | null | null | null | null | null |
['Wise, Sean', 'Bobbio, Lourdes', 'Russo, Analisa', 'Simpson, Timothy', 'Beese, Allison M.'] | 2023-02-17T14:51:12Z | 2023-02-17T14:51:12Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117487', 'http://dx.doi.org/10.26153/tsw/44368'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | ['Structural Electroplating', 'Metal-Clad Composites', 'Electroplated AM Plastic', 'Topology Optimized Design'] | Strength Comparison of Topology Optimized Lattice from Printed SLA Resin, Electroplated Resin and PBF Aluminum Alloy | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1a241942-5b58-4ebc-8a33-7b6828e2c383/download | null | Given the high cost of metal components made with powder bed fusion (PBF), we
compare the strength of two electroplated resin components against monolithic stereolithography
(SLA) polymer and BPF aluminum alloy copies of the same geometry. Using Rule of Mixtures
(ROM) analysis, validated by ASTM tensile strength measurements, two coating sequences were
designed to provide electroplated samples with half the tensile strength and approximately equal
tensile strength to PBF AlSi10Mg, respectively. All four sets were subjected to 3-point bending.
The monolithic materials had higher proportionate maximum load with respect to tensile
strength; however, the electroplated polymer parts displayed enhanced bending response relative
to their designed tensile strength. The plated resin part with weaker coating bore 85% of the load
of the PBF AlSi10Mg part while the parts with a stronger coating bore almost twice the load of
the PBF AlSi10Mg part in a 3-point bend configuration. The enhanced performance may be due
to the surface reinforcement from the high strength coating, which better resists bending and
buckling in this type of design. | null | null | null | null | null | null |
['Koju, Naresh', 'Yang, Li'] | 2024-03-27T15:58:33Z | 2024-03-27T15:58:33Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124495', 'https://doi.org/10.26153/tsw/51103'] | en | 2023 International Solid Freeform Fabrication Symposium | Open | ['lattice structure', 'strength enhancement', 'analytical model', 'failure propagation/pattern'] | Strength Enhancement of cellular structures through selective reinforcement of elements based on analytical modeling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ae88c071-eb39-4165-8a3c-ac4c14ca870c/download | University of Texas at Austin | This work investigates the strength enhancement of 2D cellular structures via individual element
thickness optimization based on the analytical model for critical elements. To focus on the
investigation of the enhancement method, a rather simplified perfectly elastic material property
was assumed, and an analytical model was utilized to identify the critical element of several
cellular structure designs. Stepwise element thickness enhancement was utilized to investigate the
effectiveness of overall strength enhancement. The results indicate that the strength of cellular
structures can be improved by selectively reinforcing critical elements. In addition, the enhanced
cellular structures also exhibit altered fracture failure characteristics that could potentially be
exploited for more application objectives. | null | null | null | null | null | null |
['Stewart, T D', 'Dalgarno, K W', 'Childs, T H C', 'Perkins, J'] | 2019-02-26T16:31:24Z | 2019-02-26T16:31:24Z | 1998 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/73482', 'http://dx.doi.org/10.26153/tsw/632'] | eng | 1998 International Solid Freeform Fabrication Symposium | Open | ['DTM', 'Rapid prototyping'] | Strength of the DTM RapidSteel 1.0 Material | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d141adff-67a6-436a-9c2f-609cf3cd3286/download | null | This paper reports the results of a study into the strength of the DTM RapidSteel 1.0 material.
Elastic modulus and strength of the metal/copper composite material was investigated as a
function of the distance from the point of copper infiltration, the furnace cycle duration, and the
furnace type. The microstructure of the RapidSteel material was also examined in an attempt to
understand the science behind the infiltration process. The results have implications for the
design of tools to be made using the RapidTool process in situations where the tool will be used
as a production tool, rather than a prototype tool. | null | null | null | null | null | null |
['Yerazunis, William S.', 'Barnwell, John C. III', 'Nikovski, Daniel N.'] | 2021-10-28T19:09:19Z | 2021-10-28T19:09:19Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89671 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['fused-filament fabrication', '5-axis additive manufacturing', 'stress tensor', 'aligned deposition paths', 'ABS', 'nylon', 'polyester', '3D printing'] | Strengthening ABS, Nylon, and Polyester 3D Printed Parts by Stress Tensor Aligned Deposition Paths and Five-Axis Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/13b5ddde-c504-44d9-984a-1291c96ac902/download | University of Texas at Austin | null | null | This paper discusses the design, build, and testing a 5-axis FFF manufacturing system that accepts a CAD model, performs a finite-element model of the part as stresses in use, and for a subset of possible parts, aligns laydown paths in five dimensions (XYZ, tip, and tilt) with the in-use stress tensor; the aligned paths are then converted to 5-axis G-code and printed on our 5-axis additive manufacturing (5AAM) printer. | null | null | null | null |
['Ghayoor, Milad', 'Mirzababaei, Saereh', 'Lee, Kijoon', 'He, Yujuan', 'Chang, Chih-hung', 'Paul, Brian K.', 'Pasebani, Somayeh'] | 2021-11-18T02:17:49Z | 2021-11-18T02:17:49Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90411', 'http://dx.doi.org/10.26153/tsw/17332'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['selective laser melting', 'nanocomposite', 'oxide dispersion strengthened alloy', '304L stainless steel'] | Strengthening of 304L Stainless Steel by Addition of Yttrium Oxide and Grain Refinement during Selective Laser Melting | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4670adb7-bee4-41a5-bff3-663cadc586ef/download | University of Texas at Austin | This study investigates the role of submicron yttrium oxide on the microstructural evolution
and mechanical properties of selective laser melted 304L oxide dispersion strengthening (ODS)
nanocomposite. 304L SS powder and a mixture of 304L SS powder and yttria nanoparticles were
used as two feedstocks for fabricating parts using selective laser melting (SLM) process. Scanning
electron microscopy and energy-dispersive X-ray spectroscopy revealed a homogenous
distribution of Si-Mn-O nanoparticles in the SLM 304L matrix and Y-Si-O nanoparticles in the
SLM 304L ODS alloy. Electron backscatter diffraction images imply that the addition of yttria
disrupts the formation of large columnar grains in SLM 304L, resulting in the formation of finer
equiaxed grains. The average microhardness values increased from 240 HV in SLM 304L to 305
HV in SLM 304L ODS alloy, due to the combined effects of grain refinement and dispersion
hardening. | null | null | null | null | null | null |
['Katz, A.', 'Nussbaum, J.', 'Crane, N.B.', 'Lusk, C.P.'] | 2021-10-13T21:42:17Z | 2021-10-13T21:42:17Z | 2014 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88790', 'http://dx.doi.org/10.26153/tsw/15724'] | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Bernoulli-Euler hypothesis', 'stress-limiting test', 'strength limits', 'test structures', 'additive manufacturing'] | Stress-Limiting Test Structures for Rapid Low-Cost Strength Assessment | Conference paper | https://repositories.lib.utexas.edu//bitstreams/260d39ee-8cf9-41ae-9f99-660c22b5bb69/download | University of Texas at Austin | This project designed and manufactured a planar structure, which under force undergoes a defined
displacement. The structure has a series of thin members which bend around circular cams of
different radii. The Bernoulli-Euler hypothesis states that the moment and hence the stresses are
proportional to the curvature. Thus the varying size of the cams puts varying strains on the
members. The cam which causes the members to fail indicates the strength of the material.
Successfully completing a displacement demonstrates a minimum strain capability of the sample.
A series of test coupons can be used to find the strength limits of the printed components without
requiring expensive testing equipment. The vibration frequency of the test structure also provides
a measure of the part stiffness and can provide a non-destructive measurement of process
consistency. This approach could be a useful process characterization/monitoring method for
additive manufacturing systems. This planar structure was used to investigate variations between
thermal extrusion parts on the same machine and between different machines. | null | null | null | null | null | null |
['Hague, Richard', 'Dickens, Phill'] | 2018-11-02T14:53:38Z | 2018-11-02T14:53:38Z | 1995 | Mechanical Engineering | doi:10.15781/T2DZ03M55 | http://hdl.handle.net/2152/69331 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['stereolithography models', 'Quickcast', 'thermoset plastic material'] | Stresses Created in Ceramic Shells Using Quickcast Models | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a8d23223-5d7a-4b7a-9916-d725b5074306/download | null | Improvements in resins and build styles, coupled with increasing experience, have meant that
ever more metal parts are being produced from stereolithography (SL) models via the investment
casting route. However, despite these advances, it is still not possible for every foundry to directly
use SL models as thermally expendable patterns and gain the same success as achieved with wax
patterns.
The central reason behind the inability to investment cast some SL parts' lies in the expansion
ofthe cured resin. The thermoset plastic material ofthe SL model does not melt during the autoclave
process and its expansion creates stresses in the ceramic wall that cause the relatively weak shell to
crack.
A work programme is in progress at the University ofNottingham to show how, why and
when these stresses are built up and compare them to the stresses created during the conventional
autoclaving ofwax parts. The eventual aim ofthe project is to gain a full understanding ofthe stresses
induced in the models and to develop new build structures that will allow the successful autoclaving
and subsequent casting ofstereolithography models.
Details ofthe work programme are outlined in this paper, along with initial results obtained. | null | null | null | null | null | null |
['Yoo, J.', 'Cima, M.J.', 'Khanuja, S.', 'Sachs, E.M.'] | 2018-05-03T16:35:56Z | 2018-05-03T16:35:56Z | 1993 | Mechanical Engineering | doi:10.15781/T28S4K62P | http://hdl.handle.net/2152/65035 | eng | 1993 International Solid Freeform Fabrication Symposium | Open | ['Departments of Materials Science and Engineering and Mechanical Engineering', 'Three Dimensional Printing', 'CAD representation', '3DP'] | Structural Ceramic Components by 3D Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d04a5e9c-a8ae-4ab4-9262-e7814aed6380/download | null | The Three Dimensional Printing (3DP) Process hasbe~nadapted for processing of fine
ceramic powders to •• prepare structllraLceramic components. Our preliminary study was
designed to reveal those aspects ofthe.3DPprocesswhichmust be modified for use with
fine ceramic powders. The basic elements of the modified process are to spread
submicron alumina powder and printJatex binder. Several methods were used to spread
thin layers of submicron powders. Gre.enparts are isostaticaUypressed followed by
thermal decomposition prior to sintering to remove the polymer. The fired alumina
components are greater than 99.2% dense and have·average flexural strength of324 MPa.
This is lower than the best conventionally prepared alumina, but we believe that the
strength results will improve as we learn more about the relationship between strength
limiting flaws and the 3DP build process. | null | null | null | null | null | null |
['Cima, M.J.', 'Yoo, J.', 'Khanuja, S.', 'Rynerson, M.', 'Nammour, D.', 'Giritlioglu, B.', 'Grau, J.', 'Sachs, E.M.'] | 2018-11-08T16:04:06Z | 2018-11-08T16:04:06Z | 1995 | Mechanical Engineering | doi:10.15781/T2T43JN7J | http://hdl.handle.net/2152/69896 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['3DP', 'initial density', 'defect-free layers'] | Structural Ceramic Components by 3D Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3377273a-bd1e-4a0f-8e7a-bb19d9105288/download | null | Several technical challenges exist in adapting Three Dimensional Printing (3DP) to processing of dense ceramic structures. The sintering rate of particulate bodies depends on the sintering mechanism, average powder size, and initial packing density. Fine powders are necessary to ensure appreciable densification rates from powders which sinter by solid state transport. A critical packing density exists for such powders below which densification does not occur. Special build strategies are, therefore, required for 3DP of ceramic structures. We have successfully demonstrated five approaches to produce dense ceramic components by 3DP. First, spray-dried granules of fine ceramic powders are spread in the existing 3DP equipment and bound using a latex binder through an ink-jet print head. The resulting components are then isostatically pressed to raise the green density to a point that the parts will fully densify when fired. A second approach uses glass powders that sinter by a viscous sintering mechanism. Such bodies sinter to full density at all initial green densities. Spray-dried granules of fine glass powders are spread and bound with latex followed by directly sintering to full density. Both of these approaches produce rather large linear shrinkage because of the low overall packing density. Large glass particles have a much higher packing density and produce bodies that sinter to full density because of the rapid viscous sintering. This third technique produces fully dense parts with linear shrinkage of about 15%. The fourth approach involves glass infiltration of porous ceramic bodies. Our results indicate that this technique can produce dense parts with less than 1% linear shrinkage. Finally, the 3DP process has been modified to permit deposition of fine powders as slurries, rather than dry powders. The resulting process considerably increases the bed density and the resulting fine ceramic parts can be sintered to full density without intermediate isopressing. | null | null | null | null | null | null |
['Agarwala, M.K.', 'Weeren, R. Van', 'Vaidyanathan, R.', 'Bandyopadhyay, A.', 'Carrasquillo, G.', 'Jamalabad, V.', 'Langrana, N.', 'Safari, A.', 'Garofalini, S.H.', 'Danforth, S.C.', 'Burlew, J.', 'Donaldson, R.', 'Whalen, P.', 'Ballard, C.'] | 2018-10-03T19:13:14Z | 2018-10-03T19:13:14Z | 1995 | Mechanical Engineering | doi:10.15781/T2N873J4Q | http://hdl.handle.net/2152/68680 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['Solid free-form fabrication', 'CAD', 'polymer/wax based binder systems'] | Structural Ceramics by Fused Deposition of Ceramics | Conference paper | https://repositories.lib.utexas.edu//bitstreams/617b8fd4-e9c5-495e-a218-afeaa0919ecb/download | null | Fused Deposition of Ceramics (FDC) is a SFF technique, based on FDMTM technology, for
fabrication of advanced structural ceramics from powderlbinder filaments. In this study, in-situ
reinforced (ISR) Si3N4 powder and polymer/wax based binder systems were used as filament
material for FDC processing using a commercially available FDMTM system, 3D Modeler.
Powderlbinder feedstocks were mixed using a torque rheometer and filaments were fabricated
using a capillary rheometer and twin screw extruder. Green FDC components were built from
these filaments and then characterized for inter-road and inter-layer bonding. Binder removal
procedures were established for FDC green components to yield brown parts without distortion or
shape change. Brown FDC parts were characterized for carbon residue, pore distribution and
dimensional changes. Brown FDC parts were then sintered and the sintered density,
microstructure, and shrinkage anisotropy were studied. | null | null | null | null | null | null |
['Klosterman, Donald A', 'Chartoff, Richard P.', 'Priore, Brian', 'Osborne, Nora', 'Graves, George', 'Lightman, Allan', 'Pak, Sung S.', 'Weaver, Jerry'] | 2018-11-09T16:08:26Z | 2018-11-09T16:08:26Z | 1996 | Mechanical Engineering | doi:10.15781/T2FQ9QR1S | http://hdl.handle.net/2152/69927 | eng | 1996 International Solid Freeform Fabrication Symposium | Open | ['LOM', 'CAD', 'Rapid prototyping'] | Structural Composites Via Laminated Object Manufacturing (LOM) | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bdd1fe03-2df1-4f71-875c-4e813f69a70f/download | null | An innovative, rapid prototyping (RP) technology is being adapted for the automated
manufacture of composite tools and molds. The technology is a direct extension ofthe
Laminated Object Manufacturing (LaM) process. LaM is an established technique that is used
to create solid prototypes by sequentially cutting and laminating layers of adhesive paper. With
this process a full scale, geometrically complex prototype can be created directly from a CAD
image in less than a day. This report provides a description ofhow LaM is being applied for the
production offunctional composite laminates, such as composite tools and molds. Several
material systems have been examined, including monolithic ceramics (SiC), ceramic matrix
composites (SiC/SiC), and polymer matrix composites (glass/epoxy). Realistic tools and molds
are being created from these materials using the LaM process with little modification. However,
post processing (ceramic densification, polymer post cure) is necessary to obtain articles with
good mechanical properties. Technical solutions are being developed for maintaining
geometrical accuracy during the post processing cycles. The mechanical properties and
performance ofthe LaM-produced parts are reported herein. Overall, this technology holds
great promise for lowering the cost oftooling due to the ability to create geometrically complex
objects rapidly using a highly automated processing sequence. | null | null | null | null | null | null |