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['Dickens, Phill', 'Reeves, Phill', 'Hague, Richard'] | 2021-10-05T15:29:56Z | 2021-10-05T15:29:56Z | 2012 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88391', 'http://dx.doi.org/10.26153/tsw/15330'] | eng | 2012 International Solid Freeform Fabrication Symposium | Open | ['Additive Manufacturing', 'Additive Manufacturing education', 'UK', 'Institution of Mechanical Engineers'] | Additive Manufacturing Education in the UK | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8e6899cc-83af-46f7-8dfb-127718e382fb/download | University of Texas at Austin | There has been and continues to be a considerable effort regarding education for
Additive Manufacturing (AM) in the UK. This generally started in 1992 with a seminar
organised by the Institution of Mechanical Engineers and an industrial exhibition stand
at Mach 92. However, before the education activities are discussed it is useful to show
the AM research landscape in the UK as this will give an indication of the level of activity
It should be noted that there will also be a considerable number of organisations
involved in using AM but not involved in research. | null | null | null | null | null | null |
['Dey, N.K.', 'Liou, F.W.', 'Nedic, C.'] | 2021-10-12T17:55:55Z | 2021-10-12T17:55:55Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88707', 'http://dx.doi.org/10.26153/tsw/15641'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'laser deposition', 'titanium', 'Ti-6Al-4V', 'aerospace repair'] | Additive Manufacturing Laser Deposition of Ti-6Al-4V for Aerospace Repair Applications | Conference paper | https://repositories.lib.utexas.edu//bitstreams/895a2fc0-e880-4da6-aa51-6a01b0fbbcc8/download | University of Texas at Austin | Parts or products from high performance metal are very
expensive, partly due to the processing complexities during
manufacturing. The purpose of this project is to use additive
laser deposition and machining processes to repair titanium
parts, thus extending the service life of these parts. The study
broadly included preparing the defects, laser deposition,
machining, sample preparation and mechanical tests.
Comparative study of mechanical properties (UTS, YS,
percentage elongation) of the repaired samples to the ideal
conditions was undertaken. The research throws up interesting
facts where the data from the test sample shows enhancement of
properties of the repaired part. | null | null | null | null | null | null |
['Knapp, C.M.', 'Lienert, T.J.', 'Chen, C.', 'Kovar, D.'] | 2021-10-12T22:25:13Z | 2021-10-12T22:25:13Z | 2014 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88755', 'http://dx.doi.org/10.26153/tsw/15689'] | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['direct metal deposition', 'Laser Engineered Net Shaping', 'AISI 1018 steel', 'heat-affected zone', 'steel substrates', 'microstructure', 'additive manufacturing'] | Additive Manufacturing of 1018 Steel: Process Observations and Calculations | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f8df7da2-641d-451e-a0e5-f5c758037e0a/download | University of Texas at Austin | The temperature distribution in the vicinity of the laser used in direct metal deposition
(DMD) plays a critical role in determining the final microstructure and mechanical properties of
the deposit and the heat-affected zone (HAZ) within the substrate. Samples were prepared using
Laser Engineered Net Shaping (LENSTM) by depositing AISI 1018 steel powder onto AISI 1018
steel substrates in multiple, overwritten passes. The laser power and speed were varied to control
the heat input and the rate of cooling. The process characteristics were then quantified and
compared across the samples to determine the effect of input parameters on the resulting deposit
microstructures. | null | null | null | null | null | null |
['Tsui, Lok-kun', 'Maines, Erin', 'Evans, Lindsey', 'Keicher, David', 'Lavin, Judith'] | 2021-11-10T21:14:14Z | 2021-11-10T21:14:14Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90177', 'http://dx.doi.org/10.26153/tsw/17098'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['UV curable resin', 'alumina pastes', 'in-situ', 'material extrusion', 'printing', 'additive manufacturing'] | Additive Manufacturing of Alumina Components by Extrusion of In-Situ UV-Cured Pastes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/eeb89f9c-c6b5-47e3-b23f-f3d91a6f49ba/download | University of Texas at Austin | Additive manufacturing of ceramic materials is an attractive technique for rapid
prototyping of components at small scales and low cost. We have investigated the printing of
alumina pastes loaded at 70-81.5 wt% solids in a UV curable resin. These can be deposited by
extrusion from a syringe head on a Hyrel System 30M printer. The print head is equipped with an
array of UV LEDs, which solidify the paste without the need for any applied heating. Parameters
optimized include print speed, layer height, applied force, and deposition rate. Using A15 alumina
and submicron A16 powder precursors, we can achieve bulk densities of 91% and 96% of
theoretical density respectively. The influence of dispersants and surfactants added to the powder
on the rheology of the pastes, the print process parameters, and the quality of the final components
are also investigated. | null | null | null | null | null | null |
['Girdis, Jordan', 'McCaffrey, Matthew', 'Proust, Gwénaëlle'] | 2021-10-27T22:48:47Z | 2021-10-27T22:48:47Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89638 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['fused deposition modeling', 'short carbon fibers', 'graphene', 'polymer composites'] | Additive Manufacturing of Carbon Fiber and Graphene – Polymer Composites using the technique of Fused Deposition Modelling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/be914ffc-d48c-4bd0-ab34-064a97b61cbd/download | University of Texas at Austin | Adding micro or nano-carbon reinforcements to polymers enhances their mechanical
and electrical properties. In this paper, the effects of the addition of short carbon fibres (SCF)
and graphene into acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) polymer
to create composite filaments for fused deposition modelling (FDM) are investigated. After
creating carbon polymer composite filaments, using a commercial 3D printer, samples were
printed and tested for mechanical and electrical properties. The measured values for these
composites were compared to those obtained for pure ABS and pure PLA. It was found that
by using only 2% SCF it was possible to achieve a 22% increase in tensile strength with no
significant impact on printability. With addition of graphene, PLA was made to be
conductive. These results show the feasibility of developing new materials for 3D printing
that will create structurally sound and conductive designs. | null | null | null | null | null | null |
['Zhang, Xinchang', 'Pan, Tan', 'Chen, Yitao', 'Liou, Frank'] | 2021-12-06T22:48:08Z | 2021-12-06T22:48:08Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90704', 'http://dx.doi.org/10.26153/tsw/17623'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'functionally graded materials', 'Cu', 'stainless steel', 'dissimilar materials'] | Additive Manufacturing of Cu on 316L Stainless Steel via Inconel 718 Intermediate Layers | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ed6892db-8d24-45b3-92bd-083a4bef3302/download | University of Texas at Austin | Joining of dissimilar materials is becoming increasingly prevalent to combine differing
material properties to enhance product design flexibility and performance. In this study, pure
copper was built on 316L stainless steel (SS316L) by laser-based additive manufacturing
technology in which copper was deposited layer-by-layer on SS316L with Inconel 718
intermediate layers. The goal is to fabricate multi-metallic structures with improved thermal
conductivity. The direct joining of Cu on SS316L would result in porosities at the interface and
the consequent poor mechanical properties, which could be addressed by Inconel 718 intermediate
layers. The microstructure, chemical composition, tensile properties, and micro-hardness were
characterized in the dissimilar materials using scanning electron microscopy, energy dispersive
spectroscopy, tensile test with digital image correlation technique, and hardness tester. Results
confirm excellent bonding when Inconel 718 intermediate layers are introduced. | null | null | null | null | null | null |
['Kulkarni, P.M.', 'Karunakaran, K.P.', 'Tewari, Asim', 'Legesse, Fisseha', 'Rana, Dhirendra', 'Bernard, Alain'] | 2021-10-18T20:21:34Z | 2021-10-18T20:21:34Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89231 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['directional heat condctuve', 'Additive Manufacturing', 'Hybrid Layered Manufacturing'] | Additive Manufacturing of Directionally Heat Conductive Objects | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4e433d7a-bce0-4854-b80f-12c723d9bedd/download | University of Texas at Austin | Purpose: Directionally Heat Conductive (DHC) objects are also known as thermal cables. DHC
objects used in cooling solid state devices as large heat sinks. This paper presents Additive
manufacturing (AM) as a new method for realization of DHC objects. AM can produce DHC
objects accurately, rapidly and economically.
Design/Methodology/Approach: It is very hard to realize DHC objects through conventional
manufacturing. The authors describe the realization of metallic DHC objects using their AM
process called Hybrid Layered Manufacturing (HLM). HLM, which uses GMAW deposition, can,
in principle, produce DHC out of any metal for which welding wire is available. . Differential
conductivity in HLM is achieved by appropriately distributing the air gaps among the beads. The
air gap distribution depends on the layer thickness and step over increment.
Findings: The authors have demonstrated the ability of HLM to produce DHC objects for Al alloy
4043. The thermal conductivity achieved on two orthogonal directions was 100.496 and 129.740
W m-1 K-1 as against 163 W m-1 K-1 for solid metal. These are significant variations.
Research Limitations/Implications: HLM realize near net shape of DHC objects, further post
processing namely machining is required.
Originality Value: AM Specifically HLM for realization of DHC objects | null | null | null | null | null | null |
['Chiroli, M.', 'Ciszek, F.', 'Baschung, B.'] | 2021-11-10T21:28:55Z | 2021-11-10T21:28:55Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90181', 'http://dx.doi.org/10.26153/tsw/17102'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['energetic materials', '3D printing', 'additive manufacturing', 'defense industry'] | Additive Manufacturing of Energetic Materials | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4ca2a243-91de-479e-829f-193d798a5294/download | University of Texas at Austin | Over the last decade, additive manufacturing gained a lot of interest within the defense
industry. However, printing energetic materials such as explosives or solid propellants remains
a challenge. A research work with the aim to suggest appropriate materials and associated 3D
printing techniques to produce energetic materials, is currently carried out. In interior ballistics,
improved weapon performance ends in reaching higher muzzle kinetic energy. This can be
achieved by adjusting the gas pressure released during the ballistic cycle by using specific
propellant grains. A former study (Baschung, MRS Symposium H, Boston, 2005) highlighted
the advantages of using co-layered propellant grains to achieve this goal. The difficulties in
producing such kind of propellants can now be bypassed thanks to 3D printers. Our approach
consists in deposing a viscous energetic paste, containing a solvent, with an adapted machine.
The layer formation and the adhesion between them are investigated in this work. | null | null | null | null | null | null |
['Pegues, Jonathan', 'Roach, Michael', 'Shamsaei, Nima'] | 2021-11-18T00:29:49Z | 2021-11-18T00:29:49Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90371', 'http://dx.doi.org/10.26153/tsw/17292'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['laser powder bed fusion', 'crack nucleation', 'twin boundary', 'heat treatment'] | Additive Manufacturing of Fatigue Resistant Materials: Avoiding the Early Life Crack Initiation Mechanisms During Fabrication | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6601581c-bb73-4eb9-9ccf-c6ab4924a19b/download | University of Texas at Austin | The full potential of additive manufacturing (AM) has been limited by the process induced
defects within the fabricated materials. Defects such as lack of fusions and gas entrapped pores act
as stress concentrators and result in premature fatigue crack initiation, severely limiting the
applicability of AM in fatigue-critical applications. However, by understanding the failure
mechanisms associated with AM materials and leveraging the intimate localized thermal input (i.e.
process conditions), the failure mechanisms for some materials may be avoided during the
fabrication process. This study investigates the crack initiation behavior of an AM austenitic
stainless steels subjected to fatigue testing. The microstructural features responsible for fatigue
crack initiation are captured at the surface by ex-situ electron backscatter diffraction. Results show
that the higher cooling rates during AM offer the opportunity to fabricate fatigue resistant
austenitic stainless steel parts by avoiding the microstructural features that are most detrimental to
fatigue performance. | null | null | null | null | null | null |
['Kishore, Vidya', 'Chen, Xun', 'Ajinjeru, Christine', 'Hassen, Ahmed Arabi', 'Lindahl, John', 'Failla, Jordan', 'Kunc, Vlastimil', 'Duty, Chad'] | 2021-10-27T23:24:26Z | 2021-10-27T23:24:26Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89642 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['semi-crystalline thermoplastics', 'PPS', 'PEKK', 'additive manufacturing'] | Additive Manufacturing of High Performance Semicrystalline Thermoplastics and Their Composites | Conference paper | https://repositories.lib.utexas.edu//bitstreams/053177a7-2704-437e-b926-a1e66dd7731b/download | University of Texas at Austin | This work investigates the use of two semi-crystalline high performance
thermoplastics, polyphenylene sulfide (PPS) and poly (ether ketone ketone) (PEKK), as
feedstock for fused filament fabrication process. Composites of PPS and PEKK are emerging
as viable candidates for several components in aerospace and tooling industries and additive
manufacturing of these materials can be extremely beneficial to lower manufacturing costs and
lead times. However, these materials pose several challenges for extrusion and deposition due
to some of their inherent properties as well as thermal and oxidative responses. To better
understand the properties of such systems specific to 3D printing and determine the critical
parameters that make them “printable”, various rheological and thermal properties have been
studied for neat as well as short fiber reinforced PPS and PEKK systems. Attempts were also
made to print these materials in a customized high temperature fused filament fabrication
system. | null | null | null | null | null | null |
['Wasley, T.', 'Li, J.', 'Ta, D.', 'Shephard, J.', 'Stringer, J.', 'Smith, P.', 'Esenturk, E.', 'Connaughton, C.', 'Kay, R.'] | 2021-10-28T22:24:18Z | 2021-10-28T22:24:18Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89718 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'process integration', 'multilayer embedded electronics', 'DLP stereolithography', 'material dispensing', 'flip chip packaging'] | Additive Manufacturing of High Resolution Embedded Electronic Systems | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3f61a9f4-3b44-4556-a47c-163d5ac2a159/download | University of Texas at Austin | Additive Manufacturing (AM) processes can facilitate the rapid iterative product
development of electronic devices by optimising their design and functionality. This has been
achieved by combining two additive manufacturing processes with conventional surface mount
assembly to generate high resolution embedded multilayer electronic circuits contained within a
3D printed polymer part. Bottom-up DLP Stereolithography and material dispensing of isotropic
conductive adhesives have been interleaved to deposit microscale features on photopolymer
substrates. The material dispensing process has demonstrated the high density deposition of
conductors attaining track widths of 134µm and produced interconnects suitable for directly
attaching bare silicon die straight to the substrate. Interconnects down to a diameter of 149µm at
a pitch of 457µm have been realized. In addition, this research developed a novel method for
producing high aspect ratio z-axis connections. These were simultaneously printed with the
circuit and component interconnects by depositing through-layer pillars with a maximum aspect
ratio of 3.81. Finally, a method to accurately embed the packaged circuit layer within the printed
part has been employed using bottom-up stereolithography. | null | null | null | null | null | null |
['Cui, Wenyuan', 'Zhang, Xinchang', 'Liou, Frank'] | 2021-11-02T19:27:08Z | 2021-11-02T19:27:08Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89874 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'high-entropy alloys', 'microstructures', 'mechanical properties'] | Additive Manufacturing of High-Entropy Alloys - A Review | Conference paper | https://repositories.lib.utexas.edu//bitstreams/d710c88e-1341-4b52-8821-a0591387b3db/download | University of Texas at Austin | High-entropy alloys have attracted increasingly interest due to their unique compositions,
microstructures and mechanical properties. Additive manufacturing has been recognized as a
promising technology to fabricate the high-entropy alloys in the recent years. The purpose of this
paper is to review the current research progress in high-entropy alloys by additive manufacturing
process. It will first highlight the important theory of the high-entropy alloys. The next aspect is
to summarize current additive manufacturing methods applied for the high entropy alloys. At last,
the correlation between the microstructures and the mechanical properties of the high-entropy
alloys will be examined and discussed. | null | null | null | null | null | null |
Basak, Amrita | 2021-11-18T00:34:01Z | 2021-11-18T00:34:01Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90372', 'http://dx.doi.org/10.26153/tsw/17293'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ["high-ℽ' nickel-based superalloys", 'additive manufacturing', 'selective laser melting', 'SLM', 'processing', 'microstructure', 'mechanical properties'] | Additive Manufacturing of High-Gamma Prime Nickel-Based Superalloys through Selective Laser Melting (SLM) | Conference paper | https://repositories.lib.utexas.edu//bitstreams/766c204a-2eeb-4098-a48a-f8b33cbb492d/download | University of Texas at Austin | High-ℽ' nickel-based superalloys are abundantly used in the aerospace, marine, nuclear,
and chemical industries where excellent corrosion and oxidation resistance, superior mechanical
properties, and exceptional high-temperature performance are required. However, selective laser
melting (SLM)-based additive manufacturing (AM) of high-ℽ' nickel-based superalloys pose
significant challenges due to these alloys’ complex chemistry. With multiple alloying elements
and high aluminum + titanium fraction, these materials when consolidated through SLM form
various secondary phases severely affecting the processability leading to the formation of cracks.
The objective of this review is to summarize the progress made so far on SLM of high-ℽ' nickel-based superalloys with a special emphasis towards elucidating the relationships between
processing, microstructures, and properties in this alloy system. | null | null | null | null | null | null |
['Platt, S.', 'Schnell, N.', 'Witt, G.', 'Kleszczynski, S.'] | 2024-03-27T03:31:38Z | 2024-03-27T03:31:38Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124467', 'https://doi.org/10.26153/tsw/51075'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['laser powder bed fusion', 'additive manufacturing', 'metal', 'sandwich sheets'] | Additive manufacturing of hybrid sandwich sheets by laser powder bed fusion of metals | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1eb07f93-e335-482c-a1bc-271f45ea5d9f/download | University of Texas at Austin | In the context of lightweight applications, laser powder bed fusion of metals allows the
creation of high-complexity structures at minimal use of material. Traditional elements of
lightweight construction are sandwich sheets, which comprise two cover sheets with a fine core
structure joined in the centre. Thus, these lightweight elements contain both geometrically
simple (cover sheets) and geometrically complex (core structure) elements. Conventional
manufacturing of core structures is limited in terms of geometrical freedom. On the other hand,
Additive Manufacturing of sheets has disadvantages in terms of economic efficiency.
Therefore, a combined process consisting of additive and conventional cost-efficient
manufacturing is proposed to eliminate both disadvantages. This publication presents a hybrid
manufacturing route to produce metal sandwich sheets. The hybrid sandwich sheets are
manufactured using a rolled cover sheet as a base plate and additive manufactured core
structures including an upper cover sheet. For this purpose, a recently developed sheet mounting
system for implementation in a laser powder bed fusion process is presented and evaluated
concerning manufacturing criteria such as process stability and dimensional accuracy of the
final components. | null | null | null | null | null | null |
['Ho, Jason', 'Lough, Cody S.', 'Mulligan, Phillip', 'Kinzel, Edward C.', 'Johnson, Catherine E.'] | 2021-11-09T18:54:44Z | 2021-11-09T18:54:44Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90117', 'http://dx.doi.org/10.26153/tsw/17038'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['shaped charge', 'liners', 'geometries', 'SS 304L', 'selective laser melting', 'additive manufacturing'] | Additive Manufacturing of Liners for Shaped Charges | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3a797230-2ced-40d8-909d-8c8ea4428ccc/download | University of Texas at Austin | A Shaped Charge (SC) is an explosive device used to focus a detonation in a desired
direction, and has applications in demolition and oil extraction. The focusing relies on a void in
the explosive mass, shaped by a metal liner that becomes a projectile during detonation. Additive
Manufacturing (AM) allows greater design freedom and geometric complexity for the liner portion
of the SC. Specifically, hierarchical structuring and functional grading can potentially provide
greater velocity, directionality, and efficiency. In this work, Selective Laser Melting (SLM) is used
to explore different geometries for an SC liner made out of SS 304L. These are detonated using
the explosive Composition C-4 to evaluate performance metrics, depth and standoff, and are
observed using high-speed imaging. The work shows the potential for advanced shaped charges
produced using SLM. | null | null | null | null | null | null |
['Grothaus, Bradley', 'Huck, Dane', 'Sutton, Austin'] | 2021-11-09T19:04:37Z | 2021-11-09T19:04:37Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90126', 'http://dx.doi.org/10.26153/tsw/17047'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['bandpass filters', '304L', 'stainless steel', 'overhangs', 'radar receivers', 'selective laser melting', 'additive manufacturing'] | Additive Manufacturing of Metal Bandpass Filters for Future Radar Receivers | Conference paper | https://repositories.lib.utexas.edu//bitstreams/974faf79-8274-404f-a250-e3e6d394639a/download | University of Texas at Austin | Selective laser melting (SLM) is a powder-bed fusion (PBF) process that bonds successive layers
of powder with a laser to create components directly from computer-aided design (CAD) files. The
additive nature of the SLM process in addition to the use of fine powders facilitates the
construction of complex geometries, which has captured the attention of those involved in the
design of bandpass filters for radar applications. However, a significant drawback of SLM is its
difficulty in fabricating parts with overhangs necessitating the use of support structures, which, if
not removed, can greatly impact the performance of bandpass filters. Therefore, in this study
bandpass filters are manufactured in two stages with 304L stainless steel where each builds only a
portion of the part to improve the reliability in manufacturing the overhangs present. The results
show that the versatility of SLM can produce difficult-to-manufacture bandpass filters with high
dimensional accuracy. | This work was funded by Honeywell Federal Manufacturing &
Technologies under Contract No. DE-NA0002839 with the U.S. Department of Energy. | null | null | null | null | null |
['Chen, Yitao', 'Liou, Frank'] | 2021-11-10T22:52:02Z | 2021-11-10T22:52:02Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90199', 'http://dx.doi.org/10.26153/tsw/17120'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'functionally graded materials', 'mechanical properties', 'laser metal deposition', 'selective laser melting'] | Additive Manufacturing of Metal Functionally Graded Materials: A Review | Conference paper | https://repositories.lib.utexas.edu//bitstreams/67e039e0-cf31-4dfe-9a1a-ad579c68cae9/download | University of Texas at Austin | Functionally graded materials (FGMs) have attracted a lot of research interest due to their
gradual variation in material properties that result from the non-homogeneous composition or
structure. Metal FGMs have been widely researched in recent years, and additive manufacturing
has become one of the most important approaches to fabricate metal FGMs. The aim of this paper
is to review the research progress in metal FGMs by additive manufacturing. It will first introduce
the unique properties and the advantages of FGMs. Then, typical recent findings in research and
development of two major types of metal additive manufacturing methods, namely laser metal
deposition (LMD) and selective laser melting (SLM), for manufacturing different types of metal
FGMs will be discussed. Finally, the major technical concerns in additive manufacturing of metal
FGMs which are closely related to mechanical properties, and industrial applications of metal
FGMs will be covered. | null | null | null | null | null | null |
['Yang, Seongun', 'Xu, Donghua', 'Yan, Dongqing', 'Albert, Marc', 'Pasebani, Somayeh'] | 2024-03-26T23:04:04Z | 2024-03-26T23:04:04Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124440', 'https://doi.org/10.26153/tsw/51048'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['laser directed energy deposition', 'oxide dispersion strengthened alloy', '316L stainless steel'] | Additive Manufacturing of ODS Steels Using Powder Feedstock Atomized with Elemental Yttrium | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fa619bf3-45b6-446d-9705-74a37404ca1b/download | University of Texas at Austin | This study investigates the microstructure and mechanical properties of an austenitic ODS steel produced
by the Laser Directed Energy Deposition (LDED) process using powder feedstock atomized with
elemental yttrium. The Microstructure of the samples was characterized by electron microscopy, and mechanical
properties were measured using a tensile test and nanoindentation. Further, the thermal stability of the LDEDproduced ODS steels were evaluated. As-printed samples showed a cellular structure with Si-Mn-Y-Oenriched nanoparticles that were found to be amorphous. After 100 hours at 1000°C in an argon atmosphere, a
partially recrystallized microstructure with a decrease in the number density of Y-O-enriched nanoparticles
with crystalline structure was revealed. The as-printed (600 W, 600 mm/min) samples exhibited an ultimate
tensile strength of 774 MPa and an elongation at a break of 22%. A lower ultimate tensile strength of 592 MPa
and higher elongation of 42% was measured after 100 hours at 1000°C. | null | null | null | null | null | null |
['Yuan, Mengqi', 'Bourell, David'] | 2021-10-18T20:17:38Z | 2021-10-18T20:17:38Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89230 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'laser sintered polyamide 12', 'lithophane', 'optical properties'] | Additive Manufacturing of Optically Translucent Parts | Conference paper | https://repositories.lib.utexas.edu//bitstreams/333d3f68-3030-401f-9473-f81556b9ad06/download | University of Texas at Austin | A lithophane is a translucent image created by varying the plate thickness; the image is
observed using a back lit light source. Additive manufacturing makes highly complex
lithophane fabrication possible. Optical properties of laser sintered polyamide (PA) 12
translucent additive manufactured parts were analyzed and applied to the lithophane fabrication.
Several parameters affecting lithophane manufacturing performance are discussed including
brightness and contrast versus plate thickness and grayscale level, surface finish quality and
manufacturing orientation. Moreover, other thermoplastic semi-crystalline materials were
analyzed for LS optically translucent part production. Plates and lithophanes were built using a
different AM platform: stereolithography (SL) with Somos® ProtoGen™ O- XT 18420 white
resin. Different optical properties and lithophane performance were observed and compared
with PA 12 parts.
It was found laser sintered polyamide 12 optical properties varied with light wavelength
and reached maximum transmission under green light. When building in the XY plane, thin
layer thickness and large maximum plate thickness led to higher contrast and gray scale level.
Lithophane quality was largely improved when fabricated in the ZX/ZY plane orientation.
Lithophanes made from SL were analyzed but showed lower contrast due to the optical
property characteristics of the white resin. | null | null | null | null | null | null |
['Claybrook, F.R.', 'Southee, D.J.', 'Mohammed, M.I.'] | 2024-03-27T03:33:53Z | 2024-03-27T03:33:53Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124468', 'https://doi.org/10.26153/tsw/51076'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'diabetic foot insoles', 'diabetes'] | ADDITIVE MANUFACTURING OF PERSON SPECIFIC DIABETIC FOOT INSOLES WITH ADJUSTABLE CUSHIONING PROPERTIES USING TPMS LATTICE STRUCTURES | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ceed04fa-3dda-4d6c-883a-9fba1cfa5639/download | University of Texas at Austin | Complications associated with diabetes are numerous, including foot problems which in
extreme cases can lead to amputations. Current management involves the use of foam diabetic
foot insoles (DFI) to provide cushioning, however load bearing capacity is limited, and designs
often do not provide a comfortable or efficacious fit. This study aspires to resolve problems
using digital fabrication workflows. The exploration of potential 3D scanning of anatomical
data, parametric modelling, and additive manufacturing was created for a patient specific DFI.
This demonstrated that patient scanning data provides means to create a custom fitting insole
template, improving overall fit. Demonstrating the use of triply periodic minimal surface
(TPMS) structures, fabricated in Thermoplastic Polyurethane (TPU), as cushioning structures,
whereby unique lattice designs allow regionally tailored mechanical loading properties of the
insole concept. The final insole realises a superior alternative to tradition DFI. | null | null | null | null | null | null |
['Radyjowski, P.P.', 'Bourell, D.L.', 'Kovar, D.', 'Ellzey, J.L.'] | 2021-12-01T21:46:51Z | 2021-12-01T21:46:51Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90625', 'http://dx.doi.org/10.26153/tsw/17544'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['cermets', 'Si-SiC', 'combustion', 'combustor', 'additive manufacturing'] | Additive Manufacturing of Si-SiC Cermets for Combustion Device Applications | Conference paper | https://repositories.lib.utexas.edu//bitstreams/35d6eee5-c128-48f9-bf85-9cd163494716/download | University of Texas at Austin | Traditional manufacturing methods for high-temperature devices are time intensive and
limited to simple shapes. Additive manufacturing (AM) reduces lead times and opens the design
space to more complex geometries. Indirect laser sintering of siliconized silicon carbide (Si-SiC)
cermets was evaluated for creating devices compatible with combustion environments. Heat
recirculating combustors especially benefit from geometric flexibility. Si-SiC process
improvements are presented for the production of cermet combustors. The effect of flame on the
material was studied by directly exposing samples to hot combustion products at 1000°C and
1260°C for 10 hours. Subsequently, three experimental Si-SiC combustors were manufactured and
fired to evaluate the practical aspects of cermet applications. Each device was operated for 70
hours under excess-air methane flames with solid temperatures up to 1405°C. The surface
oxidation and phase changes were assessed. Operating temperatures between 1200°C and 1350°C
reduce damage to the material and give a promise of long-term, high-temperature operation. | null | null | null | null | null | null |
['Saari, M.', 'Galla, M.', 'Cox, B.', 'Krueger, P.', 'Cohen, A.', 'Richer, E.'] | 2021-10-21T15:17:08Z | 2021-10-21T15:17:08Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89392 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['thermoplastic elastomers', '3D printing', 'soft parts', 'composite parts', 'feed extrusion'] | Additive Manufacturing of Soft and Composite Parts from Thermoplastic Elastomers | Conference paper | https://repositories.lib.utexas.edu//bitstreams/139a155e-64ae-420f-98bd-107c67b4dcf1/download | University of Texas at Austin | Thermoplastic elastomers (TPEs) are low-durometer materials that can support large
strains without breaking, making them attractive materials for producing 3-D printed soft
components. However, prefabricated TPE filament, especially those with low hardness, cannot
be used in typical filament feed extrusion mechanisms that are popular in material extrusion-based 3-D printers today.
Therefore, we have developed a mini-screw extruder, small enough to be incorporated on
a typical 3-D printer system, and capable of extruding various TPE formulations directly from
commercially available pellets. This paper presents the design and thermal analysis of the mini-extruder, experimental testing of the 3-D printing process for TPEs with nominal hardness in the
range of 5 – 52 Shore A, and compression and tension tests of the properties of printed parts. By
combining 3-D printing of soft TPEs with rigid thermoplastics, the new system also opens up
new possibilities in additive manufacturing of soft and hard composite parts. | null | null | null | null | null | null |
['Clymer, Daniel', 'Beuth, Jack', 'Cagan, Jonathan'] | 2021-11-01T20:48:43Z | 2021-11-01T20:48:43Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89744 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['process design', 'process outcomes', 'metal-based additive manufacturing', 'additive manufacturing'] | Additive Manufacturing Process Design | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ac4c72e3-d199-483b-9062-8840e646a571/download | University of Texas at Austin | A current issue in metal-based additive manufacturing (AM) is achieving consistent,
desired process outcomes in manufactured parts. When process outcomes such as strength,
density, or precision need to meet certain specifications, these specifications can be met by
changes in process variable selection. However, the changes required to achieve a better part
performance may not be intuitive, particularly because process variable changes can
simultaneously improve some outcomes while decreasing others. In this work, the tradeoffs
between multiple process outcomes are formalized and the design problem is explored
throughout the design space of process variables. User input for each process outcome is
considered and the best combination of process variables is found to achieve a user’s desired
outcome. | null | null | null | null | null | null |
['Moylan, Shawn', 'Land, Joshua', 'Possolo, Antonio'] | 2021-10-21T19:50:55Z | 2021-10-21T19:50:55Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89434 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'round robin studies', '3D printers', 'geometric performance'] | Additive Manufacturing Round Robin Protocols: A Pilot Study | Conference paper | https://repositories.lib.utexas.edu//bitstreams/949b4f41-9aa1-4e15-acc5-35eb0babeeff/download | University of Texas at Austin | As the number of users of additive manufacturing (AM) steadily increases, and
considering their demand for material and process specifications, the need for standard protocols
for round robin studies is increasing accordingly. Researchers at the National Institute of
Standards and Technology (NIST) have conducted and participated in several AM round robin
studies with the aim not only to characterize the AM process, and material but also to improve
the understanding of AM round robin studies themselves. One simple study, a pilot round robin
study investigating geometric performance of NIST-owned consumer-grade 3D printers,
provides excellent examples of typical results and lessons learned. While individual printers
produced relatively consistent results, there was significant variability between the printers. This
variability existed despite best efforts to ensure participants followed consistent procedures in
building the test parts. Further, the variability made it apparent that collecting pedigree data
from each build was required to draw any conclusions about potential causes of the variability. | null | null | null | null | null | null |
['Porter, Daniel A.', 'Cohen, Adam L.', 'Krueger, Paul S.', 'Son, David'] | 2021-11-04T15:06:54Z | 2021-11-04T15:06:54Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/89981', 'http://dx.doi.org/10.26153/tsw/16902'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['stock ultraviolet curable silicone', 'stock UV curable silicone', '3D printing', 'extrude and cure additive manufacturing', 'ECAM'] | Additive Manufacturing Utilizing Stock Ultraviolet Curable Silicone | Conference paper | https://repositories.lib.utexas.edu//bitstreams/277c930b-1308-4c06-8cb7-1ea667fa04de/download | University of Texas at Austin | Extrude and Cure Additive Manufacturing (ECAM) is a method that enables 3D printing
(3DP) of common thermoset materials. Ultraviolet (UV)-curable silicone is an example of a
thermoset material with a large number of industrial and medical applications. 3D printed silicone
prototype parts are obtained using a custom high pressure ram, valve, and UV exposure system.
This paper will address issues with printing stock UV curable silicone such as electrostatic
repulsion, in-nozzle curing, and extrudate slumping. One solution that addresses two issues is
adding carbon black (CB) to the mixture to reduce electrostatic repulsion while also inhibiting UV
cure depth, hence preventing material from curing in the nozzle. Evidence shows that too much
carbon black can be detrimental to the structural stiffness of the resulting part. | null | null | null | null | null | null |
['Yigit, Ismail Enes', 'Isa, Mohammed', 'Lazoglu, Ismail'] | 2021-11-15T22:04:07Z | 2021-11-15T22:04:07Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90287', 'http://dx.doi.org/10.26153/tsw/17208'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['support structures', 'modular', 'additive manufacturing', 'robotic'] | Additive Manufacturing with Modular Support Structures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4274732c-1b94-4413-bdb6-3e516dabc4c3/download | University of Texas at Austin | Additive manufacturing is praised to have low material waste compared to conventional
subtractive manufacturing methods. This is not always the case when the computer aided design
(CAD) model consists of large overhangs. In such cases, fabrication of support structures are
required to fill the space between the CAD model and the manufacturing bed. In post processing,
these support structures must be removed from the model. These supports become waste and reduce
the buy-to-fly ratio. In this paper, we present a pre-fabricated reusable modular support structure
system which minimizes the fabrication of conventional support structures. The conventional
supports are replaced with modular support blocks wherever possible. The blocks are stacked under
the overhang with a robot arm until the overhang of the model is reached. Conventional supports
can be fabricated on top when needed with fused filament fabrication. This strategy reduces
fabrication of conventional supports. Thus, faster fabrication times are obtained with higher buy-to-fly ratios. | null | null | null | null | null | null |
['Romero, L.', 'Guerrero, A.', 'Espinosa, M.M.', 'Jiménez, M.', 'Domínguez, I.A.', 'Domínguez, M.'] | 2021-10-12T20:37:49Z | 2021-10-12T20:37:49Z | 2014 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88735', 'http://dx.doi.org/10.26153/tsw/15669'] | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['RepRap', '3D printer', 'open source rapid prototying', 'rapid prototyping', 'additive manufacturing'] | Additive Manufacturing with RepRap Methodology: Current Situation and Future Prospects | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f6b179cb-2d4b-4e0f-b0e8-b9f9e16f3b0d/download | University of Texas at Austin | In February 2004, Adrian Bowyer, from the University of Bath, began an open initiative
called RepRap, with the purpose of creating an open source rapid prototyping machine
which, moreover, could replicate itself. This article analyzes the current status of the
RepRap initiative, commenting the basic components of RepRap machines, the
differences between the different 3D printers developed by the RepRap community so
far, and the technical possibilities that opens this technology from the engineering point
of view. In addition we propose some improvements that could be perfectly feasible in
the short term. For this purpose, the assembly of a RepRap Mendel Prusa was
performed, but with some modifications. | null | null | null | null | null | null |
['Chen, Yong', 'Zhou, Chi', 'Luo, Jingyuan'] | 2021-09-30T13:13:31Z | 2021-09-30T13:13:31Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88228', 'http://dx.doi.org/10.26153/tsw/15169'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', '5-axis SFF', 'CNC accumulation', 'build around inserts'] | Additive Manufacturing without Layers: A New Solid Freeform Fabrication Process based on CNC Accumulation | Conference paper | https://repositories.lib.utexas.edu//bitstreams/2d201dda-a4e9-40f2-9bb2-c19d3d1aea3a/download | University of Texas at Austin | Most current additive manufacturing processes are layer-based, that is building a physical model
layer-by-layer. By converting 3-dimensional geometry into 2-dimensional contours, the layer-based
approach can dramatically simplify the process planning steps. However, there are also drawbacks
associated with the layer-based approach such as inconsistent material properties between various
directions. In a recent NSF workshop on additive manufacturing, it is suggested to investigate alternative
non-layer based approaches. In this paper, we present an additive manufacturing process without planar
layers. In the developed testbed, an additive tool based on a fiber optics cable and a UV-LED has been
developed. By merging such tools inside a liquid resin tank, we demonstrate its capability of building
various 2D and 3D structures. The technical challenges related to the development of such a process are
discussed. Some potential applications including part repairing and building around inserts have also
been demonstrated. | null | null | null | null | null | null |
Diewald, Evan P. | 2021-12-01T22:11:49Z | 2021-12-01T22:11:49Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90634', 'http://dx.doi.org/10.26153/tsw/17553'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['additive OS', 'open-source platform', 'data management', 'IP protection', 'AM data'] | Additive OS: An Open-Source Platform for Additive Manufacturing Data Management & IP Protection | Conference paper | https://repositories.lib.utexas.edu//bitstreams/16cff5b7-663e-4109-8638-33cbe64335d7/download | University of Texas at Austin | The additive manufacturing (AM) digital thread presents unique challenges for data management
and security. While proprietary software packages solve many issues, they can be expensive and
lacking in customization. Additive OS is an open-source platform for importing, sharing,
organizing, and querying AM data. Man-in-the-middle attacks, secure print licensing, and IP theft
are addressed using custom smart contracts, ontology is preserved with a NoSQL database and
directed acyclic graph (DAG) representations, and peer-to-peer content delivery facilitates low-latency file transfer. The application includes a browser-based graphical user interface, but
developers can access the underlying API to invoke sophisticated queries, add functionality, or run
the lightweight client on low-resource hardware. | null | null | null | null | null | null |
['Frank, Matthew C.', 'Peters, Frank E.', 'Karthikeyan, Rajesh'] | 2021-09-30T14:17:24Z | 2021-09-30T14:17:24Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88254', 'http://dx.doi.org/10.26153/tsw/15195'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['Rapid Pattern Manufacturing', 'additive techniques', 'subtractive techniques', 'injection mold tooling', 'seam-free laminated aluminum', 'casting patterns'] | Additive/Subtractive Rapid Pattern Manufacturing for Casting Patterns and Injection Mold Tooling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/5a4dfef5-1b9e-4d57-8c3b-360aa6c27eb6/download | University of Texas at Austin | This paper presents a Rapid Pattern Manufacturing system that involves both additive and
subtractive techniques whereby slabs are sequentially bonded and milled using layered toolpaths.
Patterns are grown in a bottom-up fashion, both eliminating the need for multi-axis operations and
allowing small features in deep cavities. Similar approaches exist in the literature; however, this system
is able to provide a larger range of both materials and sizes, from smaller conventional injection mold
tooling to very large wood or urethane sand casting patterns. This method introduces a novel sacrificial
support structure approach by integrating a flask into the pattern build process. The system has been
implemented in an automated machine capable of producing patterns in excess of several thousand
pounds in a build envelope over 1m3. In this current research, a new layer bonding method using friction
stir welding of aluminum plates is presented. In this manner, one can create seam-free laminated
aluminum injection mold tooling using a unique combination of industrial adhesives and friction stir spot
welding to secure the slab initially, then continuous friction stir welding of layer perimeters that are
subsequently machined in a layer-wise process. | null | null | null | null | null | null |
['Lee, Seungjong', 'Ghiaasiaan, Reza', 'Shao, Shuai', 'Gradl, Paul R.', 'Shamsaei, Nima'] | 2023-01-25T13:52:26Z | 2023-01-25T13:52:26Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117285', 'http://dx.doi.org/10.26153/tsw/44166'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | ['316L stainless steel', 'Laser powder directed energy deposition', 'Heat treatment', 'Microstructure', 'Tensile properties'] | Additively Manufactured 316L Stainless Steel: Effect of Heat Treatment on Microstructure and Tensile Properties | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0bc49a77-f38c-418a-ae13-c5d73326453b/download | null | The microstructure and tensile properties of 316L stainless steel (SS) fabricated using the
laser powder directed energy deposition (LP-DED) after various heat treatment (HT) steps such as
stress-relief (SR), solution annealing (SA), and hot isostatic pressing (HIP) are characterized.
Microstructures before and after HTs are analyzed using both optical and scanning electron
microscopy (SEM). Both quasi-static uniaxial tensile and hardness tests are performed to measure
mechanical properties. The tensile results indicate that the non-heat treated (NHT) condition
possesses higher strengths but lower ductility as compared to the other HT conditions (i.e., SR,
SA, HIP, SR+SA, and SR+HIP). By employing the two-step HT conditions (i.e., SR+SA and
SR+HIP), no significant changes on tensile properties as compared to the individual single-step
HT conditions (i.e., SA or HIP) are observed. The findings suggest that two-step HTs are not
required for LP-DED 316L SS unless HIP is needed to minimize volumetric defect contents. | null | null | null | null | null | null |
['Debeau, D.A.', 'Seepersad, C.C.'] | 2021-11-04T19:37:30Z | 2021-11-04T19:37:30Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90012', 'http://dx.doi.org/10.26153/16933'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['static mechanical performance', 'dynamic mechanical performance', 'honeycomb structures', 'conformal negative stiffness', 'additive manufacturing'] | Additively Manufactured Conformal Negative Stiffness Honeycombs | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fd8c96ba-b35d-44e4-893b-58f807f184ef/download | University of Texas at Austin | This study investigates the static and dynamic mechanical performance of conformal
negative stiffness honeycomb structures. Negative stiffness honeycombs are capable of
elastically absorbing a static or dynamic mechanical load at a predefined force threshold and
returning to their initial configuration after the load is released. Most negative stiffness
honeycombs rely on mechanical loading that is orthogonal to the base of the structure. In this
study, a more three dimensional design is presented that allows the honeycomb to conform to
complex surfaces and protect against impacts from multiple directions. The conformal designs
are additively manufactured in nylon and stainless steel and subjected to quasi-static mechanical
loading and dynamic mechanical impact tests that demonstrate their impact protection
capabilities. | null | null | null | null | null | null |
['Dressler, Amber', 'Scharnberg, William', 'Abousleiman, Anthony', 'Harris, Samantha', 'New, Phil'] | 2021-10-28T22:10:06Z | 2021-10-28T22:10:06Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89714 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['fasteners', 'additive manufacturing', 'build-to-build', 'selective laser sintering'] | Additively Manufactured Fasteners | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a06d840c-6e88-4b1b-8cbf-c2008b514e01/download | University of Texas at Austin | Additive manufacturing (AM) has reached a critical point which enables production of
complex, high resolution, custom parts from robust materials. However, traditional fasteners are
still use to join these complex parts together. Integrating fasteners into additively manufactured
parts is beneficial for part production but there is uncertainty in their design. To understand how
the fasteners fit and function, mechanical property data was collected on the prototypes. This
data along with insights gained while building and testing the prototypes increased the
knowledge base of design for additive manufacturing and build-to-build variability in selective
laser sintering (SLS). | null | null | null | null | null | null |
['Slightam, Jonathon E.', 'Gervasi, Vito R.'] | 2021-10-11T22:44:26Z | 2021-10-11T22:44:26Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88673', 'http://dx.doi.org/10.26153/tsw/15607'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['additively manufactured flexible fluidic actuators', 'Selective Laser Sintered Nylon 12', 'novel fluid power actuators', 'Magnetic Resonance Imaging', 'surgery', 'rehabilitation'] | Additively Manufactured Flexible Fluidic Actuators For Precision Control in Surgical Applications | Conference paper | https://repositories.lib.utexas.edu//bitstreams/ce03f338-c232-421b-b86b-249750b14ad1/download | University of Texas at Austin | Previously, the Milwaukee School of Engineering (MSOE) demonstrated a dexterous
tele-operational robotic system where actuators, joints, and linkages were fabricated
simultaneously using Selective Laser Sintered Nylon 12. Primary motivation for this research
was to conceive novel fluid power actuators that were inherently safe, compact, and Magnetic
Resonance Imaging (MRI) compatible for surgery and rehabilitation. Although the concept of
fabricating MRI compatible fluid power devices was demonstrated, further proof of precision
control was needed. The design and implementation of additively manufactured flexible fluidic
actuators (AMFFA) for precision control, best practices, and the comparison of these actuators
with other actuation technologies are presented. | null | null | null | null | null | null |
['Muhammad, Muztahid', 'Ghiaasiaan, Reza', 'Gradl, Paul R.', 'Schobel, Andre', 'Godfrey, Donald', 'Shao, Shuai', 'Shamsaei, Nima'] | 2021-12-06T22:20:58Z | 2021-12-06T22:20:58Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90696', 'http://dx.doi.org/10.26153/tsw/17615'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'Hastelloy-X', 'microstructure', 'grain size', 'macrohardness'] | Additively Manufactured Hastelloy-X: Effect of Post-Process Heat Treatment on Microstructure and Mechanical Properties | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cad11fb7-0fd2-481a-a985-b9cf0c0861f3/download | University of Texas at Austin | In this study, the effect of post-process heat treatment on the microstructure and
mechanical properties of Hastelloy-X superalloy fabricated via two different additive
manufacturing technologies, namely, laser beam powder bed fusion (LB-PBF) and laser
powder directed energy deposition (LP-DED), is investigated. Microstructure was
examined using scanning electron microscopy (SEM) and electron backscattered
diffraction (EBSD) analysis, while mechanical properties were evaluated by macro-hardness testing using the Rockwell B method. Microstructure of the alloys was studied
thoroughly after several heat treatments that involve stress-relieving (at 1066°C for 1.5
hours), hot isostatic pressing (HIP at 1163°C for 3 hours under 103 MPa pressure), and/or
solution treatment (at 1177°C for 3 hours). The results revealed that, for both LB-PBF and
LP-DED Hastelloy-X, the post-process heat treatments resulted in uniform grain structure
as well as partial dissolution of carbides, although they have different grain sizes. | null | null | null | null | null | null |
['Muhammad, Muztahid', 'Ghiaasiaan, Reza', 'Gradl, Paul R.', 'Shao, Shuai', 'Shamsaei, Nima'] | 2021-12-06T22:23:59Z | 2021-12-06T22:23:59Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90697', 'http://dx.doi.org/10.26153/tsw/17616'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['laser powder directed energy deposition', 'Haynes 230', 'microstructure', 'tensile behavior'] | Additively Manufactured Haynes 230 by Laser Powder Directed Energy Deposition (LP-DED): Effect of Heat Treatment on Microstructure and Tensile Properties | Conference paper | https://repositories.lib.utexas.edu//bitstreams/622f2ad6-a83d-4f30-b043-383e4e240f31/download | University of Texas at Austin | The microstructure and tensile mechanical properties of Haynes 230 fabricated
through laser powder directed energy deposition (LP-DED) were investigated, varying
temperature heat treatments between 900°C to 1177°C following deposition. Scanning
electron microscopy (SEM) was employed for microstructural analysis, whilst tensile testing
was utilized to evaluate the room temperature mechanical properties of the alloy. In an as-deposited state, the initial microstructure consisted of cellular γ and M6C/M23C6 carbides. The
cellular regions seem to be fully dissolved upon solutionizing at 1177°C for 3 hours. Following
post-deposition heat-treatments, the carbides were observed to precipitate and grow along
the grain boundaries as well as in the interior of grains. Solutionizing at 1177°C for 3 hours
following stress-relieving yielded better ductility and had an insignificant effect on the
strength. | null | null | null | null | null | null |
['Zak, Gene', 'Wang, Wendy Xu'] | 2019-10-24T18:33:42Z | 2019-10-24T18:33:42Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/77423', 'http://dx.doi.org/10.26153/tsw/4512'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Adhesive Bonding | Adhesive Bonding of Sheet for Laminated Metal Tooling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/779d4eea-4f48-4402-8f71-faf858d18c14/download | null | There exists a significant body of work on metal laminate tooling built by the “cut-stack-bond”
approach; however, automation with this method is difficult. Building laminations by "stack-bond-cut"
sequence, on the other hand, is more amenable to automation. Two main challenges of "stack-bond-cut"
sequence are blind contour cutting and bonding of the sheet. In this study, we investigate the hot-roller
method of thermoplastic adhesive bonding for the metal laminations. Metal sheet, having thermal
characteristics significantly different from paper, poses its own specific problems. During the bonding
process, in order to achieve good bond strength, appropriate heat and pressure must be applied. As the
stack builds up, thermal and mechanical properties change. This inconsistency of process conditions can
potentially lead to part warpage, unless carefully controlled. Temperature measurements with a
thermocouple embedded into lamination stack showed the effect of bonding process parameters on the
laminate temperature. | We gratefully acknowledge the financial support of Centre for Automotive Materials and
Manufacturing, Ontario Innovation Trust, and Canada Foundation for Innovation. | null | null | null | null | null |
['Utela, Ben', 'Anderson, Rhonda L.', 'Kuhn, Howard'] | 2020-02-28T16:30:17Z | 2020-02-28T16:30:17Z | 2006 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80117', 'http://dx.doi.org/10.26153/tsw/7138'] | eng | 2006 International Solid Freeform Fabrication Symposium | Open | Three-Dimensional Printing | Advanced Ceramic Materials and Processes for Three-Dimensional Printing (3DP) | Conference paper | https://repositories.lib.utexas.edu//bitstreams/f1e6819c-8031-4e53-8535-c0c9d4e002c9/download | null | The University of Washington and ExOne, Inc. are collaborating in the
development of advanced ceramic materials and processes for three-dimensional printing
(3DP). The focus of the research to be presented is work funded by the National Science
Foundation to develop a biocompatible alumina-based system for medical and dental
applications. Materials design, characterization, and processing considerations will be
discussed. | null | null | null | null | null | null |
['Lyons, Alan', 'Krishnan, Shankar', 'Mullins, John', 'Hodes, Marc', 'Hernon, Domhnaill'] | 2021-09-29T18:17:14Z | 2021-09-29T18:17:14Z | 2009 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88207', 'http://dx.doi.org/10.26153/tsw/15148'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['heat sinks', 'heat sink designs', 'three-dimensional printing', 'monolithic copper structures'] | Advanced Heat Sinks Enabled by Three-Dimensional Printing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8e6ba00c-afce-483f-a4e1-db50217237a8/download | University of Texas at Austin | With the rapid rise in power dissipated by integrated circuits, improved heat sinks designs
are needed to decrease the thermal resistance between them and forced air streams.
Manufacturing methods such as extrusion, machining and die-casting have been used to fabricate
conventional longitudinal fin designs. Although these technologies add relatively little cost, they
preclude the fabrication of more complex heat sink designs. We discuss novel heat sink designs
which increase surface area and/or modulate air flow streams. Fabrication of these
unconventional designs is enabled by using 3D printing technologies with the subsequent
conversion of the printed parts into monolithic copper structures by investment casting. | null | null | null | null | null | null |
['Weisensel, L.', 'Travitzky, N.', 'Greil, P.'] | 2020-02-13T19:41:42Z | 2020-02-13T19:41:42Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/79967', 'http://dx.doi.org/10.26153/tsw/6992'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Laminated Object Manufacturing | Advanced Laminated Object Manufacturing (LOM) of SiSiC Ceramics | Conference paper | https://repositories.lib.utexas.edu//bitstreams/389142a4-face-4589-a8c2-c3e52948915a/download | null | Carbon sheets were used as a starting material for fabrication of SiSiC composites by
advanced LOM. This approach consists of three steps: First a preform was fabricated form
phenolic resin coated carbon paper with a LOM-device. Second the preform was turned into a
carbon preform by pyrolysis in N2-atmosphere. Third pressureless reactive melt infiltration of
silicon into the as fabricated carbon preform, which finally yielded a dense SiSiC composite.
SEM analysis revealed a microstructure consisting of uniformly dispersed β-SiC grains in a
matrix of silicon. The LOM fabricated material exhibited an average four point bending
strength and Youngs modulus of 115 MPa and 165 GPa, respectively. | null | null | null | null | null | null |
['Petrzelka, Joseph E.', 'Frank, Matthew C.'] | 2021-09-28T19:58:30Z | 2021-09-28T19:58:30Z | 2009 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88167', 'http://dx.doi.org/10.26153/tsw/15108'] | eng | 2009 International Solid Freeform Fabrication Symposium | Open | ['Subtractive Rapid Prototying', 'STL models', 'layer-based removal processing', 'tool accessibility'] | Advanced Process Planning for Subtractive Rapid Prototyping | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cfbe24e4-e8ab-4024-9751-eba262a2ec7d/download | University of Texas at Austin | This paper presents process planning methods for Subtractive Rapid Prototyping, which deals with
multiple setup operations and the related issues of stock material management. Subtractive Rapid
Prototyping (SRP) borrows from additive rapid prototyping technologies by using 2½D layer based
toolpath processing; however, it is limited by tool accessibility. To counter the accessibility problem,
SRP systems (such as desktop milling machines) employ a rotary fourth axis to provide more complete
surface coverage. However, layer-based removal processing from different rotary positions can be
inefficient due to double-coverage of certain volumes. This paper presents a method that employs STL
models of the in-process stock material generated from slices of the part along the rotation axis. The
developed algorithms intend to improve the efficiency and reliability of these multiple layer-based
removal steps for rapid manufacturing. | null | null | null | null | null | null |
['Hui, Du Zhao', 'Kai, Chua Chee', 'Sen, Chua Yew', 'Gek, Loh-Lee Keow', 'Tiak, Lim Ser'] | 2019-09-23T17:18:29Z | 2019-09-23T17:18:29Z | 2000 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/75980', 'http://dx.doi.org/10.26153/tsw/3079'] | eng | 2000 International Solid Freeform Fabrication Symposium | Open | Manufacturing | Advanced Sheet Metal Manufacturing using Rapid Tooling 522 | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c2ff8c60-b253-4427-bcc4-6f8d12b8ddf3/download | null | A closed loop process is proposed for making sheet metal prototyping parts by using advanced computer aided techniques and computer controlled machines. The key aspect of this process is the method used to fabricate and modify the sheet metal
forming tools, which are not necessarily for mass production but should be suitable for short run production or design evaluation of sheet metal products where the prototyping cost and lead-time are greatly reduced. Various approaches are investigated in the preparation of the tooling for onward embossing on a sheet metal. The three indirect approaches use Selective Laser
Sintering (SLS), Stereolithography(SLA), and high speed Computer Numerical Controlled (CNC) milling to build the masters from computer data models. And the masters are then served in the vacuum casting process to generate the non-ferrous
tooling. The direct approach uses DTM’s RapidSteel to produce the metal tooling without going through any secondary process. Comparisons on quality, leading time and cost are presented. | null | null | null | null | null | null |
['Asiabanpour, Bahram', 'Khoshnevis, Behrokh', 'Palmer, Kurt', 'Mojdeh, Mehdi'] | 2019-11-08T15:30:24Z | 2019-11-08T15:30:24Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78323', 'http://dx.doi.org/10.26153/tsw/5410'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | SIS Process 25 | Advancements in the SIS Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a041cdf7-afe3-470d-b02c-43f25936d5c9/download | null | Selective Inhibition of Sintering (SIS) is a new layer-based rapid prototyping process. This paper
reports the progress in research and development of the SIS process. Specific printer path
generation method, experimentation with various powder and inhibitor materials, and systematic
models leading to optimum performance given various factors affecting part strength, surface
quality, and dimensional accuracy are presented. | null | null | null | null | null | null |
['Mahela, T.', 'Cormier, D.', 'Harrysson, O.', 'Ervin, K.'] | 2020-03-09T15:23:46Z | 2020-03-09T15:23:46Z | 2007 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80197', 'http://dx.doi.org/10.26153/tsw/7216'] | eng | 2007 International Solid Freeform Fabrication Symposium | Open | Electron Beam Melting | Advances in Electron Beam Melting of Aluminum Alloys | Conference paper | https://repositories.lib.utexas.edu//bitstreams/92943da2-836d-4ab8-97fb-3aaf77fd0336/download | null | The high thermal conductivity and melt pool optical reflectivity associated with
aluminum alloys can pose significant challenges for direct-metal SFF processes. The use
of SFF processes to produce aluminum parts is often not cost effective relative to CNC
machining for simple geometries. However, the use of SFF techniques for aluminum
alloys is justified for some applications such as aerospace forgings or high surface area
heat exchangers. This paper describes recent progress in processing aluminum alloys
using the Electron Beam Melting process. Structure and properties will be discussed, as
well challenges associated with high vapor pressure alloying elements such as zinc and
magnesium. | null | null | null | null | null | null |
['Dutson, Alan J.', 'Wood, Kristin L.', 'Beaman, Joseph J.', 'Crawford, Richard H.'] | 2019-10-23T15:17:08Z | 2019-10-23T15:17:08Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/76758', 'http://dx.doi.org/10.26153/tsw/3847'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Functional Testing | Advances in Functional Testing with SFF Parts | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c4f9703f-d4d5-40e9-98e5-37dfd8accdd7/download | null | Functional testing of SFF parts represents an exciting area of research in solid freeform
fabrication. One approach to functional testing is to use similitude techniques to correlate the
behavior of an SFF model and a product. Previous research at UT Austin has resulted in
development of an empirical similitude technique to correlate the behavior of parts of dissimilar
materials and geometry. Advances in the empirical similitude technique are presented in this
paper. Sources of coupling between material and geometry characteristics that produce errors in
the current empirical similitude technique are outlined. A modified approach that corrects for
such errors is presented. Numerical examples are used to illustrate both the current and the
advanced empirical similitude methods. | null | null | null | null | null | null |
['Tompkins, J.V.', 'Laabi, R.', 'Birmingham, B.R.', 'Marcus, H.L.'] | 2018-10-03T18:43:19Z | 2018-10-03T18:43:19Z | 1994 | Mechanical Engineering | doi:10.15781/T2WS8J53D | http://hdl.handle.net/2152/68678 | eng | 1994 International Solid Freeform Fabrication Symposium | Open | ['SALD', 'Solid free-form fabrication', 'DES'] | Advances in Selective Area Laser Deposition of Silicon Carbide | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e74dc268-0af2-46e9-85a1-85234b3b7907/download | null | Selective Area Laser Deposition (SALD) is a Solid Freeform Fabrication (SFF) technique which
uses a scanning laser beam to produce solid material by locally decomposing a gas precursor. In
this work, a focused C02 laser beam strikes a substrate in the presence oftetramethylsilane
(TMS) or diethylsilane (DES), producing silicon carbide objects with high density and no binder
phase. Recent investigation has yielded growth rates up to 2.7mlnJmin in the beam area, and has
eliminated previously noted contamination ofthe optics by a byproduct which mass
spectroscopy identifies as silicon dioxide. This paper reviews a cause of non-uniform growth and
delTIOnstrates the addition of hydrogen and reduced scan speeds to lTIake lTIultilayer parts. In
addition, it presents a lTIethod for in-situ measurement of height of deposited material. | null | null | null | null | null | null |
['Amado, A.', 'Schmid, M.', 'Levy, G.', 'Wegener, K.'] | 2021-10-05T13:30:38Z | 2021-10-05T13:30:38Z | 2011 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88367', 'http://dx.doi.org/10.26153/tsw/15306'] | eng | 2011 International Solid Freeform Fabrication Symposium | Open | ['Selective Laser Sintering', 'powder characterization', 'powder flow processing'] | Advances in SLS Powder Characterization | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7166d153-eff1-4b21-8889-c1a8a20c3b01/download | University of Texas at Austin | This paper introduces a new Selective Laser Sintering (SLS) powder characterization
methodology. A better understanding regarding powder flow processing range is targeted.
Intrinsic properties of polymers are given from the basic chemical structure and non-intrinsic
ones describe characteristics caused from pre-processing and production. The non-intrinsic ones
are dedicated to the powder. Understanding the particle size distribution and shape coupled with
its ability to flow under the particular SLS processing conditions is desired. In this direction, a
system called Revolution Powder Analyzer is employed and the dynamic powder behavior is
characterized in nearly roll spreading conditions. This allows a sensitive differentiation of
powders regarding their flow-ability and predicts, to a certain extent, the behavior under SLS
conditions. | null | null | null | null | null | null |
['Jacobs, Paul F.', 'Richter, Jan'] | 2018-04-17T16:41:04Z | 2018-04-17T16:41:04Z | 1991 | Mechanical Engineering | doi:10.15781/T25T3GH0J | http://hdl.handle.net/2152/64329 | eng | 1991 International Solid Freeform Fabrication Symposium | Open | ['SLA', 'Windownpane', 'Weave', 'SLA-250'] | Advances in Stereolithography Accuracy | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cbf7f76c-0bd2-4566-90d4-5a18ad3d3460/download | null | It has been almost four years since the SLA - 1 ushered in the
new technology of StereoLithography, and about 2\ years since 3D
Systems introduced the SLA-250. Since then, nearly 300 systems
have been installed worldwide and are currently providing benefits
in a range of applications which might well be summarized by the
term "Rapid Prototyping and Manufacturing" or "RPM".
During the past year the accuracy of parts built with
stereoLithography has benefitted significantly from nine important
technological advances. The research and development efforts which
formed the foundation for this progress originated within the
Process, Chemistry and Software departments of 3D Systems.
The following is a listing, and brief description, of the key
features of each of these advances. | null | null | null | null | null | null |
['Sercombe, T.B.', 'Schaffer, G.B.'] | 2020-02-12T15:06:37Z | 2020-02-12T15:06:37Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/79934', 'http://dx.doi.org/10.26153/tsw/6960'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Selective Laser Sintering | Advances in the Production of Infiltrated Aluminium Parts Using Selective Laser Sintering | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b41459fa-1a05-4505-9d85-699423d7b2c4/download | null | Recent advances in a rapid freeform fabrication process for the production of aluminium
parts are considered. The methodology involves the formation of an unconstrained, resin bonded
aluminium powder part by Selective Laser Sintering, the burnout of the resin, the partial
transformation of the aluminium into a rigid aluminium nitride skeleton by reaction with the
atmosphere under a magnesium/alumina blanket and the subsequent infiltration with a second
aluminium alloy. Here we describe the process and consider potential applications. Strategies for
controlling the growth of the aluminium nitride are also to be discussed. | null | null | null | null | null | null |
['Liu, Fei', 'Jingchao, Wang', 'Zhi, Tan', 'Bin, Liu', 'Yue, Guo', 'Zhang, David Z.'] | 2021-11-09T18:57:26Z | 2021-11-09T18:57:26Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90119', 'http://dx.doi.org/10.26153/tsw/17040'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'selective laser melting', 'upper-stage cabin structure', 'integrated design and manufacturing'] | An Aerospace Integrated Component Application Based on Selective Laser Melting: Design, Fabrication and Fe Simulation | Conference paper | https://repositories.lib.utexas.edu//bitstreams/9cb14418-ea21-4a16-b179-4999448e6fd8/download | University of Texas at Austin | Developments in Additive Manufacturing (AM) technologies have enabled the
integrated manufacturing of complex structures with multifunctional performances. Selective
Laser Melting (SLM), as one of them, becomes the candidate for production of metallic aviation
spaceflight structures because of its high precision for controlling architecture and excellent
performance. An aerospace component named Upper-stage Cabin was selected for integrated
design without connectors, and then manufactured by a SLM system using Ti-6Al-4V powder.
The dimensional accuracy of the component was verified through testing; It’s mechanical
response was analyzed under compressive loading test, compared with the results of numerical
simulation. The study found that SLM technology is an effective means for integrated design
and manufacture of Upper-stage Cabin structures for aerospace. The dimensional precision of
the complex integrated structures formed by SLM meets the application requirements. The
formed integrated components have achieved good mechanical properties, which promote the
application of this technology in aerospace field. | null | null | null | null | null | null |
['Cho, Uichung', 'Wood, Kristin L.', 'Crawford, Richard H.'] | 2019-03-07T18:09:52Z | 2019-03-07T18:09:52Z | 1999 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/73566', 'http://dx.doi.org/10.26153/tsw/708'] | eng | 1999 International Solid Freeform Fabrication Symposium | Open | ['rapid prototyping techniques', 'industries'] | Agile Product Testing with Constrained Prototypes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8951b4bc-edc2-44c8-a19f-45538d564f4d/download | null | The means to acquire reliable functional information is a critical factor that differentiates product development time and cost. Thanks to advances in solid freeform
fabrication techniques, industries can produce geometrically complex parts within
dramatically reduced time and cost. Even though industries can save significant efforts by performing functional tests rapid prototypes, they still prefer full-scale product tests, especially in later design phases, due to inherent limitations in traditional
similarity methods (TSM). This paper describes a new method to perform reliable
functional tests with rapid prototypes that cannot be properly handled by the TSM. | null | null | null | null | null | null |
['Wudy, K.', 'Drummer, D.'] | 2021-10-27T22:15:58Z | 2021-10-27T22:15:58Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89631 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['aging behavior', 'bulk values', 'part properties', 'interrelation', 'polyamide 12'] | Aging Behavior of Polyamide 12: Interrelation Between Bulk Characteristics and Part Properties | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a249bd79-2a3a-4c30-97b3-4474c8b83901/download | University of Texas at Austin | The high process temperatures in combination with long building times during the laser
sintering process lead to chemical and physical aging mechanisms on the polymeric feed
material. The unmolten partcake material, which acts as a supporting structure, can be removed
after each building process and reused for further processes. However, material as well as bulk
properties are changed due to thermal and mechanical load during the laser sintering process.
Within this paper the interrelation between the aging state, bulk values and resulting
part properties like porosity, surface roughness and mechanical behavior are derived. Therefore,
polyamide 12 powder is used for at least five processing cycles without refreshing. Before and
after each building process, bulk characteristics and changes of the particle surface were
determined. Specimens were manufactured during the laser sintering process in order to study
the part density, roughness and mechanical behavior. | null | null | null | null | null | null |
['Palomino, Donald', 'Bian, Shijie', 'Salcedo, Pedro', 'Navarro, Erick', 'Gopalaiah, Bharath', 'Otis4, Richard', 'Li, Bingbing'] | 2023-01-26T22:00:35Z | 2023-01-26T22:00:35Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117326', 'http://dx.doi.org/10.26153/tsw/44207'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | ['Augmented Reality Training', 'Metal Additive Manufacturing', 'Text Recognition', 'Object Detection'] | AI-Powered Augmented Reality Training for Metal Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/4e9fea74-8767-4804-8338-8259b8eeb7c4/download | null | Metal additive manufacturing (AM) training can cost a company the considerable amount of
time, cost, and resources. To resolve this challenge, the NSF funded HyperSkill platform was
applied to create an innovative, immersive training program that integrates AI-powered object
detection and text recognition into a comprehensive digital twin of the metal AM machine
operation. This immersive digital twin will support the delivery of just-in-time guidance to
trainees while also monitoring their actions and providing contextual and personalized feedback
to accelerate training, foster retention, and maximize transfer to the actual job. The augmented
reality (AR) training supports the import of 3D assets, no-code authoring of workflows, standard
operating procedures (SOP), step-by-step instructions, and delivery across a wide variety of AR
devices. For this study, the specific metal AM operation is based on the Renishaw AM400 in
both its full and reduced build volume (RBV) configuration. | null | null | null | null | null | null |
['Cawley, J.D.', 'Wei, P.', 'Liu, Z.E.', 'Newman, W.S.', 'Mathewson, B.B.', 'Heuer, A.H.'] | 2018-10-03T19:18:23Z | 2018-10-03T19:18:23Z | 1995 | Mechanical Engineering | doi:10.15781/T2HH6CR12 | http://hdl.handle.net/2152/68681 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['CAM-LEM', 'Solid free-form fabrication', 'powder synthesis'] | Al2O3 Ceramics Made by CAM-LEM (Computer-Aided Manufacturing of Laminated Engineering Materials) Technology | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a17c37da-e696-40a4-bedb-e7c9d2cef556/download | null | The concept of CAM-LEM technology is presented and discussed in the context of the fabrication of Al2O3 ceramics. Particular attention is paid to the interplay of green tape characteristics and the unit operations involved in CAM-LEM. Examples of ceramic shapes
difficult to form by conventional methods are described. | null | null | null | null | null | null |
['Weiss, C.M.', 'Marcus, H.L.'] | 2021-09-30T13:37:30Z | 2021-09-30T13:37:30Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88244', 'http://dx.doi.org/10.26153/tsw/15185'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['SFF', 'Selective Area Laser Deposition', 'SALD joining', 'carbides', 'nitrides', 'ceramics', 'CVD gas decomposition', 'aluminum oxide'] | Al2O3 Precursor Evaluation for SALD Joining | Conference paper | https://repositories.lib.utexas.edu//bitstreams/56ca323d-8241-49f2-9e4f-bb7a00a057d4/download | University of Texas at Austin | SFF technology is not limited to the creation of components and objects. Freeform
technology can be a mechanism for joining of materials. By defining the space between two
objects as the boundary for a free-form object it is possible to form a three dimensional joint fill.
Selective Area Laser Deposition or SALD, has been used for free form and joining of carbides
and nitrides but has the potential to make other classes of ceramics. By selecting a metal-organic
precursor and an oxidizer, an oxide can be created by CVD gas decomposition. In this study such
oxide joint fill precursors are studied, particularly for alumina. | null | null | null | null | null | null |
['Bártolo, Paulo', 'Lagoa, Ricardo', 'Mendes, Ausenda'] | 2019-11-15T16:09:45Z | 2019-11-15T16:09:45Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78419', 'http://dx.doi.org/10.26153/tsw/5506'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | Alginate-Based | Alginate-Based Rapid Prototyping System | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c5177bf3-78b8-40e3-beaa-ee65a0d8fba1/download | null | Alginate hydrogels are an import class of ionic biopolymers for medical and biotechnological
applications, produced by the combination of alginate with a proper cross-linking agent.
During the gel formation, cross-links can be formed between the alginate chains and cationic
species, changing the elastic behaviour of the material that controls the volume change
phenomena of the gels.
This paper proposes a new rapid prototyping system to produce three-dimensional alginate
structures by extruding, layer-by-layer, a previously prepared solution of sodium alginate in
water mixed with a solution of calcium chloride, both of known concentration. The building
process to obtain these gel structures is described, from a chemical point of view, and some
obtained structures are shown. The alginate concentration over both the kinetics and accuracy
effects of the process is investigated. The preliminary findings of this research work promise
to open an exciting new area for medical applications. | null | null | null | null | null | null |
['Arndt, Alexander', 'Hackbusch, Heike', 'Anderl, Reiner'] | 2021-10-21T18:40:31Z | 2021-10-21T18:40:31Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89423 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', '3D nesting', 'optimization', 'algorithm'] | An Algorithm-Based Method for Process-Specific Three-Dimensional Nesting for Additive Manufacturing Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/2cbf39ce-e17a-4ba0-b798-801640b56a89/download | University of Texas at Austin | To achieve optimal and high-quality results through additive manufacturing, the process-and technology-specific orientation and positioning of components within the virtual space, the so-called nesting, is essential. Primarily the nesting step is examined in this paper. From a scientific
perspective it is a matter of examining this process and furthermore to analyze the optimal insertion
of supporting structures, since the critical machine-specific parameters have been insufficiently
studied. Within this paper a new multi-criteria optimization based on a conceptual algorithm is
proposed. The most important point is the consideration of a technical and not only geometric
nesting process. The objective is the demonstration of restrictions and boundary conditions and a
first developing for a new approach for the nesting process. As an example, the influence of the
orientation of the spring rate is presented with a sample component here. Furthermore, there will
be a prototype implementation and a short validation. Finally, a brief conclusion and an outlook is
given. | null | null | null | null | null | null |
['Gardner, J.A.', 'Nethercott-Garabet, T.', 'Kaill, N.', 'Campbell, R.I.', 'Bingham, G.A.', 'Engstrøm, D.S.', 'Balc, N.O.'] | 2021-11-15T21:24:49Z | 2021-11-15T21:24:49Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90278', 'http://dx.doi.org/10.26153/tsw/17199'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', '5-axis', 'tool path', 'material extrusion', 'G-code'] | Aligning Material Extrusion Direction with Mechanical Stress via 5-Axis Tool Paths | Conference paper | https://repositories.lib.utexas.edu//bitstreams/71069994-e807-495b-9b05-b025680bc454/download | University of Texas at Austin | Mechanical properties of parts fabricated via the Material Extrusion (ME) process can be
improved by optimising process settings, however, their properties are strongly influenced by
build orientation due to the stair-stepping effect initiating cracks whilst under load. 5-axis ME
enables the fabrication of parts without the layer-by-layer restrictions that conventional 3-axis
strategies impose. By aligning extrusion direction with high stress tensors, 5-axis tool paths can
be used to reduce the effects of weak inter-layer bonds.
To establish performance differences between parts manufactured by either strategy,
wave spring-inspired geometry was selected for production, due to the multi-directional tensile
loads acting throughout the material. 5-axis and 3-axis tool paths were generated via the
Grasshopper 3D virtual environment within Rhinoceros 3D and MakerBot Desktop, and
manufactured using a 5AXISMAKER and a MakerBot Replicator 2, respectively. To evaluate
performance differences between the two strategies, compression tests were conducted on the
parts. | null | null | null | null | null | null |
Drake, Samuel H. | 2018-04-10T18:56:39Z | 2018-04-10T18:56:39Z | 1990 | Mechanical Engineering | doi:10.15781/T22J68N1S | http://hdl.handle.net/2152/64247 | eng | 1990 International Solid Freeform Fabrication Symposium | Open | ['Alpha_1', 'SFF techniques', 'NURBs'] | ALPHA_I, Remote Manufacturing, and Solid Freeform Fabrication | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c3ee93b8-37d9-4fa8-89ce-08c104274c3b/download | null | Alpha_l is a nonuniform rational B-spline (NURBs) based solid modeling system that
has been developed at the University of Utah over the past 10 years. In addition to being
useful in modeling objects that are described by simple rotation and extrusion operations,
the real power of Alpha_l is demonstrated in the modeling of complex parts with sculptured
surfaces. For the past several years, a major research thrust has been to use Alpha_l to
semi-automatically generate process plan information and numerical control code to manufacture
mechanical parts directly from the models. A long term goal is to support an on-line
remote manufacturing facility for producing prototype parts. Recently, a 3D Systems stereo
lithography machine has been added to the advanced manufacturing laboratory. The stereo
lithography process and other SFF techniques are of particular interest for supporting a
remote manufacturing facility in that these processes are inherently much safer than numerically
controlled machining. Special Alpha_l interfaces including a new slicing algorithm
are being developed for the SFF machine use. By generating a SFF part directly from
its NURBs description, Alpha_l should facilitate the manufacture of complex parts while
providing smoother surfaces. | null | null | null | null | null | null |
['Schnell, N.', 'Siewert, M.', 'Kleszczynski, S.', 'Witt, G.', 'Ploshikhin, V.'] | 2021-11-18T17:27:19Z | 2021-11-18T17:27:19Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90437', 'http://dx.doi.org/10.26153/tsw/17358'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['laser powder bed fusion of metals', 'LPBF-M', 'thermocouple', 'finite element modeling', 'FEM', 'validation', 'thermocouple', 'stainless steel 1.4542', 'GP1'] | Alternative Approach on an In-Situ Analysis of the Thermal Progression During the LPBF-M Process Using Welded Thermocouples Embedded into the Substrate Plate | Conference paper | https://repositories.lib.utexas.edu//bitstreams/3947858f-d621-41fc-afb4-309cb7acbeee/download | University of Texas at Austin | Laser powder bed fusion (LPBF-M) is a very potent technology for creating highly individualized, complex, and functional metal parts. One of the major influencing factors is the thermal progression. It
significantly determines size accuracy, microstructure and process stability. Therefore, creating an enhanced understanding of thermal phenomena through measurements and simulations is crucial to increase the reliability of the technology. Current research is mainly based on temperature measurements
of the upper layer, leaving major scope for the conditions at the substrate-part-interface. This area is of
utmost technical importance because it serves as the main heat sink. Insufficient heat dissipation leads
to accumulations of heat, deformations, and process breakdowns. This contribution presents a simple
and flexible method to analyze the thermal progression close to the part inside the substrate plate. The
acquired data shows very high consistency. Additionally, the results are compared to a model created
using an ISEMP developed FEM-Software which shows promising results for validation studies. | null | null | null | null | null | null |
['Spratt, M.', 'Newkirk, J.', 'Chandrashekhara, K.'] | 2021-11-02T14:52:59Z | 2021-11-02T14:52:59Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89817 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['syntactic foam', 'aluminum matrix', 'additive manufacturing', 'microsphere flotation', 'microsphere fracture'] | Aluminum Matrix Syntactic Foam Fabricated with Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/90e3d3fe-e31f-4d93-88e6-4540ebe39c4e/download | University of Texas at Austin | Syntactic foams are lightweight structural composites with hollow reinforcing particles
embedded in a soft matrix. These materials have applications in transportation, packaging, and
armor due to properties such as relatively high specific stiffness, acoustic dampening, and impact
absorption. Aluminum matrices are the most widely studied of metal matrix syntactic foams, but
there is little to no research in regards to processing the foams with additive manufacturing. It is
theorized that the fast cooling rates and limited kinetic energy input of additive could reduce two
issues commonly associated with processing syntactic foams: microsphere flotation in the melt
and microsphere fracture during processing. In this study, 4047 aluminum blended with glass
particles was deposited on a 4047 Al substrate using an additive process. Characterization of the
foams include mechanical testing and microstructural analysis. | null | null | null | null | null | null |
['Qi, Yang', 'Zhang, Hu', 'Zhu, Haihong', 'Nie, Xiaojia', 'Zeng, Xiaoyan'] | 2021-11-18T00:47:12Z | 2021-11-18T00:47:12Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90377', 'http://dx.doi.org/10.26153/tsw/17298'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['aluminum-lithium', 'Al-Li', 'laser powder bed fusion', 'LPBF'] | An Aluminum-Lithium Allloy Produced by Laser Powder Bed Fusion | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a5ff4a4e-fb07-4515-84e6-6ef404dc0762/download | University of Texas at Austin | Aluminum-lithium (Al-Li) alloys are promising to replace traditional high-strength
aluminum alloys in aerospace and military industries due to their low density, high specific strength,
and excellent corrosion resistance. However, there is little research focused on the laser powder
bed fusion (LPBF) of Al-Li alloys due to their poor weldability and high crack susceptibility. In
this study, the feasibility of the Al-Li alloy fabricated by LPBF was investigated. The effect of the
processing parameters on the densification and crack formation behavior was studied. Finally, after
optimizing the processing parameters, crack-free and nearly fully dense 2195 Al-Li alloy 3D-printed samples were obtained. A relative density of 99.92% and a microhardness of 89.1 HV were
achieved. | null | null | null | null | null | null |
['Zhang, Y.', 'Bernard, A.'] | 2021-10-18T22:36:23Z | 2021-10-18T22:36:23Z | 2014 | Mechanical Engineering | null | https://hdl.handle.net/2152/89274 | eng | 2014 International Solid Freeform Fabrication Symposium | Open | ['Additive Manufacturing', 'feature based process planning', 'knowledge based process planning', 'CAPP system'] | AM Feature and Knowledge Based Process Planning for Additive Manufacturing in Multiple Parts Production Context | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1b6cee97-2bc9-4f92-8383-4f91e2b48493/download | University of Texas at Austin | Additive Manufacturing (AM) has played an important role in manufacturing, especially in
customized production. It is an ideal 'Concurrent Manufacturing' which enables fabricating a
group of same or even different multiple parts simultaneously within one build volume due to
its unique layer by layer processing way. However, there is very few available methods or
tools for users, e.g. the AM manufacturing service bureaus, to optimize the process and
production plan in multiple parts production context. To deal with this problem, this paper
introduces an AM feature and knowledge based systematic process planning strategy. The
main contents and key issues of process planning for AM in multiple parts production context
are analyzed. Then, a developing CAPP system based on a systematic process planning
framework for AM in this multiple parts production context is presented. Finally, some test
examples are applied to demonstrate the functions and effectiveness of some key modules of
the developing system. | null | null | null | null | null | null |
['Muhammad, M.', 'Masoomi, M.', 'Torries, B.', 'Shamsaei, N.', 'Haghsenas, M.'] | 2021-11-11T15:13:49Z | 2021-11-11T15:13:49Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90215', 'http://dx.doi.org/10.26153/tsw/17136'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['instrumented indentation', 'additive manufacturing', 'Ti-6Al-4V', 'creep stress exponent'] | Ambient-Temperature Indentation Creep of an Additively Manufactured Ti-6Al-4V Alloy | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b54a5218-389f-470c-b578-71a926cc632b/download | University of Texas at Austin | Instrumented indentation testing technique is a robust, convenient, and non-destructive
characterization method to study time-dependent plastic deformation in metals and alloys at
ambient and elevated temperatures. In this current research, the depth-sensing indentation creep
behavior of additively manufactured Ti-6Al-4V alloy and its mechanism were studied at ambient
temperature for different additive manufacturing scan direction and scan size. Indentation creep
tests were conducted through a dual-stage scheme (loading followed by a constant load-holding)
at different peak load of 250, 350, and 450 mN with holding time of 400 s. In addition,
microstructural quantitative analyses, using optical microscopy and scanning electron microscopy,
were performed. Microstructural assessments and depth-sensing creep characterizations were then
used to assess processing parameter/ microstructure/ creep properties relationships for this alloy. | null | null | null | null | null | null |
['Espalin, David', 'Arcaute, Karina', 'Anchondo, Eric', 'Adame, Arturo', 'Medina, Francisco', 'Winker, Rob', 'Hoppe, Terry', 'Wicker, Ryan'] | 2021-09-29T22:38:08Z | 2021-09-29T22:38:08Z | 2010 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88222', 'http://dx.doi.org/10.26153/tsw/15163'] | eng | 2010 International Solid Freeform Fabrication Symposium | Open | ['fused deposition model', 'additive manufacturing', 'bonding', 'bonding methods', 'thermoplastic material', 'FDM-manufactured parts', 'bonding strength'] | Analysis of Bonding Methods for FDM-Manufactured Parts | Conference paper | https://repositories.lib.utexas.edu//bitstreams/0a483bbc-75f5-40b8-a1fb-0ec631bd9c3b/download | University of Texas at Austin | The fused deposition modeling (FDM) additive manufacturing (AM) technology has been
valuable for producing a variety of concept models, functional prototypes, end-use parts and
manufacturing tools using a range of durable thermoplastic materials. The largest individual
component that can be produced in FDM depends on the dimensions of the build chamber for the
specific FDM system being used, with a maximum build chamber size available of 914 x 610 x
914 mm. This limitation is not unique to FDM as all AM systems are constrained by a build
chamber. However, by using thermoplastic materials, individual components can be bonded
together using different methods to form a single piece. Bonding can be used to help reduce
building time and support material use, and also allows for the fabrication and assembly of final
products larger than the build chamber. This work investigated different methods for bonding
FDM-manufactured parts, including the use of five different adhesives and solvents as well as
two different welding techniques (hot air welding and ultrasonic welding). The available FDM
materials investigated included acrylonitrile butadiene styrene (ABSi, ABS-M30, ABS-M30i),
polycarbonate (PC, PC-ABS, PC-ISO), polyphenylsulfone (PPSF), and ULTEM 9085. Bonding
strengths were characterized by comparing ultimate tensile strengths at break and analyzing the
mode of failure. Overall, the bonding method of hot air welding produced the strongest bond for
all the materials investigated except for ULTEM 9085 for which the strongest bond was achieved
with the two-part epoxy adhesive Hysol E-20HP. | null | null | null | null | null | null |
['Isa, Mohammed A.', 'Yiğit, Ismail Enes', 'Lazoglu, Ismail'] | 2021-11-11T16:22:27Z | 2021-11-11T16:22:27Z | 2018 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90235', 'http://dx.doi.org/10.26153/tsw/17156'] | eng | 2018 International Solid Freeform Fabrication Symposium | Open | ['freeform overhangs', 'build direction', 'mutli-axis additive manufacturing', 'additive manufacturing'] | Analysis of Build Direction in Deposition-Based Additive Manufacturing of Overhang Structures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/5be8db77-3358-4b8c-af21-96a0a263d228/download | University of Texas at Austin | Additive manufacturing (AM) has gained repute as a direct method of fabrication of
complex parts. However, the requirement for each layer to be structurally supported can make parts with
overhangs hard to produce without alterations to the parts. This work proposes using multi-axis additive
manufacturing to fabricate and analyze freeform overhangs such as bridge structures. Multi-axis AM
allows reorientation of the build direction so that overhangs can be 3D printed. Consequently, decision on
the build orientation is necessary and its result should be analyzed. The effect of the AM build
direction with respect to the overhang’s local surface directions will be studied. A Rhinoceros® plugin is
designed to generate the path of the multi-axis AM for the unsupported components like roofs, bridges and
protrusions. The effects of the build direction on the surface quality and deformation of the components are
studied. | null | null | null | null | null | null |
['Fathi, S.', 'Dickens, P. M.', 'Hague, R. J. M.', 'Khodabkhski, K.', 'Gilbert, M.'] | 2020-03-11T15:13:14Z | 2020-03-11T15:13:14Z | 2008 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80248', 'http://dx.doi.org/10.26153/tsw/7267'] | eng | 2008 International Solid Freeform Fabrication Symposium | Open | ['solid free-form fabrication', 'Ink-jetting'] | Analysis of Droplet Train/Moving Substrate Interactions in Ink-Jetting Processes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/774a34be-0bbd-40b7-9429-0bce1c54b30a/download | null | Ink-jetting technology has been applied to several processes in solid free-form
fabrication (SFF) wherein droplets impinge onto a substrate to deposit the build material.
Droplet impact behaviour on a surface has been the interest of many researchers; however,
few studies have been undertaken to investigate the interaction of droplets with the moving
substrate. This paper reports the impact behaviour of the droplets jetted at different
frequencies onto a substrate moving over a range of velocities. The phenomena associated
with the interaction were classified into three main regimes. | null | null | null | null | null | null |
['Alqahtani, Hassan', 'Keller, Eric', 'Ray, Asok', 'Basak, Amrita'] | 2021-11-18T00:43:48Z | 2021-11-18T00:43:48Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90376', 'http://dx.doi.org/10.26153/tsw/17297'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['fatigue damage', 'crack initiation', 'ultrasonic test', 'digital microscope', 'signal attenuation', 'discrete wavelet transform'] | Analysis of Fatigue Crack Evolution Using In-Situ Testing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/b292e60f-b871-4bbc-83bd-8c47207801ff/download | University of Texas at Austin | The objective of the current work is to investigate the feasibility of an in-situ technique to
characterize the evolution of fatigue failure in conventionally manufactured aluminum parts in
real time. An in-situ fatigue testing setup integrated with ultrasonic transducers and a digital
microscope allows for the systematic study of fatigue crack evolution in aluminum specimens.
The resulting data from experimentation, characterization, and analysis are integrated to gain
unprecedented insights into the evolution of fatigue failure in wrought aluminum parts. The
learning from this work will be further implemented on additively manufactured specimens. | null | null | null | null | null | null |
['Gaytan, Sara M.', 'Cadena, Monica', 'Aldaz, Mayela', 'Herderick, Edward', 'Medina, Francisco', 'Wicker, Ryan'] | 2021-10-12T17:59:57Z | 2021-10-12T17:59:57Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88708', 'http://dx.doi.org/10.26153/tsw/15642'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['ceramic fabrication', 'ferroelectric ceramics', 'binder jetting', 'dielectric capacitors', 'sensors', 'integrated circuits', 'M-Lab system', 'ExOne'] | Analysis of Ferroelectric Ceramic Fabricated by Binder Jetting Technology | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1329182a-eca5-470a-9bed-f0ab8c5ebb71/download | University of Texas at Austin | The M-Lab system from ExOne was used to fabricate 3D structures of BaTiO3 ceramic
with applications that include dielectric capacitors, sensors, and integrated circuits. For this
project, layer thicknesses of 15 and 30 μm and various percentages of binder saturation were
used to fabricate components from powder. An organic binding agent was utilized during the
printing process and later burned out at ~600°C prior to sintering. Multiple building parameters
and sintering profiles were analyzed and compared in an attempt to obtain dense parts while
examining shrinkage percentage variations. | null | null | null | null | null | null |
['Rhodes, Andrew', 'Smith, Tyler', 'Sharpe, Christian', 'Kunc, Vlastimil', 'Duty, Chad'] | 2023-01-20T16:49:50Z | 2023-01-20T16:49:50Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117265', 'http://dx.doi.org/10.26153/tsw/44146'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | LFAM | Analysis of Fiber Attrition and Mechanical Performance in Large-Format Additive Manufacturing of Long-Fiber Reinforced Polymer Composites | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c9008ad8-78ca-454a-849d-052bd8c36564/download | null | Understanding the residual fiber length of discontinuous fiber-reinforced thermoplastics in
large-format additive manufacturing (LFAM) is of significant interest since the residual fiber
length influences the mechanical properties of the final part. Currently, the attrition of long fiber
reinforcement during screw-extrusion LFAM is an understudied subject, although the residual
fiber length is among the most important microstructural properties of fiber-reinforced composites.
A contributing factor the lack of focus in this area is the questionability and variety of convoluted
fiber measurement methods. This study evaluates the relationship between printing speed, the final
fiber length, and resultant mechanical properties for 4 mm pultruded thermoplastic polyurethane
(TPU) pelletized feedstock and seeks to fully document a fiber length distribution (FLD)
measurement method. Samples were printed at several processing speeds and subjected to fiber
length analysis and tensile testing. Fiber length analysis was performed using a combination of
novel and proven techniques for improved repeatability and reliability of results. This study seeks
to improve understanding in the choice of machine design, material selection, and processing
parameters for optimal mechanical properties. | null | null | null | null | null | null |
['Cholewa, S.', 'Jacksch, A.', 'Drummer, D.'] | 2024-03-25T22:01:08Z | 2024-03-25T22:01:08Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124310', 'https://doi.org/10.26153/tsw/50918'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['flow', 'polymer', 'laser', 'powder bed', 'manufacturing', 'engineering', '2023 Solid Freeform Fabrication Symposium'] | Analysis of Flow Additives in Laser-Based Powder Bed Fusion of Polymers: Implications for Flow Behavior, Processing, Temperature Profile, and Part Characteristics | Conference paper | https://repositories.lib.utexas.edu//bitstreams/6c4f9f85-4d9a-4bc9-966c-df447ff87c94/download | University of Texas at Austin | Powder bed fusion of polymers requires the use of flow additives to ensure adequate flowability of the
feedstock material. However, information regarding flow additives and their load is limited, as is an
understanding of their impact on processing conditions. This study investigates the flow behavior using
static and dynamic measurements under process conditions, focusing on the influence of flow additives.
Subsequently, processing studies are conducted using thermography to analyze the laser-material interaction.
The characteristics of parts produced from Polypropylene and Polyamide 12 systems are also examined. The
findings of this research enhance the understanding of the impact of flow additives on the processing conditions
of laser-based powder bed fusion of polymers, potentially leading to optimized process parameters and
improved part quality and mechanical properties. | null | null | null | null | null | null |
Cunico, Marlon Wesley Machado | 2021-11-04T18:14:34Z | 2021-11-04T18:14:34Z | 2017 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/89994', 'http://dx.doi.org/10.26153/16915'] | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'flexible manufacturing systems', 'production'] | Analysis of Hybrid Manufacturing Systems Based on Additive Manufacturing Technology | Conference paper | https://repositories.lib.utexas.edu//bitstreams/72e89985-b1c1-41a8-ad6a-e3bfb9f83a30/download | University of Texas at Austin | Along the last year, additive manufacturing technologies has been proving to be a real game
changer in several market segments. Nevertheless, the main foundation of production and flexible
manufacturing systems generally considers classical technologies. For that reason, the present
work aim to propose and investigate manufacturing systems which includes additive manufacturing
technologies as part of the main or secondary production flow. As result, it was identified that
several marketing segments, types of components and different annual volumes tend to be better
attended by hybrid flexible manufacturing systems which includes additive manufacturing
technologies. | null | null | null | null | null | null |
['Pitz, K.', 'Anderl, R.'] | 2021-11-18T16:44:28Z | 2021-11-18T16:44:28Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90422', 'http://dx.doi.org/10.26153/tsw/17343'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['dentures', 'CAD', 'CAM', 'layering strategies', 'thickness measurements'] | Analysis of Layer Arrangements of Aesthetic Dentures as a Basis for Introducing Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/63956822-c032-456c-9d57-856ef0b27503/download | University of Texas at Austin | Aesthetic dentures are highly individual products, needing to adapt to the patient’s natural
dentition in both color and shape. In general, dentures are geometrically complex structures,
consisting of several layers of different materials, which are applied consecutively. This is why
efforts are being made to introduce additive manufacturing into the production process of aesthetic
dentures which is to date largely based on manual work of skilled professionals. In order to
successfully apply additive manufacturing accurate models of the denture to be produced are
essential. In this paper the layer arrangements of dental crowns from real patient cases are analyzed.
Different approaches, based on normal vectors, cylindrical coordinates, spherical coordinates and
paraxial rays, are compared to each other. The emphasis of this comparison lies on transferring
layering strategies from analyzed patient cases to future patient cases where the geometry might be
slightly different but a similar optical impression is desired. The most suitable approach for this
purpose has been identified, implemented and tested. | null | null | null | null | null | null |
['Johnston, Scott R.', 'Reed, Marques', 'Wang, Hongqing V.', 'Rosen, David W.'] | 2020-03-02T14:58:38Z | 2020-03-02T14:58:38Z | 2006 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80129', 'http://dx.doi.org/10.26153/tsw/7150'] | eng | 2006 International Solid Freeform Fabrication Symposium | Open | Stereolithography Apparatus | Analysis of Mesostructure Unit Cells Comprised of Octet-truss Structures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1b33effd-6aba-4f63-a72b-b76eefdb89ea/download | null | A unit truss finite element analysis method allowing non-linear deformation is employed to
analyze a unit cell comprised of n
3
octet-truss structures for their stiffness and displacement
compared to their relative density under loading. Axial, bending, shearing, and torsion effects are
included in the analysis for each strut in the octet-truss structure which is then related to the
mesostructure level (unit cell). The versatility of additive manufacturing allows for the
fabrication of these complex unit cell truss structures which can be used as building blocks for
macro-scale geometries. The finite element calculations are compared to experimental results for
samples manufactured on a Stereolithography Apparatus (SLA) out of a standard resin. | null | null | null | null | null | null |
['Lopes, Amit J.', 'Ramos, Luis C.', 'Saenz, David', 'Morton, Philip', 'Terrazas, Cesar A.', 'Choudhuri, Ahsan', 'Wicker, Ryan'] | 2021-11-30T20:46:03Z | 2021-11-30T20:46:03Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90541', 'http://dx.doi.org/10.26153/tsw/17460'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['powder removal', 'Ti-6Al-4V', 'electron beam powder bed fusion', 'electron beam melting'] | Analysis of Powder Removal Methods for EBM Manufactured Ti-6Al-4V Parts | Conference paper | https://repositories.lib.utexas.edu//bitstreams/cc789d5f-dbb5-45cc-b3af-2770523a2fed/download | University of Texas at Austin | Additive Manufacturing (AM) allows the creation of complex geometries that are not
achievable through subtractive manufacturing. Regardless of the advantages that 3D Printing
offers, technology limitations often constraints the desired geometry. When fabricating Ti-6Al4V parts in Electron Beam Powder Bed Fusion (EBPBF), the electron beam is used to preheat the
powder bed to maintain the desired temperature gradient during the build. One disadvantage of
EBPBF during the fabrication process is the trapped powder within internal channels gets partially
sintered and require extra processing. This research analyzes several powder removal methods
and compares their effectiveness. This work utilizes two types of samples, both made of Ti-6Al4V in EBPBF; with geometries that resemble typical features when designing a component. The
target weight of each cylinder is calculated based on dimensions and effective density of the
sample. The results summarizing the effectiveness of each method are presented. | null | null | null | null | null | null |
['Mireles, Jorge', 'Adame, Arturo', 'Espalin, David', 'Medina, Francisco', 'Winker, Rob', 'Hoppe, Terry', 'Zinniel, Bob', 'Wicker, Ryan'] | 2021-10-04T21:16:01Z | 2021-10-04T21:16:01Z | 2011 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88348', 'http://dx.doi.org/10.26153/tsw/15287'] | eng | 2011 International Solid Freeform Fabrication Symposium | Open | ['Additive Manufacturing', 'fluid pressure', 'Fused Deposition Modeling', 'sealant', 'end-use applications'] | Analysis of Sealing Methods for FDM-fabricated Parts | Conference paper | https://repositories.lib.utexas.edu//bitstreams/90d5327d-5b37-431e-b5a6-4ca3ac8f19c2/download | University of Texas at Austin | As a result of the layer-by-layer deposition characteristics of Additive Manufacturing
(AM) processes, fabricated parts exhibit limiting qualities and have yet to achieve the
requirements for end-use applications. Specifically, the use of AM-fabricated parts in fluid
pressure applications is limited due to part porosity as well as non-optimized building variables
(e.g., build orientation and material properties). In an effort to extend the use of AM in more
applications involving fluid pressure, parts manufactured with Fused Deposition Modeling
(FDM) were sealed with a variety of sealants and tested under applied pressure. Eleven sealants
with diverse chemical properties were applied to multiple geometries of FDM-fabricated
pressure caps through brushing or vacuum infiltration. The caps were installed on pressure
vessels and subsequently tested while safety precautions were taken to avoid catastrophic failure
(i.e., exploding) caused by pressure differentials. Results of the testing provides a sealing
method using BJB TC-1614 that enables FDM-fabricated parts to withstand pressures up to ~276
kPa (40psi) through brushing and ~138 kPa (20 psi) through vacuum infiltration. Other
noteworthy sealants (Minwax Sanding Sealer, Minwax Polyurethane Oil Based, PRO Finisher
Water-Base Polyurethane) that are readily available to consumers and easy to apply (i.e. no
mixing ratios to follow, long working times) also had notable results by withstanding pressures
up to ~207 kPa (30 psi). In addition, an analysis on dimensional changes was performed to
determine the absolute difference between as-built and surface-treated parts. Parts that were
infiltrated with BJB TC-1614 showed less dimensional changes (average absolute change of
0.104 mm) than parts that were brushed (average absolute change of 0.231 mm) however one-part sealants had smaller dimensional changes (maximum absolute change for one-part sealants
of 0.065 mm for infiltration and 0.171 for brushing) with noteworthy results in pressure testing.
Benefits of filling voids within FDM-manufactured parts enables end-use applications such as
hermetic housings for biomedical devices and pipes/covers for thermodynamic systems such as
heat exchangers. | null | null | null | null | null | null |
['Szucs, Tamas D.', 'Brabazon, Dermot'] | 2020-03-10T15:17:21Z | 2020-03-10T15:17:21Z | 2007 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/80215', 'http://dx.doi.org/10.26153/tsw/7234'] | eng | 2007 International Solid Freeform Fabrication Symposium | Open | Tissue Engineering | Analysis of the Effects of 3DP Parameters on Part Feature Dimensional Accuracy | Conference paper | https://repositories.lib.utexas.edu//bitstreams/69be293d-1c59-4a0a-9067-76ca858d519f/download | null | 3D printing (3DP) is a widely investigated scaffold manufacturing process for Tissue
Engineering (TE). Useful scaffold geometries should have high porosity (60-80%) with small
(100-500 μm) interconnected pores. Therefore dimensional accuracy on the micron level is one
of the crucial parameters of the bone scaffolds. Previously it was shown that the behavior of
scaffold geometries can be well simulated with Finite Element Modeling (FEM) however the
prediction of actual strength and stiffness values are dependent on dimensional accuracy. This
accuracy is in turn dependent on several parameters including particle size and shape, powderbinder interaction, and machine setup. In this work different scaffold strut sizes (0.3 - 0.5 mm)
have been fabricated using two different plaster powders (zp102 and zp130) with variations in
shell saturation levels, part print position, and part print orientation. The parameters for each
powder were analyzed using a full 35
factorial experimental design. It was found that the part size
and orientation had a significant effect on the dimensional accuracy while the influence of the
shell saturation and position was relatively small. The results allow for better dimensional
specification for scaffold geometry fabrication by defining the process parameters in 3DP that
may be used further in scaffold accuracy optimization. | null | null | null | null | null | null |
['Jamal, N.M.', 'Dalgarno, K.W.'] | 2019-10-24T17:41:54Z | 2019-10-24T17:41:54Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/77404', 'http://dx.doi.org/10.26153/tsw/4493'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Viscoelasticity | Analysis of the Influence of Viscoelasticity in Curl Development in SLS | Conference paper | https://repositories.lib.utexas.edu//bitstreams/a60491fb-caba-4435-8ebc-97a123fc11c2/download | null | Curl in selectively laser sintered parts arises mainly from thermal distortion of parts within
the build volume during processing. This results in nominally flat surfaces which lie
horizontally in the part bed becoming warped. This paper reports on the use of finite element
techniques to model curl development in polymer materials, and in particular on the influence of
viscoelasticity on how curl develops. The development of time-dependent material models is
reported, and the results of the implementation of these models presented, together with a
comparison of the results with experimental data. | null | null | null | null | null | null |
['Hoppe, B.', 'Enk, S.', 'Schleifenbaum, J.H.'] | 2021-11-18T18:23:23Z | 2021-11-18T18:23:23Z | 2019 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90456', 'http://dx.doi.org/10.26153/tsw/17377'] | eng | 2019 International Solid Freeform Fabrication Symposium | Open | ['laser powder bed fusion', 'schlieren', 'shadowgraph', 'process development', 'shielding gas flow', 'process stability', '316L stainless steel'] | Analysis of the Shielding Gas Dependent L-PBF Process Stability by Means of Schlieren and Shadowgraph Techniques | Conference paper | https://repositories.lib.utexas.edu//bitstreams/2ab19423-1f87-496e-84db-218ae4a76bf5/download | University of Texas at Austin | Ensuring a robust and reproducible Laser Powder Bed Fusion (L-PBF) process depends on
the design of the shielding gas flow in the corresponding manufacturing system. The gas flow
assures the removal of particles from the process zone that emerge from the interaction with the
laser irradiation. Minor disturbances may influence the stability of the L-PBF-Process and cause
defects in final parts produced. The objective of this work comprises visualizing the convection
processes and particle dynamics to analyze their influence on process stability. Therefore, a high
speed camera based Schlieren and Shadowgraph setup is used to visualize convection flows as well
as trajectories of metallic condensate and particles with up to 10,568 fps. This arrangement allowed
investigating the influence of shielding gas flow conditions on single melt tracks. Corresponding
results and studies on the interaction between laser irradiation and particles in varying shielding
gas flow conditions are contents of this work. | null | null | null | null | null | null |
['Lee, Cheol H.', 'Thomas, Charles L.'] | 2018-12-06T22:23:40Z | 2018-12-06T22:23:40Z | 1997 | Mechanical Engineering | doi:10.15781/T28W38N9T | http://hdl.handle.net/2152/71436 | eng | 1997 International Solid Freeform Fabrication Symposium | Open | ['CAD', 'manufacturability'] | An Analysis Technique for Layered Manufacturing Based on Quasi-Wavelet Transforms | Conference paper | https://repositories.lib.utexas.edu//bitstreams/aacf7bed-19c8-4c46-892b-d0149cb090b9/download | null | An analysis technique based on the Wavelet transform (WT) has been recently introduced
that allows the spatial frequency content of objects produced by layered manufacturing (LM)
techniques to be interpreted in terms ofmanufacturable features. (Lee and Thomas, 1997) Using
Haar's wavelet as a basis function, layers with vertical edges are modeled exactly. Using
analysis, a 3D model can be transformed, filtered, and inverse transformed resulting in an image
ofthe part as it would look if constructed from layers of a specific thickness. In order to extend
this analysis to construction techniques using higher order edges (ruled surface edges or curved
edges), the quasi-wavelet transform (QWT) is introduced. QWT analysis is conceptually the
same as WT analysis, except that the basis function can be selected by the user, allowing exact
analysis of layered manufacturing techniques using higher order construction algorithms. This
work is supported by a grant from the University ofUtah Research Foundation. | null | null | null | null | null | null |
Cunico, Marlon Wesley Machado | 2021-11-03T20:19:15Z | 2021-11-03T20:19:15Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89922 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'finite element method', 'anisotropy'] | Analytical and Experimental Characterization of Anisotropic Mechanical Behaviour of Infill Building Strategies for Fused Deposition Modelling Objects | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1e8c1d21-9e0d-453a-acfc-daf30e3ff795/download | University of Texas at Austin | As consequence of the 3d printing extraordinary rising along the last years, product development
fields are facing new challenges. In addition, it is notary that low cost additive manufacturing, as
such fused filament fabrication (FFF), result in objects with anisotropic mechanical behaviour.
Nevertheless, there is still lacking studies that highlight a proper specification of those mechanical
proprieties. For that reason, the main goal of this work is to present a mechanical characterization
of anisotropic behaviour of FFF objects as a function of infill strategy using a finite element
method. In this work, the main effect of building parameters were investigated in addition the
identification of generalized elasticity and failure mode formulations. By the end, the general
recommendation for objects building was sketched in order to support new strength based
developments. | null | null | null | null | null | null |
['Schonrath, Hanna', 'Wegner, Jan', 'Frey, Maximilian', 'Soares Barreto, Erika', 'Elspab, Arno', 'Schnell, Norman', 'Erdmann, Benjamin H.R.', 'Neises, Julian', 'Ellendt, Nils', 'Busch, Ralf', 'Kleszczynski, Stefan'] | 2024-03-26T16:56:27Z | 2024-03-26T16:56:27Z | 2023 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/124372', 'https://doi.org/10.26153/tsw/50980'] | en_US | 2023 International Solid Freeform Fabrication Symposium | Open | ['bulk metallic glasses', 'additive manufacturing', 'PBF-LB/M', 'Rosenthal model'] | Analytical Modeling of Cooling Rates in PBF-LB/M of Bulk Metallic Glasses | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bd4ba854-85d5-43e8-b351-4026847cb444/download | University of Texas at Austin | Additive manufacturing through laser powder bed fusion (PBF-LB/M) inheres great
potential for the processing of bulk metallic glasses (BMGs). The size-independent high cooling
rates during the process benefit the fabrication of large and elaborate amorphous components.
Albeit, partial crystallization poses a challenge in additively manufactured BMGs, potentially
limiting the resulting mechanical properties. In this matter, the complex thermal history during
processing often states a remaining uncertainty. Besides in situ measurements and numerical
estimations, analytical models can be used to achieve a deeper understanding of the transient
temperature evolution. In this work, an iterative solution to the analytical Rosenthal equation is
developed and applied to ZrCuAlNb- and CuTiZrNi-BMGs to predict melt pool dimensions
and cooling rates during PBF-LB/M. Therefore, temperature-dependent thermal properties are
determined via laser flash measurements. The effective absorptivity of the two materials is
measured, and single-line experiments were performed as a validation for the approach. | null | null | null | null | null | null |
['Lindermann, C.', 'Jahnke, U.', 'Moi, M.', 'Koch, R.'] | 2021-10-05T18:39:19Z | 2021-10-05T18:39:19Z | 2012 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88402', 'http://dx.doi.org/10.26153/tsw/15341'] | eng | 2012 International Solid Freeform Fabrication Symposium | Open | ['additive manufacturing', 'product lifecycle', 'activity based costing', 'cost drivers'] | Analyzing Product Lifecycle Costs for a Better Understanding of Cost Drivers in Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1e98472c-0a13-4fed-8db5-c965d9192dd1/download | University of Texas at Austin | The costs of additive manufactured parts often seem too high in comparison to those of
traditionally manufactured parts, as the information about major cost drivers, especially for
additive manufactured metal parts, is weak. Therefore, a lifecycle analysis of additive
manufactured parts is needed to understand and rate the cost drivers that act as the largest
contributors to unit costs, and to provide a focus for future cost reduction activities for the
Additive Manufacturing (AM) technology. A better understanding of the cost structure will
help to compare the AM costs with the opportunity costs of the classical manufacturing
technologies and will make it easier to justify the use of AM manufactured parts. This paper
will present work in progress and methodology based on a sample investigated with business
process analysis / simulation and activity based costing. In addition, cost drivers associated
with metal AM process will be rated. | null | null | null | null | null | null |
['Yang, Zhuo', 'Lu, Yan', 'Lane, Brandon', 'Kim, Jaehyuk', 'Ndiaye, Yande', 'Krishnamruty, Sundar'] | 2021-12-01T22:32:45Z | 2021-12-01T22:32:45Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90640', 'http://dx.doi.org/10.26153/tsw/17559'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['remelting conditions', 'melt pool monitoring', 'data fusion', 'overhang build', 'powder bed fusion'] | Analyzing Remelting Conditions based on In-Situ Melt Pool Data Fusion for Overhang Building in Powder Bed Fusion Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fcd09475-e9b1-4fe3-a93b-c67017633e90/download | University of Texas at Austin | Coaxial melt pool monitoring (MPM) images provide in-depth insights into the building process of laser
powder bed fusion additive manufacturing. An in-situ MPM image captures the independent melting condition
at specific positions within each build layer. However, identifying material defects such as horizontal lack-of-fusion using individual, discontinuous MPM images poses multiple challenges. This paper builds upon the
authors’ previous work on data registration and data fusion to analyze material remelting conditions based on
co-axial MPM images. MPM data are fused to formulate layerwise remelting ‘maps’ to evaluate printing
quality. A 3D part with various overhang features was built to verify the method. A regular layer with solid
support from the previous layers has around 30 % remelting ratio for the given laser scan conditions. In
contrast, overhang regions remelted at about 10 % with the same process setting, whichis too low to provide
sufficient material fusion, resulting in lack-of-fusion between melting tracks. The negative impact in
remelting would not immediately disappear in subsequent layers following the overhang regions. Results
shows three additional layers are required to fully recover the remelting condition back to normal. The
remelting results from MPM are also visible within layerwise optical images of the same surface. | null | null | null | null | null | null |
['de Smit, Bram', 'Broek, Han J.'] | 2020-02-17T14:42:54Z | 2020-02-17T14:42:54Z | 2004 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/79999', 'http://dx.doi.org/10.26153/tsw/7024'] | eng | 2004 International Solid Freeform Fabrication Symposium | Open | Extruded Polystyrene Foam | Analyzing the Cutting Process of a Heated Flexible Blade in Extruded Polystyrene Foam | Conference paper | https://repositories.lib.utexas.edu//bitstreams/9eeff267-8a09-4c50-9f58-f6b46bcc52b7/download | null | For the “Free Form Thick Layered Object Manufacturing” technology that is being
developed at the Delft University, it is vital that Extruded Polystyrene Foam (XPS) can be cut
accurately with a heated blade. The shape of the blade is actively controlled during the cutting
process, which results in double curved cutting surfaces. In order to make this cutting process
controllable it must be known how the cutting behavior is under varying conditions, like cutting
speed, cutting angle and heating power. The authors executed a range of experiments, analyzed
the results and describe a practical model for the cutting process of XPS with a heated blade. | null | null | null | null | null | null |
['Niebling, F.', 'Otto, A.', 'Geiger, M.'] | 2019-10-24T17:54:50Z | 2019-10-24T17:54:50Z | 2002 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/77409', 'http://dx.doi.org/10.26153/tsw/4498'] | eng | 2002 International Solid Freeform Fabrication Symposium | Open | Macroscopic | Analyzing the DMLS Process by a Macroscopic FE-Model | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8be69f88-0c09-4d79-a0d5-a8526a6a0722/download | null | The presented macroscopic FE-model allows to analyze the thermal fields and the
resulting stress built up during Selective Laser Sintering. Process and material parameters are
focused on Direct Metal Laser Sintering (DMLS). The FE-model is introduced and the
assumptions for the model are given. Three different geometric models are discussed. The 3Dmodel shows the sintering of a single line, whereas 2D-models are used for longitudinal and
crosscuts of the sintering process. Aim of the investigation is a more basic knowledge about the
process, which will lead to a stabilization and optimization of the process. | These investigations were financially supported by the DFG. | null | null | null | null | null |
['Hernandez, R.', 'Slaughter, D.', 'Whaley, D.', 'Tate, J.', 'Asiabanpour, B.'] | 2021-10-28T14:15:19Z | 2021-10-28T14:15:19Z | 2016 | Mechanical Engineering | null | https://hdl.handle.net/2152/89645 | eng | 2016 International Solid Freeform Fabrication Symposium | Open | ['tensile properties', 'compressive properties', 'flexural properties', 'ABS plastics', 'P430', '3D printing', 'printing orientation', 'fused deposition modeling'] | Analyzing the Tensile, Compressive, and Flexural Properties of 3D Printed Abs P430 Plastic Based on Printing Orientation Using Fused Deposition Modeling | Conference paper | https://repositories.lib.utexas.edu//bitstreams/83296808-1f7d-4da6-9578-a5c0f923cecb/download | University of Texas at Austin | To achieve the optimum functionality and mechanical properties in the AM-based parts, it is
vital to fully characterize parts under static mechanical loadings (tension, compression, and
flexure) that are built in different orientations. This research reports the results of the
compression (ASTM standard D695), 4-point flexure (ASTM D790), and tensile (ASTM D 638
Type I) tests on the ABS plastic specimens that are designed according to the ASTM standards
and are built in different orientations using the uPrint SE Plus 3D printer. This study examined
the effects that printing 3D parts in different orientations (build angles) has on the mechanical
properties of ABS P430 plastic. A total of 45 samples (15 tension, 15 compression, and 15
flexure) were printed in 5 orientations; 0 degrees in the XY plane, 45 degrees in the XY plane,
90 degrees in the XY plane, 45 degrees in the Z plane, and 90 degrees in the Z plane. The
hypothesis was that the samples printed 0 degrees in the XY plane would be the strongest in
compression and flexure, and also have the greatest modulus of elasticity. The samples printed
90 degrees in the XY plane were predicted to be the strongest in tension, having the largest
tensile strength and lowest modulus of elasticity. The findings showed that printing 90 degrees in
the XY plane resulted in the highest tensile strength compared to the other orientations, but not
by a significant margin. Printing 0 degrees in the XY plane significantly increased the
compressive and flexure strengths of the material compared to other orientations. | null | null | null | null | null | null |
['Jiang, T.', 'Lin, F.', 'Kaltman, Steven I.', 'Sun, W.'] | 2019-09-23T17:25:05Z | 2019-09-23T17:25:05Z | 2000 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/75983', 'http://dx.doi.org/10.26153/tsw/3082'] | eng | 2000 International Solid Freeform Fabrication Symposium | Open | Reconstruction | Anatomical Modeling and Rapid Prototyping Assisted Surgical Reconstruction 555 | Conference paper | https://repositories.lib.utexas.edu//bitstreams/5a11940a-c8c4-446e-b2f2-3bdb686ecfaa/download | null | A CAD-based approach to generate three-dimensional anatomical modeling and its application in analysis and rapid prototyping for surgical reconstruction is presented. The process of modeling technique, starting from processing computed tomography segmentation profiles, reverse engineering to reconstruct 3D anatomical model, and rapid prototyping to fabricate physical models are described. Methods of applying the least-square fitting criteria to simplify CT or MRI anatomical data, to generate NURBS based curves, surfaces, and solids, and to develop a CAD-based anatomical modeling for femur are introduced.
Feasibility of using finite element method for femur structural analysis and using rapid prototyping to reproduce tactical medical model for surgical reconstruction is also discussed. | We gratefully acknowledge the support from NSF 9980298 project funding to graduate student T.
Jiang during the course of this research. | null | null | null | null | null |
['Conway, Kaitlynn M.', 'Romanick, Zachary', 'Cook, Lea M.', 'Morales, Luis A.', 'Despeaux, Jonathan D.', 'Ridlehuber, Marcus L.', 'Fingar, Christian', 'Doctor, Daquan', 'Pataky, Garrett J.'] | 2021-11-30T22:26:39Z | 2021-11-30T22:26:39Z | 2021 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/90570', 'http://dx.doi.org/10.26153/tsw/17489'] | eng | 2021 International Solid Freeform Fabrication Symposium | Open | ['cellular materials', 'anisotropy', 'yield envelope'] | The Anisotropic Yield Surface of Cellular Materials | Conference paper | https://repositories.lib.utexas.edu//bitstreams/08e4611c-24d8-43aa-ad5f-1030ce8d2045/download | University of Texas at Austin | Mechanical metamaterials are often limited in engineering applications because of uncertainty in
their deformation behavior. This uncertainty necessitates large factors of safety and behavior
assumptions to be included in mechanical metamaterial designs, detracting from the largest
benefit of metamaterials: their ultralight weight. In this study, a yield envelope was created for
both a bending dominated and a stretching dominated cellular material topology to improve the
understanding of the response of cellular materials under various load types and orientations.
Experimental studies revealed that the shear strength of a cellular material is significantly less
than that predicted by the Mohr’s criterion, necessitating a modification of the Mohr’s yield
criterion for cellular materials. Both topologies experienced tension-compression anisotropy and
anisotropy dependent on the topology orientation during loading with the stretching dominated
topology experiencing the largest anisotropies. | null | null | null | null | null | null |
['Kamatchi Subramanian, P.', 'Vail, N.K.', 'Barlow, J.W.', 'Marcus, H.L.'] | 2018-10-03T16:55:21Z | 2018-10-03T16:55:21Z | 1994 | Mechanical Engineering | doi:10.15781/T29Z90X3G | http://hdl.handle.net/2152/68667 | eng | 1994 International Solid Freeform Fabrication Symposium | Open | ['alumina powders', 'selective laser sintering', 'copolymer'] | Anisotropy in Alumina Processed by SLS. | Conference paper | https://repositories.lib.utexas.edu//bitstreams/1cf8e989-c83f-4525-8e81-ac02ddda3ef0/download | null | Alumina powders of 15~m size and 2~m size were processed by SLS using PMMA and a
copolymer. The 2~m powders were agglomerated and mixed with the polymer powder before
being processed by SLS. SLS bend strength specimens were made with parts built along
different orientations. The variation of the strength with incident energy density and with
orientation was studied. | null | null | null | null | null | null |
['Munguia, J.', 'Dalgarno, K.W.'] | 2021-10-11T22:41:55Z | 2021-10-11T22:41:55Z | 2013 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/88672', 'http://dx.doi.org/10.26153/tsw/15606'] | eng | 2013 International Solid Freeform Fabrication Symposium | Open | ['Ankle-Foot-Orthoses', 'composite reinforncement', 'thermoforming polymer sheets'] | Ankle Foot Orthotics Optimization by Means of Composite Reinforcement of Free-Form Structures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/c37847b4-6714-456b-82c9-780231f6f23c/download | University of Texas at Austin | Ankle-Foot-Orthoses (AFOs) are assistive devices prescribed for a number of physical and
neurological disorders affecting the mobility of the lower limbs. Traditional AFO design is
based on thermoforming polymer sheets around a plaster cast with a characteristic stiffness
depending on the selected trim-line with the inherent design limitations. Additive
Manufacturing has been explored as an alternative process; however it has proved to be
inefficient cost-wise. This work explores the possibilities of generating modular AFO
elements: calf, shank, and footplate with localized composite reinforcement that aids in the
optimization of the device in terms of functionality, aesthetics, rigidity and cost. | null | null | null | null | null | null |
['Dehghan-Niri, E.', 'Hespeler, S.C.', 'Juhasz, M.', 'Halliday, H.S.', 'Lang, M.'] | 2023-04-03T17:47:53Z | 2023-04-03T17:47:53Z | 2022 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/117730', 'http://dx.doi.org/10.26153/tsw/44609'] | eng | 2022 International Solid Freeform Fabrication Symposium | Open | Additive manufacturing | Anomal Detection for In-situ Quality Control of Directed Energy Deposition (DED) Additive Manufacturing | Conference paper | https://repositories.lib.utexas.edu//bitstreams/9448763b-3492-4d02-8e4c-5d01554d5a3b/download | null | One common cause for the rejection of parts produced during metal Additive
Manufacturing (AM) is the presence of unacceptable defects within the part. While
powerful, post-processing nondestructive techniques can be unapproachable due to time
constraints or simply impractical for certain inspection and quality control applications of
the AM, especially with parts of high complexity. The AM process requires a layer-by-
layer execution to build parts, allowing for a unique opportunity to collect data and monitor
the process in real/semi-time. The incipient phase of AM monitoring and control typically
consists of developing an automated unsupervised statistical anomaly detection
algorithm that is capable of detecting irregularities through parameter measurement and
sensing features. In this paper, we develop a simple and effective method for detecting
anomalies through use of statistical distances from data collected during the laser-based
Directed Energy Deposition (DED) AM process. | null | null | null | null | null | null |
['Prakash, Sashikanth', 'Boddu, Mallikharjuna Rao', 'Liou, Frank'] | 2019-11-20T16:35:29Z | 2019-11-20T16:35:29Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78476', 'http://dx.doi.org/10.26153/tsw/5561'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | Diagnostic Tool | Application of a Diagnostic Tool in Laser Aided Manufacturing Processes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/e336f304-4b83-4aa6-9d63-87969a6e5a0d/download | null | Lasers play a vital role in producing parts with high dimensional accuracy, strength and
quality in today's rapid prototyping industry. In the process of Laser Metal Deposition, many
problems are encountered where the part quality does not meet the required standards. This could
be due to the nonconformity of control parameters or unnecessary interactions between the
control factors. This paper discusses the implementation of Dr. Genichi Taguchi’s optimization
techniques using Design of Experiments (DOE) where a series of fractional factorial experiments
are performed on the laser deposition process. The results from these experiments are evaluated
with respect to the rate of deposition alongside the part quality and the optimized level setting of
control parameters are determined efficiently. This tool can be used to detect and diagnose flaws
and discrepancies in the Laser Metal Deposition process and optimize it accordingly. | This research was supported by the National Science Foundation Grant Number
DMI-9871185, Missouri Research Board, and Army Research Office. Their support is gratefully
appreciated. | null | null | null | null | null |
['Loughnane, Gregory T.', 'Kuntz, Sarah L.', 'Klingbeil, Nathan', 'Sosa, John M.', 'Irwin, Jeff', 'Nassar, Abdalla R.', 'Reutzel, Edward W.'] | 2021-10-20T21:31:26Z | 2021-10-20T21:31:26Z | 2015 | Mechanical Engineering | null | https://hdl.handle.net/2152/89366 | eng | 2015 International Solid Freeform Fabrication Symposium | Open | ['Laser Engineered Net Shaping', 'Widmanstätten ⍺-lath', 'wall thickness', 'uncertainty quantification', 'Ti-6Al-4V'] | Application of a Microstructural Characterization Uncertainty Quantification Framework to Widmanstätten ⍺-laths in Additive Manufactured Ti-6Al-4V | Conference paper | https://repositories.lib.utexas.edu//bitstreams/7c32e9c9-c76a-4e1e-8906-a50862f45d99/download | University of Texas at Austin | This work applies statistical analysis and uncertainty quantification tools developed for
characterizing virtual microstructures in three dimensions to a two-dimensional experimental
investigation of Ti-6Al-4V Widmanstätten ⍺-lath thicknesses obtained from back-scattered
electron (BSE) or electron back-scatter diffraction (EBSD) images on two thin-walled samples
manufactured via the LENS® process. The Materials Image Processing and Automated
Reconstruction (MIPAR™) software optimizes unique recipes for conversion of the BSE or
EBSD images to binary data, and subsequently computes the inverse of the linear intercept for
each ⍺-lath. Mean ⍺-lath thicknesses and discrete probability density functions (PDFs) of
inverse intercepts are used to make quantitative comparisons of ⍺-lath structures at different
heights throughout the thin walls. Real-time thermal data collected during the LENS®
experiment is then compared to quantitative microstructural results in order to determine trends
between ⍺-lath structures, thermal gradients, and melt pool areas across experimental process
parameters. | null | null | null | null | null | null |
['Melvin, Lawrence S. III', 'Beaman, J.J.'] | 2018-04-19T17:10:13Z | 2018-04-19T17:10:13Z | 1992 | Mechanical Engineering | doi:10.15781/T2Z31P56K | http://hdl.handle.net/2152/64386 | eng | 1992 International Solid Freeform Fabrication Symposium | Open | ['SLS', 'microgravity', 'Department of Mechanical Engineering', 'magnetostatic system'] | The Application of an Artificial Body Force to the Selective Laser Sintering Process | Conference paper | https://repositories.lib.utexas.edu//bitstreams/da3efd8a-1c18-4529-8137-3c48c4ae247b/download | null | An artificial body force generated by a magnetic
field is applied to the green powder bed of a ferromagnetic
powder during the Selective Laser Sintering process.
Preliminary experiments and theory are formed to
determine whether the artificial body force is beneficial to
the Selective Laser Sintering process and if it is usable
within that process. Several applications are discussed
including microgravity situations and two phase sintering
processes. It is determined that the magnetic body force is
beneficial to the Selective Laser Sintering process. | null | null | null | null | null | null |
Pegna, Joseph | 2018-10-03T20:19:41Z | 2018-10-03T20:19:41Z | 1995 | Mechanical Engineering | doi:10.15781/T2M902N5H | http://hdl.handle.net/2152/68688 | eng | 1995 International Solid Freeform Fabrication Symposium | Open | ['functional prototypes', 'multimodal structures', 'construction automation'] | Application of Cementitious Bulk Materials to Site Processed Solid Freeform Construction | Conference paper | https://repositories.lib.utexas.edu//bitstreams/615cbbec-7f69-424a-9865-8e25860b693c/download | null | This paper reports a radical departure from generally accepted concepts in construction
automation and demonstrates that new techniques of layered manufacturing can be applied
effectively to construction. In the process, we also modified material processing of cement to
adapt it to the requirements ofSolid Freeform Fabrication.
Our purpose is illustrated with sample structures manufactured by incremental deposition of
reactive bulk materials (cement and Silica in this instance), a characterization of their material
properties, and an assessment of their potential for Solid Freeform Fabrication of large structures.
For example, we estimated that it would take about months to build a structure the size
ofa 3000 sq. ft. house. | null | null | null | null | null | null |
['Bitar, Isam S.', 'Aboulkhair, Nesma T.', 'Leach, Richard'] | 2021-11-02T19:11:49Z | 2021-11-02T19:11:49Z | 2017 | Mechanical Engineering | null | https://hdl.handle.net/2152/89868 | eng | 2017 International Solid Freeform Fabrication Symposium | Open | ['carbon fiber', 'through thickness', 'composite', 'mechanical behavior', 'additive manufacture'] | The Application of Composite Through-Thickness Assessment to Additively Manufactured Structures | Conference paper | https://repositories.lib.utexas.edu//bitstreams/8257f635-2b40-404b-a4be-29c897d70199/download | University of Texas at Austin | This study looks into the applicability of through-thickness assessment to additive
manufacturing (AM) carbon-fibre reinforced polymers (CFRPs). The study utilised a material
extrusion printer that uses fused filament fabrication and composite filament fabrication
technologies to manufacture functionally-graded polymer and composite polymer parts. The
matrix material of choice was nylon 6. Samples were printed exploring a range of
reinforcement volume content. In summary, this study presents an assessment of the
applicability of through-thickness testing to AM CFRP specimens and provides a performance
comparison between AM composite through-thickness properties and the properties of
equivalent CM CFRP specimens. | null | null | null | null | null | null |
['Weinmann, J.', 'Ip, H.', 'Prigozhin, D.', 'Escobar, E.', 'Mendelson, M.', 'Noorani, R.'] | 2019-11-20T16:55:05Z | 2019-11-20T16:55:05Z | 2003 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/78484', 'http://dx.doi.org/10.26153/tsw/5569'] | eng | 2003 International Solid Freeform Fabrication Symposium | Open | RapidPrototyped | Application of Design of Experiments (DOE) on the Processing of Rapid Prototyped Samples | Conference paper | https://repositories.lib.utexas.edu//bitstreams/bf67d8aa-effb-42d8-b1de-aca241ddae31/download | null | The purpose of this experiment was to improve the Fused Deposition Modeling Process by
examining the tensile strength of samples fabricated in a Stratasys FDM 1650 Machine utilizing
the methods of Design of Experiments. A two-level, four-factor, full factorial experiment was
conducted. The selected factors were temperature, air gap, slice thickness, and raster orientation.
A regression equation determined the level each factor should be set in order to optimize the
FDM machine settings. It was found that single factors - small air gap, small layer thickness
and low raster orientation, as well as the interaction between high temperature and small layer
thickness yielded the greatest effect the response. | null | null | null | null | null | null |
['Walish, J.', 'Sutaria, M.', 'Dougherty, M.', 'Vaidyanathan, R.', 'Kasichainula, S.', 'Calvert, P.'] | 2019-03-11T16:36:53Z | 2019-03-11T16:36:53Z | 1999 | Mechanical Engineering | null | ['https://hdl.handle.net/2152/73581', 'http://dx.doi.org/10.26153/tsw/723'] | eng | 1999 International Solid Freeform Fabrication Symposium | Open | ['silicon nitride powders', 'DOE'] | Application of Design of Experiments to Extrusion Freeform Fabrication (EFF) of Functional Ceramic Prototypes | Conference paper | https://repositories.lib.utexas.edu//bitstreams/2bf9343d-8a42-4a45-a09c-1cc5ace2471a/download | null | Extrusion Freeform Fabrication (EFF) is an adaptation of the Stratasys Fused Deposition
Modeling (FDM) process for the Solid Freeform Fabrication (SFF) of functional ceramic
prototypes. It is a complex process involving many process variables, including parameters that
are operation, machine, materials, and geometry specific. A Taguchi factorial Design of
Experiments (DOE) technique was utilized to study the effects of machine specific process
parameters as well as their interactions based on the mechanical and physical properties of
sintered ceramics specimens. Post-processing software was developed to control and modify these
parameters. This software interface wasdesigned to mimic the Quickslice™ interface for setting
motion parameters based upon the material and the operation. The results of this investigation
provided useful information for the experimental analysis of the machine specific process
parameters. Suitable parameters were selected for the EFF process for fabricating representative
ceramic prototypes. With the optimized parameters, complicated parts were successfully
fabricated using both Kyocera SN282 and Starck M-11 silicon nitride powders. | null | null | null | null | null | null |
['Deng, Xioaming', 'Beaman, Joseph J.'] | 2018-04-19T17:54:23Z | 2018-04-19T17:54:23Z | 1992 | Mechanical Engineering | doi:10.15781/T2X34N85V | http://hdl.handle.net/2152/64394 | eng | 1992 International Solid Freeform Fabrication Symposium | Open | ['SLS', 'Department of Mechanical Engineering', 'sintering geometry'] | Application of Factorial Design in Selective Laser Sintering | Conference paper | https://repositories.lib.utexas.edu//bitstreams/fe9c566f-307c-491e-9118-d755f46708b9/download | null | Selective Laser Sintering (SLS) is a complex process involving many process parameters.
These parameters are not all independent. A factorial design technique is utilized to study the
effects of three main process parameters, laser power, laser beam scanning speed, and powder
packing density as well as their interactions on the sintering depth and fractional density. The
results of this investigation provide useful information for the further experimental analysis of
the process parameters and for selecting suitable parameters for SLS process. | null | null | null | null | null | null |