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---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
['Lee, Insup', 'Manthiram, A.', 'Marcus, H.L']
|
2018-10-03T18:17:05Z
|
2018-10-03T18:17:05Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T26970H2C
|
http://hdl.handle.net/2152/68668
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['optimum composite system', 'solid freeform fabrication', 'CAD']
|
Selective Laser Sintering of Alumina-Boron Oxide Composites
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e9feabc5-da14-4bae-8bbf-4bec8c3176ca/download
| null |
The selection of an optimum composite system for selective laser sintering (SLS) is based on
materials properties such as the melting point and the wettability between the components in the
composite powder. The alumina-boron oxide composite system is attractive for SLS because the
presence of the low melting component B203 (melting point 4500 C) can enhance sintering. A
better wetting of solid alumina powder by molten boron oxide can also aid densification process.
The alumina-boron oxide conlposite system has been investigated by SLS and selective laser
reactive sintering (SLRS). The role of boron oxide content as a binder, laser power density, and
secondary heat treatment on the microstructure and mechanical properties is discussed.
| null | null | null | null | null | null |
['Lee, Insup', 'Manthiram, A.', 'Marcus, H.L.']
|
2018-10-03T20:53:54Z
|
2018-10-03T20:53:54Z
|
1995
|
Mechanical Engineering
|
doi:10.15781/T2GM82732
|
http://hdl.handle.net/2152/68689
|
eng
|
1995 International Solid Freeform Fabrication Symposium
|
Open
|
['SLS', 'alumina', 'x-ray diffraction']
|
Selective Laser Sintering of Alumina-Zinc Borosilicate Glass Composites using Monoclinic HB02 as a Binder
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e61f83db-2f43-41a3-ae15-303451ba7297/download
| null |
Selective Laser Sintering (SLS) process has been employed to fabricate alumina-glass
composites using as an inorganic binder monoclinic HB02. Subsequent post-thermal processing
of green SLS parts at various temperatures yielded glass-ceramic composites. The crystalline
phases and microstructural evolution at each fIring temperature were identified by X-ray diffraction
analysis and Scanning Electron Microscopy. The role of glass content, firing temperature, and
alumina particle size on the densification and bend strength of fired samples were studied. In
addition, further densification was made through infiltration of colloidal silica into the fIred, porous
samples.
| null | null | null | null | null | null |
['Manriquez-Frayre, J.A.', 'Bourell, D.L.']
|
2018-04-10T18:38:39Z
|
2018-04-10T18:38:39Z
|
1990
|
Mechanical Engineering
|
doi:10.15781/T2B27Q79P
|
http://hdl.handle.net/2152/64245
|
eng
|
1990 International Solid Freeform Fabrication Symposium
|
Open
|
['Center for Materials Science and Engineering', 'laser processing', 'energy dispersive spectroscopy']
|
Selective Laser Sintering of Binary Metallic Powder
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/a94e6660-f638-4fb0-91a9-6fd5375a0d29/download
| null |
A selective laser sintering technique has been used to process metal powders and
powder blends. Precursor powders include copper, tin, a 70Pb-30Sn solder and their blends.
Excessive balling due to surface free energy effects occurred in single layer tests when the
laser fluence was sufficient to cause melting of monolithic tin or solder. Improvements in
single layer quality were obtained using copper-solder powder blends in a reducing
atmosphere. The binary powder layers were characterized metallographically and the effect of
processing parameters such as laser fluence and scan speed were assessed. Post-process
annealing improved interparticle wetting and part strength. The influence of ZnCl2 flux was
investigated when present as a coating in copper-solder blends. Multiple layer tests were
performed on the most promising powder blends and the results are presented.
| null | null | null | null | null | null |
['Lorrison, J.C.', 'Goodridge, R.D.', 'Daigarno, K.W.', 'Wood, D.J.']
|
2019-10-22T17:23:44Z
|
2019-10-22T17:23:44Z
|
2002
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/76320', 'http://dx.doi.org/10.26153/tsw/3409']
|
eng
|
2002 International Solid Freeform Fabrication Symposium
|
Open
|
Sintering
|
Selective Laser Sintering of Bioactive Glass-Ceramics
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/f706ae15-7e4e-4dbc-8305-31662761440a/download
| null |
An initial investigation was held into the feasibility of producing bone replacement
implants from a bioactive glass-ceramic using the Selective Laser Sintering (SLS) process. The
work presented considers both a direct and an indirect approach, where the material is sintered
with a polymer binder and subsequently post-processed. An existing material with potentially
suitable biological and mechanical properties was selected from the range of apatite-mullite
glass-ceramics in the SiO2-Al2O3-CaO-CaF2-P2O5 series. The viability of using this material with
the SLS process was then tested, and the process route and resulting material properties
characterised. It is concluded that both direct and indirect SLS processes have potential in the
manufacture of personalised bone replacement applications.
| null | null | null | null | null | null |
['Lee, Goonhee', 'Barlow, J.W.']
|
2018-05-03T20:05:32Z
|
2018-05-03T20:05:32Z
|
1993
|
Mechanical Engineering
|
doi:10.15781/T26Q1T10X
|
http://hdl.handle.net/2152/65082
|
eng
|
1993 International Solid Freeform Fabrication Symposium
|
Open
|
['Selective Laser Sintering', 'SLS', 'Department of Chemical Engineering']
|
Selective Laser Sintering of Bioceramic Materials for Implants
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/a7d9750a-4121-4be2-9f91-2b5643c5ca6a/download
| null |
Selective Laser Sintering (SLS) process is employed for fabrication of biocerarnics
for orthopedic implants. Hydroxyapatite and Calcium Phosphate ceramics are coated with
polymer as a intermediate binder by using a spray drier. Polymer coated materials are
SLS processed to make green parts, which are infiltrated and fired to remove the polymer.
SLS processed green parts of hydroxyapatite have low density due to the small particle
size with large specific surface area. This paper discusses the possibilities and problems in
free-form fabrication of bioceramic.
| null | null | null | null | null | null |
['Lee, Gonhee', 'Barlow, J.W.']
|
2018-10-03T15:29:00Z
|
2018-10-03T15:29:00Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T25D8P040
|
http://hdl.handle.net/2152/68645
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['selective laser sintering', 'Polymeric Binder', 'Powder X-ray diffraction']
|
Selective Laser Sintering of Calcium Phosphate Powders
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/47677941-00c0-4206-b379-bc9fe3079ea6/download
| null |
Since Dejong first observed the similarity between powder X - ray diffraction
pattern ofthe in vivo mineral and the hydroxyapatite (Cas(OH)(P04h ,HA) in 1926,
the calcium phosphate ceramics have received attention as a bone substitute material.
Five calcium phosphates which exhibit different X-ray diffraction patterns are
known to be precipitated from aqueous solution at normal pressure. [1] These are
Ca(HzP04h, Ca(HzP04h-H20, CaHP04 , CaHP04-2H20, and crystalline
precipitate of variable composition of hydroxyapatite with the base formula
Cas(OH)(P04h. Various forms of calcium phosphate compounds, Ca/P ratio range
from 0.5 to 1, are prepared from HA by reacting with phosphoric acid. Thermally
dehydrated calcium phosphates are known to form a CaO and P20 S binary system. It
is known that for the CaO and P20S binary system, the chain phosphates appear
between the orthophosphate (mole ratio ofCaO/P20 S =3) and metaphosphate (mole
ratio ofCaO/P20s =1) and ultraphosphate for which mole ratio ofCaO/P20 s iess
than 1. Particularly in the case ofmetaphosphate, very high degree of
polymerization and as a consequence, good mechanical properties are reported. In
this binary system, mole ratio ofCaO/P20 S less than 55145 forms a glass-like
structure from the melt, and its mechanical properties are known to be nearly same as
those of natural teeth.[2]
| null | null | null | null | null | null |
['Lakshminarayan, Uday', 'Ogrydiziak, Stan', 'Marcus, H.L.']
|
2018-04-10T16:30:03Z
|
2018-04-10T16:30:03Z
|
1990
|
Mechanical Engineering
|
doi:10.15781/T2MG7GC58
|
http://hdl.handle.net/2152/64235
|
eng
|
1990 International Solid Freeform Fabrication Symposium
|
Open
|
['Center for Materials Science and Engineering', 'Department of Mechanical Engineering', 'Selective Layer Sintering', 'SLS']
|
Selective Laser Sintering of Ceramic Materials
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/ce95e944-890f-46ac-a6e4-59de3505f3fa/download
| null |
This paper will focus on efforts to develop the alumina - ammonium phosphate
material system for Solid Freeform Fabrication. When the powder mix is irradiated
with a laser beam, ammonium phosphate ( m.p. """ 190 0 C ) melts and forms a glassy
phase between the alumina grains. The "green part" obtained by laser processing is
then subjected to secondary heat treatment to optimize the properties of the final
composite. The effect of various material, laser and machine parameters on the density,
strength, surface finish and microstructure of the final part are described. One of the
applications for selective laser sintering is its use in directly manufacturing ceramic
molds for the investment casting process. We will describe some of the the results we
have obtained so far in fabricating composite ceramic molds directly and using them to
cast metals.
| null | null | null | null | null | null |
['Frayre-Manriquez, J.A.', 'Bourell, D.L.']
|
2018-04-17T18:21:12Z
|
2018-04-17T18:21:12Z
|
1991
|
Mechanical Engineering
|
doi:10.15781/T2CF9JQ1W
|
http://hdl.handle.net/2152/64343
|
eng
|
1991 International Solid Freeform Fabrication Symposium
|
Open
|
['Center for Materials Science and Engineering', 'SLS', 'Selective Layer Sintering', 'Polymer']
|
Selective Laser Sintering of Cu-Pb/Sn Solder Powders
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e081bb9d-b0a9-45d5-bf97-1687967d1e97/download
| null |
Solid Freeform Fabrication (SFF) as an overall approach in the
manufacturing field has been applied to very different areas and on
different materials systems including polymers, ceramics, metals and
vapor phase. Even though it is clear that polymers have enjoyed a rapid
and successful advance in terms of applications, research in the other
areas have shown potential applications as well.
In this paper, Cu-Sn/Pb solder and Cu-Sn blends have been used as
starting material for the Selective Laser Sintering (SLS) manufacture of
SFF objects. The general properties of the objects thus produced are
presented. In particular, density and microstructural characterizations
results are discussed..
| null | null | null | null | null | null |
['Neff, Clayton', 'Hopkinson, Neil', 'Crane, Nathan B.']
|
2021-10-21T16:57:33Z
|
2021-10-21T16:57:33Z
|
2015
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89405
|
eng
|
2015 International Solid Freeform Fabrication Symposium
|
Open
|
['diamond lattice structures', 'selective laser sintering', 'elastic modulus']
|
Selective Laser Sintering of Diamond Lattice Structures: Experimental Results and FEA Model Comparison
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/c6234856-921d-4c72-8923-3a20fab99170/download
|
University of Texas at Austin
|
Nature utilizes multiple materials with varying properties to create high performance,
integrated systems. In contrast, most additive manufacturing processes are limited to a small set of
compatible materials to fabricate a device. However, the large geometric freedom of AM could
be used to create the effect of multiple properties by creating lattice structures. Prior work has
focused on using this concept to reduce weight in high stiffness structures. This paper will consider
the use of a diamond lattice structures to create the effect of materials with a low elastic modulus
materials. Low stiffness regions are advantageous for energy absorption, vibration isolation, and
reduction of stress due to dimensional or temperature mismatches. The diamond lattice possesses
Face-Centered-Cubic (FCC) elemental configuration possessing tetrahedral angles of 109°
between elements. This allows for a pliable moment exerted on the structure yielding a flexible
and energy absorbent arrangement. A range of devices was fabricated in Nylon 12 (PA 2200)
through Laser Sintering (LS) process with variable element size (thickness) and unit cell size. The
effective stiffness of the structures is compared as a function of these parameters and compared to
numerical simulation. The results show the possibility of tuning the effective elastic modulus by
over four orders of magnitude.
| null | null | null | null | null | null |
['Sriram, Vinay', 'Wood, Kristin', 'Bourell, David', 'Beaman, Joseph J.']
|
2019-11-21T18:37:37Z
|
2019-11-21T18:37:37Z
|
2003
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/78563', 'http://dx.doi.org/10.26153/tsw/5619']
|
eng
|
2003 International Solid Freeform Fabrication Symposium
|
Open
|
DuraForm
|
Selective Laser Sintering of DuraForm Polyamide with Small-Scale Features
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/ceb2ceaa-0985-4e90-96e3-5bab44d5b19f/download
| null |
Selective Laser Sintering (SLS) has been used to make a fiber management module
having very small feature size and ratios. Currently these modules are made out of
Stereolithography using standard epoxy acrylate materials. SLS has been chosen to make
these modules by the virtue of the material system it offers. The material system was chosen
based on the flame retardant properties. The material used for this study is a DuraformTM
Polyamide and Alumina-Ammonium Phosphate system. Ammonium Phosphate served as the
binder in the Alumina-Ammonium Phosphate system. Experiments were done in order to find
out the minimum feature size possible with the two material systems. Minimum hole
diameters and maximum possible l/d ratios are determined by particle size, shape and
processing conditions. Builds were made in different directions to understand the effect of the
various processing parameters on the system. One particularly noteworthy observation was
that part growth as a proportion of hole diameter became increasingly significant as hole size
decreased. Optical microscopy was performed to measure the hole diameters and also to
reveal the surface roughness. Results indicate material system determines the minimum
diameter of micro-sized holes that can be effectively manufactured using Selective Laser
Sintering.
| null | null | null | null | null | null |
['Das, S.', 'Harlan, N.', 'Beaman, J. J.', 'Bourell, D. L.']
|
2018-11-09T15:21:58Z
|
2018-11-09T15:21:58Z
|
1996
|
Mechanical Engineering
|
doi:10.15781/T2Q815C0Q
|
http://hdl.handle.net/2152/69925
|
eng
|
1996 International Solid Freeform Fabrication Symposium
|
Open
|
['HIP', 'SLS', 'encapsulate powder']
|
Selective Laser Sintering of High Performance High Temperature Materials
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/4a8d1699-d194-4681-8be0-fb0de494fca3/download
| null |
Hot Isostatic Pressing (HIP) of high performance metal parts is currently done using either a shaped
metal container or a pre-fabricated ceramic mold depending on the part material and geometry. An
alternative method of HIP encapsulation that allows complex part geometry, short cycle time and
minima) potential for container-powder bed interaction is desired. Integral, fully dense metal skins
with complex geometry can potentially be constructed by direct selective laser sintering (SLS). The
advantages ofin-situ HIP encapsulation by direct SLS include the elimination of a secondary container
material and any associated container-powder bed interaction, reduced pre-processing time and a short
HIP cycle. Single and multi-layer specimens of Inconel625, Ti-6AI-4Vand 17-4 PH stainless steel
were produced by direct SLS. Closed porosity in Inconel625 and 17-4 PH stainless steel samples
ranged from 0 to 12% and area porosity from 0.5 to 20%, depending on the laser energy density.
Direct SLS samples ofInconel 625 were subjected to helium leak testing and found to be impervious,
with a leak rate less than lxl0-10 atm eels. These samples met the criteria for containerless hot
isostatic pressing.
| null | null | null | null | null | null |
['Hostetler, John M.', 'Goldstein, Jonathan T.', 'Urbas, Augustine M.', 'Gutierrez, Rodrigo E.', 'Bender, Theresa E.', 'Wojnar, Charles S.', 'Kinzel, Edward C.']
|
2021-10-28T14:24:59Z
|
2021-10-28T14:24:59Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89648
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['silica parts', 'thermal expansion', 'low density', 'low coefficient', 'selective laser sintering']
|
Selective Laser Sintering of Low Density, Low Coefficient of Thermal Expansion Silica Parts
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/b33959fa-e3b4-4b55-ad02-3df8c5094c56/download
|
University of Texas at Austin
|
This paper presents a study of selective laser sintering of silica-gel. The objective of this
work is to investigate a technique to create free-form, low to zero coefficient of thermal
expansion structures. This offers potential cost savings over the conventional casting of large
pieces of glass-ceramic followed by machining lightening features. In this paper, A CO2 laser is
coupled through a gantry system and focused onto a binder-free silica-gel powder bed (15-40 µm
particles). Prior to writing each layer, powder is dispensed by sifting it onto the build platform
as opposed to a conventional wiper system. This avoids contacting and potentially damaging
sensitive parts. After deposition, the parts are annealed in a furnace to increase their
strength. The influence of various process parameters including scan speed and laser power on
final shape is investigated. In addition, the flexural strength of annealed parts is measured via
three-point bending tests.
| null | null | null | null | null | null |
['Hejmadi, Uday', 'McAlea, Kevin']
|
2018-11-09T15:35:21Z
|
2018-11-09T15:35:21Z
|
1996
|
Mechanical Engineering
|
doi:10.15781/T2KH0FJ5G
|
http://hdl.handle.net/2152/69926
|
eng
|
1996 International Solid Freeform Fabrication Symposium
|
Open
|
['SLS process', 'CAD', 'RapidTool process']
|
Selective Laser Sintering of Metal Molds: The Rapidtool Process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/b60c6f61-b5b1-4d20-bf9e-e95b8c03ccba/download
| null |
Complex three dimensional parts can be manufactured directly from CAD data using rapid
prototyping processes. SLS® Selective Laser Sintering is a rapid prototyping process developed
at the University ofTexas at Austin and commercialized by DTM Corporation. SLS parts are
constructed layer by layer from powdered materials using laser energy to melt CAD specified cross
sections. Polymer, metal, and ceramic powders are all potential candidate materials for this
process. In this paper, a commercial SLS process - the RapidTool Process - which allows metal
molds to be rapidly manufactured is described. With this process, a polymer coated carbon steel
powder is used to fabricate a "green part" in the SLS machine. The green part is then placed in a
furnace with blocks of copper and, in a single furnace cycle, the polymer coating is removed and
the steel skeleton is infiltrated with the copper. The resulting steel/coPPer composite material has
durability and thermal conductivity similar to aluminum and can be hand finished using standard
techniques. A finished mold core and cavity set which can be used to mold at least 50,000 parts
with most plastics can be prepared in approximately ten days. The cost to produce most mold
geometries with the RapidTool Process is also comPetitive with traditional mold-making methods.
| null | null | null | null | null | null |
['Klatt, Timothy', 'Haberman, Michael', 'Conner Seepersad, Carolyn']
|
2021-10-12T18:56:05Z
|
2021-10-12T18:56:05Z
|
2013
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88719', 'http://dx.doi.org/10.26153/tsw/15653']
|
eng
|
2013 International Solid Freeform Fabrication Symposium
|
Open
|
['bistable structures', 'mesostructures', 'honeycombs', 'selective laser sintering']
|
Selective Laser Sintering of Negative Stiffness Mesostructures for Recoverable, Nearly-Ideal Shock Isolation
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e0f51767-358c-447a-94bb-06774051a85a/download
|
University of Texas at Austin
|
Honeycomb materials are well known for providing lightweight stiffness, strength, and
energy absorption capabilities. For most honeycomb materials, energy absorption occurs when
individual cells collapse progressively. Although it is possible for honeycombs with very low
relative density to collapse via elastic buckling, honeycombs with typical relative densities
collapse due to plastic yielding and buckling of the cell walls, such that the energy absorption is
nonrecoverable. In this paper, mono-stable negative stiffness unit cells are investigated for
constructing honeycomb mesostructures with high levels of recoverable energy absorption.
Negative stiffness is achieved by incorporating curved beams into each unit cell. When subject
to transverse loading, the curved beams exhibit negative stiffness behavior as they transition
from one curved geometry to another in a snap-through type of motion that absorbs energy
elastically at a relatively constant plateau stress. The plateau stress at which this energy
absorption occurs can be tailored via the geometry of the unit cell. Preliminary experiments
indicate that the structures can absorb significant amounts of energy by requiring nearly-constant-force to increase deformation as the structure transitions between snap-through
configurations. Unlike traditional honeycombs, the negative stiffness mesostructures are self-resettable and therefore reusable. Using SLS as a means of fabrication, they can also be
customized for specific shock events and even functionally graded to offer shock isolation for
transient loads of various amplitudes.
| null | null | null | null | null | null |
['Schultz, Jeffrey P.', 'Martin, Julie P.', 'Kander, Ronald G.', 'Suchicital, Carlos T.A.']
|
2019-09-20T18:28:35Z
|
2019-09-20T18:28:35Z
|
2000
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/75927', 'http://dx.doi.org/10.26153/tsw/3026']
|
eng
|
2000 International Solid Freeform Fabrication Symposium
|
Open
|
Alloying
|
Selective Laser Sintering of Nylon 12-PEEK Blends Formed by Cryogenic Mechanical Alloying
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/532d12ec-ee5d-4f45-aedb-f14b358246cc/download
| null |
Cryogenic mechanical alloying (CMA) has been shown to be an effective means for producing composite powders with co-continuous phases throughout each particle. Consolidation of these composite particles via SLS presents the possibility of forming parts with a co-continuous microstructure. In this work the effects of milling time and PEEK volume fraction on the microstructure and mechanical properties of laser sintered Nylon 12-PEEK blends is studied. In both blends, the PEEK phase is incorporated to increase mechanical strength, stiffness and heat deflection temperature. Transmission electron microscopy and scanning electron microscopy is utilized to investigate the microstructure of the CMA powder and laser sintered parts.
| null | null | null | null | null | null |
['Faustini, Mario C.', 'Neptune, Richard R.', 'Crawford, Richard H.', 'Stanhope, Steven J.']
|
2020-02-27T20:36:29Z
|
2020-02-27T20:36:29Z
|
2006
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80102', 'http://dx.doi.org/10.26153/tsw/7123']
|
eng
|
2006 International Solid Freeform Fabrication Symposium
|
Open
|
Passive dynamic ankle-foot orthoses
|
Selective Laser Sintering of Passive Dynamic Ankle-Foot Orthoses
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/f17d54af-5b69-41fc-a227-514c3855aa69/download
| null |
Passive dynamic ankle-foot orthoses (AFO’s) are used to improve gait performance in
those with various neuromuscular disorders. An important design characteristic of passive
dynamic AFOs is the storage and release of elastic energy within its structure to help satisfy the
energetic demands of walking. Thus, minimizing energy dissipation through internal friction is a
fundamental criterion for selecting the appropriate AFO material. This study compared the
mechanical damping of a carbon-fiber AFO to three geometrically identical AFO’s fabricated
using selective laser sintering with different materials. Mechanical damping characteristics
ranked the materials as Nylon 11 (best), followed by DuraformTM PA and DuraformTM GF
(worst).
| null | null | null | null | null | null |
['Childs, T.H.C.', 'Cardie, S.', 'Brown, J.M.']
|
2018-10-03T18:22:47Z
|
2018-10-03T18:22:47Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T2XS5K244
|
http://hdl.handle.net/2152/68670
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['sintering of polycarbonate', 'selective laser sintering', 'temperature distribution']
|
Selective Laser Sintering of Polycarbonate at Varying Powers, Scan Speeds and Scan Spacings
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/3487242d-8b34-41a1-8b34-24a12d726ee2/download
| null |
A benchmark study (1) has shown selective laser sintering to be the equal of or to
have accuracy advantages over other processes for creating parts of size over 10 mm.
Experience is needed to achieve best accuracies, as with other processes. This paper is
(for us) a first step in understanding the relation between sintering parameters, part
size and acuracy.
Work at the University of Texas at Austin (2-4) has established that the sintering
of polycarbonate can be understood in terms of a rate model driven by viscous and
surface tension effects. Material properties are such that a sharp boundary exists
between sintered and unsintered material. When full density is not achieved in a part,
density within a single layer varies from fully sintered to totally unsintered; measured
part density is thus a mean of widely varying values. Published work (3-4) uses a onedimensional
non-steady state heat flow model to calculate the temperature profile and
densification beneath the surface and concentrates on the effects on this of material
properties varying with temperature and during sintering. In this paper, these
variations are ignored but a three dimensional non-steady heat flow is used to enable
edge effects to be estimated. Density gradients at edges are assumed to be responsible
for variations of accuracy with sintering parameters, part size, part shape and
orientation.
| null | null | null | null | null | null |
['Wahab, M. S.', 'Dalgarno, K. W.', 'Cochrane, R. F.']
|
2020-03-09T15:30:48Z
|
2020-03-09T15:30:48Z
|
8/21/07
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80200', 'http://dx.doi.org/10.26153/tsw/7219']
|
eng
|
2007 International Solid Freeform Fabrication Symposium
|
Open
|
polymer nanocomposite
|
Selective Laser Sintering of Polymer Nanocomposites
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/bde27445-6d43-477b-bf37-f9abb136fe67/download
| null |
This paper describes the fabrication and characterization of polymer nanocomposite (PNC)
materials for use in the selective laser sintering (SLS) process. PNC materials are of great
interest generally because of their excellent physical properties, and offer excellent potential
in rapid manufacturing of structural polymeric parts. Three different nano additive materials
have been used: cerium oxide IV, yttrium stabilized zirconia, and layered Hectorite clay.
These materials have been used to reinforce PA6 polymer using solution blending and spray
drying to create powder with particle sizes in the range of 5-40 µm. The mechanical
properties and microstructure of the PNC materials have been evaluated and the results
compared to those of unfilled polymer.
| null | null | null | null | null | null |
['Wang, Hongyun', 'Bourell, David L', 'Beaman Jr., Joseph J.']
|
2018-12-05T20:37:14Z
|
2018-12-05T20:37:14Z
|
1997
|
Mechanical Engineering
|
doi:10.15781/T2VT1H935
|
http://hdl.handle.net/2152/71416
|
eng
|
1997 International Solid Freeform Fabrication Symposium
|
Open
|
['SLS', 'CAD']
|
Selective Laser Sintering of Quartz Powder
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/db73e8e5-1412-4756-9cf6-fd9ae13bdd6f/download
| null |
This research describes the feasibility of fusing quartz powder by Selective Laser Sintering
(SLS). SLS is a method of rapid prototyping three-dimensional objects from a computer-aided
design database. The effects of different processing parameters, including powder size, laser
power and scan mte were explored. Single and multiple layer specimens have been made. The
resulting structures were evaluated using SEM and the density of the multiple-layer structure was
detected by a geometrical mass/volume technique. It was determined that particle size was the
dominant variable affecting part quality. Smaller and spherical unifonn particles are preferred.
Future work will concentrate on optimizing powder size and shape and higher laser power.
| null | null | null | null | null | null |
['Gill, Toby', 'Hon, Bernard']
|
2019-10-25T16:05:05Z
|
2019-10-25T16:05:05Z
|
2002
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/77441', 'http://dx.doi.org/10.26153/tsw/4530']
|
eng
|
2002 International Solid Freeform Fabrication Symposium
|
Open
|
Laser Sintering
|
Selective Laser Sintering of SiC/Polyamide Matrix Composites
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/9db2ff3f-bcf2-425b-8171-b443ffe46305/download
| null |
This paper presents an experimental study into the production of particulate Silicon
Carbide/Duraform Polyamide matrix composites via the selective laser sintering (SLS) process.
FEPA standard SiC grits, F240 and F360, were each individually blended with the commercially
available Duraform Polyamide, to produce blend compositions of 50 and 60 volume percent SiC
for direct SLS processing. A full factorial experimental approach was applied to examine the
effects and interactions of laser power, scan speed, scan spacing and layer thickness, with
regards to the mechanical and physical properties of sintered parts. Analysis of parameter
interactions and individual main effects as well as Pareto analysis for all parameter combinations
are presented for the responses of part porosity and strength.
|
The authors would like to acknowledge the financial support from the EPSRC and the
technical support and assistance of the PIDC.
| null | null | null | null | null |
['Hauser, C.', 'Childs, T.H.C.', 'Dalgamo, K.W.']
|
2019-03-12T17:55:45Z
|
2019-03-12T17:55:45Z
|
1999
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73606', 'http://dx.doi.org/10.26153/tsw/748']
|
eng
|
1999 International Solid Freeform Fabrication Symposium
|
Open
|
['Rapid prototyping', 'Selective laser sintering']
|
Selective Laser Sintering of Stainless Steel 314S HC Processed Using Room Temperature Powder Beds
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/d5b54c32-7bb3-4eed-b890-8e7b570e27d7/download
| null |
Metal powder bed pre-heating is a proposed route for the homogenisation of
temperature gradients that can otherwise cause individual layer warping and cracking in direct
metal Selective Laser Sintering (SLS). However, the high temperatures involved complicate a
relatively simple process. This paper reports on the conditions for successful small scale SLS
of binderless stainless steel 314S powders within the surrounds of a room temperature powder
bed. Results show that a scan length around 15.0mm and a scan spacing around 0.275mm
produce sintered layers showing no signs of warping. Experimentation also indicates that
single layer shape. effects warping but length oflayer propagation does not.
| null | null | null | null | null | null |
['Harlan, Nicole', 'Park, Seok-Min', 'Bourell, David L.', 'Beaman, Joseph J.']
|
2019-03-12T20:46:42Z
|
2019-03-12T20:46:42Z
|
1999
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73609', 'http://dx.doi.org/10.26153/tsw/751']
|
eng
|
1999 International Solid Freeform Fabrication Symposium
|
Open
|
['SLS', 'tetragonal']
|
Selective Laser Sintering of Zirconia with Micro-Scale Features
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/a2b10c56-09f5-413e-a26a-5311a95ce2a4/download
| null |
Recent work in Selective Laser Sintering of ceramics at the University of Texas at Austin demonstrates
the capability to produce zirconia parts with fine features. Zirconia powder was pre-processed into
spherical particles, laser sintered with a sacrificial polymer binder, infiltrated and post-sintered to higher
density. Optical micrographs show that hole sizes of 180 /-tm are possible in fully ceramic components.
| null | null | null | null | null | null |
['Klocke, F.', 'Wirtz, H.']
|
2019-02-26T20:58:40Z
|
2019-02-26T20:58:40Z
|
1998
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73502', 'http://dx.doi.org/10.26153/tsw/652']
|
eng
|
1998 International Solid Freeform Fabrication Symposium
|
Open
|
['Investment Casting', 'Selective Laser Sintering']
|
Selective Laser Sintering of Zirconium Silicate
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/fb7dc01e-5ce3-467e-bb5d-9c9bb074ffde/download
| null |
The Fraunhofer Institute of Production Technology (IPT) and the Fraunhofer Institute of
Laser Technology (ILT) have joined forces in a project dedicated to Selective Laser Sintering
(SLS) ofmetals and ceramics, funded by the German Government and 6 industrial partners.
Selective Laser Sintering of zirconium silicate as a ceramic material used for investment
casting shells and cores is an attractive alternative to the conventional, time-consuming way of
producing these shells from a wax master. This paper will present current process results
concerning laser sintering of shells made from zirconium silicate and explain the related
potentials and benefits.
| null | null | null | null | null | null |
['Williams, John', 'Miller, David', 'Deckard, Carl']
|
2018-11-16T15:47:32Z
|
2018-11-16T15:47:32Z
|
1996
|
Mechanical Engineering
|
doi:10.15781/T2T43JN9H
|
http://hdl.handle.net/2152/70290
|
eng
|
1996 International Solid Freeform Fabrication Symposium
|
Open
|
['selective laser sintering', 'radiation', 'thermal gradients']
|
Selective Laser Sintering Part Strength as a Function of Andrew Number, Scan Rate and Spot Size
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/9a2f3611-67e0-42c7-bbb3-f869af44f4d4/download
| null |
Selective Laser Sintering has been modeled analytically and numerically, and
studied experimentally. Further investigation is necessary to couple the results of
modeling with experimental data. At Clemson University, numerical modeling of
heat transfer phenomena is used to predict temperatures within the powder layer
as a function of process parameters. Efforts are focused on delivering process
speed up through improved process understanding. Initial modeling results and
current understanding of the effects of process parameters on the strength
properties offreeform parts produced by the SLS process are presented.
| null | null | null | null | null | null |
['Cottle, Rand D.', 'Birmingham, Britton', 'Eliezer, Zwy', 'Marcus, Harris L.']
|
2018-11-08T15:07:43Z
|
2018-11-08T15:07:43Z
|
1995
|
Mechanical Engineering
|
doi:10.15781/T2GT5G157
|
http://hdl.handle.net/2152/69883
|
eng
|
1995 International Solid Freeform Fabrication Symposium
|
Open
|
['SLS', 'nanostructuring', 'powder reprocessing']
|
Selective Laser Sintering Preparation and Tribological Testing of Nanostructured Tungsten Carbide-Cobalt Composites
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/b1c494f2-22bb-4555-b9e8-2880799a67c8/download
| null |
This paper describes the results to date ofresearch done to compare and contrast the
tribological properties ofnanostructured tungsten carbide-cobalt composites consolidated by
selective laser sintering (SLS) and conventional grain size composites ofthe same chemical
composition consolidated by conventional commercial methods. The powder preprocessing and
selective laser sintering methods will briefly be described. The tribological testing methods will be
discussed, and the tribological properties ofthe selective laser sintered and commercially
consolidated materials will be compared. It will be seen that the nanosized WC-Co composites
have far superior harness and wear resistance compared to their microsized counterparts.
| null | null | null | null | null | null |
['Shi, Dongping', 'Gibson, Ian']
|
2019-03-11T16:31:43Z
|
2019-03-11T16:31:43Z
|
1999
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73579', 'http://dx.doi.org/10.26153/tsw/721']
|
eng
|
1999 International Solid Freeform Fabrication Symposium
|
Open
|
['Rapid Prototyping', 'Selective Laser Sintering']
|
Selective Laser Sintering Process Management Using a Relational Database
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/915a2f6d-dca5-4334-8ccb-fb794ee842c5/download
| null |
With more and more materials used in the Selective Laser Sintering (SLS) process, it is
becoming necessary to use a database to manage the process efficiently. In this paper, a
relational database for the SLS process is described. The database includes powdered material
data, sintering parameters, machine characteristics, mechanical properties and surface quality of
prototypes. Use ofthis database will make it is easy to store and retrieve processing information
and make decisions for planning the SLS. This paper will go on to describe how the database
can be extended to include other RP technologies.
| null | null | null | null | null | null |
['Weiss, Wendy', 'Bourell, D.L.']
|
2018-04-17T18:40:33Z
|
2018-04-17T18:40:33Z
|
1991
|
Mechanical Engineering
|
doi:10.15781/T2G737M79
|
http://hdl.handle.net/2152/64350
|
eng
|
1991 International Solid Freeform Fabrication Symposium
|
Open
|
['Center for Materials Science and Engineering', 'intermetallic', 'metallographic techniques', 'x-ray powder']
|
Selective Laser Sintering to Produce NI-SN Intermetallics
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/ef4f9387-f6cf-4f92-98b2-0ff04e053922/download
| null |
A model system has been employed to investigate .the use of selective laser sintering (SLS) with
a post-processing step to produce a compound having different properties than the precursor
powders. The powder mixture examined consisted of95% (59% Ni and 41%8n) plus 5% ZnC12.
This weight fraction of nickel and. tin produces. the intermetallic compound Ni3Sn upon equilibrium
annealing. ZnCl2 was used as a wetting agent. Parts were fabricated using SLS and were then
post-process annealed to create the intermetallic. Metallographic techniques and x-ray powder
diffraction were used.to characterize the parts before and after annealing.
| null | null | null | null | null | null |
['Khoshnevis, Behrokh', 'Gao, Xiang', 'Barbara, Brittany', 'Nouri, Hadis']
|
2021-11-04T15:30:09Z
|
2021-11-04T15:30:09Z
|
2017
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/89986', 'http://dx.doi.org/10.26153/tsw/16907']
|
eng
|
2017 International Solid Freeform Fabrication Symposium
|
Open
|
['selective separation shaping', 'additive manufacturing', 'cementitious', 'composite']
|
Selective Separation Shaping (SSS) – Large-Scale Fabrication Potentials
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/a2cfbfca-d7f5-4ef0-ae4a-1fe5fc7f21dc/download
|
University of Texas at Austin
|
Selective Separating Shaping is a new additive manufacturing technique which is
capable of processing polymeric, metallic, ceramic and composites including cementitious
materials. In earlier experiments the capabilities of SSS in making metallic and ceramic
parts have been demonstrated. The focus of the research reported in this paper has been on
exploration of capabilities of SSS for creation of large-scale cementitious composite parts.
A prototype machine has been used to create specimens made of regular construction
cement (lime based), Sorel cement (magnesia based) and gypsum based composites. The
fabrication results, surface quality and flexural strength for these experiments are
presented.
| null | null | null | null | null | null |
['Nouri, H.', 'Khoshnevis, B.']
|
2021-11-04T15:26:46Z
|
2021-11-04T15:26:46Z
|
2017
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/89985', 'http://dx.doi.org/10.26153/tsw/16906']
|
eng
|
2017 International Solid Freeform Fabrication Symposium
|
Open
|
['selective separation shaping', 'polymeric parts', 'nylon', '3D printing']
|
Selective Separation Shaping of Polymeric Parts
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/6d5728ab-b926-4b27-b3c4-aff124eede74/download
|
University of Texas at Austin
|
Additive manufacturing (AM), or 3D printing has enjoyed a recent surge of attention over the past decade.
AM is a process in which digital 3D design data is used as input to build physical objects by combining
sequence layers of material. By increasing demand in use of additive manufacturing for fabrication of end-user
parts, there is considerable interest in developing new techniques which can offer high quality customized parts
at low cost. Selective Separation Shaping (SSS) is a new AM technology developed with the goal of fabricating
low cost, high resolution 3D parts. The main advantage of SSS is that this process enables building fully
functional pieces without the need of any intermediate binder or high cost laser operation. This process has been
primarily applied to metallic, and ceramic materials and test cases were successfully built. There has been no
study on fabrication of parts using polymeric material and the goal of this research is to examine successful
fabrication of polymer parts. Nylon 6,6 has been used as starting base material and several test cases were
fabricated to identify key factors in success of this process. Different classes of nylon are studied to achieve
better understanding of material properties on success of fabrication and achieve an effective binding between
layers. Finally, 3D printed parts built by SSS are presented.
| null | null | null | null | null | null |
['Zhang, Jing', 'Khoshnevis, Behrokh']
|
2021-10-19T17:52:08Z
|
2021-10-19T17:52:08Z
|
2015
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89309
|
eng
|
2014 International Solid Freeform Fabrication Symposium
|
Open
|
['Selective Separation Sintering', 'Additive Manufacturing', 'ceramics', 'metal']
|
Selective Separation Sintering (SSS) A New Layer Based Additive Manufacturing Approach for Metals and Ceramics
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/11e1d9dd-64b8-485b-8bd1-26dfcc130b88/download
|
University of Texas at Austin
|
Selective Separation Sintering (SSS) is a powder layer based Additive Manufacturing
approach. SSS can fabricate high temperature ceramic and metallic parts at comparatively
lower cost with high quality. In the printing process a dry powder of higher sintering temperature
is deposited into the base material which makes up the part. The inserted powder defines the
boundary of the part and separates the part from its surroundings. When printing of all layers is
completed the deposited dry powder serves as a separation coating which defines the shape of
the part. In the sintering process the base material is sintered into a solid part while the
separation coating remains as loose powder. The part is then separated from the surrounding
area at the separation coating surfaces, and is post processed if necessary. Preliminary results
have proven the capability of SSS in successfully printing ceramic and metallic parts. Future
experiments are planned for improving the process resolution.
| null | null | null | null | null | null |
['Khoshnevis, Behrokh', 'Zhang, Jing']
|
2021-10-28T20:44:54Z
|
2021-10-28T20:44:54Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89696
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['selective separation sintering', 'SSS', 'sintering', 'powder deposition', 'additive manufacturing']
|
Selective Separation Sintering for Metallic Part Fabrication
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/5c5887cd-765b-484d-8a1d-563202856090/download
|
University of Texas at Austin
|
Selective Separation Sintering (SSS) is a powder layer based additive manufacturing
approach. In the printing process a dry powder of higher sintering temperature is deposited into
the base material which makes up the part. The inserted powder defines the boundary of the
part and separates the part from its surroundings. A post sintering of the part is carried out in
the furnace where the base material is sintered and the inserted powder remain loose due to its
higher sintering temperature. The part is separated from the surrounding redundant material
along the loose inserted powder region. A stable deposition rate of S-powder is the key for
generating parts of easy separation and smooth surface. Factors that affect the flow rate are
analyzed and the analyzed results are implemented to stabilize the process. With the progress
in powder deposition rate control, bronze parts have been fabricated which demonstrate good
quality.
| null | null | null | null | null | null |
['Bournias-Varotsis, A.', 'Friel, R.J.', 'Harris, R.A.', 'Engstrom, D.']
|
2021-11-01T21:59:46Z
|
2021-11-01T21:59:46Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89771
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['aluminum foils', 'insulating layer', 'embedded electronic circuits', 'electronic circuits', 'anodic aluminum oxide', 'ultrasonic additive manufacturing']
|
Selectively Anodised Aluminum Foils as an Insulating Layer for Embedding Electronic Circuitry in a Metal Matrix via Ultrasonic Additive Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/376e25f9-8bfe-4fd2-b2fc-9e0201334c25/download
|
University of Texas at Austin
|
Ultrasonic Additive Manufacturing (UAM) is a hybrid Additive Manufacturing (AM)
process that involves layer-by-layer ultrasonic welding of metal foils and periodic machining to
achieve the desired shape. Prior investigative research has demonstrated the potential of UAM for
the embedding of electronic circuits inside a metal matrix. In this paper, a new approach for the
fabrication of an insulating layer between an aluminium (Al) matrix and embedded electronic
interconnections is presented. First, an Anodic Aluminium Oxide (AAO) layer is selectively grown
onto the surface of Al foils prior to bonding. The pre-treated foils are then welded onto a UAM
fabricated aluminium substrate. The bonding step can be repeated for the full encapsulation of the
electronic interconnections or components. This ceramic AAO insulating layer provides several
advantages over the alternative organic materials used in previous works.
| null | null | null | null | null | null |
['Crane, N.B.', 'Tuckerman, J.', 'Nielson, G.N.']
|
2021-09-30T20:25:31Z
|
2021-09-30T20:25:31Z
|
9/23/10
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88296', 'http://dx.doi.org/10.26153/tsw/15237']
|
eng
|
2010 International Solid Freeform Fabrication Symposium
|
Open
|
['additive manufacturing', 'biological growth', 'performance benefits', 'performance challenges', 'self-assembly errors', 'miniature thermoelectric devices', 'microscale photovoltaic cells']
|
Self Assembly as an Additive Manufacturing Process: Opportunities and Obstacles
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/f41f01b8-ea68-4f27-87b7-8cc83650f350/download
|
University of Texas at Austin
|
While additive manufacturing processes typically integrate functionally identical building
blocks, biological growth depends on the precise assembly of molecular building blocks to
achieve the remarkable functionality observed in living systems. This paper considers potential
performance benefits and challenges of producing systems by controlled assembly of functional
components. The work will consider the impact of self-assembly errors in two energy
applications: miniature thermoelectric devices and microscale photovoltaic cells. In both, high
performance is possible by assembling microscale components. While assembly errors can
reduce system performance, performance models show that high levels of system performance
can be achieved through system design and/or self-assembly process control.
| null | null | null | null | null | null |
['Nassar, A.R.', 'Spurgeon, T.J.', 'Reutzel, E.W.']
|
2021-10-12T21:51:09Z
|
2021-10-12T21:51:09Z
|
2014
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88750', 'http://dx.doi.org/10.26153/tsw/15684']
|
eng
|
2014 International Solid Freeform Fabrication Symposium
|
Open
|
['defect detection', 'directed-energy additive manufacturing', 'additive manufacturing', 'metals', 'optical emission spectroscopy']
|
Sensing Defects during Directed-Energy Additive Manufacturing of Metal Parts using Optical Emissions Spectroscopy
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e487fbdf-212a-42c5-993f-bd58edc0a857/download
|
University of Texas at Austin
|
Critical components produced via additive manufacturing must be free of unwanted defects.
While defects may be detectable after deposition using nondestructive testing techniques,
detecting defects during the deposition process offers many benefits: it may enable users to
interrupt deposition to repair the part, or to abort deposition to minimize further loss of time and
material. Here, we present a method for real-time defect detection during directed-energy
additive manufacturing of metals. The method utilized optical emission spectroscopy and a
custom-built data acquisition and control infrastructure. It was implemented on a LENS MR-7
machine, and employed during manufacturing of Ti-6Al-4V components in which defects were
intentionally introduced. Emission spectra were correlated with defect locations, determined via
computed tomography and metallographic cross-sectioning. Preliminary results indicated that
defect formation was correlated with atomic titanium (Ti I) and Vanadium (V I) emissions and
that measurement of the line-to-continuum ratio for line emissions could be used for defect
detection. Based on these findings, sensing strategies for defect detection and, potentially, in-situ-defect repair may be realizable.
| null | null | null | null | null | null |
['Fan, Zhiqiang', 'Phatak, Kaushik', 'Liou, Frank']
|
2020-02-21T16:04:29Z
|
2020-02-21T16:04:29Z
|
8/30/05
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80065', 'http://dx.doi.org/10.26153/tsw/7087']
|
eng
|
2005 International Solid Freeform Fabrication Symposium
|
Open
|
Laser Metal Deposition
|
Sensitivity Analysis of Process Parameters in Laser Deposition
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/ea8beb7e-d6df-49e0-82a2-36fd784c2b77/download
| null |
In laser cladding with powder injection process, process output parameters, including
melt pool temperature and melt pool dimensions, are critical for part quality. This paper uses
simulation and experiments to investigate the effect of the process input parameters: laser power,
powder mass flow rate, and scanning speed on the output parameters. Numerical simulations and
experiments are conducted using a factorial design. The results are statistically analyzed to
determine the significant factors and their interactions. The simulation results are compared to
experimental results. The quantitative agreement/disagreement is discussed and further research is
outlined.
| null | null | null | null | null | null |
['Vasudevarao, Bharath', 'Natarajan, Dharma Prakash', 'Henderson, Mark', 'Razdan, Anshuman']
|
2019-09-23T15:55:41Z
|
2019-09-23T15:55:41Z
|
2000
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/75946', 'http://dx.doi.org/10.26153/tsw/3045']
|
eng
|
2000 International Solid Freeform Fabrication Symposium
|
Open
|
Parameter
|
Sensitivity of RP Surface Finish to Process Parameter Variation 251
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/d1a23107-9fba-4ba0-8e8c-7a9156e975cc/download
| null |
In the rapid prototyping process, surface finish is critical as it can affect the part accuracy, reduce the post processing costs and improve the functionality of the parts. This paper presents an experimental design technique for determining the optimal surface finish of a part built by the Fused Deposition Modeling (FDM) process. The design investigates the effect of the parameters; build orientation, layer thickness, road width, air gap and model temperature on the surface finish. Experiments were conducted using a fractional factorial design with two levels for each factor. The results are statistically analyzed to determine the significant factors and their interactions. The significant factors, their interactions and the optimum settings are proposed.
| null | null | null | null | null | null |
['Liravi, Farzad', 'Das, Sonjoy', 'Zhou, Chi']
|
2021-10-19T15:36:53Z
|
2021-10-19T15:36:53Z
|
2014
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89302
|
eng
|
2014 International Solid Freeform Fabrication Symposium
|
Open
|
['bottom-up stereolithography', 'bottom-up additive manufacturing', 'finite element analysis', 'separation force', 'cohesive delamination', 'optimization']
|
Separation Force Analysis Based on Cohesive Delamination Model for Bottom-Up Stereolithography Using Finite Element Analysis
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/65027874-7aaf-48f6-bc28-9b61f146b12b/download
|
University of Texas at Austin
|
Bottom-up (constrain-surface) Additive Manufacturing (AM) systems have been widely used in
industry. Compared to traditional open-surface AM technology, properties like better vertical resolution, higher
material filling rate, less production time, and less material waste make bottom-up AM technology a suitable
candidate for fabrication of complex three dimensional materials with high accuracy. However during the
pulling up stage, the substantial force generated between the formed part and the material container has high
risk of breaking the part and therefore reduces the process reliability. In this paper, an optimization-based
method is developed to model bottom-up AM process using finite element analysis (FEA). The FEA model is
developed using ABAQUS to model the behavior of the cohesive delamination at the interface of the formed
part and a hyper-elastic intermediate which has been used to reduce the pulling up force. An optimization
model is also established to evaluate the cohesive stiffness parameters that cannot be calculated directly from
closed formulas or mechanical tests. The results of this work will be used to develop an adaptive closed-loop
mechanics-based system to control the pulling up process and achieve a reliable technology.
| null | null | null | null | null | null |
['Ljungblad, U.', 'Hultman, A.']
|
2021-09-30T13:40:06Z
|
2021-09-30T13:40:06Z
|
2010
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88246', 'http://dx.doi.org/10.26153/tsw/15187']
|
eng
|
2010 International Solid Freeform Fabrication Symposium
|
Open
|
['Electron Beam Melting', 'orthopedic implants', 'statistical process control']
|
Serial Production with EBM
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/6c0233d8-e8d8-4ef6-9199-7a6dc2248fb6/download
|
University of Texas at Austin
| null | null |
Moving from prototyping to production is a major challenge for the additive
manufacturing industry. It requires a robust and reliable technology having high and
verifiable repeatability. The transition into production is not possible without the
technology being capable of sustaining a high product quality as well as productivity in
par or better than traditional manufacturing.
Electron Beam Melting (EBM) has since 2007, been used for manufacturing of CE-certified standard orthopedic implants with more than 20’000 units produced in several
EBM systems. High productivity combined with process stability has been key factors for
this application to emerge. Added product value in form of engineered surface porosity
has been vital to promote the step into serial production.
Development of EBM has been focused on system reliability, process stability,
material quality, productivity and means for process validation to reach proven
requirements for production. Statistical process control (SPC) has been a very powerful
tool to carry out this development in an efficient way.
| null | null | null | null |
['Manzur, Tariq', 'Roychoudhuri, Chandra', 'Marcus, Harris']
|
2018-11-14T19:49:11Z
|
2018-11-14T19:49:11Z
|
1996
|
Mechanical Engineering
|
doi:10.15781/T21V5C03W
|
http://hdl.handle.net/2152/70258
|
eng
|
1996 International Solid Freeform Fabrication Symposium
|
Open
|
['CAD/CAM', 'SLS', 'SFF']
|
SFF Using Diode Lasers
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/28b8533e-977f-419a-b34d-8c1c12a9841f/download
| null |
Rapid prototypings using direct selective laser sintering (SLS) ofmetal/ceramic powders
have a great potential for design and fabrication of near net shape ofmetal/ceramic parts.
At presents CO2, Nd:YAG and Excimer are the only possible solutions for the heavy duty
manufacturing applications. At the University ofConnecticut, researchers advanced the
concept ofrapid prototyping and other desk top manufacturing tasks such as welding,
sintering, drilling, marking, soldering of electronic components, face hardening ofmetal
and other materials applications by the use ofhigh power diode lasers.
Utilizing SLS techniques and approaches designed to harness the full potential of diode
lasers, computer controlled sintering system was developed. The system is capable of
producing complex three dimensional shapes ofmetal/ceramic parts from CAD/CAM
solid model data files. In the paper direct sintered Fe-Bronze parts using high power laser
diodes has been demonstrated. The system comprises ofhigh power laser diodes (25 W
cw, A=980 nm and 60 W pulse or cw, A=81 0 nm), beam scanning systems, atmospheric
controlled chamber, and CAD/CAM software.
| null | null | null | null | null | null |
['Xu, Anping', 'Shaw, Leon L.']
|
2020-02-17T14:19:56Z
|
2020-02-17T14:19:56Z
|
2004
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/79995', 'http://dx.doi.org/10.26153/tsw/7020']
|
eng
|
2004 International Solid Freeform Fabrication Symposium
|
Open
|
['functionally graded materials', 'Equal distance offset', 'Solid freeform fabrication']
|
SFF-Oriented Modeling and Process Planning of Functionally Graded Materials Using a Novel Equal Distance Offset Approach
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/d293c4f7-1d4b-4a1e-9562-0a4339a57a01/download
| null |
This paper deals with the modeling and process planning of solid freeform fabrication
(SFF) of 3D functionally graded materials (FGMs). A novel approach of representation and
process planning of FGMs, termed as equal distance offset (EDO), is developed. In EDO, a
neutral arbitrary 3D CAD model is adaptively sliced into a series of 2D layers. Within each
layer, 2D material gradients are designed and represented via dividing the 2D shape into
several sub-regions enclosed by iso-composition contours. If needed, the material
composition gradient within each of sub-regions can be further determined by applying the
equal distance offset algorithm to each sub-region. Using this approach, an arbitrary-shaped
3D FGM object with linear or non-linear composition gradients can be represented and
fabricated via suitable SFF machines.
| null | null | null | null | null | null |
['Bernitsas, Michael M.', 'Suryatama, Danet', 'Byungsik, Kang', 'Dale, G. Karr']
|
2018-10-03T15:59:04Z
|
2018-10-03T15:59:04Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T2R78676V
|
http://hdl.handle.net/2152/68656
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['LEAP Theory', 'selective laser sintering', 'Solid free-form fabrication']
|
Shape and Topology Structural Redesign by Large Perturbations
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/19cd8728-dc10-4270-a38f-4728e445b56d/download
| null |
The ultimate goal in concurrent engineering of structures is to achieve simultaneously in the
design stage the following objectives: (1) A shape that performs itsfunction, conforms with the
boundary conditions,and can support the external loads. (2) A product with structural integrity,
i.e. with stress levels remaining below acceptable limits. (3) A product with acceptable
performance, e.g. modal dynamics, i.e. with natural frequencies and mode shapes that do not
amplify external dynamic loads; and static, i.e. acceptable deflection. (4) A composite
microstructure that can optimally satisfy the above topology/ shape, load, and performance
constraints. (5) A microstructurefabrication process that efficiently produces the above optimal
structure. The purpose of our ONR funded project is to address the complete problem in
concurrent structural design by further developing the LargE Admissible Perturbations (LEAP)
theory which is being developed at the University of Michigan since 1983, and combiningit with
micromechanicsconstitutive equations. At the fabrication end, the Selective Laser Sintering (SLS)
process will be simulated so that the SLS variables are defined as the final product of the
concurrent structuraLdesign optimization process. LEAP theory -- as implemented in Code
RESTRUCT (REdesign of STRUCTures) -- produces the final design without trial and error or
repeated Finite Element Analyses (FEAs), thus, shortening the redesign process and contributing
to rapid prototyping.
| null | null | null | null | null | null |
['Merz, R.', 'Prinz, F.B.', 'Ramaswami, K.', 'Terk, M.', 'Weiss, L.E.']
|
2018-09-26T15:47:56Z
|
2018-09-26T15:47:56Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T2BK1781C
|
http://hdl.handle.net/2152/68579
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['Department of Mechanical Engineering', 'CAD/CAM', 'SFF', 'Shape Deposition']
|
Shape Deposition Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/8ddbfacb-0827-4a15-9fe6-3a149ff24c7e/download
| null |
One challenge for solid freeform fabrication has been to develop the capability to directly
create functional metal shapes which are dense, metallurgically bonded, geometrically accurate
and with good surface appearance. Shape Deposition is a manufacturing paradigm which attempts
to address these issues. It incorporates the advantages of several processes including solid freeform
fabrication (complex geometries, rapidly planned), 5-axis CNC machining (accuracy,
smooth surfaces), shot-peening (for stress relief) and 'microcasting' (a high-performance, weldbased
material deposition process). These processes are integrated within a CAD/CAM system
using robotic automation. This paper will present the current research in this effort.
| null | null | null | null | null | null |
['Weiss, L.', 'Prinz, F.', 'Neplotnik, G.', 'Padmanabhan, K.', 'Schultz, L.', 'Merz, R.']
|
2018-11-08T19:39:06Z
|
2018-11-08T19:39:06Z
|
1996
|
Mechanical Engineering
|
doi:10.15781/T2MG7GF74
|
http://hdl.handle.net/2152/69916
|
eng
|
1996 International Solid Freeform Fabrication Symposium
|
Open
|
['SDM', 'SFF', 'manufacturing process']
|
Shape Deposition Manufacturing of Wearable Computers
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/85ac1852-f05c-402c-9911-5f9ff302b0a1/download
| null |
Shape Deposition Manufacturing (SDM) is a solid freefrom fabrication methodology which
can fabricate heterogeneous structures, i.e., multi-material structures with embedded components.
One application is to build-up electromechanical devices such as conformally shaped computer
packages with embedded electronics. The goal is to be able to quickly design and manufacture, in
small lots, personalized, rugged units for specialized applications. One example, which is
described in this paper, is the manufacture of an underwater computer, the 'Frogman', which is
built-up in layers of polyurethane.
| null | null | null | null | null | null |
['Zhou, Wenchao', 'Loney, Drew', 'Fedorov, Andrei G.', 'Degertekin, F. Levent', 'Rosen, David W.']
|
2021-10-04T21:44:23Z
|
2021-10-04T21:44:23Z
|
8/17/11
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88358', 'http://dx.doi.org/10.26153/tsw/15297']
|
eng
|
2011 International Solid Freeform Fabrication Symposium
|
Open
|
['ink-jet printing', 'droplet deposition', 'droplet impact']
|
Shape Evolution of Droplet Impingement Dynamics in Ink-Jet Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/1346c739-c744-46a4-90c9-d9e0aece91b4/download
|
University of Texas at Austin
|
Ink-jet printing enables more efficient, economic, scalable manufacturing for a wide variety of materials
than other traditional additive techniques. The impact of droplets onto a substrate is critical for accuracy control
and optimization of the droplet deposition process. However, most previous research about droplet impact
focused on the spreading radius of the droplet, which does not provide enough information for manufacturing
purposes. This paper presents new methods to model and characterize droplet shape change during impact so
that the droplet deposition process can be optimized to build desired geometries. A validated numerical model is
used to study the shape change of the droplet impingement on a solid surface. A dimensional analysis is
conducted to reduce the number of parameters of the impact conditions by matching Reynolds, Weber, and
Froude numbers as well as possible. In addition, a new method of characterizing droplet shape is presented that
measures its similarity to a desired shape. The shape evolution of a wide range of impact conditions is simulated
with the validated numerical model using both physical and dimensionless quantities. The effects of the
dimensionless numbers on the shape evolution are examined and analyzed. Successive multiple droplets impact
is also simulated.
| null | null | null | null | null | null |
['Utela, B.', 'Anderson, R.', 'Kuhn, H.', 'Ganter, M.']
|
2020-03-09T15:14:25Z
|
2020-03-09T15:14:25Z
|
8/21/07
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80194', 'http://dx.doi.org/10.26153/tsw/7213']
|
eng
|
2007 International Solid Freeform Fabrication Symposium
|
Open
|
Three Dimensional Printing
|
Shape Training of Nitinol Wire Using Three-Dimensional (3DP) Fixtures
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/401afcbd-4a4f-4ae5-ab95-86c439242682/download
| null |
The presented research focuses on work done at the University of Washington on
process development for the training of nitinol shape memory alloy wire using Three
Dimensional Printing (3DP). Fixtures are created using the commercial stainless steel
printing system produced by Ex One. Superelastic nitinol wire is set by restraining the
wire in a fixture and thermal processing. A two dimensional test array was designed and
fabricated to examine the effects of fixture curvature on the final wire shape. Three
dimensional coils and spheres were created to demonstrate the potential of this process
for more complicated shapes.
| null | null | null | null | null | null |
['Yang, Li', 'Harrysson, Ola', 'West, Harvey', 'Cormier, Dennis']
|
2021-10-21T19:14:10Z
|
2021-10-21T19:14:10Z
|
2015
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89426
|
eng
|
2015 International Solid Freeform Fabrication Symposium
|
Open
|
['auxetic structure', 're-entrants', 'shear properties', 'electron beam melting']
|
Shear Properties of the Re-Entrant Auxetic Structure Made via Electron Beam Melting
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/ae906d6b-cffe-4744-bf25-af438bcb82be/download
|
University of Texas at Austin
|
While the tensile/compressive mechanical properties of the re-entrant auxetic cellular structure
have been relatively well modeled, their shear properties including the shear modulus and shear
strength have not been investigated. This paper focuses on the analytical modeling of the shear
properties of this auxetic structure utilizing beam analysis. The modeling results were further
compared with results from both simulation and experimentation. It was found that in addition
to the effective length reduction effect, the size effect also becomes significant for the shearing
of this re-entrant auxetic structures. Due to the size effect, it was expected that the re-entrant
auxetic structure could not be effectively homogenized based on the developed analytical
property model, and additional design factors must be considered in the future.
| null | null | null | null | null | null |
Steinchen, W.
|
2018-11-02T16:53:55Z
|
2018-11-02T16:53:55Z
|
1995
|
Mechanical Engineering
|
doi:10.15781/T2891294T
|
http://hdl.handle.net/2152/69340
|
eng
|
1995 International Solid Freeform Fabrication Symposium
|
Open
|
['strain analysis', 'vibration isolation', 'optimization']
|
Sheareography - a Practical Optical Testing and Measuring Method
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/27b4222f-ea28-4dc0-995e-6aa491a4f66c/download
| null |
Shearography is a laser optical method which is suited for either nondestructive testing or for
strain analysis. Contrary to holography which measures surfach displacements, shearography
measures derivatives of surface displacements. Since strains are functions of displacement
derivatives, shearography allows strains to be determined without numerical differentiating
displacement data. Defects in object normally create strain concentrations; it is easier using
shearography to correlate defects with strain anomalies rather than displacement anomalies
applying holography. Furthermore, rigid body motions do not produce strain, thus shearography
is insensitive against such motions and does not need adopting any particular device for vibration
isolation. It is an industrial tool suited very well for the following ares:
1. strain measurement and strain analysis
2. nondestructive testing and quality assurance system
3. optimization ofmachine parts and structures of any material
| null | null | null | null | null | null |
['Kletetzka, I.', 'Klippstein, H.', 'Sural, I.', 'Schmid, H.-J.']
|
2023-03-29T16:16:58Z
|
2023-03-29T16:16:58Z
|
2022
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/117676', 'http://dx.doi.org/10.26153/tsw/44555']
|
eng
|
2022 International Solid Freeform Fabrication Symposium
|
Open
|
laser sintering
|
Shelf Life of Polyamide 12 (PA2200) Laser Sintering Powder
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/0240d80f-fdb1-403d-8551-46ba427136d1/download
| null |
It is a very well-known fact that polyamide powders age during processing in laser
sintering. Therefore, the recycling rate of used powder is typically limited to around 50 % and it
has to be mixed with new, virgin powder, before the next build job can be started. The aging of the
polymer powder between its production and processing, in contrast, has hardly been investigated
so far and has received little attention. In order to investigate the effects of storage time, optical,
thermal and rheological tests were carried out on two batches of PA2200 powder, which had been
stored for 5.5 and 6.5 years respectively. Compared to freshly produced powders, aging effects
were clearly visible.
| null | null | null | null | null | null |
['Yao, W. L.', 'Leu, Ming C.']
|
2019-02-25T17:45:13Z
|
2019-02-25T17:45:13Z
|
1998
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73477', 'http://dx.doi.org/10.26153/tsw/627']
|
eng
|
1998 International Solid Freeform Fabrication Symposium
|
Open
|
['Rapid Prototyping', 'Investment Casting']
|
Shell Cracking In Investment Casting with Laser Stereolithography Patterns
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/38b318eb-09a7-4930-b162-482f82a5ceef/download
| null |
This paper presents an investigation of ceramic shell cracking during the burnout process
in investment casting with internally webbed laser stereolithography patterns. We hypothesize
that shell cracking will occur when the rupture temperature of the ceramic shell is lower than
both the glass transition temperature of the pattern material and the web· link buckling
temperature. The hypothesis is validated by our experimental observations which confirm the
numerical predictions from our fillite element analysis. This provides a basis for design of the
internal web geometry of a lithography pa.tternand evaluation ofthe burnolltprocesswithsuch a
pattern. We show the shell cracking and web link buckling temperatures to be functiollsofthe
pattern geometry (including the cross~sectional dimensions and span length of the web link) and
the shell thickness.
| null | null | null | null | null | null |
['Dilip, J.J.S.', 'Anam, Md Ashabul', 'Pal, Deepankar', 'Stucker, Brent']
|
2021-10-28T21:11:22Z
|
2021-10-28T21:11:22Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89702
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['additive manufacturing', 'selective laser melting', 'alloy IN625', 'single track deposits']
|
A Short Study on the Fabrication of Single Track Deposits in SLM and Characterization
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/66e18862-6618-4434-b47e-ea737d9fb564/download
|
University of Texas at Austin
|
The present investigation is focused on fabrication of single track deposits, with multiple laser
power and scan speed combinations to turn understanding their effect on the formation of the
melt pool. In this study alloy, IN625 powder from EOS was used to produce single track
deposits. Surface morphology and dimensions of single track deposits were characterized using
SEM. The cross-section of the single track deposits was studied, and the geometrical features of
melt pools were evaluated. The results indicate that melt pool characteristics provide significant
information that is helpful for process parameters selection. These single track experiments will
be being extended to fabricate samples with multiple layers in the future study. This approach of
investigating single track deposits, when used to narrow down the window of process parameters
can provide a path to speed up the tedious and time-consuming experiments for optimization of
process parameters.
| null | null | null | null | null | null |
['McIntosh, Joseph J.', 'Danforth, Stephen C.', 'Jamalabad, Vikram R.']
|
2018-11-29T20:20:48Z
|
2018-11-29T20:20:48Z
|
1997
|
Mechanical Engineering
|
doi:10.15781/T2513VG0Q
|
http://hdl.handle.net/2152/70338
|
eng
|
1997 International Solid Freeform Fabrication Symposium
|
Open
|
['CAD', 'SLS']
|
Shrinkage and Deformation in Components Manufactured by Fused Deposition of Ceramics
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/8ccc53e8-a835-4750-9431-5a35f3953900/download
| null |
Fused Deposition of Ceramics (FDC) presents a new processing technique that may contribute
to anisotropic shrinkage and deformation, which are critical issues in the manufacture of
ceramic components. The aim ofthis study is to identify and quantify key FDC parameters and
their influence on shrinkage and deformation. The study was divided into two focus areas. The
first was the effect ofthe FDC build parameters on the shrinkage of ceramic parts. The second
focused on the interaction of the FDC build process with the geometrical features of a part. A
series of experimental design techniques have been implemented in order to gain a thorough
understanding of said parameters, as well as any possible interactions between parameters
Studies have been conducted across each processing step, from the green manufacture of the
part, through binder removal, and sintering. The data and knowledge gained from these
experiments will allow us to redesign the original CAD component files to compensate for the
shrinkage and deformation encountered when using the FDC technique
| null | null | null | null | null | null |
['Bhargava, P.', 'Bandyopadhyay, A.', 'Rangarajan, S.', 'Qi, G.', 'Dai, C.', 'Wu, S.', 'Danforth, S.', 'Safari, A.']
|
2018-12-05T19:53:23Z
|
2018-12-05T19:53:23Z
|
1997
|
Mechanical Engineering
|
doi:10.15781/T2WS8J63V
|
http://hdl.handle.net/2152/71407
|
eng
|
1997 International Solid Freeform Fabrication Symposium
|
Open
|
['FDC', 'heating schedule']
|
Shrinkage, Weight Loss and Crack Prevention During Binder Burn Out of Components Produced" by Fused Deposition of Ceramics (FDC)
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/483638ce-bfc2-44a1-9110-444bbb302e94/download
| null |
In the present study the sequential stages ofthe previously established binder bum out (BBO)
route were characterized by obtaining precise shrinkage and weight loss measurements from
interrupted runs. A DoE (Design of Experiments) approach was adopted to systematically
investigate the effect of process variables; such as the heating rates during critical segments, part
dimensions and environment (flowing nitrogen vs vacuum) on the shrinkage, weight loss and
cracking during binder bum out. A stepwise TGA was performed to study the effect of ramp rate
and dwell time on the kinetics of binder bum out, and an experiment was conducted to determine
optimum wicking conditions. The results from this study have been used to maximize the weight loss
and minimize the cracking during binder bum out cycle for FDC parts with different sizes.
| null | null | null | null | null | null |
['Stierlen, Peter', 'Schanz, Peter', 'Eyerer, Peter']
|
2019-02-26T20:39:02Z
|
2019-02-26T20:39:02Z
|
1998
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73499', 'http://dx.doi.org/10.26153/tsw/649']
|
eng
|
1998 International Solid Freeform Fabrication Symposium
|
Open
|
['high density ceramic structure', 'carbon binding structure']
|
Si/SiC-Ceramic low process shrinkage - high temperature material for the Laser Sinter process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/f8a8b6ba-df71-46ea-96e1-5bc6ad0c4a9c/download
| null |
Actual RP-systemsare very limited in producing adequate ceramic prototypes. In the
presented process, the SiC..green part manufacturing bythe laser sintering process in combination
with special postprocessing allows the fast production of SUSiC prototypes. A mixture of SiC
powder and a reactive polymer binder system is used in the Laser Sinter process. In the following
postprocessing the porous green part has to be .infiltrated with a precursor resin, carbonised and
finally infiltrated withimolten silicon.•Incontrast to cold isostatic moulding or slip casting the
shrinkage is very low (2-4 0/0).• Experiments with suitable materials/and process conditions were
successful. This paper will show the state of and the possible further investigation into process.
| null | null | null | null | null | null |
['Stierlen, Peter', 'Eyerer, Peter']
|
2019-03-12T20:01:05Z
|
2019-03-12T20:01:05Z
|
1998
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73608', 'http://dx.doi.org/10.26153/tsw/750']
|
eng
|
1999 International Solid Freeform Fabrication Symposium
|
Open
|
['precursor·resin', 'silicon']
|
Si/SiC-Ceramic Prototypes via LS2I-Process (Liquid Silicon Infiltration of Laser Sintered C-SiC Parts)
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/c4061c09-873d-4fd5-9b93-2d9d02d66fa5/download
| null |
The liquid silicon infiltration of laser sinteredC-~iC parts (LS2
I) is solidfreeform
fabrication technique which allows the production of complexshapedSi/SiC prototypes. A
mixture of SiC powder and reactive polymer binder isused in the las~r sinteringprocessto
generate a porous green part. In the\postprocessing, the porous green part structure has to be
infiltrated with a.precursor·resin, carbonised and finally·.infiltrated•. with molten silicon. The
infiltrated silicon reacts with the residualcarbontobuild~~SiC.Results generated by the use of
reduced primary particle sizes as well asaltemative infiltration materials and the use of other·RPtechniquesfor the green partfabrication will be discussed in this paper.
| null | null | null | null | null | null |
['Melvin III, Lawrence S.', 'Beaman Jr., Joseph J.']
|
2018-11-08T15:39:49Z
|
2018-11-08T15:39:49Z
|
1995
|
Mechanical Engineering
|
doi:10.15781/T2FX74H89
|
http://hdl.handle.net/2152/69891
|
eng
|
1995 International Solid Freeform Fabrication Symposium
|
Open
|
['powder application', 'bed density experiment', 'sieve feed system']
|
A Sieve Feed System for the Selective Laser Sintering Process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/303042ca-d234-414d-aeab-1d1d1438758e/download
| null |
A sieve feed system has been designed for use with the Selective
Laser Sintering process. The sieve feed system uses
electrostatic charge to help apply polymer powder to a green
powder bed. The sieve feed system was found to help the
application of polymer powder as measured by a 10 to 15%
increase in final part density. The sieve feed system has
many potential applications, including material property design,
and material mixing during the sintering process.
| null | null | null | null | null | null |
['Taft, Douglas', 'Ogale, Amod', 'Paul, Frank', 'Hunt, Elaine', 'Ahzi, Said']
|
2018-12-05T17:11:39Z
|
2018-12-05T17:11:39Z
|
1997
|
Mechanical Engineering
|
doi:10.15781/T2XS5K333
|
http://hdl.handle.net/2152/71399
|
eng
|
1997 International Solid Freeform Fabrication Symposium
|
Open
|
['StereoLithography', 'solid models']
|
Silica Filled Resins for Rapid SLA Tools
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/507d2a5d-7432-4538-905c-1d2adb898d06/download
| null |
A stable silica /SL epoxy resin suspension has been developed at Clemson
University. It has been processed to make parts in a commercial StereoLithography
Apparatus (SLA). Results oftesting show that the composite material has a higher
modulus and increased abrasion resistance over the neat epoxy resin. An injection
molding die has been made with the reinforced resin in the SLA and tested.
| null | null | null | null | null | null |
['Mi, Jian', 'Gillespie, Josh', 'Johnson, Ryan W.', 'Bondi, Scott N.', 'Lackey, W. Jack']
|
2019-11-21T18:22:08Z
|
2019-11-21T18:22:08Z
|
2003
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/78556', 'http://dx.doi.org/10.26153/tsw/5612']
|
eng
|
2003 International Solid Freeform Fabrication Symposium
|
Open
|
Silicon Carbide
|
Silicon Carbide Growth Using Laser Chemical Vapor Deposition
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/fb3821c8-ce1f-48bc-b2cc-b8e38d00f41a/download
| null |
Silicon Carbide (SiC) has been grown from methyltrichlorosilane (MTS) and
hydrogen using the Georgia Tech Laser Chemical Vapor Deposition (LCVD) system. A
morphology study of LCVD-SiC fibers and lines was completed. Graphite and single
crystal silicon were used as the substrates. In order to provide guidance to future growth
of SiC, thermodynamic calculations for the C-H-Si-Cl system were performed using the
SOLGASMIX-PV program.
| null | null | null | null | null | null |
['Vail, N.K.', 'Barlow, J.W.', 'Marcus, H.L.']
|
2018-05-03T19:06:51Z
|
2018-05-03T19:06:51Z
|
1993
|
Mechanical Engineering
|
doi:10.15781/T25X25W7S
|
http://hdl.handle.net/2152/65059
|
eng
|
1993 International Solid Freeform Fabrication Symposium
|
Open
|
['Selective Laser Sintering', 'SLS', 'Department of Chemical Engineering', 'Center for Materials Science and Engineering', 'Silicon Carbide', 'Encapsulation', 'Polymer', 'Composites']
|
Silicon Carbide Preforms for Metal Infiltration by Selective Laser Sintering™ of Polymer Encapsulated Powders
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/de3d507b-e987-44c3-bf3d-f1fa765acc96/download
| null |
A polymer encapsulated silicon carbide system has been developed for
use with Selective Laser Sintering. Extensive studies with this material
have provided information pertaining to processing and material
parameters which most affect the strengths and densities of resulting
green parts. The important parameters considered were particle size
distribution of the powders, laser scanning conditions, and laser beam
diameter. Simple and complex shapes were easily produced with this
material using optimized parameters. Green objects were infused with
metal by Lanxide using their pressureless infiltration process to produce
both metal matrix and ceramic matrix composites.
(Key Words: Silicon Carbide, Encapsulation, Polymer, Selective Laser
Sintering, Composites).
| null | null | null | null | null | null |
['Birmingham, B.R.', 'Tompkins, J.V.', 'Marcus, H.L.']
|
2018-10-03T18:19:38Z
|
2018-10-03T18:19:38Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T22J68P93
|
http://hdl.handle.net/2152/68669
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['SALDVI', 'selected laser area deposition', 'solid freeform fabrication']
|
Silicon Carbide Shapes By Selected Area Laser Deposition Vapor Infiltration
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/efc3902b-fd12-4374-b248-af1b996d95b1/download
| null |
Selected Area Laser Deposition Vapor Infiltration (SALDVI) is a unique
combination ofselected area laser deposition, chemical vapor infiltration and layered
powder handling techniques that can be used to fabricate silicon carbide (SiC)/SiC
composite shapes. This paper discusses a SALDVI process under investigation which
selectively infiltrates SiC powder with SiC generated by decomposition of a gas precursor
under a scanned laser beam. A general description of the process, including some of its
inherent advantages is presented. Experimental results which explore beam interaction,
powder size and infiltration time effects are also presented.
| null | null | null | null | null | null |
['Flach, Lawrance', 'Chartoff, Richard P.']
|
2018-10-03T15:36:15Z
|
2018-10-03T15:36:15Z
|
1994
|
Mechanical Engineering
|
doi:10.15781/T2NG4HB3F
|
http://hdl.handle.net/2152/68649
|
eng
|
1994 International Solid Freeform Fabrication Symposium
|
Open
|
['Polymer shrinkage', 'stereolithography', 'Photopolymerization']
|
A Simple Polymer Shrinkage Model Applied to Stereolithography
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/6796957d-2c6b-4a2e-8a76-619c18df2c58/download
| null |
A simple polymer shrinkage model has been successfully applied to the stereolithography
process. The shrinkage model, which computes specific volume changes from the degree of
conversion of monomer to polymer, incorporates a lag between conversion and shrinkage. An
overall process model used to simulate the stereolithography process was modified by inclusion
of the shrinkage model. Use of the modified stereolithography process model allows prediction
of the shrinkage that might be expected to occur when fabricating a strand of plastic. By varying
the lag between conversion and shrinkage it is shown that faster shrinking resins should exhibit
lower overall shrinkage than slower shrinking resins. This is a direct result of the fact that less
shrinkage occurs after the strand has been scanned for the faster shrinking resins.
| null | null | null | null | null | null |
['Karunakaran, K. P.', 'Solanki, P. D.', 'Sahasrabudhe, Onkar S.', 'Pushpa, Vishal', 'Dwivedi, Rajeev', 'Kovacevic, Radovan']
|
2020-02-24T15:01:18Z
|
2020-02-24T15:01:18Z
|
2005
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80077', 'http://dx.doi.org/10.26153/tsw/7098']
|
eng
|
2005 International Solid Freeform Fabrication Symposium
|
Open
|
Rapid Prototyping
|
Simplified Production of Large Prototypes using Visible Slicing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/3e33460f-7a79-40de-b0ab-8a48375b2318/download
| null |
Rapid Prototyping (RP) is a totally automatic generative manufacturing
technique based on a “divide-and-conquer” strategy called ‘slicing’. Simple
slicing used on 2.5-axis kinematics of the existing RP machines is responsible for
the staircase error. Although thinner slices will have less error, the slice thickness
has practical limits. Visible Slicing overcomes these limitations. A few visible
slices exactly represent the object. Each visible slice can be realized using a 3- axis kinematics machine from two opposite directions. Visible slicing is
implemented on Segmented Object Manufacturing (SOM) machine under
development. SOM can produce soft large prototypes faster and cheaper with
accuracy comparable to that of CNC machining.
| null | null | null | null | null | null |
['Flood, Aaron', 'Liou, Frank']
|
2021-11-18T17:40:01Z
|
2021-11-18T17:40:01Z
|
2019
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90442', 'http://dx.doi.org/10.26153/tsw/17363']
|
eng
|
2019 International Solid Freeform Fabrication Symposium
|
Open
|
['laser beam quality', 'laser beam distance', 'Ti-64', 'aluminum', 'steel', 'blown powder', 'metal additive manufacturing']
|
Simulated Effect of Laser Beam Quality on the Robustness of Laser-Based AM System
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/4650a2a1-d050-4fbc-9d8b-be4f91841594/download
|
University of Texas at Austin
|
In many metal AM techniques, a laser is used as the heat source and in some applications, it
can be advantageous to work off of the focal plane. When operating outside of focus, the beam
quality of the laser can have drastic impacts on the ability to manufacture quality parts. This
study investigates the effect of the beam quality and distance from the focal plan on the ability
to deposit Ti-64, aluminum, and steel through the simulation of the blown powder process.
| null | null | null | null | null | null |
['Costa, L.', 'Vilar, R.', 'Réti, T.']
|
2020-02-17T15:03:30Z
|
2020-02-17T15:03:30Z
|
2004
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80004', 'http://dx.doi.org/10.26153/tsw/7029']
|
eng
|
2004 International Solid Freeform Fabrication Symposium
|
Open
|
Multilayer laser powder deposition
|
Simulating the Effects of Substrate Pre-Heating on the Final Structure of Steel Parts Built by Laser Powder Deposition
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/ea036650-8ed0-4efa-b3d7-013be6c8ae8e/download
| null |
Tool steel parts built by laser powder deposition often present a heterogeneous distribution of
properties caused by the complex structural transformations that occur during the deposition
process. A model describing these transformations has been developed. It couples finite element
heat transfer calculations with transformation kinetic theory to predict the final microstructure
and properties of the material and their variation across a laser powder deposited part.
Pre-heating is often used to reduce the residual stresses and the risk of thermal distortion and
cracking. However, this changes the heat transfer conditions and affects the final microstructure
and properties. In this work the proposed model was used to evaluate the effects of substrate preheating on the final hardness distribution. The results show that the final hardness depends
considerably on the initial temperature of the substrate.
| null | null | null | null | null | null |
['López, Omar', 'Martínez-Hernández, Uriel', 'Ramírez, José', 'Pinna, Christophe', 'Mumtaz, Kamran']
|
2021-10-26T18:46:03Z
|
2021-10-26T18:46:03Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89554
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['Cellular Automata - Finite Element', 'CA-FE', 'AA-2024', 'microstructure', 'selective laser melting']
|
Simulating the Microstructural Evolution of a Selective Laser Melted AA-2024
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/cc17bba6-d9b0-45fb-a1d6-16040789146b/download
|
University of Texas at Austin
|
A two-dimensional Cellular Automata (CA) – Finite Element (FE) (CA-FE) coupled model has
been developed in order to predict the microstructure formed during melting of a powdered AA-2024 feedstock using the Additive Manufacturing (AM) process Selective Laser Melting (SLM).
The presented CA model is coupled with a detailed thermal FE model computing heat flow
characteristics of the SLM process. The developed model takes into account the powder-to-liquid-to-solid transformation, tracks the interaction between several melt pools within a melted track,
and several tracks within various layers. It was found that the simulated microstructures bared a
close resemblance with fabricated AA-2024 SLM samples. With these observed capabilities of the
model, the porosity within a SLM produced part can be predicted, and used to optimise the
fabrication parameters of a sample.
| null | null | null | null | null | null |
['Childs, T.H.C.', 'Hauser, C.', 'Taylor, C.M.', 'Tontowi, A.E.']
|
2019-09-20T18:21:07Z
|
2019-09-20T18:21:07Z
|
2000
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/75925', 'http://dx.doi.org/10.26153/tsw/3024']
|
eng
|
2000 International Solid Freeform Fabrication Symposium
|
Open
|
Sintering
|
Simulation and Experimental Verification of Crystalline Polymer and Direct Metal Selective Laser Sintering 100
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/fcbec39b-777c-4397-a2b2-5382707b4bca/download
| null |
A previously developed two-dimensional finite element simulation of the SLS of amorphous polymers has been extended to the study of crystalline polymers and metals. For crystalline polymers, three developments have been needed: the treatment of latent heat of melting, the modifying of a viscous densification law to allow for the crystalline fraction of material during melting and, to obtain agreement with experiments, a consideration of the absorption depth of CO2 laser radiation into the powder bed; but the two-dimensional treatment remains sufficient. For metals, a different densification law and three-dimensional modelling have been needed for agreement with experiments on stainless steel powder beds.
| null | null | null | null | null | null |
['Kellner, I.N.', 'Zaeh, M.F.']
|
2021-09-30T19:52:18Z
|
2021-09-30T19:52:18Z
|
2010
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88287', 'http://dx.doi.org/10.26153/tsw/15228']
|
eng
|
2010 International Solid Freeform Fabrication Symposium
|
Open
|
['Additive Layer Manufacturing', '3D inkjet printing', 'polymerization', 'product quality', 'multi-scale simulation models', 'material design', 'process design']
|
Simulation Models for 3D Inkjet Printing – Material and Process Design
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/4652b1e3-6cec-4a98-b434-05f4dce9f0be/download
|
University of Texas at Austin
|
Due to the ability to produce complex parts with no need for pre-tooling, Additive Layer
Manufacturing (ALM) is a future technology with 3D inkjet printing being one of them. The
latter is based on the polymerization of a liquid dispensed into a powder bed. However, the
special challenges which have to be met here are to increase product quality such as tensile
strength and density on a repeatable base. Consequently multi-scale simulation models were
developed to support material researchers as well as users of the technology in their daily work
and therefore to contribute to process stability and material reliability of 3D printers and their
products.
| null | null | null | null | null | null |
['Tikare, Veena', 'Griffith, Michelle', 'Schlienger, Eric', 'Smugeresky, John']
|
2018-12-07T17:08:46Z
|
2018-12-07T17:08:46Z
|
1997
|
Mechanical Engineering
|
doi:10.15781/T2GF0NG8W
|
http://hdl.handle.net/2152/71450
|
eng
|
1997 International Solid Freeform Fabrication Symposium
|
Open
|
['microstructures', 'SEM micrograph']
|
Simulation Of Coarsening During Laser Engineered Net Shaping
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/b2791c2a-cd9e-465c-9db4-e9969045d610/download
| null |
Laser Engineered Net_Shaping, otherwise known as LENSTM, is an advanced manufacturing
technique used to fabricate complex near net shaped components directly from engineering solid
models without the use of dies or machining. The ultimate objective ofthis project is to develop
predictive simulation capability which will allow the LENSTM processors to determine fabrication
conditions given the material, shape, and application ofthe final part. In this paper, we will
present an incremental achievement to meeting the ultimate goal, a model capable ofsimulating
the coarsening ofmicrostructural features under the unique thermal history to which a LENSTM
part is subjected during processing. The simulation results show how grains ofvery different
shapes and sizes form within the same deposition line. They also show that relatively minor
changes in the dynamic temperature profile results in microstructures with vastly different
characteristics. The implications ofthis work for LENSTM fabrication is that controlling the
temperature profile is essential to tailoring the microstructure of a component to its application.
| null | null | null | null | null | null |
['Yan, Lei', 'Li, Wei', 'Chen, Xueyang', 'Zhang, Yunlu', 'Newkirk, Joe', 'Liou, Frank', 'Dietrich, David']
|
2021-10-27T21:31:01Z
|
2021-10-27T21:31:01Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89621
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['cooling rate', 'crack formation', 'direct laser deposition', 'Ti-48Al-2Cr-2Nb']
|
Simulation of Cooling Rate Effects on Ti-48Al-2Cr-2Nb Crack Formation in Direct Laser Deposition
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/9ad7e2dd-485d-4dee-a28c-7b6ed1fc1152/download
|
University of Texas at Austin
|
Transient temperature history is vital in direct laser deposition (DLD) because it reveals the
cooling rate at specific temperatures, which directly relates to phase transformation and types of
microstructure formed in deposit. FEA simulation was employed to study the transient
temperature history and cooling rate at different experimental setups in Ti-48Al-2Cr-2Nb DLD
process. In this paper, an innovative model was described, which combines a moving Gaussian
distribution heat source and element birth and death technology in ANSYS, help to analysis
cooling rate control method and guide crack-free deposits build process.
| null | null | null | null | null | null |
['Zhao, Xushan', 'Wang, Yuanxun', 'Wang, Guilan', 'Zhang, Haiou']
|
2021-11-18T17:35:16Z
|
2021-11-18T17:35:16Z
|
2019
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90440', 'http://dx.doi.org/10.26153/tsw/17361']
|
eng
|
2019 International Solid Freeform Fabrication Symposium
|
Open
|
['welding with rotation compression', 'WAAM', 'deformation control', 'residual stress']
|
Simulation of Hybrid WAAM and Rotation Compression Forming Process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/4828c80a-3715-428e-ac0d-83d6d0e2f658/download
|
University of Texas at Austin
|
Wire arc additive manufacturing (WAAM) has been studied and widely applied due to its high
forming efficiency and low production cost. In the process of WAAM, there are problems of
cracking, deformation, large residual stress, insufficient properties, and instability caused by
repeated rapid heating and chilling. Welding with rotation compression can control the performance
and shape synchronously in the semi-solidified state of the weld pool. In this study, a new solution
of hybrid WAAM and rotation compression is presented using follow-up rotating device to form
the weld bead layer by layer. Base on the finite element analysis result of the hybrid process, the
force energy curve of the rotation forming metal flowing process is obtained by arranging history
monitory points and paths on the bead, and the relationship between the shape and forming load is
revealed. The simulation model was verified by forming tests on middle carbon steel.
| null | null | null | null | null | null |
['Flach, Lawrance', 'Jacobs, Michelle A.', 'Klosterman, Donald A.', 'Chartoff, Richard P']
|
2019-02-25T17:27:10Z
|
2019-02-25T17:27:10Z
|
1998
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73475', 'http://dx.doi.org/10.26153/tsw/625']
|
eng
|
1998 International Solid Freeform Fabrication Symposium
|
Open
|
['LOM', 'lamination']
|
Simulation of Laminated Object Manufacturing (LOM) with Variation of Process Parameters
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/da50e362-709e-420c-b29d-d19a913ad486/download
| null |
A previously developed and verified thermal model for Laminated Object Manufacturing
(LOM) was used to investigate the effects of various processing parameters on the temperature
profile in a LOM part during the build cycle. The mathematical model, based on 3-dimensional
transient heat conduction in a rectangular geometry LOM part, allows calculation ofthe transient
temperature distribution within the part during the application of a new layer as well as during
other periods ofthe LOM build cycle. The parameters roller temperature, roller speed, chamber
air temperature, base plate temperature, and laser cutting time were independently varied, and the
LOM process response simulated. The results were analyzed in order to gain insight into
potential strategies for intelligent process control.
| null | null | null | null | null | null |
['Wang, Z.', 'Smith, D.E.']
|
2021-11-18T17:33:44Z
|
2021-11-18T17:33:44Z
|
2019
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90439', 'http://dx.doi.org/10.26153/tsw/17360']
|
eng
|
2019 International Solid Freeform Fabrication Symposium
|
Open
|
['melt flow', 'fiber orientation', 'numerical simulation', 'Galerkin Finite Element Method', 'polymer composites', 'polymer deposition additive manufacturing']
|
Simulation of Mutually Dependent Polymer Flow and Fiber Filled in Polymer Composite Deposition Additive Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/cdb68d7f-ab31-4c3b-b0fb-4581c5bd84b5/download
|
University of Texas at Austin
|
Short fiber-filled polymers experience increasing applications in melt extrusion additive
manufacturing. As the filled polymer is melted and extruded, the fiber-filled polymer suspension
exhibits mutually dependent effects, such that flow kinematics influence fiber orientation while
the fiber alignment affects the formation of melt flow. This paper presents a fully-coupled
numerical scheme to characterize the mutually dependent effects between melt flow and fiber
orientation in a non-Newtonian axisymmetric extrusion flow including a free surface using the
Galerkin Finite Element Method. The power law fluid model is employed to characterize the shear
thinning rheological behaviors of polymer melts. This approach is used to solve the fully-coupled
flow velocity and the fiber orientation fields for the nozzle extrusion flow in a large-scale polymer
deposition additive manufacturing process. Computed results obtained from both the weakly-coupled and fully-coupled schemes exhibit notable differences in the flow velocity, fiber
orientation tensor fields, die swell of free extrudate, and predicted elastic constants.
| null | null | null | null | null | null |
['Heller, B.P.', 'Smith, D.E.', 'Jack, D.A.']
|
2021-11-03T20:54:46Z
|
2021-11-03T20:54:46Z
|
2017
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89931
|
eng
|
2017 International Solid Freeform Fabrication Symposium
|
Open
|
['polymer melt flow', 'melt flow', 'fiber orientation', 'planar deposition', 'finite element analysis', 'fused filament fabrication']
|
Simulation of Planar Deposition Polymer Melt Flow and Fiber Orientation in Fused Filament Fabrication
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/1fb0aa5c-a1a2-4b31-a0a0-901318a465ee/download
|
University of Texas at Austin
|
Mechanical and thermal properties of a 3D printed part are improved by adding discrete
carbon fibers to the Fused Filament Fabrication (FFF) polymer feedstock. The properties of the
fiber-filled composite are significantly influenced by the orientation of the carbon fibers within
the extruded bead where fiber orientation in the bead is affected by the nozzle internal flow
geometry, extrudate swell, and the deposition flow during the FFF process. In this work, a 2D
Stokes flow finite element analysis is performed to evaluate FFF extrusion for a large-scale
deposition extruder where special attention is given to the deposition of polymer melt on the
moving platform below the nozzle. The shape of the extruded polymer is computed using a free
surface normal velocity minimization technique. Once the velocity field and flow boundary is
computed for the bead deposition process, fiber orientation and the resulting mechanical
properties of the solidified composite are computed within the printed bead.
| null | null | null | null | null | null |
Brown, Stuart
|
2018-05-03T18:16:41Z
|
2018-05-03T18:16:41Z
|
1993
|
Mechanical Engineering
|
doi:10.15781/T2348H04J
|
http://hdl.handle.net/2152/65052
|
eng
|
1993 International Solid Freeform Fabrication Symposium
|
Open
|
['Department of Materials Science and Engineering', 'SFF', 'SFF geometry', '3D Printing']
|
Simulation of Solid Freeform Fabrication
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e30cb355-63c1-47e0-84bd-9dd2c71ab0cd/download
| null |
Solid freeform fabrication involves highly coupled, nonlinear, thermomechanical processes. This
investigation simulates the formation of a simple SFF geometry, a right, rectangular prism with
aspect ratios of 1: 1:2. We include the effects of material variation, deposition path, and initial conditions
to predict resulting distortion.
| null | null | null | null | null | null |
['Lee, Y.S.', 'Kirka, M.M.', 'Raghavan, N.', 'Dehoff, R.R.']
|
2021-11-03T20:29:47Z
|
2021-11-03T20:29:47Z
|
2017
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89924
|
eng
|
2017 International Solid Freeform Fabrication Symposium
|
Open
|
['spot melting', 'scan strategy', 'solidification', 'columnar to equixaed transition', 'metal additive manufacturing']
|
Simulation of Spot Melting Scan Strategy to Predict Columnar to Equiaxed Transition in Metal Additive Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/14b633c5-5b49-4d2e-a7b2-259422adae6a/download
|
University of Texas at Austin
|
Recently, additive manufacturing (AM) processes are transforming from rapid
prototyping technology to mass industrial production due to increase in the fidelity of the AM
machines. This trend triggers the process optimization for various applications. In prior
literature, high-fidelity numerical models have been presented to understand the rapid
solidification conditions occurring during the process which includes heat transfer, fluid flow
and beam interaction with the raw material. However, most of these models are simulating few
melt passes and it is computationally expensive to simulate an entire layer of the component
being fabricated. In this study, we use a low-fidelity model to simulate an entire layer. We also
introduce a new melt strategy to control the solidification microstructure (i.e. columnar to
equiaxed transition). The response of the solidification morphology to process parameters (ex.
point offset, power, spot time) are investigated in terms of thermal gradient G and solidification
rate R. The model is validated with the experimental microstructure data.
| null | null | null | null | null | null |
['Temur, R.', 'Coole, T.', 'Bocking, C.']
|
2019-10-18T16:35:13Z
|
2019-10-18T16:35:13Z
|
2001
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/76254', 'http://dx.doi.org/10.26153/tsw/3343']
|
eng
|
2001 International Solid Freeform Fabrication Symposium
|
Open
|
Electrochemical
|
Simulation of the Electrochemical Machining Process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/d94cde53-8b9d-4715-99db-6aeea1d0abed/download
| null |
Electrochemical machining (ECM) or erosion, is a process for shaping materials by means of the
anodic dissolution of a work-piece using suitably shaped cathodes? However, the predictability
of the process is poor due to current density variations over the electrode contour leading to poor
dimensional tolerances.
This paper describes how the process can be entirely simulated by computer. A model of the
electric field during erosion is constructed based on the Laplace equations for the field. From the
distribution of the electric field, it is possible to continuously calculate the current density at each
point on the work-piece for the whole machining process. In this way, it is possible to predict the
final work-piece contour by running the simulation program instead of the real process.
Simulations for cylindrical, conical and spherical electrodes were carried out and compared to
actual eroded parts.
| null | null | null | null | null | null |
['Weinhold, Benjamin', 'Heck, Blake', 'Albright, Ashton', 'Wang, Keran', 'Grote, Jon-Michael', 'Adeniji, Emmanuel', 'Masoomi, Mohammad', 'Thompson, Scott']
|
2021-12-01T21:44:03Z
|
2021-12-01T21:44:03Z
|
2021
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90623', 'http://dx.doi.org/10.26153/tsw/17542']
|
eng
|
2021 International Solid Freeform Fabrication Symposium
|
Open
|
['distortion', 'part-to-substrate location', 'build orientation', 'part quality', 'laser powder bed fusion']
|
Simulation of the Laser-Powder Bed Fusion Process for Determining the Effects of Part-to-Substrate Location and Orientation on Distortion in a Connecting Rod
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/628518cb-2d61-46d6-8033-4fe55077df19/download
|
University of Texas at Austin
|
The use of process simulation for designing parts and ensuring their effective additive
manufacture can result in reduced product development times which would otherwise require
costly trial-and-error manufacturing and testing experiments. The goal of this project was to
determine the effects of part-to-substrate location and part build orientation on final part quality
as measured via distortion. A connecting rod from an engine was selected for re-design for mass
reduction and additive manufacturing via laser powder bed fusion (L-PBF). The rod was
modeled and optimized using the topology optimization features of ANSYS® Workbench. A
mass reduction of ~44% was achieved and unique design features were revealed. After topology
optimization, the L-PBF process was simulated using the ANSYS Workbench Additive Wizard
while having the optimized rod in three separate orientations at two different substrate locations.
In all cases investigated, build orientation proved to have a more significant impact on distortion
than substrate location. The effect of over supporting the part for distortion control can be
investigated further to circumvent location/orientation dependencies.
| null | null | null | null | null | null |
['Seefried, M.', 'Zaeh, M.F.', 'Meindl, M.']
|
2020-02-13T21:04:52Z
|
2020-02-13T21:04:52Z
|
8/31/04
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/79980', 'http://dx.doi.org/10.26153/tsw/7005']
|
eng
|
2004 International Solid Freeform Fabrication Symposium
|
Open
|
Indirect Metal Laser Sintering
|
Simulation of the Process Step Polymer Removal in Indirect Metal Laser Sintering
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/309d90f1-2abe-4387-9ba4-33a8c096d97a/download
| null |
With the Indirect Metal Laser Sintering and by means of a heat treatment in an oven process
metal components can be produced. In the first step the polymer is transformed from the solid
state into the gas phase. This takes place all over the component at different velocities depending
on the local temperatures and temperature gradients. The creation of the gas phase develops a
pressure inside of the component because the diffusion of the polymer within the part has a finite
velocity. The pressure may contribute to a damage of the component. This essay deals with the
procedure to simulate the gas pressure on the basis of the implementation of kinetic models in the
Finite-Element-Analysis.
| null | null | null | null | null | null |
['Steinberger, J.', 'Shen, J.', 'Manetsberger, K.', 'Muellers, J.']
|
2019-09-23T16:40:36Z
|
2019-09-23T16:40:36Z
|
2000
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/75962', 'http://dx.doi.org/10.26153/tsw/3061']
|
eng
|
2000 International Solid Freeform Fabrication Symposium
|
Open
|
Optimization
|
The Simulation of the SLS Process as the Basis of a Process Optimization 377
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/60f11499-1c84-47cb-8cb5-8b7195896451/download
| null |
In this work, a new model of the SLS process is introduced, offering the chance of analytically optimizing Selective Laser Sintering. The laser energy input is calculated by considering multiple scattering in the powder bed. The heat transfer is described by a new model which considers the heat flow through the growing sintering neck, and the sintering dynamics are determined by a new viscoelastic sintering model. All theoretical models are verified through experiments at near SLS conditions and are implemented in an enhanced FEM simulation of the process. Through this simulation, the major problems of the Selective Laser Sintering are illustrated and approaches for optimization of the SLS process are shown.
| null | null | null | null | null | null |
['Delfs, Patrick', 'Herale, Ashrith Ananthraj', 'Li, Zhiyuan', 'Schmid, Hans-Joachim']
|
2021-10-18T22:32:25Z
|
2021-10-18T22:32:25Z
|
2014
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89273
|
eng
|
2014 International Solid Freeform Fabrication Symposium
|
Open
|
['laser sintering', 'surface roughness', 'surface topography']
|
Simulation of the Surface Topography on Laser Sintered Polymer Parts
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/fccddedd-470c-48fc-976e-6af6a81cbb71/download
|
University of Texas at Austin
|
One barrier of laser sintering (LS) to become the main process for Direct Manufacturing (DM)
is the surface quality of LS parts. Hence, the property which has to be improved is the rough
surfaces of LS parts due to the layered structure. Another additional effect is the incomplete melting
of powder particles on the surface due to the high process temperature. In this paper we demonstrate
our approach of a theoretical model for the topography of LS part surfaces.
We investigated the surface roughness as a function of surface orientation. Considering that the
model involves further variables as layer thickness, particle density and particle size distribution to
describe the topography precisely. Experimental results were used to optimize and check the results
of the model.
| null | null | null | null | null | null |
['Zhang, Kai', 'Liu, Tingting', 'Liao, Wenhe', 'Zhang, Changdong', 'Zheng, Yi', 'Shao, Huang']
|
2021-11-15T20:39:52Z
|
2021-11-15T20:39:52Z
|
2018
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90263', 'http://dx.doi.org/10.26153/tsw/17184']
|
eng
|
2018 International Solid Freeform Fabrication Symposium
|
Open
|
['thermal behavior', 'molten pool', 'solidification', 'selective laser melting', 'alumina']
|
Simulation of the Thermal Behavior and Analysis of Solidification Process During Selective Laser Melting of Alumina
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/2f44e69e-f889-43b4-8c60-d4b7fad92c73/download
|
University of Texas at Austin
|
Selective laser melting (SLM) has rapidly developed in the past decade. High
precision-complex ceramics parts can be directly fabricated using this technology. To study
the thermal behavior of molten pools in the selective laser melting of alumina (Al2O3), we
established a three-dimensional model based on ANSYS. Then, combined with simulation
results, the physical phenomena during the rapid solidification process were discussed. The
simulation results showed that the laser power and scanning speed exerts a marked influence
on the maximum temperature, liquid lifetime, dimensions, and temperature gradient of the
molten pool. Owing to the different temperature gradients in the molten pool, the thermal
capillary force on the free surface varies. As a result, a slight difference exists between the
stripy solidification structures. Different orientations of columnar crystals can be obtained.
The underlying mechanism controls the direction of the temperature gradient with suitable
processing routes, such as decreasing the scanning speed.
| null | null | null | null | null | null |
['Gartner, P.', 'Krischke, N.', 'Benfer, M.', 'Bender, M.', 'Lanza, G.', 'Fleischer, J.', 'Dost, G.']
|
2023-04-05T13:58:09Z
|
2023-04-05T13:58:09Z
|
2022
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/117777', 'http://dx.doi.org/10.26153/tsw/44656']
|
eng
|
2022 International Solid Freeform Fabrication Symposium
|
Open
|
AM parts
|
Single Part Tracking Enabled by Fluorescent Polysecure Tracing Particles in Am Parts
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/b1e6dbf5-1de1-41f8-9fff-0615b2084400/download
| null |
Traceability is widely recognized as a core enabler of many industry 4.0 technologies. The
necessary identification of products is often realized through label-based systems, but tracing
products with particular geometric constraints that prohibit the use of such systems remains an
issue. A promising alternative of label based identification is the pattern based identification. This
contribution portrays a novel method to utilize fluorescent particles integrated in polymer-based
products and optical pattern recognition to facilitate the identification of products with specific
geometric constraints. The particles are integrated into the polymer and the unique random
distribution of fluorescent particles triggered by an LED flash is used to recognize individual
products. To demonstrate the approach, polymer-based gear wheels were printed using ARBURG
plastic freeforming and an automatic identification system was designed. The presented approach
could be a reliable alternative to other surface-structure-based approaches for product identification
and enable comprehensive tracing of components throughout value-chains.
| null | null | null | null | null | null |
['Borish, Michael', 'Roschli, Alex', 'Wade, Charles', 'Post, Brian', 'White, Liam', 'Adkins, Cameron']
|
2024-03-26T20:16:54Z
|
2024-03-26T20:16:54Z
|
2023
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/124391', 'https://doi.org/10.26153/tsw/50999']
|
en_US
|
2023 International Solid Freeform Fabrication Symposium
|
Open
|
['slicing', 'manufacturing', 'spiralization', 'continuous fiber deposition', 'single path', 'graph theory', 'topological hierarchy']
|
Single Path Generation for Closed Contours via Graph Theory and Topological Hierarchy
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/532730f7-7bb8-4098-8f07-18b7bef1e79a/download
|
University of Texas at Austin
|
Slicing converts a 3D object into a set of 2D polygons that are filled with multiple path types. These
paths involve travels where the extruder of the machine must stop building, lift, travel to the next path, lower,
and resume construction. Travels are considered wasted time as construction of the object is not occurring.
Further, the start/stop point, called a seam, causes both reduced aesthetic and weaker material properties. To
address these issues, an algorithmic approach was developed to compute a continuous single path from closed
contours. The algorithm utilizes graph theory and a topological hierarchy to produce a single path for an
individual layer. This approach can be combined with spiralization techniques to compute a single path for
entire objects. The resulting objects can be constructed quicker and have improved material properties as
verified via tensile testing.
| null | null | null | null | null | null |
['Gong, Haijun', 'Teng, Chong', 'Zeng, Kai', 'Pal, Deepankar', 'Stucker, Brent', 'Dilip, J.J.S.', 'Beuth, Jack', 'Lewandowski, J.']
|
2021-10-28T21:05:11Z
|
2021-10-28T21:05:11Z
|
2016
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89700
|
eng
|
2016 International Solid Freeform Fabrication Symposium
|
Open
|
['single track', 'support structure', 'powder bed', 'Ti-6Al-4V', 'selective laser melting']
|
Single Track of Selective Laser Melting Ti-6Al-4V Powder on Support Structure
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/8c3eb163-6248-43b7-ae34-097f3eff0983/download
|
University of Texas at Austin
|
Melt pool shows inconsistency due to the varied heat conditions in selective laser melting (SLM)
process, even if identical process parameters are used. The characterization of the actual melt pool
shape is highly desired in order to eventually control the quality and property of additive
manufacturing products. It has been well understood that base plate provides high thermal
conduction while powder bed is low thermal condition for fusion energy to be dissipated. Based
on former study of melt pool characterization on a base plate, this study creates single tracks on
the support structure, which is considered the similar heat condition of the Ti-6Al-4V powder bed.
Various patterns of the support structure are fabricated for single track deposition, in order to
investigate the effect of the support structure on melt pool consistency and continuity. Different
laser melting parameters are used in the experiments to understand their effects on the melt pool
morphology.
| null | null | null | null | null | null |
['Ramos, Jorge A.', 'Murphy, Jeremy', 'Lappo, Karmen', 'Wood, Kristin', 'Bourell, David L.', 'Beaman, Joseph J.']
|
2019-10-23T14:40:08Z
|
2019-10-23T14:40:08Z
|
2002
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/76749', 'http://dx.doi.org/10.26153/tsw/3838']
|
eng
|
2002 International Solid Freeform Fabrication Symposium
|
Open
|
Superalloy
|
Single-Layer Deposits of Nickel Base Superalloy by Means of Selective Laser Sintering
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/04a1c55c-eeaf-4df0-a564-50099e7d0586/download
| null |
Single layer deposits consisting of Mar-M 247 powder were consolidated on
Alloy 718 polycrystalline flat sheets by means of the Selective Laser Melting (SLM)
technique. The deposition process consisted in selectively fusing a powder bed precompacted using of an insulating non-wettable mask trough. The mask-powder-substrate
arrangement was pre-heated inside a processing chamber under high vacuum. An inertreducing atmosphere was applied, and a focused Nd:YAG laser beam was then raster
scanned at high speed along the contour of the trough, providing energy to induce a
melting front to propagate along the powder as well as over the surface of the plate. As
the laser beam moved forward a solidification front was left behind with a metallurgical
bond between the substrate and the deposited layer. Optical microscopy revealed that
epitaxial growth occurred in the [001] direction from the melted substrate to about half
the height of the deposits. Above that height, the [001] dendritic front bowed towards the
[100] direction. A dendritic-equiaxed transition appeared near the free surface of the
deposit. These results indicate that the SLM technique could have potential application
for growing single crystal structures as well as in repairing damaged or worn turbine
blades.
|
Funding for this project was provided by Rolls-Royce North America and the
University of Texas at Austin.
| null | null | null | null | null |
['Nelson, Christian', 'Barlow, J.W.']
|
2018-04-12T17:20:57Z
|
2018-04-12T17:20:57Z
|
1990
|
Mechanical Engineering
|
doi:10.15781/T2GM8256M
|
http://hdl.handle.net/2152/64269
|
eng
|
1990 International Solid Freeform Fabrication Symposium
|
Open
|
['Department of Chemical Engineering', 'Selective laser sintering', 'SLS machine']
|
Sintering Rates in the Selective Laser Sintering Process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/345d3ebb-fc9b-4c4a-8814-9043bf8b58f4/download
| null |
This paper presents. a procedure to determine rates of sintering as a function of
temperature using an isothermaloven. The rate of height change of a powder sample in the
oven at temperatures near the Tg or Tm is measured. From this information an activation
energy is calculated. This activation energy is similar to activation energies calculated from
viscosity versus ternp.erature curves for polymer melts. This similarity suggests that
viscous sint~ring models such. as those by Frenkel and Scherer are appropriate. A
comparison between sintering rates of polymer coated alumina powder and mixed powders
of the polymer with alumina, suggest that better sintered products may result from the
coated powders than from simple mixtures.
| null | null | null | null | null | null |
['Khoshnevis, Behrokh', 'Asiabanpour, Bahram', 'Mojdeh, Mehdi', 'Koraishy, Babar', 'Palmer, Kurt', 'Deng, Zongliang']
|
2019-10-24T18:17:50Z
|
2019-10-24T18:17:50Z
|
2002
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/77416', 'http://dx.doi.org/10.26153/tsw/4505']
|
eng
|
2002 International Solid Freeform Fabrication Symposium
|
Open
|
Powder Sintering
|
SIS-A New SFF Method Based on Powder Sintering
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/fc60b55b-d7e2-4a38-9493-866d022f4f96/download
| null |
Selective Inhibition of Sintering is a layered fabrication process which is capable of rapidly
producing accurate functional parts out of polymers and metals using a relatively inexpensive
machine. This article presents a brief overview of the research and development aimed at
establishing the feasibility and the potential of the process.
|
This material is based upon work supported by the National Science Foundation under SGER
Grant No. 0088135, and Long Range Scientific and Technology Program of Office of Naval
Research.
| null | null | null | null | null |
['Wu, Yan', 'Yang, Li']
|
2021-11-09T20:33:01Z
|
2021-11-09T20:33:01Z
|
2018
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90159', 'http://dx.doi.org/10.26153/tsw/17080']
|
eng
|
2018 International Solid Freeform Fabrication Symposium
|
Open
|
['fracture behavior', 'cellular structures', 'size', 'topology effects', 'bending', 'stretching']
|
Size and Topology Effects on Fracture Behavior of Cellular Structures
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/3addc476-8837-45fe-8b24-6d92f7261ce5/download
|
University of Texas at Austin
|
Cellular structures can deform by either the bending, stretching or both of the cell walls or
cell struts. In this study, the fracture characteristics of multiple typical cellular structures that
represent both the bending-dominated and stretching-dominated structures were investigated.
An analytical model based on the matrix displacement method was established for the analysis
of the fracture progression of the cellular structures, which was consequently employed for the
fracture analysis of the cellular structures under various geometry design conditions including
cell topology, cell size and number of unit cells. From the results, it was shown that the fracture
propagation patterns and stress characteristics of the two cellular designs (diamond and
triangular) exhibit different dependencies on their geometry designs and cellular patterns. While
the stretch-dominated triangular structure exhibit higher fracture strength compared to the
bending-dominated diamond structure, it also exhibits more rapid fracture propagation and
more significant size effect.
| null | null | null | null | null | null |
['Eiamsa-ard, Kunnayut', 'Zhang, Jun', 'Liou, F.W.']
|
2019-09-26T17:27:00Z
|
2019-09-26T17:27:00Z
|
2001
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/76026', 'http://dx.doi.org/10.26153/tsw/3125']
|
eng
|
2001 International Solid Freeform Fabrication Symposium
|
Open
|
Manufacturing
|
Skeleton-based Geometric Reasoning for Adaptive Slicing in a Five-axis Laser Aided Manufacturing Process System
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e638211b-26b4-4257-92c8-e7adc08f7374/download
| null |
Multi-axis Laser Aided Manufacturing Process (LAMP) is an additive manufacturing process similar to laser cladding. This process can produce full functional parts [1]. Traditional Layered Manufacturing processes produce parts with limited surface quality; and also the build time is often long due to the deposition of sacrificial support structure. The multiple degrees of freedom endow the LAMP system a capability to build parts without support structure. An algorithm for adaptive slicing based on skeleton is presented in this paper. The skeleton is useful for many applications such as feature recognition, robot path planning, shape analysis, and etc [2]. The near optimal build direction can be generated using information provided by the part skeleton, which is a 2D (or less) “surfaces” embedded 3D space containing the general form of the object.
| null | null | null | null | null | null |
['Chesser, Phillip', 'Post, Brian', 'Lind, Randy', 'Roschli, Alex', 'Atkins, Celeste', 'Boulger, Alex', 'Mhatre, Paritosh', 'Lloyd, Pete']
|
2021-11-18T18:32:51Z
|
2021-11-18T18:32:51Z
|
2019
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/90459', 'http://dx.doi.org/10.26153/tsw/17380']
|
eng
|
2019 International Solid Freeform Fabrication Symposium
|
Open
|
['SkyBAAM', 'large-scale fieldable deposition system', 'concrete deposition system', 'Oak Ridge National Laboratory']
|
SkyBAAM Large-Scale Fieldable Deposition Platform System Architecture
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/83844e5d-8f3a-40ed-9567-ec1f7d89aedb/download
|
University of Texas at Austin
|
Oak Ridge National Laboratory (ORNL) is currently developing a concrete deposition
system for infrastructure-scale printed objects. This system, called SkyBAAM, uses a cable driven
motion platform to manipulate the print head. This work focuses on the general aspects of the
system architecture, including arrangement of the cable driven platform, general high-level control
methodology, and system accuracy, along with concrete deposition methods. Results and
demonstration prints will be shown.
| null | null | null | null | null | null |
['Pang, Thomas', 'Figueroa, Israel', 'Fong, John', 'Melisaris, Anastasios', 'Wang, Renyi', 'Hanna, Stephen', 'Nguyen, Hop', 'Guertin, Michelle', 'Phan, Cathy']
|
2018-12-05T17:27:29Z
|
2018-12-05T17:27:29Z
|
1997
|
Mechanical Engineering
|
doi:10.15781/T2P844G4D
|
http://hdl.handle.net/2152/71401
|
eng
|
1997 International Solid Freeform Fabrication Symposium
|
Open
|
['SFF', 'SLA technology']
|
SL 5410: High Humidity, Water, and Heat Resistant Resin for Stereolithography
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/c6cd7884-df3e-4c94-af19-451be3f2eeeb/download
| null |
A new Stereolithography (SL) resin, CibaTool® SL 5410, which imparts good humidity
and heat resistance, was released in July, 1997. This epoxy based resin for SLA-500 was
developed mainly to eliminate the relatively weak resistance to high humidity and high heat that
the first generation ofresins suffered from. Namely, with this new resin, strength ofQuickCast
part and solid parts can now be maintained under high relative humidity. Even when immersed
into water, part strength of SL 5410 is essentially preserved. Thermomechanical properties have
also improved significantly relative to those of SL 5180. Heat deflection temperature and Tg
values increased by +15°C to +40°C, to as high as 88°C and 105°C, respectively, for SL 5410,
when parts were additionally thermally postcured. Improvements in mechanical properties are
also included in this paper. These property enhancements were achieved while further improving
part accuracy, vertical surface finish, and productivity. Productivity may increase by as much as
2.5-fold over SL 5180. Also, SL 5410 requires no predip delay, hence cutting the overhead time.
These newly achieved resin characteristics for SL 5410 are expected to improve the ease-of-use
in today's applications, and open new fields of applications in the near future.
| null | null | null | null | null | null |
['McPherson, Jace', 'Bliss, Adam', 'Smith, Flora', 'Hariss, Edmund', 'Zhou, Wenchao']
|
2021-11-02T20:24:01Z
|
2021-11-02T20:24:01Z
|
2017
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/89887
|
eng
|
2017 International Solid Freeform Fabrication Symposium
|
Open
|
['slicer', 'mobile printer', 'cooperative 3D printing', 'fused deposition modeling']
|
A Slicer and Simulator for Cooperative 3D Printing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/12030264-9fd0-4f80-9c54-d293a7b9d41d/download
|
University of Texas at Austin
|
Cooperative 3D printing is an emerging technology that aims to increase the 3D printing
speed and to overcome the size limit of the printable object by having multiple mobile 3D
printers (or printhead-carrying mobile robots) work together on a single print job on a factory
floor. It differs from traditional layer-by-layer 3D printing due to the requirement for multiple
mobile printers working simultaneously without interfering with each other. Therefore, a new
approach for slicing the CAD model and generating commands for the mobile printers is needed,
which has not been discussed in the literature before. We propose a chunk-by-chunk based slicer
that divides an object into chunks so that different mobile printers can print different chunks
simultaneously without interfering with each other. In this paper, we developed a slicer for
cooperative 3D printing with two mobile fused deposition modeling (FDM) printers. In order to
validate our slicer and visualize the cooperative 3D printing process, we have also developed a
simulator environment, which can be a valuable tool in optimizing cooperative 3D printing
strategy. Results show that the developed slicer and simulator are working effectively.
| null | null | null | null | null | null |
['Sundaram, R.', 'Choi, J.']
|
2019-10-18T16:02:13Z
|
2019-10-18T16:02:13Z
|
2001
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/76245', 'http://dx.doi.org/10.26153/tsw/3334']
|
eng
|
2001 International Solid Freeform Fabrication Symposium
|
Open
|
5-Axis
|
A Slicing Procedure for 5-Axis layered Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/49e382be-21a3-4302-8ed0-e199448232cf/download
| null |
The 5-axis layered manufacturing technology facilitates fabrication of a part with
overhanging features without the use of supports, thereby making a direct-to-use part from the
layered manufacturing technology a reality. In this paper we describe a direct slicing procedure
for a CAD model, a crucial process planning task for the 5-axis layered manufacturing. The
neutral exchange format IGES is used as the slice format. The G and M codes for a CNC 5-axis
laser deposition machine are generated from the slice format and the deposition process is
simulated. Implemented examples are included to explain the slicing procedure. Exciting
possibilities for the future work on the slicing procedure are discussed.
| null | null | null | null | null | null |
['Haeseong, J. Jee', 'Lee, Byong-Yeol']
|
2019-03-12T16:15:30Z
|
2019-03-12T16:15:30Z
|
1999
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/73595', 'http://dx.doi.org/10.26153/tsw/737']
|
eng
|
1999 International Solid Freeform Fabrication Symposium
|
Open
|
['SFF', 'CAD']
|
Slicing STEP-based CAD Models for CAD/RP Interface
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/a0586a06-7c8b-48f7-a258-782369df17b9/download
| null |
SFF technologies have an ability of creating a physical part directly .•. from its computer
model by. adding material on a layer by layer basis. One of the problems lies in their
current file fonnat for CAD data exchange. Current method using the de facto industry
standard STL have at times resulted in problems such< as accuracy, redundancy, and
integrity in its representing CAD models. In this paper we propose a method of slicing
and editing STEP...based. RP models for the new data transfer paradigm between CAD
systems and RPsystems using STEP
| null | null | null | null | null | null |
['Ainsley, C.', 'Hon, K.K.B.']
|
2018-11-09T16:40:53Z
|
2018-11-09T16:40:53Z
|
1996
|
Mechanical Engineering
|
doi:10.15781/T2JH3DN57
|
http://hdl.handle.net/2152/69934
|
eng
|
1996 International Solid Freeform Fabrication Symposium
|
Open
|
['free form fabrication', 'ceramic industry', 'casting']
|
Slip Casting as a Rapid Tooling Process
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/f1be120a-cb2a-43b8-b8c1-3c3589da54ee/download
| null |
The paper discusses the slip casting ofstainless steel as a method offorming injection
moulding tooling. Main steps involved in the precision slip casting ofstainless steel
and the effects ofmajor parameters such as casting rate have on accuracy are fully
discussed. The slip casting process has numerous technical advantages over
conventional and rapid tooling processes especially there is strong potential for
producing mass production tooling.
| null | null | null | null | null | null |
['Hagedorn, Y.-C.', 'Balachandran, N.', 'Meiners, W.', 'Wissenbach, K.', 'Poprawe, R.']
|
2021-10-05T14:19:35Z
|
2021-10-05T14:19:35Z
|
8/17/11
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/88376', 'http://dx.doi.org/10.26153/tsw/15315']
|
eng
|
2011 International Solid Freeform Fabrication Symposium
|
Open
|
['Additive Manufacturing', 'Selective Laser Melting', 'ceramics', 'dental restorations']
|
SLM of Net-Shaped High Strength Ceramics: New Opportunities for Producing Dental Restorations
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/0ddef393-a609-4565-971d-34905b818c06/download
|
University of Texas at Austin
|
Oxide ceramics yield excellent mechanical properties along with outstanding thermal and
wear resistance. However, little work on additive Manufacturing (AM) of high-strength ceramics
has been stated. In the present paper the current state of development in Selective Laser Melting
(SLM) of pure ceramic specimens is reviewed. During the present approach the eutectic mixture
of pure alumina (Ah0 3) and zirconia (Zr02) powder is completely molten while crack formation
is prevented by a high-temperature C02-Iaser preheating. This approach yields net-shaped, fully
dense specimens reaching flexural strengths of above 500 MPa without post-processing. One
potential application for this technology are fully-ceramic dental restorations frameworks, as the
demanded maximum loads of above I 000 N are met. Alternative preheating strategies are
presented to allow for manufacturing larger volumetric parts.
| null | null | null | null | null | null |
['Haberer, Marc', 'Zak, Gennady', 'Park, Chul', 'Paraschivoiu, Marius', 'Benhabib, Beno']
|
2019-09-23T16:29:25Z
|
2019-09-23T16:29:25Z
|
2000
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/75956', 'http://dx.doi.org/10.26153/tsw/3055']
|
eng
|
2000 International Solid Freeform Fabrication Symposium
|
Open
|
Ribre-Reinforced
|
Slot-Coating for Rapid Manufacturing of Fibre-Reinforced Parts 333
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/85e3e941-a805-46f8-a093-db010808a6c9/download
| null |
Mechanical properties of parts manufactured through photolithography process are
improved through the addition of short glass fibres. A lithography-based prototyping system for
the manufacture of such composite parts has been under development in our laboratory. This
paper will specifically detail a novel Liquid Layer Formation Subsystem (LLFS) for the creation
of thin layers of glass-fibres/photopolymer mixture for this system. New LLFS combines a
unique external mixing subsystem with a precisely controlled slot coater in order to deposit
layers of uniform fibre volume fraction throughout the fabrication process. Evaluation of the
mixing subsystem found it capable of delivering liquid with the expected fibre content, and
examination of the geometric quality of the individual layers formed by the LLDS shows its
ability to consistently build layers of correct height.
| null | null | null | null | null | null |
Boivie, Klas
|
2019-09-23T15:16:02Z
|
2019-09-23T15:16:02Z
|
2000
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/75932', 'http://dx.doi.org/10.26153/tsw/3031']
|
eng
|
2000 International Solid Freeform Fabrication Symposium
|
Open
|
Sintering
|
SLS Application of the Fe-Cu-C System for Liquid Phase Sintering 141
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/d161fe81-14ea-4fca-be7b-7f958da09ad6/download
| null |
The present work suggests the possibility to exploit the phenomena of copper swelling, and the controlling effect of carbon during liquid phase sintering, to be used in SLS technology to achieve temperable tooling materials in a single furnace cycle. As a basic investigation of this possibility, four powder samples of different copper and carbon content were tried and evaluated in respect to SLS and furnace behavior. The possibility to form green bodies was verified and the different sintering behaviors were studied. It was concluded that this material system holds several interesting phenomena that, if properly managed and if sufficient fractional packing density could be reached, could open distinct possibilities to achieve high quality material for SLS tooling purposes.
| null | null | null | null | null | null |
['Kim, J.H.', 'Creasy, T.S.']
|
2019-10-23T14:42:49Z
|
2019-10-23T14:42:49Z
|
2002
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/76750', 'http://dx.doi.org/10.26153/tsw/3839']
|
eng
|
2002 International Solid Freeform Fabrication Symposium
|
Open
|
Nanoparticle
|
The SLS Characteristics of 1.8wt% Clay Nanoparticle/Nylon 6 Composite
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/e0fdc923-6400-460b-87d4-7857dbbcbe6e/download
| null |
Selective laser sintering (SLS) characteristics of clay nanoparticle/Nylon 6 composite
were studied for the applications in Rapid Prototyping and Manufacturing (RP&M). Differences
of sintering behaviors between the nanocomposite and standard SLS polymers were investigated.
Nanoparticles change the material’s properties and this requires, modification of SLS processing
parameters. An attritor ground the as-received pellets into 100µm-sized particles. The
nanocomposite's sintering behavior showed higher porosity compare with standard polymers.
| null | null | null | null | null | null |
['Niino, Toshiki', 'Sakai, Yasuyuki', 'Huang, Hongyun', 'Naruke, Hiromichi']
|
2020-02-27T20:58:25Z
|
2020-02-27T20:58:25Z
|
9/14/06
|
Mechanical Engineering
| null |
['https://hdl.handle.net/2152/80106', 'http://dx.doi.org/10.26153/tsw/7127']
|
eng
|
2006 International Solid Freeform Fabrication Symposium
|
Open
|
Polycaprolactone powder
|
SLS Fabrication of Highly Porous Model Including Fine Flow Channel Network Aiming at Regeneration of Highly Metabolic Organs
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/f8a8f554-6364-4222-80b8-06b93ee65865/download
| null |
Fabrication of very porous scaffold for regeneration of highly metabolic organs is
reported. Polycaprolactone (PCL) powder was mixed with fine salt grains as filler and
SLS processed to develop a model including fine flow channel network. The fabricated
model was rinsed with water to dissolve the salt, and high porosity of 90% was
successfully obtained. Additionally, residual powder in the channels was effectively
removed by solution of the filler. Through micro-CT observation, it was confirmed that
channels of which diameter was smaller than 1mm were successfully fabricated and
repeating branching and merging. Result of culture test is also reported.
| null | null | null | null | null | null |
['Evans, R. S.', 'Bourell, D. L.', 'Beaman, J. J.', 'Campbell, M. I.']
|
2020-02-20T21:11:09Z
|
2020-02-20T21:11:09Z
|
2005
|
Mechanical Engineering
| null |
https://hdl.handle.net/2152/80056
|
eng
|
2005 International Solid Freeform Fabrication Symposium
|
Open
|
Rapid prototyping
|
SLS Materials Development Method for Rapid Manufacturing
|
Conference paper
|
https://repositories.lib.utexas.edu//bitstreams/8762714a-6d67-4e78-860b-852853597713/download
| null |
As soon as SFF technology development began to make Rapid Prototyping possible the
interest in Rapid Manufacturing (RM) began to grow. The advantages in terms of
functional integration, elimination of tooling and fixtures and mass customization make a
compelling case for RM, leading some in the field to call it the next industrial revolution.
Yet without the materials properties necessary to provide the function and variety
currently available from mass production methods, the application of RM will remain
limited. Developing new materials for the SLS process, one immediate step toward a
larger portfolio of RM materials, is very challenging. The formation of high quality SLS
parts relies on appropriate powder characteristics, thermal cycles and sintering behavior.
Based on a brief examination of the key factors in SLS processing and a research project
to develop a new binder material for Silicon Carbide composites, a systematic materials
development method is proposed in this paper. The method provides guidance for
introducing new SLS materials, support for educating new SLS users and researchers and
direction for several future research projects.
| null | null | null | null | null | null |
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