The Twentieth Annual International Solid Freeform Fabrication (SFF) Symposium, held at The
University of Texas in Austin on August 3-5, 2009, was attended by 123 national and international
researchers from 9 countries. Papers addressed SFF issues in computer software, machine design,
materials synthesis and processing, and integrated manufacturing. The diverse domestic and foreign
attendees included industrial users, SFF machine manufacturers, university researchers and
representatives from the government. The Symposium organizers look forward to its being a
continuing forum for technical exchange among the expanding body of researchers involved in SFF.
The Symposium was again organized in a manner to allow the multi-disciplinary nature of the SFF
research to be presented coherently, with various sessions emphasizing process development, design
tools, modeling and control, process parameter optimization, applications and materials. We
believe that documenting the changing state of SFF art as represented by these Proceedings will
serve both those presently involved in this fruitful technical area as well as new researchers and
users entering the field.
New this year was recognizing outstanding research by a senior and junior researcher. The
recipient of the first Freeform and Additive Manufacturing Excellence (FAME) Award was Phill
Dickens of Loughborough University. The junior award, the International Outstanding Young
Researcher in Freeform and Additive Manufacturing Award, went to Carolyn Seepersad of The
University of Texas at Austin. These awards include a framed certificate, a small honorarium and a
The awards were presented at a conference banquet Monday evening, August 3. As part of the
celebration of the twentieth anniversary of the International Solid Freeform Fabrication
Symposium, several special presentations were given. Tom Mueller of Express Pattern described
the manufacture of the FAME trophies which were donated by his company. The trophy art was
designed by digital artist, Sheba Grossman. She described the artwork and some of the details of its
development. Finally, Harris Marcus, the founder of the SFF Symposium, made some remarks
about the circumstances surrounding the first SFF Symposium held in 1990.
This year’s best oral presentation was given by Christopher Williams of Virginia Tech University.
Selection is based on the overall quality of the paper, the presentation and discussion at the meeting,
the significance of the work and the manuscript submitted to the proceedings. The paper title was,
“Design and Manufacture of Formula SAE Intake System Using Fused Deposition Modeling and
Fiber-Reinforced Composite Materials” by Ryan Ilardo and Christopher B. Williams. Selected
from 84 oral presentations, his presentation appears on Page 770 of this Proceedings. The best
poster presentation selected from 15 posters was given by David Espalin of The University of Texas
at El Paso (co-authored by K. Arcaute, D. Rodriguez, F. Medina, M. Posner, R. Wicker). The paper
title was, “Fused Deposition Modeling of Polymethylmethacrylate for Use in Patient-Specific
Reconstructive Surgery”, and the paper starts on Page 569.
The editors would like to extend a warm “Thank You” to Rosalie Foster for her detailed handling of
the logistics of the meeting and the Proceedings, as well as her excellent performance as registrar and problem solver during the meeting. We would like to thank the Organizing Committee, the
session chairs, the attendees for their enthusiastic contributions, and the speakers both for their
significant contribution to the meeting and for the relatively prompt delivery of the manuscripts
comprising this volume. We look forward to the continued close cooperation of the SFF
community in organizing the Symposium. We also want to thank the Office of Naval Research
(N00014-09-1-0940) and the National Science Foundation (CMMI-0905636) for supporting this
meeting financially. The meeting was co-organized by the University of Connecticut at Storrs, and
the Mechanical Engineering Department, Advanced Manufacturing Center, and Laboratory for
Freeform Fabrication at The University of Texas at Austin.
Browsing 2009 International Solid Freeform Fabrication Symposium by Issue Date
(University of Texas at Austin, 2009-09) Kirka, Michael; Bansal, Rohan; Das, Suman
This paper presents recent progress on scanning laser epitaxy, a laser manufacturing
technique being developed for achieving single crystal growth in nickel‐based superalloys.
Investigations have been performed for creating monolithic deposits on like chemistry
single‐crystal nickel superalloy substrates. Progress in the areas of microstructure development
and process control will be discussed in the context of repairing high‐value single‐crystal turbine
engine components. This work is funded by the Office of Naval Research contract
(University of Texas at Austin, 2009-09) Lyons, Alan M.; Mullins, John; Barahman, Mark; Erlich, Itay; Salamon, Todd
Superhydrophobic surfaces exhibit a range of properties such as large contact angle, low contact
angle hysteresis and decreased hydrodynamic drag. These properties make superhydrophobic
surfaces of fundamental and commercial interest as they can enable a wide variety of
applications including microfluidic components, biomedical devices, and micro-batteries.
Superhydrophobic behavior is achieved through a combination of the hydrophobicity of the
polymer and the roughness of the surface. We have used a commercially available multi-jet
modeling rapid prototyping machine to fabricate 3D objects where the superhydrophobic surface
is monolithic with the part. This approach was used to fabricate non-planar components with
novel structures including helical conduits and porous meshes. In addition, we have developed a
robotic dispensing tool that enables greater freedom of material selection. Both approaches have
been used to fabricate arrays of surface features with diameters below 175 microns and with
aspect ratios greater than 8:1. The fabrication and wetting properties of surfaces made using
these two techniques will be discussed.
The design and manufacture of individually customised products is generally restricted to
bespoke clothing or footwear for very wealthy customers. The aim of the Custom-Fit project was
to develop a fast, flexible and economically viable route for the manufacture of individually
customised parts. These products not only provide improved comfort levels but also provide
better functional performance, including enhanced safety for the user. This 4.5 year, European
Commission subsidised €16 million project, supported by the EU, involving 30 partners across
the breadth of the Europe finished in early 2009. This paper will showcase the technology
developed: CAD packages which automate the design process and three new rapid
manufacturing methods. It will also include case studies on a range of customised products,
including customised Motorcycles helmets. The case studies not only demonstrate the
performance benefits of individual customisation but also show the potential for new approaches
to product design. More information at www.Custom-Fit.org.
(University of Texas at Austin, 2009-09) Pulugurtha, Syamala R.; Newkirk, Joseph; Liou, Frank; Chou, Hsin-Nan
Fabrication of functionally graded materials (FGMs) by laser metal deposition (LMD) has the
potential to offer solutions to key engineering problems over the traditional metal-working
techniques. But the issues that need to be addressed while building FGMs are intermixing in the
layers and cracking due to the residual stresses. This paper is to present the study of the effect of
process parameters (laser power and travel speed) on the degree of dilution between the substrate
(or, previous layer) and powder material for few metallurgical systems.
(University of Texas at Austin, 2009-09) Lao, S.C.; Koo, J.H.; Moon, T.J.; Hadisujoto, B.; Yong, W.; Pilato, L.; Wissler, G.
Neat polyamides 11 and 12 lack high strength/high heat resistance and flame retardancy.
The incorporation of selected nanoparticles is expected to enhance these properties to a
level that is desired and required for performance driven applications. This enhancement
may result in additional market opportunities for the polyamide 11 and 12 polymer
manufacturers. The objective of this study is to develop polyamide 11 polymer
nanocomposites with enhanced thermal, flammability, and mechanical performance for
selective laser sintering (SLS) rapid manufacturing. Three types of nano-alumnia (X-0
needle, X-25SR, and X-0SR) with different organic treatments were melt-compounded
into polyamide 11 in three different weight loadings of the nanoparticles (2.5%, 5%, and
7.5%). Injection molded specimens were fabricated for thermal, flammability, and
mechanical properties characterization. Although nano-alumina was uniformly dispersed
in polyamide 11 and better thermal stability of the nanomodified materials was observed,
the desired FR characteristics of the nanomodified polyamide 11 was not achieved. None
of the materials passed the desired UL 94 V0 rating.
(University of Texas at Austin, 2009-09) Weiss, C.M.; Aindow, M.; Marcus, H.
The method of Selective Area Laser Deposition (SALD) and Vapor Infiltration
(SALDVI) has been successfully used to fabricate small three-dimensional SiC/SiC and
SiC/metal powder parts. Ceramic joints made by this technique have been limited by the
throwing power of the laser resulting in incomplete joint penetration. Studies were performed to
show the effectiveness of a fiber laser, with a wavelength of 1070 nm, for a joining process. The
ability of the laser to penetrate a powder bed was utilized in the joint fabrication. The
combination of powder fill, and deep laser penetration into the powder bed shows potential in the
field of ceramic joining.
(University of Texas at Austin, 2009-09) Lin, Yafu; Huang, Guohui; Huang, Yong; Tzeng, Jeremy; Chrisey, Douglas
Matrix-Assisted Pulsed-Laser Evaporation Direct-Write (MAPLE DW) has been emerging as a
promising biological construct fabrication technique. The post-transfer cell viability in MAPLE
DW depends on various operation conditions such as the applied laser fluence. For wide
implementation of MAPLE DW-based biofabrication, the effect of laser fluence on the
post-transfer cell viability should be first carefully understood. This study investigates the effect
of laser fluence on the post-transfer cell viability in transferring of human colon cell HT-29. It
has been observed that: 1) the HT-29 cell viability decreases from 95% to 78% as the laser
fluence increases from 258 to 1,500 mJ/cm²; and 2) cell injury in this study is mainly from the
process-induced mechanical stress during the cell droplet formation and cell landing processes
while the effects of thermal influence and ultraviolet radiation are below the level of detection.
(University of Texas at Austin, 2009-09) Fu, Tian; Sparks, Todd E.; Liou, Frank; Newkirk, Joseph; Fan, Zhiqiang; Pulugurtha, Syamala R.
300M steel is used extensively for aircraft landing gears because of its high strength, ductility
and toughness. However, like other high-strength steels, 300M steel is vulnerable to corrosion
fatigue and stress corrosion cracking, which can lead to catastrophic consequences in the landing
gear. Stainless steels offer a combination of corrosion, wear, and fatigue properties. But for an
aircraft landing gear application a higher surface hardness is required. A laser cladding process
with fast heating and cooling rates can improve the surface hardness. AISI 4340 steel is used as a
lower cost alternative to 300M due to its similar composition. In this study, the influence of laser
cladding process parameters, shield gas, and composition of the deposition and dilution zone has
been investigated. The microstructures and composition analysis were evaluated by Scanning
Electron Microscopy (SEM) and Optical Microscopy. The deposition hardness varies from
330HV to 600HV.
(University of Texas at Austin, 2009-09) Oakes, Thomas; Kulkarni, Parimal; Landers, Robert G.; Leu, Ming C.
In the Freeze-form Extrusion Fabrication (FEF) process, extrusion-on-demand (EOD)
refers to the ability to control the start and stop of paste extrusion on demand and is vital
to the fabrication of parts with complex geometries. This paper describes the
development of EOD for ceramic FEF through modeling and control of extrusion force,
selection of appropriate process parameters, and a dwell technique for start and stop of
extrusion. A general tracking controller with integral action is used to allow tracking of a
variety of reference forces while accounting for the variability in the paste properties.
Experiments are conducted to model the process and tune the controller. The developed
technique for EOD is demonstrated to fabricate a number of cross sections and three-dimensional parts from alumina paste.