The Twenty-ninth Annual International Solid Freeform Fabrication (SFF) Symposium – An Additive
Manufacturing Conference, held at The University of Texas in Austin on August 13-15, 2018, was
attended by 680 researchers from 18 countries. The number of oral and poster presentations increased
to 517 this year. The meeting was held on the Hilton Austin in the downtown area and consisted of a
Monday morning plenary, 59 parallel technical sessions, and a poster session.
The conference attendance continued to grow, reflective
of the interest at large in the area.
The recipient of the International Outstanding Young
Researcher in Freeform and Additive Manufacturing
Award was Dr. Guha Manogharan from Penn
State University. Dr. Chee Kai Chua from Nanyang
Technological University in Singapore received the
International Freeform and Additive Manufacturing
Excellence (FAME) Award.
There are 212 papers in the conference proceedings. Papers marked “REVIEWED” in the title area
were peer reviewed by two external reviewers. We have sequentially numbered the pages of the papers to facilitate citation. Manuscripts for
this and all preceding SFF Symposia are available for free download below and at the conference website: http://
The editors would like to thank the Organizing Committee, the session chairs, the attendees for their
enthusiastic participation; 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 additive manufacturing community in organizing the Symposium.
We also want to thank the Office of Naval Research (N00014-18-1-2558) and the National Science
Foundation (CMMI-1826959) for supporting this meeting financially. The meeting was co-organized by
the Mechanical Engineering Department/Lab for Freeform Fabrication under the aegis of the Advanced
Manufacturing and Design Center at The University of Texas at Austin.
The 2019 SFF Symposium is set for August 12-14, 2019 in Austin, Texas USA.
Browsing 2018 International Solid Freeform Fabrication Symposium by Title
(University of Texas at Austin, 2018) Bowa, M.; Dean, M.E.; Horn, R.D.
Additive manufacturing is revolutionizing the way we build and produce a plethora of
products spanning many industries. It has shown strong potential in reduced energy use,
sustainability and cost effectiveness. Exploring avenues that this technology can be utilized is key
to improve productivity and efficiencies in various applications including electronic systems and
devices manufacturing. Electronic systems and sub-systems are built using a variety of material
and processes, which require a large carbon footprint, significant waste material and high
production time. We propose the application of 3D printing technology to support an integrative
process for combining circuit board fabrication, solder mask process, electronic component pick
and place and enclosure manufacturing. The integration of these separate processes into a single
high efficiency additive manufacturing process will yield significant savings in energy use, carbon
footprint, waste product and production time and cost.
(University of Texas at Austin, 2018) Delgado Camacho, Daniel; Clayton, Patricia; O'Brien, William J.; Jung, Kee Young
The construction industry has shown increasing interest in AM technologies and has
successfully implemented various proof of concept projects using different AM processes. Much
of the research on AM in the construction industry has focused on development of new large-scale
extrusion printing systems and on development of cementitious materials for AM applications,
whereas research exploring new applications of already existing AM technologies and materials
suitable for construction applications has been scarce. This paper explores the use of existing,
small-scale material extrusion 3D printers to create fastener-free connections that could be used in
structural or non-structural applications. These connections, inspired by traditional wood joinery
and modern proprietary connections were printed using polylactic acid (PLA) material. The
flexural strength of the connections was then tested using a four-point bending test to evaluate
their potential structural performance and to identify connection types that warrant further research
in this exploratory proof of concept study.
(University of Texas at Austin, 2018) Wang, Qinguri; Tian, Xiaoyong; Huang, Lan
Most of the current 4D printing technologies have the following
defects: 1) the deformation shape is simple; 2) the deforming precision is
poor; 3) the deformation process is always uncontinuous. In this study, a
new 4D printing process based on the composites with embedded
continuous fibers is proposed. In this process, a bilayer structure
consisting of the top layer of continuous fibers and the bottom layer with
resin is 3D printed. Due to the different thermal expansion coefficient and
elastic modulus of the top and bottom layers, the structure will produce
bending deformation when the temperature changes. It is found that the
curvature value and the curvature direction of the composite structure can
be precisely controlled by the angle of the intersecting fibers. The
influence of fiber trajectory on curvature is studied, and then, the
controllable deformation of any developable surface is achieved.
(University of Texas at Austin, 2018) Kouprianoff, D.; Luwes, N.; Yadroitsava, I.; Yadroitsev, I.
One of the main drawbacks of laser based powder bed fusion, is lack of fusion
between tracks due to non-optimal input process parameters, scanning and building
strategies and/or inhomogeneity in the delivered powder layer. Unstable geometrical
characteristics of single tracks and high roughness of the powder layer can cause porosity in
3 dimensional printed parts. In this study a non-destructive online monitoring technique,
using acoustic emission was utilized to determine lack of fusion and balling effect of single
tracks. This phenomenon was simulated by using an increased powder layer thickness. Short
Time Fourier Transform was used as a tool for analysis of the acoustic behaviour of the
system and it was compared with the acoustic emission (AE) recorded during processing of
(University of Texas at Austin, 2018) Tsui, Lok-kun; Maines, Erin; Evans, Lindsey; Keicher, David; Lavin, Judith
Additive manufacturing of ceramic materials is an attractive technique for rapid
prototyping of components at small scales and low cost. We have investigated the printing of
alumina pastes loaded at 70-81.5 wt% solids in a UV curable resin. These can be deposited by
extrusion from a syringe head on a Hyrel System 30M printer. The print head is equipped with an
array of UV LEDs, which solidify the paste without the need for any applied heating. Parameters
optimized include print speed, layer height, applied force, and deposition rate. Using A15 alumina
and submicron A16 powder precursors, we can achieve bulk densities of 91% and 96% of
theoretical density respectively. The influence of dispersants and surfactants added to the powder
on the rheology of the pastes, the print process parameters, and the quality of the final components
are also investigated.
(University of Texas at Austin, 2018) Chiroli, M.; Ciszek, F.; Baschung, B.
Over the last decade, additive manufacturing gained a lot of interest within the defense
industry. However, printing energetic materials such as explosives or solid propellants remains
a challenge. A research work with the aim to suggest appropriate materials and associated 3D
printing techniques to produce energetic materials, is currently carried out. In interior ballistics,
improved weapon performance ends in reaching higher muzzle kinetic energy. This can be
achieved by adjusting the gas pressure released during the ballistic cycle by using specific
propellant grains. A former study (Baschung, MRS Symposium H, Boston, 2005) highlighted
the advantages of using co-layered propellant grains to achieve this goal. The difficulties in
producing such kind of propellants can now be bypassed thanks to 3D printers. Our approach
consists in deposing a viscous energetic paste, containing a solvent, with an adapted machine.
The layer formation and the adhesion between them are investigated in this work.
(University of Texas at Austin, 2018) Ho, Jason; Lough, Cody S.; Mulligan, Phillip; Kinzel, Edward C.; Johnson, Catherine E.
A Shaped Charge (SC) is an explosive device used to focus a detonation in a desired
direction, and has applications in demolition and oil extraction. The focusing relies on a void in
the explosive mass, shaped by a metal liner that becomes a projectile during detonation. Additive
Manufacturing (AM) allows greater design freedom and geometric complexity for the liner portion
of the SC. Specifically, hierarchical structuring and functional grading can potentially provide
greater velocity, directionality, and efficiency. In this work, Selective Laser Melting (SLM) is used
to explore different geometries for an SC liner made out of SS 304L. These are detonated using
the explosive Composition C-4 to evaluate performance metrics, depth and standoff, and are
observed using high-speed imaging. The work shows the potential for advanced shaped charges
produced using SLM.
(University of Texas at Austin, 2018) Grothaus, Bradley; Huck, Dane; Sutton, Austin
Selective laser melting (SLM) is a powder-bed fusion (PBF) process that bonds successive layers
of powder with a laser to create components directly from computer-aided design (CAD) files. The
additive nature of the SLM process in addition to the use of fine powders facilitates the
construction of complex geometries, which has captured the attention of those involved in the
design of bandpass filters for radar applications. However, a significant drawback of SLM is its
difficulty in fabricating parts with overhangs necessitating the use of support structures, which, if
not removed, can greatly impact the performance of bandpass filters. Therefore, in this study
bandpass filters are manufactured in two stages with 304L stainless steel where each builds only a
portion of the part to improve the reliability in manufacturing the overhangs present. The results
show that the versatility of SLM can produce difficult-to-manufacture bandpass filters with high
(University of Texas at Austin, 2018) Chen, Yitao; Liou, Frank
Functionally graded materials (FGMs) have attracted a lot of research interest due to their
gradual variation in material properties that result from the non-homogeneous composition or
structure. Metal FGMs have been widely researched in recent years, and additive manufacturing
has become one of the most important approaches to fabricate metal FGMs. The aim of this paper
is to review the research progress in metal FGMs by additive manufacturing. It will first introduce
the unique properties and the advantages of FGMs. Then, typical recent findings in research and
development of two major types of metal additive manufacturing methods, namely laser metal
deposition (LMD) and selective laser melting (SLM), for manufacturing different types of metal
FGMs will be discussed. Finally, the major technical concerns in additive manufacturing of metal
FGMs which are closely related to mechanical properties, and industrial applications of metal
FGMs will be covered.