1. The World of Rapid Prototyping
By Terry Wohlers
Published in the Proceedings of the Fourth International Conference On Desktop Manufacturing, September 24-25,
1992, San Jose, California
Copyright 1992 by Wohlers Associates
An estimated 436 rapid prototyping (RP) systems are running at customer sites around
the world. As many as 12 RP system manufacturers have sold and shipped systems to
customers. Six are U.S. manufacturers, three are Japanese, two are European and one
is Israeli.
In addition, at least 32 universities, government laboratories and corporations around
the globe are developing various forms RP technology. An estimated 19 of them
(including the 12 mentioned above) have produced sample parts from their systems.
The following is an overview of these organizations and their work.
StereoLithography Apparatus (SLA) by 3D Systems
The StereoLithography Apparatus from 3D Systems (Valencia, CA) is by far the most
widely installed system, owning about 73 percent of the worldwide market based on
unit sales. The SLA makes parts from thin layers of liquid photopolymer. You first
create a 3D surface or solid model of a part with a CAD system, and then create a
support structure and attach it to the bottom of the CAD model. Especially critical for
parts which contain overhanging geometry, the support structure attaches the part to
the SLA's elevator platform and supports the part as the machine builds it. It is
removed after building the part.
The SLA-250, 3D Systems' most popular model, consists of several parts. The system
includes a computer to run the company's proprietary slicing software and a DOS-
based 386 PC to run the SLA control software. 3D Systems offers two options for the
slice computer: a 386-based PC running the Unix 386 operating system, or a Unix-
based Silicon Graphics Personal Iris workstation. The SLA-250 uses a galvanometer
mirror x-y scanner, laser and an elevator mechanism housed inside a vat filled with
ultraviolet sensitive liquid polymer.
3D Systems offers the SLA-190, SLA-250 and SLA-500 models. The primary
differences between the three models are build chamber size, speed and cost. The
SLA-500 uses a more powerful Argon-ion laser instead of a Helium Cadmium (HeCd)
laser used in the SLA-250 and SLA-190. This permits the SLA-500 to process
significantly faster. The SLA-500 laser moves at 100" (254 cm) per second, while the
SLA-250 and SLA-190 laser moves at only 15" (38 cm) per second. The overall speed

2. of SLA-190 parts is about one-half that of SLA-250 parts. This is mostly due to the
lack of a wiper blade, which plays an important role in speeding the layer recoating in
the SLA-250 and 500.
The SLA-500 is capable of producing parts of up to 20" x 20" x 24" (508 mm x 508
mm x 610 mm), compared to the SLA-250's maximum part size of 10" x 10" x 10"
(254 mm x 254 mm x 254 mm) and the SLA-190's 7.5" x 7.5" x 9.8" (190 mm x 190
mm x 250 mm) maximum part size. The SLA-500 requires 67 gallons (254 liters) of
polymer, while the SLA-250 uses 7.8 gallons (29.5 liters). The SLA-190 requires only
5.5 gallons (20.1 liters). The price of the SLA-190 is $95,000, compared to $210,000
for the SLA-250 and $420,000 for the SLA-500.
According to a statement issued jointly by 3D Systems and Quadrax in February of
this year, the two companies settled the patent litigation that started in September
1990. Under the terms of the settlement, Quadrax transferred its laser modeling patent
and related technology to 3D in exchange for 130,000 shares of 3D common stock. At
the time, the stock was worth about $325,000. As part of the agreement, Quadrax has
discontinued marketing its laser modeling equipment.
The Quadrax technology that 3D Systems now owns includes a special resin
applicator which quickly deposits the material from the top. In comparison, the SLA
lowers the part into the resin which requires considerable time for resin leveling and is
why 3D Systems uses a wiper blade to help speed the process. As the Quadrax
applicator spreads the new layer, the part remains stationary. As a result, the resin
surrounding the part remains motionless. The SLA process, on the other hand, creates
turbulence in the liquid when the part lowers into the liquid. This movement can
create uneven tension in and around the part. Since the Quadrax applicator is about 10
times faster, expect to see it in a future version of the SLA.
Selective Laser Sintering (SLS) by DTM
DTM Corporation's (Austin, TX) announcement in 1988 was among the first after the
1987 introduction of the SLA. DTM (formally Nova Automation Corp.) has made
their Sinterstation 2000 system available to five beta customers during the first half of
this year.
Selective Laser Sintering operates on the same basic layer-by-layer principle as the
SLA. However, it uses powder material instead of liquid. A leveling mechanism
spreads an even layer of powder material on a platform and the machine sinters the
powder. The sintering process uses a laser to raise the temperature of the powder to a
point of fusing without actually melting it.

3. To reduce the laser energy needed to sinter the powder, the system preheats the
powder in the build chamber. For example, the system raises the temperature to 365
degree Fahrenheit for nylon powder. This also helps to reduce thermal shrinkage of
the layers, thus reducing part distortion. A half-ton air conditioning unit cools the
system. Pre-heating can take 45 minutes.
For some applications, the SLS process may offer advantages over liquid-based
system. For example, the surrounding powder material serves as a natural support,
minimizing the need for support structures to support overhanging geometry. This
saves time during the creation of the part, as well as after you remove it from the
machine. Also, the SLS process can produce parts in several materials, including
polycarbonate, polyvinyl chloride (PVC), investment casting wax and nylon.
Polycarbonate parts approach a density of 85 percent. This means that 15 percent of
the part is air. Parts of low density are usually weaker than solid parts.
The SLS process can produce parts at a rate of 0.5" (12.7 mm) to better than 1.0"
(25.4 mm) per hour, depending on the size and layer thickness of the part. Therefore,
you can build a four-inch tall part in 4-8 hours. If you buy a Sinterstation 2000
prepared for use with one material ($397,000), you can later add other materials. The
cost for each additional material is $25,000. A Sinterstation 2000 prepared for use
with four materials costs $427,000.
SOLIFORM by Teijin Seiki
DuPont Imaging Systems (Wilmington, DE) followed in 1989 with the announcement
of their SOMOS 1000 Solid Imaging System, a technology similar to 3D Systems'
SLA. Eight SOMOS systems are running at various DuPont facilities, including a
DuPont service bureau in Delaware.
Late last year, DuPont licensed the SOMOS rapid prototyping technology to Teijin
Seiki of Tokyo, Japan. Teijin Seiki is a global industrial company with annual sales
exceeding $500 million. The Japanese company has gained exclusive rights to the
technology for Asia, with an option to gain the remaining worldwide rights within one
year. DuPont has chose not to manufacture SOMOS systems.
Teijin Seiki reports their RP system, called SOLIFORM, is now available in Asia. The
system uses an Argon ion laser and a SPARCstation Unix workstation from Sun
Microsystems. Matsushita Electric Industrial in Japan purchased a SOLIFORM
system for 50,000,000 yen (about $385,000).

4. DuPont has retained the associated SOMOS materials technology and provides the
materials to Teijin Seiki. DuPont also supplies SOMOS resins to users of 3D Systems'
SLA products and Electro Optical Systems' Stereos 400.
Laminated Object Manufacturing (LOM) by Helisys
Formally named Hydronetics, Helisys, Inc. (Torrance, CA) first developed a powder-
based system similar to DTM's SLS. Later, they abandoned it to concentrate on
Laminated Object Manufacturing. Company president Michael Feygin of Russia
invented LOM and began to discuss his invention publicly in 1988.
The LOM process is similar in concept to liquid and powder-based layering systems.
However, the LOM machine builds parts using sheet material. The machine
automatically positions a thin sheet of paper material from a roll on an elevator
platform. It then uses a CO2 laser to cut the sheet using a computer-controlled Roland
pen plotter to direct the laser beam. The cut corresponds precisely to the first cross
section of the CAD model - in STL format.
The machine bonds fresh sheet material to the previous sheet using a heated roller that
presses the two sheets together. The heat from the roller causes the polyethylene-
coated paper to fuse together. The laser then cuts the next sheet and the process
repeats until the part is complete. When the user of the LOM machine removes the
part, the unwanted pieces fall from the part. This material supports the part during the
building process; no additional support is necessary. LOM parts do not require post-
curing.
LOM parts have the look and feel of wood. For certain parts, the LOM process
promises to be faster than other layering processes because the laser outlines the
periphery of the part instead of making contact with the entire surface of the part. The
machine produces thick walls as fast as thin ones. Also, cutting the material, instead
of solidifying it, preserves the original properties of the material. The LOM-1015
system is $85,000, while the larger LOM-2030 unit is available for $140,000.
Solid Ground Curing (SGC) by Cubital
Cubital America Inc. (Troy, Michigan) is a wholly-owned subsidiary of Cubital, Ltd.
Two West German and two Israeli corporations jointly own Cubital, Ltd. of Herzlia,
Israel. The Cubital unit, called the Solider 5600 Solid Ground Curing system weighs
4.5 tons and is complex. Yet the machine will simultaneously build as many parts as
you can position in a 20" x 14" x 20" (508 mm x 356 mm x 508 mm) volume and
maintains accuracy of 0.1 percent according to the company. The Solider system
irradiates and solidifies a whole layer in a few seconds, regardless of size, complexity

5. and number of parts. Therefore, processing speed may be an advantage of this system
if you are making large or multiple parts.
The system charges a glass mask plate as it passes over an ion gun, which in turn
shoots ions on the glass at a resolution of 300 dot per inch (118 dots per cm). This
forms a pattern which is a negative image of the cross section. The system presents
black electrostatic toner which adheres to the ion charged portions of the plate. The
transparent areas reflect precisely the cross section of the part(s). The system positions
the plate closely over the top of a thin layer of liquid polymer, and an intense flood of
ultraviolet light shines through the plate, exposing the entire layer.
After being exposed to the light for a few seconds, the polymer solidifies and the
system moves the partially finished part away from the exposing chamber. The
solidified layer then undergoes several processes before the system produces a new
layer. While these processes are underway, the system wipes the toner from the glass
plate and processes the next cross section.
The system removes, by suction, the unhardened liquid surrounding the hardened
layer. A thin layer of wax is then spread over the entire layer, filling the areas that
before held liquid polymer. The wax, which goes through a cooling process,
surrounds and supports the part. Finally, the partially finished part moves to a milling
station. It mills the layer and produces a flat surface ready for the next layer. All of
this repeats, automatically, until the part is complete. The surrounding wax must be
melted away using hot tap water, a hot air gun, a microwave oven, or a conventional
dish washer.
The system, priced at $490,000, constructs parts at a rate of about 1.5 cubic inches
(28.1 cubic mm) per hour. Additionally, the process requires about 20 minutes of
preprocessing time - from raw CAD file to the first layer built. The company has sold
several systems in the U.S. and Europe.
Fused Deposition Modeling (FDM) by Stratasys
The 3D Modeler from Stratasys, Inc. (Minneapolis, MN) uses a spool of 0.050" (1.27
mm) diameter modeling filament resembling wire. The system feeds the filament
through a heated head and nozzle. Just before deposition, the head heats the
thermoplastic filament to a temperature slightly above its solidification state. As it
deposits material, the material solidifies.
FDM is simple compared to most other RP processes. It consists of the main 3D
Modeler unit, ProtoSlice slicing software and a Silicon Graphics workstation. The
light weight FDM head operates at up to 15" (38.1 cm) per second. Successive

6. laminations adhere to one another to form models up to 12" x 12" x 12" (30.5 cm x
30.5 cm x 30.5 cm) in size. The system does not waste material during or after
producing the model, so the process requires little cleanup.
The system, priced at $182,000, uses thermoplastic materials, including a machinable
wax, an investment casting wax, a nylon-like material called Plastic200 and a new
tough plastic material called Plastic300. The investment wax material is appropriate
for lost wax investment castings, leaving little residue in the cavity. You can achieve a
glassy finish by applying a fluid to the surface of the part.
Stratasys has beta tested the 3D-Modeler at GM, 3M, Biomet, Pratt & Whitney and
Texas Instruments. Since then, the company has sold production units to Pittsburg
State University (Pittsburg, Kansas), Tri-Tech Precision (Anaheim, CA) and Marbeth
Industries (Pico Rivera, CA). Tri-Tech and Marbeth are service bureaus. Recently,
Stratasys secured Marubeni Hytech, a $1.5 billion corporation, to serve as an
exclusive distributor of the 3D Modeler in Japan. Stratasys also reports they have sold
at least one system in Japan.
In July of this year, Stratasys was issued a U.S. patent for the development of Fused
Deposition Modeling techniques. The following month, 3M and Stratasys announced
a joint development agreement. The partnership will accelerate the development of
FDM materials and related technology, according to Stratasys. The company now
employs 25 people.
Solid Object Ultraviolet Laser Plotter (SOUP) by CMET (Mitsubishi)
Solid Object Ultraviolet Laser Plotter (SOUP) is what Mitsubishi's CMET (Tokyo,
Japan) calls their stereolithography system, which is similar to the SLA. CMET has
sold 56 units to organizations such as Mercedes, Fujitsu, Matsushita Electric, two
Japanese universities and Dornier Deutsche Aerospace in Germany. In addition to a
customer, Dornier serves as a SOUP distributor in Europe.
CMET offers the SOUP 600 and 850 versions of the product. The 600 uses either a
Helium Cadmium or Argon ion laser and produces parts up to 600 x 400 x 400
millimeters (24 x 16 x 16 inches) in epoxy resin. The 850 uses the more powerful
Argon ion laser and produces parts up to 850 x 600 x 500 millimeters (33 x 16 x 20
inches). Rather than using a galvanometer mirror x-y scanner, the SOUP system uses
an X,Y plotter mechanism to direct the laser light onto the surface of the liquid resin.
The laser beam, therefore, stays perpendicular to the surface of the resin, which
minimizes the undesirable spread light.
Solid Creation System (SCS) by DMEC (JSR/Sony)

7. Japan Synthetic Rubber (JSR) and Sony's D-MEC company of Tokyo, Japan, have
sold 10 of their Solid Creation Systems, which uses stereolithography technology
similar to the SLA. The system uses an Argon-ion laser similar to 3D Systems' SLA-
500, but offers a larger build chamber. The company has announced an improved
version, called the SCS-1000HD, featuring laser drawing speed that is twice as fast as
3D Systems' fastest model, the SLA-500. Toyota bought an SCS for about $500,000.
Stereos 400 by Electro Optical Systems (EOS)
Electro Optical Systems (EOS) of Munich, Germany, offers two versions of a
stereolithography system, which are similar to the SLA. The smaller of the two has a
build chamber of about 16" x 16 " x 10" (40.64 cm x 40.64 cm x 25.4 cm); the larger
system has a build chamber of about 16" x 16" x 24" (40.64 cm x 40.64 cm x 60.96
cm). The smaller system uses a 25 mW HeCd laser, while the larger system uses a 300
mW Argon-ion laser. Both systems use a RISC-based workstation for slicing and a
386 personal computer for process control. The Stereos 400 allows you to quickly
change vats of liquid resin without draining and rinsing the vat. EOS uses and
distributes DuPont's SOMOS resin materials in Europe.
Three-Dimensional Printing by MIT
The Department of Mechanical Engineering at the Massachusetts Institute of
Technology (Cambridge, MA), has developed a rapid prototyping device that uses a
jetting mechanism -- the same technology used in ink jet printers. The system spreads
a thin layer of ceramic powder on a flat bed, similar to the way DTM's SLS system
spreads powder. Using the jetting mechanism, the system solidifies layers as it
deposits a fine jet of ceramic binder onto the powder. Following a heat treatment, the
unbound powder drops from the formed part as you remove it from the powder.
MIT's prototype system can produce 3D ceramic parts constructed of multiple layers,
each 0.005" thick (0.127 mm). The process employs jetting head, a stepper motor and
an X/Y positioning device controlled by a 386-based personal computer. Overall, the
accuracy of the system is promising, but surface quality needs improvement.
Direct Shell Production Casting (DSPC) by Soligen
Soligen, Inc. (Northridge, CA) licensed MIT's ceramic 3D printing process several
months ago. The company, which is focusing exclusively on the casting industry, has
shipped three units to beta customers. With DSPC, you can produce expendable
ceramic shells (molds) complete with cores, directly with the RP device. This
eliminates the need for wax patterns and tooling for cast metal parts.

8. Several of the company's employees are former employees of 3D Systems. Soligen
CEO Yehoram Uziel was vice president of engineering at 3D. Chick Lewis, also with
Soligen, was 3D's first employee and helped engineer the SLA product line.
Printed Computer Tomography (PCT) by Texas Instruments
Texas Instruments (McKinney, TX) is developing an RP system using jetting
technology called Printed Computer Tomography. They call their working prototype
unit the ProtoJet 3D Printing System. It uses an inexpensive ink jet printing
mechanism to deposit wax material, layer by layer.
The ProtoJet system produces wax parts up to 12" x 12 " x 12" in size. Resolution in
the X,Y direction is 0.004 inch. Part accuracy in the Z direction depends on the layer
thickness. The ProtoJet system software creates cross sections from an STL file as it
prints them.
The system's design, according to Texas Instruments, reduces operation, maintenance
and material costs, compared to other RP systems. The machine does not use toxic
materials, so it can operate in an office environment. Support structures, for
overhanging geometry, generate automatically in a water-soluble material. You can
remove the support material by soaking the part in warm water.
Ballistic Particle Manufacturing (BPM) by BPM Technology
Formally, Perception Systems, BPM Technology, Inc. (Greenville, SC) is working on
a rapid prototyping system similar to TI's ProtoJet ink jet system. Bill Masters,
founder of the company, calls his technology Ballistic Particle Manufacturing.
Initially, Automated Dynamics Corp. (Troy, NY) pursued the technology, but they
abandoned the project due to a lack of funding.
The company is designing a new BPM prototype that will deposit a second material,
an approach that Texas Instruments uses with their ProtoJet system. The BPM system
will use polyethylene glycol, water-soluble synthetic wax, to physically support
overhanging geometry. The cost of production should be relatively low because the
system will use off-the-shelf parts.
BPM has secured Jon Leonard to serve as company president and CEO. Dr. Leonard
was formally a chief scientist at Hughes Aircraft, with degrees in mathematics,
engineering, physics and molecular biology/physiology. The company hopes to
introduce one system in the $50,000 range and another in the $15,000 range. Product
introduction may be 12-18 months away.

9. Visual Impact Corporation
Visual Impact (Windham, NH) has developed a second generation alpha machine that
also uses jetting technology. Richard Helinski, a co-founder of the company, was
recently awarded a patent that covers jetting of two materials. The primary material is
a plastic that is supported by a secondary support material. Since the two materials
differ in solubility and melting temperature, the support material can be removed
leaving only the primary material. The company claims the materials are safe and do
not require special environmental permits.
The company plans to ship beta units in the second quarter of next year. The beta
system will enable you to build parts that fit inside a six inch cube. The company says
the device is about the size of a standard office laser printer and operates as a desktop
computer peripheral. It will sell for under $20,000 when it becomes available in early
1994.
Design-Controlled Automated Fabrication (DesCAF) by Light Sculpting
Dr. Efrem Fudim, president of Light Sculpting (Milwaukee, WI), has developed a
process he calls Design-Controlled Automated Fabrication. Like the Cubital Solider
system, Fudim's DesCAF process irradiates a whole layer based on cross section data.
It uses a mask containing transparent and opaque areas similar to Cubital's Solider
system; however, a person must create each of the DesCAF masks using a
photoplotter. Also, a person must manually position each of the masks - one by one.
The system irradiates each layer using conventional lamps.
Fudim says his smallest system, called the LSI-0609MA, creates parts up to 6" x 6" x
9" (152.4 mm x 152.4 mm x 229 mm) in size and costs $99,600. The company also
offers two larger systems for $129,700 and $159,500. Fudim developed the DesCAF
concept in 1986 and delivered the first DesCAF part to an aerospace company the
same year. The company also operates as a service bureau for the automotive,
aerospace, medical and casting industries.
Stereophotolithography (SPL) by Laser 3D
Laser 3D (Nancy, France) has developed a process called stereophotolithography. The
product itself is called the SPL 1000/LSA. Claude Medard, managing director of
Laser 3D, compares it to stereolithography technology from 3D Systems, but claims it
is about 10 times faster. The SPL system uses a powerful >1 watt laser. By
comparison, the SLA-250 uses a 16mW laser; the SLA-500 uses a 200mW laser.
(1000 mW = 1 W)

10. The SPL 1000/LSA will be operational this summer or fall in France. Later this year,
the company hopes to install systems in the U.S., operated by service bureaus.
Companies in the U.S. that want to gain access to the SPL system will purchase and
install a front-end to the system. The front-end reportedly permits you to prepare a
CAD file for processing on the SPL system and enables you to send it to the service
bureau by modem. A source close to the company (not an employee) claims the
system software is about 50 times faster than software used by other RP
manufacturers.
In addition to the liquid SPL system, Laser 3D is developing RP technologies that use
solid films and powders. Laser 3D has access to research facilities at a university in
France.
Shape Melting Technology (SMT) by Babcock & Wilcox
Babcock & Wilcox (Alliance, OH) has developed a process they call Shape Melting
Technology. The SMT process uses robotics and arc welding to fabricate parts from
weld metal. The process produces very strong parts from layers of material of
controlled thickness. Much of their work consists of huge piping parts, such as elbows
and flanges, for the U.S. Navy.
Hot Plot by Sparx AB
Sparx AB (Sweden) is selling a $12,900 rapid prototyping system. The unit, called
Hot Plot, bonds 0.040 inch (1 mm) sheets of polystyrene. The machine cuts the
material using a flat-bed plotter equipped with a heated cutting electrode. An operator
must manually position the polystyrene sheets. The system uses AutoCAD and HPGL
files as input.
Photochemical Machining (PCM) by Formigraphic Engine Company, Battelle
and Osaka Prefecture
Photochemical machining is rapid prototyping technique that has been explored. It
functions similarly to other liquid and laser-based systems. However, instead of
solidifying the layers on the surface of the liquid, solidification occurs in the interior
of the material. The technique uses two lasers of different wave lengths to initiate
cross-linking. PCM chemically alters and solidifies polymer at the intersection point
of the two beams.
Researchers are exploring several possibilities. One would involve a solid block,
where the scanned areas would become cross-linked and insoluble. The final part
would appear after soaking the block in a solvent. Another possibility would involve a

11. block of soft gel, hardening where the laser beams meet. Yet another process would
use a frozen solution. Only the unscanned material would liquefy when heated,
leaving a free-standing part. Finally, the PCM process could degrade unwanted
material from a solid block. This would be like machining the part with the two lasers.
Organizations that have researched PCM include Formigraphic Engine Company
(Bolinas, CA), Battelle (Columbus, OH) and Osaka Prefecture (Japan). Formigraphic
Engine holds patents on the process and had teamed up with Battelle. However, their
work has been delayed due to a lack of funding. Osaka Prefecture has received a
patent in Japan on a PCM-like technology.
Electrosetting by Electroset Synergistic Technology (EST)
Dr. Ronald Reitz of the U.S. Navy's David Taylor Research Center (Annapolis, MD)
has worked on a process involving an electrosetting technique. Electrodes made from
a standard pen plotter or laser printer are stacked, submerged in a container of liquid
resin and subjected to an intense electrical charge. The process involves the Winslow
Effect, the solidification of a fluid by imposition of a biasing electric field through the
fluid, invented by Willis Winslow in 1939.
Experiments indicate the process would involve only standard office equipment. An
early prototype unit produces parts in silicon, epoxy, polyurethane and polyester. Dr.
Reitz has formed Electroset Synergistic Technologies Corporation to develop and
eventually license or commercialize the electrosetting technology.
Incremental Fabrication by Incre, Inc.
David Gore of Incre (Corvallis, OR) is developing an RP system using a variation of
ballistic particle manufacturing. Gore calls his invention Incremental Fabrication, a
process that builds thin layers by ejecting small droplets of molten metal. Gore hopes
to complete a prototype system by the end of this year.
Thermal Spray Metal Deposition by Carnegie Mellon
Carnegie Mellon University (Pittsburgh, PA) is developing an RP process that makes
metal parts using a thermal spray metal deposition technique. The process creates thin
layers by spraying metal through a paper mask. It uses a CO2 laser to cut the masks,
similar to the way the Helisys LOM system cuts sheet material.
Colamm by Mitsui Ship Building

12. Mitsui Ship Building has developed a stereolithography system, called Colamm, but
the company has not reported recent developmental or sales activity. Little is known
about the system.
Laser Fare
Laser Fare (Smithfield, RI) is working on a second generation RP system that may be
complete by the end of this year. The new system will employ thin film technology
for mask generation and nonlinear optics, and will produce parts from a wide range of
polymers. Rather than manufacturing systems, the company plans to license the
technology.
Cybervid
Cybervid (Nashua, NH) is developing Macintosh software that cuts and scores sheet
material. An individual then folds the material to create a three-dimensional object,
similar to a sheet metal development.
Landfoam Topographics
Norman Kinzie of Landfoam Topographics (Needham, MA) has patented a LOM
process that involves the coloration of each layer. This would permit the production of
multi-colored parts from a desktop output device. Currently, RP systems can produce
single color parts only. A working prototype is not yet available. Kinzie is discussing
the process with companies interested in building a working prototype and bringing a
system to market.
Summary
As new and attractive technologies become available, system prices may drop. For
now, prices remain high, although the price/performance ratio continues to improve as
existing technologies advance in speed, accuracy, material quality, surface finish, ease
of use and safety.
As for desktop manufacturing, none of the systems on the market today sit on a
desktop. Very thick concrete-top manufacturing is more accurate. Yet the industry
wants a small and inexpensive device that can build models quickly using materials
that are not hazardous or troublesome. Companies such as Visual Impact, Texas
Instruments, BPM Technology and several others are working vigorously on solutions
that meet this demand.
Copyright 1992 by Wohlers Associates