Companies That Provide Rapid Prototyping Services
Kinneir Dufort Industrial Design
"We can take a company's idea for a new product from the design stage--starting with a two-dimensional drawing--straight through to CNC-machined parts or stereolithographic models," says Ian Hollister, who heads the rapid prototyping department at Kinneir Dufort Industrial Design (Bristol, UK). The company's in-house facilities include two 3-D CAD workstations and a vacuum casting department; stereolithography is outsourced. Medical device design and prototyping is the company's core business, according to Hollister, who cites a recent project that involved the production of plastic surgical products. "We had stereolithography apparatus (SLA) models that were produced from a 3-D CAD design and then cast into silicone tools. A number of polyurethane parts were produced and assembled and then used for testing," says Hollister, noting that the entire operation was done much faster and at a lower cost than could have been possible using conventional methods. "Once you've got the 3-D CAD information, the cost saving using SLA is immense--up to 15 times less--and an SLA machine can run 24 hours a day. We can literally phone up for a model and have it the next day," Hollister says.
Optec S.A.
Specializing in lasers for rapid prototyping applications, Optec S.A. (Hornu, Belgium) produces laser-based microdrilling systems that can mill 3-D structures and polymer tools as small as 10 µm. "They can drill virtually any shape in virtually any material except Teflon," says company partner Rod Andrew, and they do so with remarkable throughput and accuracy. He cites one medical application that involved drilling a series of submicron-size holes in a 23-µm-thick membrane.
Rapid Prototyping Inc.
"We are a one-stop shop--we can do just about everything from the design to the production of the prototype," says Phil Bailey, sales engineer at Rapid Prototyping Corp. (Longmont, CO, USA). By creating a silastic mould based on the SL model, as many as 50 parts can be produced for such purposes as market analysis and market acceptability studies. "Then the company can come back to us with changes and we can adjust a few parameters, grow a new part, and send it out again," says Bailey. Because several key members of the staff used to work in injection moulding, "we have injection moulding in the back of our minds when we design a part," he adds. "We give serious thought to repeatability." The company also offers low-temperature arc vapour deposition. "The vapour deposition embeds itself into the outside substrate, producing a finish with Rockwell type hardness depending on the thickness of the coating," Bailey says. The treatment is anticorrosive and prevents oxygenation, yet it is so thin that it doesn't affect dimensional stability.
Stratasys
A manufacturer of rapid prototyping devices, Stratasys (Eden Prairie, MN, USA) uses its proprietary fused deposition modeling process to create 3-D ABS, wax, or polyamide models directly from 3-D CAD files. The company recently launched the FDM 1650, which, says Sharon Christopherson, "has three times the output of previous fused deposition modeling systems." In addition, the system can accommodate a variety of materials--medical-grade ABS is available and a line of elastomers is in development--and features accuracy of ±0.127 mm. A 3-D printer also was recently commercialized by the company. "The Genisys is based on technology Stratasys acquired from IBM in 1995," Christopherson says. "It is meant to be used early in the design cycle, when you know that you'll be making a lot of revisions." The printer, which deposits 0.33-mm road widths of material at a rate of 102 mm/sec, allows designers to print numerous concept iterations from their workstations. "It's not designed for functional prototypes," says Christopherson. "It uses a single material and is suited for look, feel, and some fit and form testing."
Materialise
One of the main activities at Materialise (Leuven, Belgium) is the development of software used with rapid prototyping equipment to convert medical imaging data into prototypes. "The software is used primarily in orthopaedics," says division manager Bart Swaelens. "Instead of using old bones, implant designers can work with copies of bones taken from live patients. For example, they can select the femur from the imaged data, import the data into their CAD system, and develop the prosthesis." The software has also been used to test medical devices. For a new catheter system, "we took an MRI of a patient's brain and made a model of the blood vessels that were then used to test the catheter," says Swaelens. He predicts that computer simulations will become standard operating procedure for manufacturers by allowing them to cut back on tests using humans and animals. The company also has expertise in stereolithography and vacuum casting, and recently developed a technique for selectively coloured stereolithographic models. For more information on this, see the September/October 1996 issue of European Medical Device Manufacturer.
Pearson Matthews Design Partnership
"We have developed a CNC method that enables us to prototype plastic parts with enormous accuracy," says Mike Pearson of Pearson Matthews Design Partnership (Kingston-upon-Thames, Surrey, UK). "It is ideal for situations where you're not just looking for something that resembles the finished part but where you want to check the fit and you need to examine the performance." The CNC process is accurate to ±0.02 mm and enables the production of parts made from materials and with a surface finish virtually identical to those of the finished product. Recently, Pearson Matthews saw the culmination of a seven-year project with the commercial launch of a nonsystemic, noninvasive contraceptive, Persona. The product was completely specified in 3-D, and a number of rapid prototyping techniques were used to examine design fit and feel. One of the principal challenges in designing the device, according to Pearson, was the absence of any other product or prototype that could be used as a benchmark.
Cubital
A supplier of rapid prototyping equipment, Cubital (Bad Kreuznach, Germany) uses the solid-ground curing (SGC) technique, which, according to Curtis Peel, is from "8 to 10 times faster than the stereolithography process and is just as accurate." Unlike SL systems, which are limited in throughput because they can only cure one photopolymer liquid dot at a time, Cubital's SGC technology permits the flash curing of an entire model layer with a single exposure to a powerful UV light. "We can build multiple parts at one time without any incremental increase in time . . . you can add a hundred parts to our process and it won't take any longer," says Peel. In addition, the machine's dual-tasking capability allows the SGC 5600 to create a photomask for the next model layer while curing the current one. Cubital SGC data front ends are designed to accept most CAD file formats.
ProtoMod Ltd.
"Typically, a manufacturer comes to us with a 2-D drawing or 3-D wire frame, and we develop and generate the computer model," says Jeff Lart, technical director at ProtoMod Ltd. (Cranfield, Beds, UK). While the actual production of stereolithographic models is outsourced, the company does have in-house CNC machining capabilities. "CNC allows us to produce parts quicker in the real material than we could going the SLA route," says Lart. The company is currently engulfed in prosthetics work, he adds, but its core expertise lies in injection-moulded plastic components.
DCA Design Consultants
"We started using stereolithography and related processes about 5 years ago, but we have been involved in rapid prototyping for about 20 years," points out Rob Bassil, technical director at DCA Design Consultants (Warwick, UK). "High-speed milling is a bit tarnished, I suppose, because it is a traditional process, but it can be just the thing for certain geometries," Bassil says. "It can be faster than stereolithography and you end up with a prototype in a material that is much closer to your end product. We don't discount the process--it's one of the options we offer." In-house facilities include a prototyping workshop and assembly area, which is often used for medical products, according to Bassil. "For low-volume medical products, we often end up doing the entire production run." One such project involved the redesign of a syringe pump. "The manufacturer had been producing the syringe pump using fabricated caseworks--basically just flat sheets glued together. We came up with a design that allowed the company to move over to a resin casting with relatively low tooling costs. Ordinarily, these castings would be used to produce a few prototypes and then we would move to an injection-moulded part, but in this case it was viable to use the resin casting in the production process as well." DCA was recently appointed the exclusive UK agent of Schneider Prototyping GmbH (Bad Kreuznach, Germany). Schneider's specialized rapid prototyping expertise complements DCA's in-house range of fast-track design facilities and multidisciplinary product design and development skills, according to the company.
3D Systems
A supplier of SL systems, 3D Systems Europe (Darmstadt, Germany) recently acquired the assets of Keltool Inc. (St. Paul, MN, USA), a producer of steel tooling for plastic injection moulding machines based on a patented process and involving 3D Systems' rapid prototyping systems. The Keltool process, according to Arthur B. Sims, company chairman and CEO, is the "only economically viable alternative for rapidly providing sintered steel tool inserts for prototype or production runs of hundreds to millions of plastic injection-moulded parts. With Keltool, users can go from CAD file to first article part in as little as two weeks." To be renamed 3D Keltool, the Keltool process broadens 3D Systems' products scope, which includes the recently launched Actua 2100 concept modeler, a network-ready machine that enables design engineers to print solid 3-D models based on CAD files in a matter of hours. The company also manufactures the SLA 350 series of SL apparatus, designed for midrange prototyping solutions, which feature solid-state lasers that provide consistent power for a minimum of 5000 hours; the Zephyr Recoating System, allowing for easy trapped-volume part building without part modification; and an automatic resin refill system. 3D Systems holds more than 60 patents on its technology and processes and has installed more than 650 rapid prototyping systems worldwide.
