PRODUCT UPDATE
The New Pace of Production
Benjamin Lichtman
Rapid prototyping technology answers industry's call for faster, more flexible production.
"In the end, it's always helpful to work with something that you can hold in your hands and examine," says Tim Heller, managing director, Europe, at Stratasys GmbH (Frankfurt, Germany). Heller explains the benefits of rapid prototyping technology with the metaphor of the paperless office: "Working with a text document on the computer gives you certain advantages over working with paper, but you never really eliminate the need for a hard copy. That's what rapid prototyping provides: portable, 3-D output."
As device manufacturers seek out innovative methods to improve their products, reduce costs, and streamline their development cycles, rapid prototyping techniques are emerging as a practical solution. From the early conceptual stages of product development to design and production, rapid prototyping can be used to evaluate ergonomics, check assembly, and perform selected functional tests at significantly reduced costs.
Cut Time and Costs
According to Paul Haima, head of a task force on medical device technology at the TNO Institute of Industrial Technology (Eindhoven, Netherlands), the main advantage of rapid prototyping is the possibility to produce—without moulds or dies—functional models that can be tested and put to use even before making the considerable investments associated with tooling. The prototypes can be evaluated, and changes can be incorporated into the next iteration. This process can be repeated until the latest stages of a product's development at significantly lower costs than traditional prototyping methods.
Because they can reduce the cost of small-series production runs, rapid prototyping processes also hold great potential for the customization of finished medical devices, says Harry Schrott, director of marketing at EOS GmbH (Planegg/München, Germany). Specifically, Schrott highlights laser sintering as a useful technique. "Plastic and metal prototypes can be created—in series material, if necessary—for functional and ergonomic testing during the development process, and small, cost-effective production runs can be carried out quickly."
In addition to speed, rapid prototyping offers some inherent advantages over traditional manufacturing methods. Techniques such as stereolithography, laser sintering, and 3-D printing are additive processes, and they allow for the production of models that would be extremely difficult or even impossible to create by traditional methods.
The influence of this technology is not limited to design offices or manufacturing facilities. Rapid prototyping, it seems, has also found a home in the doctor's office. Robert Baumgartner, vice president for marketing and sales in Europe at 3D Systems GmbH (Darmstadt, Germany) highlights the application of "phantom models" that represent the natural construction of body tissues. Such models can be used in irradiation therapies to simulate the effects of radiation on the body.
A vital link in the application of this technology in clinical settings is the data interface between rapid prototyping machines and medical imaging equipment. Materialise (Leuven, Belgium) markets a software programme that translates scanned medical images into CAD or stereolithography data. The company also has a service bureau that can take projects from a computer file to a prototype and on to in-house casting and small-series production. A recent project found the company producing customized drilling templates for use in surgical applications such as dental implants. The templates were customized to patients' bone structures by converting scanned images into prototypes built in a medical-grade material.
3D Systems is planning to expand its operations in the end-user sphere. "Our goal is to place the ThermoJet [3-D printer] in clinical environments for use in applications such as presurgery support, research and evaluation, and facial reconstruction modelling," says Baumgartner. Noting the company's progress in this area, Baumgartner cites a recent application where 3D's SLA 250 stereolithography machine was used to produce models for craniofacial surgery in a study carried out jointly by Zürich University Hospital and the Institute of Information Technology in Zürich, Switzerland.
Some observers predict that the next focus of technical innovation in rapid prototyping will be the development of new materials. "In the medical device industry, companies are looking for rapid production of parts in final-series materials, such as polycarbonate," says TNO's Haima. To this end, TNO recently constructed a pilot rapid prototyping machine that can process all high-temperature engineering plastics to create functional prototypes. "The idea is that you should be able to come with your stereolithography or 3-D CAD file of the product and a bag of granulate and leave with the product in that material a few hours later," explains Haima.
Fusing Prototyping and Production
The ultimate goal of rapid prototyping technology is rapid manufacturing, the rapid construction of products in final form. EOS is concentrating its efforts in this area with its DirectTool technique, which offers rapid production of tooling for injection moulding and die-casting applications, says Schrott. "The challenge is to produce earlier prototypes of series quality—effectively a fusion of prototyping and production; that will be the real breakthrough," he adds.
No matter which corner of the medical device industry calls rapid prototyping its own, the technology is here to stay. "Machines are getting smaller and less expensive," says Terry Wohlers, president of the consulting firm Wohlers Associates Inc. (Fort Collins, CO, USA). "I think we'll start to see more 3-D printers in offices. The growth in the use of 3-D CAD will act as fuel for this fire."
Heller, too, is upbeat on the prospects of this young technology: "People are learning the value of holding a 3-D model in their hands, and they want more. They're asking themselves: 'What can I do to build more of these, faster and cheaper?'"
If you think your company could benefit from this technology, review the following descriptions of the industry's leading suppliers of rapid prototyping equipment and services.
Materialise
Originally a spin-off of the University of Leuven, a software developer for the rapid prototyping industry offers a programme designed specifically for medical applications. The Mimics programme converts scanner images from MRI or CT machines into sets of data that can be read by 3-D CAD systems or rapid prototyping equipment. The software is most often used in medical modelling applications to create physical prototypes of a patient's anatomy on the basis of medical scanner images. "A user might begin with a scanned image of a hip and extract the femur out of this data set for rapid prototyping," explains Kris Wouters, medical applications engineer at Materialise (Leuven, Belgium). Such models have a variety of applications in device testing, presurgical planning, and in the casting of customized implants. The software programme has been approved by US FDA.
Materialise also offers expertise in stereolithography, selective laser sintering, 3-D plotting, and high-speed milling through its service bureau operations.
TNO Institute of Industrial Technology
The TNO Institute of Industrial Technology (Eindhoven, Netherlands) has formed a pan-European task force on medical device technology. The task force, founded in 1998 and partly funded by the EU, focusses on rapid prototyping applications for clients within three areas: devices for medical treatment and diagnostics, laboratory automation equipment, and medical disposables and reusables. Products and technology developed by the task force are to be marketed by external partners. Members are working toward the establishment of technology-based programmes in collaboration with industrial partners and the Dutch Ministry of Economic Affairs.
Paul Haima, head of the task force, says, "We basically apply the one-stop-shopping principle to product development. We can provide our customers not only with an external cover or housing, but with a functional, operational product."
Wohlers Associates Inc.
An independent consulting firm works closely with manufacturing organizations to provide solutions in rapid product development. Since 1986, Wohlers Associates Inc. (Fort Collins, CO, USA) has collected and analyzed market data from a global base of sources in the rapid prototyping industry. The company's principal consultant and president, Terry Wohlers, has extensive experience as an adviser to major organizations in Europe, Asia, and the United States. Wohlers predicts an increasingly important role for 3-D printers in the future market. "[The printers] have been slow to gain a foothold in the marketplace," he says, "but as speed, material, and price points improve, they will help propel unit sales to new levels." Wohlers notes that several suppliers of rapid prototyping equipment have recently introduced enhanced versions of their 3-D printers.
Wohlers Associates Inc. publishes a consulting report on the state of the rapid prototying industry. The report's table of contents may be viewed at the company's Web site along with an extensive library of information on rapid prototyping and links to several related sites.
EOS GmbH
A rapid prototyping machine is reportedly the first commercial system to offer direct laser sintering of steel powder for rapid production of high-quality tooling suited for injection moulding and die-casting applications. Tools can be created from steel and other metal powders directly from 3-D CAD data.
The EOSINT M system uses a process called direct metal laser sintering to produce parts and tools directly in metal. Parts are built from a patented metal-powder mixture by an infrared, CO2 laser beam. The EOSINT M 250 Xtended builds metallic parts in volumes up to 250 x 250 x 185 mm3. The materials used do not require any binder or preheating and exhibit negligible shrinkage during the building process. Harry Schrott, director of marketing at EOS GmbH (Planegg/München, Germany), says, "A common application of this technology is the production of tools and inserts for plastic injection moulding, rubber vulcanization, and similar processes."
EOS specializes in the development and worldwide marketing of laser sintering products. The company began as a supplier of stereolithography technology and in 1994 expanded its product range to include laser sintering. The company also produces sintering machines that build in plastic.
Stratasys GmbH
A manufacturer of rapid prototyping devices for industrial, medical, and consumer OEMs offers a new system based on the company's patented fused-deposition modelling (FDM) technology, which creates three-dimensional ABS, wax, elastomer, or polyester compound models directly from 3-D CAD files. The FDM Quantum system from Stratasys GmbH (Frankfurt, Germany) produces ABS parts in build envelopes up to 600 x 500 x 600 mm. Models can be built from the company's ABSi material, which withstands gamma sterilization. A revised command center gives the unit a simplified control system and allows users to select build options and check build status and material levels. The system software runs on Windows NT, Hewlett-Packard, Silicon Graphics, and Sun Microsystems platforms.
The company, founded in 1989, also offers a line of 3-D printers for office environments.
3D Systems GmbH
A solid-object printer is designed for operation in an office environment. Manufactured by 3D Systems GmbH (Darmstadt, Germany), the ThermoJet printer offers rapid output of three-dimensional parts direct from CAD software. The machine produces detailed models that require minimal finishing. Parts can be produced in any of three colours, and output can be used as a master pattern for casting.
The ThermoJet, which is similar in size and power requirements to an office copy machine, requires no training and connects to any office network. Vice president Robert Baumgartner says, "A designer who has just created a mechanical part using CAD software can send the file to the ThermoJet over an ordinary office network and receive a sample for evaluation within hours."
The machine creates solid objects with a variation on the technology widely used in ink-jet printing. The material used is a proprietary wax-based thermopolymer that is solid at room temperature and liquefies when heated above 90°C.
The company also manufactures a line of stereolithography machines that deliver high build speeds and near-production-level parts. Proprietary photopolymers are also supplied.
Product Innovation and Development Centre
The Product Innovation and Development Centre (PIDC) is a university-based design and rapid prototyping bureau located in Liverpool, UK. An in-house design team provides services including concept generation, 2-D graphic illustration, material selection, supplier identification, product modelling, simulation, and photorealistic imaging. Capabilities include 3-D CAD, stereolithography, vacuum casting, laser sintering, and high-speed machining. "Our rapid prototyping and rapid tooling activities are developing fast," says business and marketing manager Andy Chittenden.
