"Perspectives" is a column co-authored by Terry Wohlers. The
following was published
in the February 2002 issue of Time-Compression Technologies magazine.
New advance and trends yield surprises.
Few new technologies have impacted product development as much as rapid prototyping. This impact continues to increase as organizations discover new, creative uses for the technology. As RP further develops, additional applications will be discovered, and it will continue to expand into industries that have largely ignored or resisted it.
Today, methods of rapid prototyping are being used in applications and in industries that range from dentistry, orthodontics and medicine to Hollywood filmmaking, hearing aid production and MicroElectroMechanical Systems (MEMS). The following examples capture the breadth of new and unusual applications.
Interesting Applications of RP
Cynovad (Montreal, Canada) announced an agreement to purchase several hundred ThermoJet printers from 3D Systems (Valencia, CA), which are to be re-branded as WaxPro. Cynovad is the exclusive reseller of these machines to the more than 50,000 dental labs around the world for the production of crowns, bridges and other types of dental restorations. The machines produce wax patterns needed for the investment casting process.
Formula 1 Racecars
In England, a service provider named 3T RPD (Berkshire, UK) is using RP to supply parts for the Jordan-Honda Formula 1 racecars. Some of the 20 different parts are used as prototypes, but many are produced as final production parts for cars built to win races. These parts include replacement panels that form aerodynamic skins, cooling ducts and electrical boxes. According to 3T RPD president Tim Plunkett, the company is supplying Jordan-Honda with an average of 35 laser sintered parts per week with a typical deliver of only 48 hours (see Figure 1).
Figure 1: Front end of a Formula 1 racecar.
Using 3-D printing (3DP) technology from the Massachusetts Institute of Technology (MIT), Specific Surface (Franklin, MA) is manufacturing highly complex ceramic filters that are applied to everything from making soy sauce to filtering diesel emissions. Using its CeraPrint process, Specific Surface produces filters in quantities of 10 to 100,000.
Bill Rogers of the University of Texas at San Antonio conducted a study, sponsored by the Veteran's Administration, to determine whether selective laser sintering (SLS) can produce superior sockets for below-the-knee amputees. Clinical results indicated that the amputees were pleased with the fit, comfort and functionality of the sockets that include design features feasible only through RP.
Therics, Inc. (Princeton, NJ) uses its 3DP license from MIT to manufacture medical products that include time-released, customized, oral medications; resorbable Òscaffolding;Ó and implants for cartilage, tendon and bone substitutes. Therics makes it possible to produce resorbable tissue structures, such as a bone graft or an eye socket, from CT scan data using the company's proprietary CADLink conversion software and TheriForm 3-D printing process.
Doug Greenwood of Product Development Service (Durham, NC) has used DSM Somos' (New Castle, DE) WaterClear material to model a human nasal passage for CIIT Centers for Health Research. The transparency of the cured photopolymer permits visualization of air and particulate flow for improved understanding of chemical interaction with the nasal membrane. Both companies believe that the complexity of this internal passage makes it nearly impossible to physically model using any method other than RP (see Figure 2).
2: Nasal passage
RP processes are producing very small parts, some as tiny as a red blood cell. The University of Southern California is using a process it calls electrochemical fabrication that electro-deposits nickel layer-by-layer using a masking technique. With this method, it is possible to produce working mechanisms that measure 100 microns (0.004 inch) in height.
In Duisburg, Germany, a company named microTEC can produce 150 miniature photopolymer parts per hour using its proprietary stereolithography process. Layers are an amazing one micron (0.00004 inch) in thickness.
Meanwhile, researchers at Osaka University (Osaka, Japan) are using two lasers and liquid photopolymer to produce very small parts. Remarkably, they were successful in producing a detailed representation of a bull that measures 10 microns from tail to nose - the size of a red blood cell.
World's Smallest Robot
Using stereolithography, Sandia National Laboratories (Albuquerque, NM) has built what it believes is the world's smallest untethered robot. The mobile unit weighs less than one ounce and measures 0.25 cubic inch.
Many of the major manufacturers of hearing aids are in the early stages of using RP to mass customize their products in impressive volumes. Some of these companies produce more than 1,000 in-the-ear hearing aids per day, each being unique in its shape and size. A silicone rubber impression of the ear canal is digitized with an optical scanner, which leads to an STL file and RP for the rapid production of the hearing aid shell.
Injection Mold Design
Companies are using color 3-D printing from Z Corp. (Burlington, MA) to optimize the design of injection molds. Using mold filling simulation software, such as that from Moldflow, it is possible to output files that can be read into Z Corp.'s Z406 and Z402 color 3-D printers. The result is a model that visually represents mold filling and cooling characteristics - a powerful aid for design and evaluation.
RP is being using to produce custom-fit masks that reduce scarring on burn victims. The process begins by digitizing the patient using non-contact optical scanning. The scan data is used to produce an RP model of a mask that fits perfectly to the patient's face.
Developments and Trends
These examples highlight just a few of the developments in RP and some of the new and exciting applications. This information, coupled with research into ongoing developments, illustrates several interesting trends.
RP for the Production of Finished
An increasing number of companies have demonstrated RP's ability to produce finished goods. These progressive companies have laid the groundwork for others to follow. Additional examples include: Bell Helicopter (Fort Worth, TX) using RP to produce metal castings for its helicopters; Technikon Free State (Bloemfontein, South Africa) using laser sintering to manufacture a monitoring device for fitness centers; and a user of Stratasys' (Eden Prairie, MN) FDM Titan producing a polycarbonate replacement pulley for an industrial belt sander.
Growing Demand in the Medical Industry
Many medical applications demand some level of personal customization, and RP has demonstrated the ability to address this need. Andy Christensen of Medical Modeling LLC (Golden, CO) says the demand for RP models in the medical industry has doubled during the past two to three years. Align Technology (Santa Clara, CA) has developed more than one million RP models, using its stereolithography machines to produce its Invisalign invisible plastic aligners for straightening adult teeth. Separately, Interpore Cross International (Irvine, CA), a medical device company, is using seven ModelMaker machines from Solidscape (Merrimack, NH) to manufacture spinal implants.
With computers and hand-held electronic devices shrinking, the appetite for small parts grows. RP's style of building parts in layers, coupled with lasers, makes it possible to produce very small parts and assemblies that are highly complex. The number of activities in this area suggests that a trend is developing for the production of miniature parts through RP for wide ranging applications and products such as actuators and sensors.
The range of new and usual applications of RP continues to expand. These uses, combined with the many new developments and innovations around the world, are leading to advances and trends that are reshaping the RP industry as a whole. Brace yourself because this is only the tip of the iceberg. Growth into new markets and industries will redefine the role of RP. This, in turn, will alter our future in ways that are difficult for many of us to envision.
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