Additive Manufacturing: Not Just For Rapid Prototyping
Although many people just think of processes and equipment that produce parts via layering or sintering plastic or metal materials as “rapid prototyping” and consequently as a cheap, flexible and fast way to create test parts prior to production, material availability has traditionally limited the technology from being anything more. But now, with ongoing advances in plastics and metal materials, the door has been opened for more applications. So no longer is this just for prototyping, but for end products, as well.
For example, Direct Metal Laser Sintering (DMLS) is an additive process that uses a laser to fuse metal powders into solid. It has been around since the mid-90s, but its real benefits are just starting to be seen in North America, says Andrew Snow, Electro Optical Systems (EOS; eos.info) North American Sales Manager. He says in addition to prototyping, the technology is becoming commonly used for low-quantity manufacturing by the dental, medical, aerospace and consumer products industries.
Like plastic-based additive processes, speed is the obvious benefit of DMLS. No special tooling is required to create the end product. But unlike plastic-based processes, DMLS-created parts are durable enough to be used even in jet and car engines. According to Snow, a growing trend is low-quantity manufacturing for unmanned aerial vehicles (UAVs). These are typically small aircraft intended for surveillance and data-gathering operations. Because the production runs tend to be low, DMLS works well to produce components. The tooling necessary for machining them would be prohibitively expensive. What’s more, while tooling can take days or weeks to prepare, DMLS can produce the parts in a matter of hours. If the product needs to be altered, the designer can go right back into its CAD file to make the changes, and build the part again in a matter of hours.
“Materials drive applications in this industry,” says Snow, who adds that EOS’ ultimate vision is to create machines and materials that ultimately serve more of the manufacturing, rather than the prototyping, environment. Presently, the company’s EOSINT M 270 DMLS system can produce parts with bronzes and steels, cobalt chrome, aluminum, nickel, and titanium in complex geometries at speeds of up to 20 mm³ per second.
EOS also manufactures laser sintering (LS) machines that build parts in high-performance plastic polymers. One material, EOS PEEK HP3, is a high-performing polymer featuring advanced tribiological, physical and chemical properties. Snow says thousands of small medical instruments can be made within days with the EOSINT P 800 LS system. This is significantly faster to market than traditional machining practices, he says. Again, no tooling is required.
Traditional plastic-based rapid prototyping techniques like stereolithography (SLA) and fused deposition modeling (FDM) are also suitable for low-end production parts, specifically in the electronics, alternative energy and medical industries. Rey Chu, Director of Manufacturing Technology at Phoenix Analysis and Design Technologies (PADT; padtinc.com) says protective covers for electronic controllers are a common application. Recently, Chu says, PADT used a Stratasys FDM 2000 Prodigy Dimension machine to create 150 covers in high-strength ABS plastic. The parts were delivered to the customer within two days. “If we were cutting injection molds, that would easily be $5,000 in tooling, even for short-run tooling—and it’s going to take three weeks to do it,” he says. The covers, Chu says, were produced at about one-third of that price.
As for the future of additive methods being used for end products, Chu says to expect the focus to be on niche markets. “They’re going to make some incremental industry-specific headway,” he says. “The manufacturers can work with the industries—aerospace, energy, automotive—look at their material requirements, and they can focus on those.”
