Rapid Manufacturing Breaks Down Old Production Constraints

Jan. 13, 2011
The technology has evolved from a niche tool for building prototypes to one gaining wider acceptance for batch manufacturing.

Greg Morris is a believer in manufacturing the unmanufacturable.

His company, Morris Technologies, specializes in producing highly complex components for aerospace, medical and industrial applications. While his machine shop features an array of traditional high-end CNC machines, it has increasingly relied on an ever-expanding lineup of direct metal laser sintering systems to produce parts of unusual, intricate geometric designs.

There are eight of these machines in Morris' shop, representing arguably the highest concentration of DMLS capacity in the world. These machines aren't spitting out prototypes. Rather, Morris Technologies is now churning out production parts in high-growth applications, which in many ways represents the realization of the technology's promise.

Whether it's called rapid manufacturing, direct digital manufacturing, solid freeform fabrication or low-volume-layered manufacturing, the technology is still built on the same principle of creating an object by stacking one layer of material -- either plastic or metal -- on top of another.

"It's opening up new design paradigms," says Morris. "By virtue of how it builds in an additive nature, you can combine multiple components into one. You can reduce weight. You can get performance enhancement out of a part that you couldn't dream of before. Many of the constraints of traditional manufacturing are just gone."

Morris Technologies produced a stator for an aerospace gas-turbine application made from nickel alloy IN718 using one of its direct metal laser sintering systems. Photo: Morris Technologies This has been enabled by two key trends. First, the technology has advanced from being a niche tool limited to designers and engineers, to one of wider acceptance across multiple industries, including among manufacturing engineers. Second, the price point has dropped dramatically, making the investment more palatable to a greater number of manufacturers.

When Northrop Grumman's aerospace systems division began using rapid prototyping 15 years ago, it was mainly for use on disposable parts, such as fabricating tools and drill jigs. But because of innovations on the material front, where metals and plastics can now meet aerospace performance requirements, Northrop Grumman is using the technology for the production of ducts, clips and brackets.

"Over time, the technology has allowed for higher performance on materials both structurally and with temperature capability," says Tim Shinbara, manufacturing engineer at Northrop Grumman Aerospace Systems.

Boeing, meanwhile, has made extensive use of rapid prototyping machines to produce parts, tooling and manufacturing aids for its F-18 and other military aircraft.

Perhaps the biggest impact over the last five years has been the emergence of fused deposition modeling to build jigs and fixtures. Stratasys, one of the largest makers of rapid prototyping systems on the market, has built a foothold in the industry by focusing on this area. According to Jon Cobb, global vice president of marketing for Stratasys, nearly 20% of the company's customers are using 3-D printers for jigs and fixtures.

BMW used a fused deposition modeling system for such use, building a more ergonomically designed handheld assembly device at its production facility in Regensburg, Germany. One tool, used for attaching bumper supports, was changed from metal to plastic, reducing the weight by 72%.

But that might only be the tip of the iceberg. The area of highest growth has been in using additive manufacturing to produce finished production parts, according to Terry Wohlers, an analyst who publishes an annual report on the state of the rapid prototyping industry. Seven years ago the technology wasn't remotely capable of such production. In his most recent survey, additive manufacturing part production represented 15.6% of respondents business -- and is expected to grow to 36% by 2013.

"You can make tooling inserts and jigs and fixtures and that addresses a big area," says Morris. "But the real dollars, in my opinion, will be when we're using this equipment just like you would be using a multi-axis CNC machine."

The biggest barrier in recent years and going forward still relates to materials. Additive parts have long been viewed skeptically for not measuring up to those that are machined, molded or cast when it comes to tensile strength and other properties.

That is only partially true. According to Northrop Grumman's Shinbara, the biggest question mark comes from a lack of data.

"The structural performance on the metal side is actually very attractive," says Shinbara. "But on the polymer side, the structural performance of the materials is still lacking. We would like to expand the capabilities beyond relatively small, simple ducts and clips and brackets and go toward more structural and complex parts. But for now, it's really the structural material of the polymers that is holding that back."

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