Fully dense direct metal prototypes arrive

Precision Optical Manufacturing (POM), Plymouth, Mich., has introduced a new technique that provides manufacturers with the capability to produce fully dense metal prototypes. The DMP (Direct Metal Prototype) technique, introduced at Rapid Prototyping & Manufacturing 2000 in the US, is akin to the conventional stereolithographic (SLA) technology used to produce plastic prototype parts.

However, DMP enables users to produce fully functional, 100-percent dense, near net-shaped parts from tool steels, aluminium, copper and other metallic materials directly from a solid model CAD design. And, unlike the selective laser sintering (SLS) process, which relies on polymer binders to fuse powder metal during fabrication, this technology produces fully dense metal parts — without binders — directly from native CAD file formats. ‘This is going to dramatically change the face of rapid prototyping,’ said Timothy Skszek, POM’s vice president of operations. ‘The DMP technique not only yields functional metallic prototype parts, it also provides the capability to imbed objects such as sensors, copper heat sinks, thermal barrier, ceramic matrices and/or internal passages previously not available in the marketplace.’ DMP parts are manufactured using POM’s revolutionary Direct Metal Deposition (DMD) process technology, a layer-additive micro-casting technology, that aims take the rapid prototyping and metalworking industries in an entirely new direction.

The DMD technology is the result of blending five common technologies: lasers, CAD, CAM, sensors and powder metallurgy. The resulting process creates a metal prototype part by focusing an industrial laser beam onto a metallic workpiece or preformed part, creating a molten pool of metal.

A stream of metallic powder is then injected into the melt pool, increasing the size of the molten pool. By moving the laser back and forth under CNC control, tracing out a pattern defined by the CAD geometry, the prototype part is built line by line, one layer at a time. With this process and its translating laser energy source, the molten pool solidifies at a rapid rate, resulting in a fully dense, refined microstructure. Prototype parts fabricated by DMD and the DMP technique have physical properties, which exceed those of conventional wrought of cast materials, providing superior quality and increased strength. More importantly, with this technology, the metallic composition can be altered ‘on-the fly’ by injecting different types of metal powders into the melt pool, providing the feasibility of fabricating composite hybrid material metallicparts. ‘Its an entirely new concept in rapid prototyping,’ said Skszek. ‘Direct Metal Prototyping provides manufactures the ability to fabricate and test fully functional metal prototype parts without the time and cost associated with the design and build of prototype tooling. This fabrication process can significantly reduce the product development time cycle and time-to-marketassociated with new product introduction.’

Web site: http://www.pom.net