Bayer, Solid Composites developing new high-tech materials for laser sintering

July 11, 2012
Bayer MaterialScience and Fraunhofer spinoff Solid Composites are developing thermoplastic polyurethane (TPU) powders for selective laser sintering to fabricate three-dimensional structures.

Leverkusen and Voerde, Germany -- Partners Bayer MaterialScience and Solid Composites GmbH, a spinoff of the Fraunhofer Institute for Environmental, Safety and Energy Technology (UMSICHT), are developing thermoplastic polyurethane (TPU) powders for selective laser sintering to fabricate three-dimensional structures. The new high-tech materials, licensed and marketed by Solid Composites under the brand name Desmosint, opens the door to numerous potential applications, from automotive to sporting goods to robotics to aerospace engineering.

"Solid Composites has made a name for itself as a creative developer and supplier of thermoplastic powders for laser sintering and electrostatic coating, among other things, and is therefore the partner of choice for us when it comes to successfully marketing our TPU innovation," stated Jurgen Hattig, TPU marketing specialist at Bayer MaterialScience.

Selective laser sintering is a digital manufacturing method for the additive manufacturing of plastic parts. A part is made from a thermoplastic powder based on structural design data; guided by CAD software, a laser fuses successive layers of a powder bed at selected points where the part is to emerge, effectively growing the part layer by layer. Eliminating the need for molds cuts costs considerably, and unlike injection molding, parts with complex geometries (e.g. cavities and undercuts) can be rendered, noted Marcus Rechberger, general manager of Solid Composites.

Primarily soft, elastic materials and rigid thermoplastics such as polyamide have been commercially available for selective laser sintering. Bayer's TPU materials close this gap with qualities of high toughness, elasticity, and strength, and enable significant energy and cost savings. They can be processed layer by layer at a constant temperature of only 80°C, whereas polyamide is processed at slightly below its melting temperature -- resulting in significant energy savings. TPU also has a very low tendency to warp, and non-sintered powder does not age inside the processing space and can be reused. And at the end of the part's service life, the plastic is fully recyclable.

Selective laser sintering is particularly suited to the additive manufacturing of short to extremely short runs, for example in the production of components of housing parts, bellows, and hoses for full-size and luxury sedans. Using TPU materials opens the door to produce more custom components such as orthopedic shoe inlays, athletic shoes, helmets, and prosthetic devices -- and could extend to high-volume production of other parts and applications requiring intricate geometries and where injection molding costs would be high. "In these scenarios, the use of several sintering machines can be more cost efficient," Rechberger explains.

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