Electric circuits are molded into plastic housings in a new technology introduced at K 2010 by A. Schulman, a plastics compounder based in Akron, OH.
Schulman showed an electrically conductive plastic compound developed for Hella KGaA Hueck & Co., a Finnish lighting manufacturer.
Copper and tin are loaded at a very high level (60 and 25 percent respectively) in polyamide 6. The tin acts like a solder connecting the copper fibers.
“The conductivity of the compound is 1,000 times better than the next most conductive plastic compound available (plastic loaded with steel fibers),” says Thilo Stier, innovation manager for A. Schulman.
The first production part is a light that can be used for automotive or other end-market applications.
The production process is novel.
First, the ABS plate and the PMMA (acrylic) reflector are injection molded in a three-component process. The electrical resistor, diodes, LED and contact pins for the plug are inserted and connected with the new conductive compound, which is called Schulatec TinCo 50. The ABS-coated reflector is then mounted to ensure watertight encapsulation.
Stier says the material can be used for housings and lighting applications. The new technology permits new design opportunities while also reducing costs through integration of structural and electrical functions into one part.
The specific electrical conductivity of the compound is in the range of 5 x 105 S/m. The conductivity of copper alone is 5.69 x 107 S/m.
Development of the technology began with Siemens in 1998 and was later supported by IKV Aachen, a German research organization.
Source : www.designnews.com