Originally Published EMDM January/February 2002
MATERIALS
Interest heats up for thermally conductive TPEs
As power densities increase, conventional plastic products become prone to overheating, thus causing component failure. Thermally conductive plastics can solve this problem while enhancing design flexibility in moulded products. Cool Polymers Inc. (Warwick, RI, USA) introduced some recent medical applications of such materials at the K 2001 show.
Among other products, the company exhibited a temperature monitor the size of a watch battery that incorporates a thermally conductive liquid crystalline polymer. The monitor acts like a heat pipe, conducting body heat at rates up to 50 w/m per degree Kelvin to a sensor that sends the data to a computerized monitoring system by means of a wireless connection. The company also showed an integrated high-torque motor and driver (pictured) suited for use in medical equipment. The component is aimed at designers who want the simplicity of onboard electronics without the expense of an indexer on each axis. The part uses a thermally conductive polycarbonate to draw away heat from the controller and dissipate it into the surrounding air.
Thermally conductive materials can be formulated with most base thermoplastics. They feature a low coefficient of thermal expansion and contribute to a reduction or elimination of additional parts and assembly processes. The materials are available in electrically insulative and conductive grades and meet UL flammability requirements; some grades are also suitable for EMI and RFI shielding applications.
Norbert Sparrow
Copyright ©2002 European Medical Device Manufacturer
