A new system for heating molds much faster by electromagnetic induction is being used by Germany's KraussMaffei (U.S. office in Florence, Ky.), with its Long-Fiber Injection (LFI) process.

A new system for heating molds much faster by electromagnetic induction is being used by Germany's KraussMaffei (U.S. office in Florence, Ky.), with its Long-Fiber Injection (LFI) process. LFI chops and blends fiberglass roving with PUR in the mixhead as an alternative to SRIM with fiberglass mat. The new rapid heating system was presented by KraussMaffei at the recent 2007 Polyurethanes Technical Conference in Orlando, Fla., sponsored by the Center for the Polyurethanes Industry (CPI). Called the Cage System, it was developed by RocTool in France (U.S. office in Atlanta). In trials of a part measuring 1.3 x 0.6 meters, the glass/PUR mix was poured into the lower tool half by a robot. Starting temperature of the water-cooled mold was 40 C (104 F). The induction heating coil around the mold was designed so that its circuit closed when the mold halves came together. The coil heated just the surface of the mold, bringing the PUR mix up to 90 C (194 F) in under 30 sec, vs. several minutes with typical mold heating. LFI with induction heating produced part quality equal to that obtained with standard molds at less than one-third the typical cure time (90 vs. 300 sec). Overall cycle time was cut more than half from 356 to 146 sec. KraussMaffei notes that molds must be adapted to the Cage System for optimum performance. KM's new Tooling Technologies Div. developed the molds for these trials. Although induction-heated molds cost more and use somewhat more energy, they compensate with faster cycles that require fewer molds and mold carriers. KM: (859) 283-0200/www.kraussmaffei.com . RocTool: (866) 260-2572/www.roctool.com

KraussMaffei Corp.
7095 Industrial Road P.O. Box 6270
Florence, KY 41022-6270
Phone (859) 283-4316 Fax (859) 283-0290