RocTool North America

Injection molders are warming up to the idea of cycling their tool surface temperature during the molding cycle rather than keeping it constant.

An induction process for rapid mold heating, originally designed for composites, is now available for thermoplastic and thermoset injection molding of parts requiring high surface quality, says process developer RocTool of France. (RocTool North America is in Atlanta.) The company patented in 2004 its Cage System, which heats just the surface of a tool “almost instantly” by electromagnetic induction and then cools that surface just as quickly with fluid channels close to the tool surface.

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.

Molds that can change configuration, automated tape laying and winding, robotic sprayup, and faster prepreg molding processes highlighted the focus on productivity at the international composites show in Paris. RTM innovations round out this news report.

Topping the news from the year’s biggest composites show are PP ballistic panels, “stealth” composites, thermoplastic RTM, new tooling concepts, microwave curing, “instant” SMC, and laser projection for QC and ply layup.

New molding technologies seen at the JEC Composites Show in Paris in April promise dramatically faster cycles than are achievable with autoclaves or RTM. One novel technique rapidly heats and cools a thin tool by "floating" it on a flexible bladder—similar to a water bed—that is flooded with heat-transfer fluid.

Modifications to the common core pin can be a simple solution, but don’t expect all resins to behave the same. Gas assist is also worth a try.