Foaming process for injection molding

Kunststoffinstitut Lüdenscheid (Lüdenscheid, Germany) and Wittmann Battenfeld (Kottingbrunn, Austria) have announced a foaming process for plastics injection molding that produces parts parts free of sink marks, low in warpage, lighter than compact injection molded parts and with a high-quality, smooth surface. The core component/stages of the new process are: injection of the melt blended with a foaming agent; cyclical inductive heating of the mold; cyclical tempering and cooling of the mold with double-circuit tempering devices. One advantage of the process cited by the manufacturer is that injection of the melt into a hot cavity allows the outer crust of the part to become very compact. This reportedly improves surface aesthetics and improves mechanical strength. In addition, the fine, even foam structure in the core prevents sink marks and warpage. Kunststoffinstitut Lüdenscheid developed the inductive mold heating technology. Wittmann Battenfeld applied the tempering technology, which operates with two water inlet temperatures.