Roehr's Collapsible Core is a major breakthrough for molding plastic parts requiring internal threads, undercuts, protrusions or cut-outs. The patented design incorporates only three moving parts... which utilize conventional mold movements.

In addition to being automatic in operation... the Collapsible Core enables one to produce parts that, until now, have been considered impossible to mold. Parts with internal protrusions, dimples, interrupted threads, and cutouts can now be economically produced on a high or low volume basis.

For conventional threaded parts, the Collapsible Core could cut one's cycle time up to 30% when compared with unscrewing or other complex actuating mechanisms.

Full technical details, including basic stripper plate mold construction, core grinding instruc-tions, and core and mold machining dimension are available from Roehr upon request.

Collapsible Mini-Cores broaden the applications of collapsible core molds for closures as small as 13mm. Due to the smaller diameters involved, these Mini-Cores employ three larger collapsing segments combined with three narrow, non-collapsing blades which are an integral part of the center pin. As a result, up to 80% full threads or undercuts can be molded. The function of the collapsing core also permits threads to stop at any point along the molded length ... threads need not run out to the top of the cores as with unscrewing molds. If a seal is required in the top of the closure, an undercut can be molded into the part to hold such a seal in place. The collapsing action also permits a longer threaded area to be formed, without adding to cycle time or requiring long rack and pinion mechanisms. In addition to threads, other configurations such as dimples, cut-outs or protrusions beyond the capabilities of unscrewing molds can be successfully molded. Three standard sizes of collapsible are available, for 13-16, 17-20, and 21-24mm closures.