Multi-component injection molding using turntable mold, includes workstation with sensor moving mold core to follow shrinkage of molded preform

摘要

A molding core (1) and two or more dies are located at one of the workstations. The dies can be moved towards the core. One die (2) molds a preform. Others are used when over-injecting the preform. On or in the core, a follower is arranged. This is designed to track the shrinking, molded preform, which it contacts on the underside, during die closure. The follower is moved towards the shrinking preform by one or more adjustable springs. It is moved using a pneumatic- or hydraulic cylinder. The degree of preform shrinkage, or its movement to the side, is detected by a probe. From this measurement, a computer determines the velocity or path (Sn) of the follower. A corresponding signal is relayed to an electromagnetic actuator, which moves the follower.