Methods and systems for co-extruding multiple polymeric material flow streams into a mold having a plurality of cavities to produce a plurality of multi-layer polymeric articles each having a consistent coverage of an interior core layer are disclosed herein. In an example method, a flow rate of a first skin material into a cavity is individually controlled for each cavity before initiation of co-injection of a second core material into the cavity, which may address inconsistent interior core layer coverage for articles from different cavities.

Methods and systems for co-extruding multiple polymeric material flow streams into a mold having a plurality of cavities to produce a plurality of multi-layer polymeric articles each having a consistent coverage of an interior core layer are disclosed herein. In an example method, a flow rate of a first skin material into a cavity is individually controlled for each cavity before initiation of co-injection of a second core material into the cavity, which may address inconsistent interior core layer coverage for articles from different cavities.

Methods and systems for co-extruding multiple polymeric material flow streams into a mold having a plurality of cavities to produce a plurality of multi-layer polymeric articles each having a consistent coverage of an interior core layer are disclosed herein. In an example method, a flow rate of a first skin material into a cavity is individually controlled for each cavity before initiation of co-injection of a second core material into the cavity, which may address inconsistent interior core layer coverage for articles from different cavities.

A rotor core molding system, for molding magnets in an unmolded rotor core to provide a molded rotor core for an electrical motor, comprises first and second molds arranged to allow clamping at least one unmolded rotor core between the molds, a pre-adjustment arrangement for allowing to pre-adjust a distance between the molds in a preset open configuration of the molds to a pre-adjusted distance, and a mold closure arrangement for allowing to close the molds from the preset open configuration to a closed configuration by moving the molds towards one another to clamp unmolded rotor core(s) provided between the molds with a predetermined pressure in between the molds in the closed configuration. The pre-adjustment arrangement is configured to provide a relatively long-range distance movement, especially corresponding to one or more rotor core heights. The mold closure arrangement is configured to provide a relatively short-range distance movement.