Processing, thermosets parting lines

Injection molding is capable of accommodating the broadest range of materials. Nearly all the thermoplastics can be injection molded and, with special equipment, even many thermoset materials can be used. The mold capabilities of the process are also a major asset. Moldmakers have succeeded in constructing incredibly complex molds using side actions to create holes perpendicular to the parting line, split cavities for imusual shapes, and cores which collapse to permit withdrawal from undercuts. 

The fabrication of composite laminates having a thermosetting resin matrix is a complex process. It involves simultaneous heal, mass, and momentum transfer along with chemical reaction in a multiphase system with time-dependent material properties and boundary conditions. Two critical problems, which arise during production of thick structural laminates, are the occurrence of severely detrimental voids and gradients in resin concentration. In order to efficiently manufacture quality parts, on-line control and process optimization are necessary, which in turn require a realistic model of the entire process. In this article we review current progress toward developing accurate void and resin flow portions of this overall process model. 

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