What is hot press moulding?

A matched metal tool is placed between the platens of a hydraulic press and heated to between 130°C and 170°C. The prepreg or reinforcement material is placed in the tool which has a cavity in the shape of the component required. The tool is rapidly closed and the cure is completed within 2-3 minutes. The tool is opened and the component removed. In order to aid removal of the component from the tool, release agents are either incorporated into the resin mix or applied to the surface of the tool.

This method uses the various compounds including SMC (Sheet Moulding Compound), DMC (Dough Moulding Compound) and BMC (Bulk Moulding Compound). The compounds use polyester resin, filler, catalyst, pigment and other additives. The fibre preforms are typically a sprayed chopped fibre and binder or thermally deformed Chopped strand mat containing a thermoplastic binder. This method does allow for a high production rate and is preferred by the automotive industry.

Some of the key points of this method include: