Caul plate

A consolidation technique in which a laminate is sealed under a flexible airtight film and the air is evacuated so that atmospheric pressure compacts the plies during cure. It removes trapped air and excess resin and is used with wet lay-up, prepreg and infusion processes.

Intermediate vacuum compaction of a partially completed prepreg stack, carried out periodically during lay-up to remove trapped air and seat the plies before further layers are added. Regular debulks reduce wrinkling, bridging and final void content, especially on curved tooling.

The application of pressure, with or without heat, to compact a laminate, bring the plies into intimate contact and drive out entrapped air. Adequate consolidation is essential to achieving the design fibre volume fraction and low void content.

The moulds, mandrels, jigs and fixtures on and in which parts are laminated, formed and cured. Tooling material selection, from GRP and epoxy tooling board through to nickel alloy and steel, is driven by cure temperature, thermal expansion match, accuracy requirements and production volume.