Debulking

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.

Reinforcement fibre pre-impregnated with a controlled quantity of resin, usually a partially cured (B-staged) thermoset, supplied in rolls and stored chilled or frozen until layup. Prepregs give precise fibre and resin content and are the standard material form for high-performance aerospace and motorsport laminates.

The proportion of a cured laminate's volume occupied by trapped air or volatiles rather than fibre or resin. Elevated void content degrades interlaminar shear strength and fatigue performance, so it is controlled through debulking, vacuum and cure pressure and checked by testing or non-destructive inspection.

The process of placing reinforcement plies into or onto a mould in the specified sequence and orientation, by hand or by machine; also used as a noun for the resulting stack or its design. Hand layup with wet resin remains the basic process for GRP boat building and GRP roofing.

The manufacture of composite parts from reinforcement pre-impregnated with a controlled amount of partially cured resin. Plies are cut, laid into a mould and debulked, then consolidated and cured under heat and pressure, typically in an autoclave or oven, giving very consistent fibre and resin content.

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.