Rigid tooling with compliant forming surface for forming parts from

Abstract

A tooling concept having a compliant forming surface for forming composite parts. The tooling concept utilizes a rigid support substructure that has a thin compliant forming surface. In the preferred embodiment of the invention, the tooling concept is used to form a composite sine wave spar. A preferred embodiment of the tooling concept includes upper and lower tool inserts and side tool inserts. The upper tool insert has a compliant forming surface that is located in between a rigid support substructure and the composite material used to form the composite part. Composite prepreg is laid up over a sine wave contour on the upper and lower tool inserts to form upper and lower U-shaped composite workpieces. The upper and lower tool inserts and workpieces are then brought together to form a sine wave I-beam. Radius fillers are then applied to the intersections between the upper and lower composite workpieces and cap strips are placed over the flanges of the joined composite workpieces. Side tools and end tools are then placed around the joined upper and lower tool inserts. The resulting assembly is covered with a breather cloth, baked in a vacuum bag and cured in an autoclave. During curing, the autoclave applies a hydrostatic pressure on the upper tool insert and thus compliant forming surface. The compliant forming surface in turn applies a consolidation and forming pressure to the composite workpiece within the tools. During curing, the compliant forming surface deforms slightly to account for thickness variations in the composite workpiece in order to produce a better quality formed composite part.