Characterization of the fabric/tool and fabric/fabric friction during the thermostamping process

The thermostamping of quality composite parts using thermoplastic woven fabrics may require the use of in-plane forces to prevent fabric wrinkling for compound-curvature surfaces. These in-plane forces are developed during the stamping process by the friction between the fabric and tool. For multilayer stampings, the in-plane force is also a consequence of the interaction of the adjacent layers of fabric. If the in-plane forces are too low, then the stamped parts may wrinkle as the fabric deforms to assume the shape of the punch. If the in-plane forces are too high, then the fabric can become damaged by tearing and yarn separation. Thus, controlling the in-plane forces is critical to achieving a quality part. In the current research, a load-control friction testing apparatus is used to quantify the fabric/tool and fabric/fabric friction behavior of a commingled balanced plain-weave fabric.