Stamping of continuous fiber thermoplastic composites

Abstract Despite demonstrated success in low volume aerospace and defense applications, structural composites remain at the periphery of high volume industries such as construction, automotive, and consumer goods because of long cycle times. Stamping provides a means of making composite sheet products at rates ten to a hundred times faster than any existing continuous fiber processes. However, to make composites stamping a viable process, one must understand how the combination of fabric architecture, tool design, and process conditions interact to produce a part free of wrinkling and tearing. In this paper, the effect of temperature, stamping rate, and boundary constraints on the material deformation is presented. The focus of this study is a co‐mingled glass/polypropylene fabric, in the form of a layer of unidirectional yarns held together by stitches. The results show that temperature variations have the greatest effect on deformation. In addition, a finite element model of parallel strips with linear constraints was shown to successfully simulate the sliding deformation or draw‐in of the stitched unidirectional material.