Chapter 2 - Manufacture of 3D Fibre Preforms

Abstract

The manufacture of three-dimensional (3D) fiber preforms for composite structures can be accomplished in a variety of ways. However, all the processes that have been developed for composite applications are essentially derived from one of the four groups of traditional textile procedures—weaving, braiding, knitting, and stitching. Weaving is a manufacturing method that produces the vast majority of single-layer, broadcloth carbon, and glass fabric that is currently used as a reinforcement material for composite components. The braiding process can be used with mandrels to make quite intricate preform shapes. By suitable design of the mandrel and selection of the braiding parameters, braided fabric can be produced over the top of mandrels that vary in cross-sectional shape or dimension along their length. The knitted carbon and glass fabric that can be produced on standard industrial knitting machines has particular properties that potentially make it ideally suited for certain composite components. Two traditional knitting processes—weft knitting and warp knitting—are available to manufacture preforms for composite structures. Both of these techniques can be performed upon standard, industrial knitting machines with high-performance yarns such as glass and carbon.