STUDY ON ACCURACY OF ADVANCED COMPOSITE TOOLS

Many high precision composite parts, fabricated by means of either hand lay-up or resin transfer molding, are now formed on advanced composite tools (ACTs). Trial and error methods for making accurate ACTs are time consuming and expensive. This paper investigates the effects of processing on the accuracy of ACTs for flat plates. Plate-shaped tools made of woven fabric graphite/epoxy were tested. The accuracy increased considerably as the laminate thickness increased, and it was found that 16 plies, at least, should be adopted in an ACT. Curing of ACTs at a lower temperature and then postcuring at a high temperature resulted in reduced curvature. The metallography revealed a volume-fraction gradient through the laminate thickness. This volume-fraction gradient always resulted in convex upward curvature. In addition, the accuracy of angle composite components with various radii was tested. The results showed that the accuracy of angle composite components was independent of the tool radius.