Experimental study on the accuracy of advanced composite tools for slanted shapes

Abstract High quality advanced composite tools (ACTs) have been introduced to the growing tooling market. Since ACTs are used for high precision composite parts, even minor warpage in a tool might render the parts useless. Trial and error in making or remaking an accurate ACT are time‐consuming and expensive. This paper is devoted to investigating the effects of processing on the accuracy of ACTs for slanted shapes. An experimental design based on the Taguchi Method is employed. The experimental parameters investigated are postcure, mold material, laminate thickness, cure temperature, preheat, bleeder, pressure, and caul sheet. Warpage is used to verify the accuracy of ACTs. Optimum processing conditions and critical parameters have been found. The warpage that results under optimum processing conditions decreased significantly. Based on the findings in fiber volume fraction gradients, the observed convex and concave angle differences in warpage can be explained. To overcome the tendency to warpage, by means of an asymmetric doubler or insert in angle corners, a proper amount of asymmetry is implemented, which successfully improves the accuracy of the ACT shape.