Effect of process parameters on the surface quality of air cushion method

Abstract

A new method of the vacuum-assisted resin transfer molding process, called air cushion method, has been developed to manufacture composite parts. The process utilizes additional air cushions bound into the bagging film beneath. After the preform is sealed by the bag and evacuated, distribution channels are created between air cushions to enhance resin flow during infusion. Once the resin infusion is completed, the binding interfaces between the air cushion and the bagging film are cut and distribution channels collapse. The vacuum bag entirely compacts the preform. The goal of this study is to utilize a 24 full factorial design to evaluate the effects of process variables, including the number of the air cushion (factor A), thickness of the air cushion (factor B), elasticity of the bagging film (factor C), and vacuum pressure in the cavity (factor D), on the surface quality of air cushion method components. Results show that the process parameters ranked in decreasing order of importance are B, D, A, and C for affecting the surface height difference. Compared with traditional vacuum-assisted resin transfer molding, air cushion method at the optimum settings reduces the infusion time by 68.4% but increases the surface height difference by 0.0312 mm.