The Influence of Charge Pattern on Bending Properties of SMC Compression Molding Products
Fujita Akihiro; Furuta Yasuhisa; Tanigaki Etsuko; Hasegawa Tomomi; Hamada Hiroyuki
Abstract:SMC (Sheet Molding Compound) is one of composite materials used in compression moldings. SMC products have smooth surface without any particular technique. This is superior point of SMC products. SMC molding process is rather simple, namely easy to fabricate complex shape products. SMC products has been used in structural parts of transportation vehicles, water tank, bathtub and other variety of products. In the SMC products, material flow during manufacturing process affects fiber distribution of reinforcement. Fiber distribution which lead to scatter of mechanical properties of SMC products. In this study, three point bending tests of SMC products were performed. Short and long glass fibers random mats were used for the reinforcement. The charge patterns and ratio of charge were varied in order to investigate their influence on bending properties. Material flow behavior during molding was different by the charge pattern. It became clear that bending properties were greatly influenced by the fiber orientation occurred during material flow. Furthermore, the bending stress at knee point by the occurrence of initial crack was calculated. It seems that ratio of the knee point stress to maximum stress is one of the useful parameter to evaluate the bending properties of SMC. Key Words:sheet molding compound, charge pattern, fiber orientation, flow behavior, knee point