Center Clamp Forming of a Rectangular Cup with Bottom Edge Trimming Using a Continuous Carbon-Fiber-Reinforced Thermoplastic Sheet

Center clamp forming method has been applied to avoid wrinkles in the press forming of a rectangular cup with bottom edge trimming using a continuous woven carbon fiber-reinforced plastic plate. Trimming of a bottom edge during forming is a convenient method to obtain smooth bottom without any other successive process. But it closes the die profile that may cause fiber wrinkle. By the center clamp forming compared with free forming, it is confirmed that this is one of the methods to achieve smooth top flat surface of the cup without wrinkles. Monitoring pressure using pressure sensors elucidated pressure application process during the press forming and cooling process. Difference of the pressure holding time in the cooling process was observed between the pressure on the side plate and that on the top flat plate. Sliding descent during the cooling under constant load indicated the solidification finishing time of the thermoplastic resin.