Effect of forming temperature on the quality of hot diaphragm formed C-shaped thermosetting composite laminates

Hot diaphragm-forming process is a promising technology for production of angle-shaped thermosetting composites with high efficiency and consistent quality. This technique can be used to form prepreg laminates with abrupt or complex structures before final cure in an autoclave. In this work, the mechanism of the forming process using double diaphragms for carbon fiber/epoxy resin prepreg laminate with C-shaped structure was discussed, and the effect of the forming temperature on the quality of formed laminate was investigated using a designed hot diaphragm-forming device. A testing system was set up to evaluate the frictional resistance of prepreg at different temperatures. The results indicate that a proper forming temperature is essential for quality control of the process and there is a close relationship between prepreg properties and forming qualities of parts.