Hot diaphragm forming of carbon fiber composite with C-shaped structure

The device of hot diaphragm forming was designed. The preforms of carbon fiber composite with C-shape structure were fabricated. The variations of temperatures on the preforms and the mould were measured. Furthermore, the influences of the forming temperature and the size of perform on the processing quality and internal defect were investigated. It shows the combination of preheating of mould with the radiation heating effect during the hot diaphragm forming could guarantee the temperature of the prepreg distributes homogeneously. When the forming temperature is low, the viscidity of the prepreg is relatively great and the ability of slipping between prepreg is poor which cause the fiber wrinkle at the corner of preform and high poriness. In addition, the preform tends to warp, when the size of preform is close to that of the mould. This phenomenon results from the diaphragm bridging and large deformation of the preform, hence proper size proportion between preform and mould must be controlled.