Enhanced formability of thin carbon fiber reinforced plastic sheets in cold/warm embossing with ductile dummy sheets of different thicknesses

For light and stiff structural parts, the use of carbon-fiber-reinforced plastics (CFRPs) is currently a topic of research. However, the current manufacturing time of CFRP products is too long to enable mass production. A new sheet forming process for solidified CFRPs with dummy sheets was developed. The process can be applied to conventional press forming for mass production. It is necessary for CFRP sheets to be pressed under a tensile load because they are weak under compression load. When the neutral plane under a forming was moved inside the bending curve, the specimen could be formed under tensile load. In this study, the position of the neutral plane was moved by changing the thicknesses of dummy sheets on the inside and outside of the bending curve. Observation by microscopy, computed tomography scanning and tensile tests were performed to determine the relationship between internal defects and tensile strength.