Author(s)

K. Tanaka, T. Yamada, K. Moriito, T. Katayama

Abstract

The press molded parts using the stampable sheets of CFRTP (carbon fiber reinforced thermoplastics) chopped materials have high strength because they can keep a longer fiber length than the injection molding method. Although the mechanical properties of molded parts using stampable sheets are lower than those of continuous fiber reinforced composite materials, they have higher shape flexibility. However, in the stampable sheets of randomly oriented chopped materials, it has been reported that the ends of their fiber bundles can be the initiation of the fracture. Therefore, to reduce the end effect of their fiber bundles, the use of paper-type intermediate material, of which reinforcing fibers are dispersed as individual single fibers, is expected to be used for intermediate materials. In paper-type intermediate materials, reinforcing fibers and matrix resin fibers are dispersed by the paper-making method. Since reinforcing fibers which are placed randomly are crossed densely, high molding pressure is required for production of these material. However, the effect of the molding pressure on the mechanical properties of the molded parts has not been clarified yet. In this study, CFRTP using paper-type intermediate materials were molded at different molding pressures and the effects of the molding pressure on their mechanical and surface properties were evaluated. While it is possible to reduce the voids by using high molding pressure, lower mechanical properties are obtained at the molding pressure of more than 15 MPa due to the breakages of reinforcing fibers during the molding process.

Keywords

thermoplastic composites, carbon fiber, polyamide 6, paper-type intermediate material, chopped materials