Billet flow formation of discontinuous carbon fiber ribbed square panels from continuous carbon fibers

This paper presents a newly-developed billet flow formation method, which produces discontinuous carbon fiber thermoplastic ribbed panels by using the die cushion motion of a press. Billets of discontinuous fiber reinforced thermoplastic were extruded into rib cavities by die cushion motion while press-forming a panel of continuous fiber reinforced thermoplastic. Using billet flow formation, 200 mm long, 46 mm high, 1.4 mm thick ribs comprised of 30 mm long discontinuous fibers were formed on 400 mm wide, 300 mm depth, 50 mm high panels. The rigidity of a ribbed panel was five times greater than a panel without ribs. The tensile strength of the formed ribs was approximately 250 MPa, the same strength of the material before forming. Material behavior such as fiber flow and billet deformation during formation is discussed. This study has shown that the billet flow formation can create ribs with high mechanical strength using only a press with a die cushion.