Co-authors​ :

 Hayato HIGASHIYAMA , Seirann MURATA , Kazuaki NISHIYABU (JAPAN) 

Carbon fiber reinforced plastic (CFRP) is light weight and high rigidity. therefore, it is expected to be used in various industries. Thermoplastic and thermosetting resins are used as base matrix. Comparing thermoplastic resin with thermosetting resins, thermoplastic resins have a shorter curing time, which allows for shorter molding time. In addition, thermoplastic resins soften on heating and solidify on cooling, which allows for secondary molding. Examples of such moldings include ultrasonic welding and rivet molding [1]. In general, thermoplastic CFRP (CFRTP) molding, first, the material is heated to soften the resin. then, the resin is impregnated under pressure, and finally cooled. However, thermoplastic resins are known to be difficult to impregnate because of their high resin viscosity. The above problem can be solved by using a prepreg sheet called an intermediate material, in which the resin is impregnated into the fibers in advance. However, prepreg sheets are expensive to manufacture. Therefore, the use of prepreg sheets tends to increase the manufacturing cost of CFRTP molding. In contrast, the use of semipreg sheets reduce it. There are various types of semipreg sheets, but in common, semipreg sheets are manufactured at low cost by adjusting the degree of resin impregnation. In addition, Semipreg sheet is so flexible that it is not necessary to be slit when being formed. There are various methods of applying resin to sheets in the production of semipreg sheet. The sheets used in this study were produced by the powder method. One of the characteristics of this method is that the resin impregnation distance is shorter than that of the commingle method or the film method.
In this paper, the wire having rectangular cross-section were made by pultrusion forming with CF/PPS semipreg sheet. Pultrusion apparatus includes unwinders, preforming devices, mold, and winders. The unwinder is equipped with a powder brake and is capable of unwinding under constant tension. And the unwinder can twist sheets by rotating itself. The preforming devices can fold the sheet twice evenly. The mold is equipped with a nest that can be moved up and down, thus it allows adjustment of the pressurizing force. The winder can adjust the pull-out speed by changing the rotation speed of the motor. In the experimental procedure, first, the sheet is rolled out under constant tension, then inserted into the preform device and folded. Second, The sheet is inserted into the mold and heated, pressurized, and cooled. Finally, the sheet is rolled up by a winder. This study investigates the effects of molding temperature, molding pressure, and drawing speed on the impregnation behavior of resin in pultrusion molding of semipreg sheets. We also investigate the effects of fiber orientation on the mechanical properties of wires by twisting and optimize forming conditions for pultrusion forming with semipreg sheets.