| 摘要 |
PROBLEM TO BE SOLVED: To facilitate preform forming work, especially, core removing work to enhance workability and to prevent the generation of the disturbance of reinforcing fibers at a time of the removal of a core by roughening the surface of the core covered with a flexible tube around which a winding layer of reinforcing fibers is formed. SOLUTION: The surface of a round cylinder made of steel is subjected to sand blasting using particles with an average particle size of 100μm under pressure of 2kgf/cm<2> to be roughened to form a preform forming core material with surface roughness Ra of 0.5μm or more. This core material is covered with a flexible tube made of nylon with a folded diameter of 24mm and reinforcing fibers are wound around the tube while reciprocated 15 times in such a state that the unwinding tension from a creel is set to 1000g so that the orientation angle thereof becomes±45 deg. with respect to the tube axial direction. After the reinforcing fibers are wound up, the fixing of the core material on a tail stock side is released and the core material can be easily removed by the hand. Therefore, the generation of the disturbance of reinforcing fibers at a time of the removal of the core material can be prevented and an FRP product of good quality can be obtained. |
