2016 年 65 巻 8 号 p. 606-610
Because mechanical properties of carbon fiber reinforced thermoplastic composites (CFRTPs) are strongly affected by fibers state, e.g., fiber length, fiber orientation and fiber dispersion, and such fibers state is modified with resin flow in injection molding, detection of fiber state in molded composites is inevitable for assuring strength of injection molded products. In order to develop simple and rapid monitoring method for fiber state in molded parts it was studied how heating of carbon fibers by induction varied depending on their length and orientation. In this study MHz-band frequency was employed to heat efficiently the fibers dispersed separately in injection molded specimens and temperature rise on the surface was monitored by a pyrometer. Variation in temperature rise was observed between specimens whose mean fiber length were 0.12mm and 0.16mm each. It was also observed that temperature rise differed depending on specimen settings, where the cross angle between fiber orientation and the direction of magnetic field changed. Moreover, it was proved possible to extract weld part by using a differential image between the images of specimens with and without weld.