INTERNAL DAMAGE EVALUATION OF CFRTP CUT BY A CIRCULAR SAW

In recent years, due to the serious environmental issues, the development of the gasoline mileage improvement technology has become essential in the automotive industry. Weight-saving of the car body can contribute to improving the gasoline mileage. CFRP (Carbon Fiber Reinforced Plastics) are widely used as structural material for airplanes, various kinds of sports gear and premium automobiles because of their low density and high performance in mechanical properties. In CFRP, CFRTP (Carbon Fiber Reinforced Thermoplastics) are expected to be used for lightweight component parts because of their high recycling efficiency and high productivity. Accordingly, a high-efficiency machining method of CFRTP has been needed; however, CFRTP are known as difficult-to-machine materials. Delamination and huge burrs are major problems in CFRTP cutting. Although a circular saw that can be used at high speed is usually used as a cutting tool, the internal damage of CFRTP resulting from machining has not been clarified yet. In this study, in order to evaluate the influence of cutting speed on the internal damage of CFRTP cut by circular saw, the internal damage depth and the temperature of specimens during cutting process were measured. The internal damage occurred by circular saw processing and the internal damage depth were decreased in the case of fast cutting speed. The temperature of the specimen was increased in the case of slow cutting speed because of the longer contact time of the circular saw with the specimen.