Abstract
This paper presents machining quality of circular piercing hole produced by punch press in CFRP laminates under low-velocity impact load. A piercing hole was produced by using a punch with flat surface under low-velocity impact load and quasi-static load. After piercing process, damages and burrs on the surface and cross sections of the specimen were microscopically observed. Internal damages were then observed using X-ray radiography. In addition, roundness of a piercing hole was examined using three displacement diagrams. It was proved from X-ray radiography and roundness evaluation of the hole after the piercing process under high impact energy that the least amount of internal damage was generated and the roundness was high compared to that at the piercing process under quasi-static load. It was found that the clearance between the punch and die was one of the most important parameters to amount of internal damage.
