Authors:
Kwang-Woon Jung
Yousuke Kawahito
Seiji Katayama
Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

Laser cutting of carbon fiber reinforced plastics (CFRPs) has been known to be difficult due to the thermal damage to CFRP material. Therefore, with the objectives of evaluating the cutting possibility for long- or short-fiber pellet CFRP sheets of 3 mm in thickness and obtaining narrower heat affected zone (HAZ) for better cut quality, ultra-high speed cutting was conducted by using a continuous-wave high brightness disk laser. The increase in the laser power rendered the cutting time shorter and the kerf depth deeper for CFRP full cut. It was revealed that CFRP cut with narrow HAZ of less than 50 μm could be produced under the conditions of the laser powers of 2–5 kW, the cutting speed of 5 m/s, the time interval between repeated runs of 1 s, and the defocused distance of 0 mm. It was also confirmed that short fiber pellet CFRP was more easily cut and suffered less thermal damage in comparison with long fiber one. Furthermore, it was demonstrated that the tensile strength of fully laser-cut CFRP was almost equal to that of the base CFRP specimen. This means the laser-cut surfaces of the CFRP sheet were not degraded in mechanical properties.