Carbon fiber reinforced thermo plastics (CFRTP), which is expected to reduce the weight of transportations and is made higher speed and lower cost than these of CFRP (thermosetting plastics), was cut by a CO_2 gas laser (10μm, 800W, 20kHz, lm/min), CW single-mode fiber laser (1.07[im, 300W or 2000W, CW, lm/min or 7m/min) and a machining with a cemented carbide end milling. Although the high-power laser cutting processes make it possible to improve cutting rate of CFRTP, the laser-cut specimens clearly showed a thermal damage with a heat-affected zone (HAZ) identified by a micro X-ray CT analysis. These specimens were lower tensile strjpnth and fatigue strjpnth than milling-cut specimens. In laser-cut specimens, specimens cut by the CO_2 gas laser exhibited the lowest strjpnth of all processes. And, the 2000W CW single-mode fiber laser (7m/min), which is the highest cutting speed and the shortest waveljpnths, was reduced the degradation of strjpnth as compared with the 300W CW single-mode fiber laser (lm/min) and the CO_2 gas laser.
