We have demonstrated high-precision cutting and drilling of CFRP using a 3-kW CW single-mode fiber laser and a galvanometer scanner. A 3-mm-thick thermoset CFRP was successfully cut with 100 scans at the scanning speed of 13 m/s, which corresponds to effective cutting speed of 7.8 m/min. We employed the multi-pass method, in which a laser is scanned on the same position at high speed, and the optimized scanning position shift to realize short-time cutting. The time interval between scans was less than 20 ms, which was much shorter than general time interval in multi-pass method. Even with such short interval, the width of heat-affected zone (HAZ) was controlled to 97 μm on average. Drilling demonstration was carried out by using the same setup as the cutting experiment. Holes with a diameter of 6.4 mm have been successfully drilled on a 2-mm-thick thermoset CFRP. The processing time was 2.7 seconds, which was equivalent to that in mechanical processing. Since a HAZ tends to expand in the direction of the carbon fibers due to their high heat conductivity, it is difficult to reduce the width of HAZ in all directions around the processed area. To overcome this challenge, we optimized the gas injection condition as well as the scanning condition. As a result, the widths of HAZs were successfully controlled to about 100 μm in all directions.
|