APPLYING A DOE MODEL FOR THE DETERMINATION OF APPROPRIATE PROCESS WINDOWS FOR NANOSECOND LASER PROCESSING OF CFRP

摘要

Carbon fibre reinforced plastics (CFRP) are of high interest for the lightweight construction within many industrial sectors. The implementation of CFRP is limited by the lack of automatable, reliable and costefficient processing. One main research focus within the field of laser processing of CFRP is the influence of laser and process parameters on the process quality. In terms of laser cutting, the extent of the heat affected zone (HAZ) of the CFRP at the cutting edge is one important indicator for the process quality. Pulsed laser cutting offers a wide range of parameter combinations which influence the size of the HAZ. Significant parameters are the scanning velocity, pulse duration, repetition rate and average laser power. For the purposes of this study, the authors investigated the influence of these parameters on the average width of the HAZ. 0.5 mm thick epoxy-based CFRP with 2 layers of carbon fibre fabric was used as test material. In order to optimize the experimental work, the parametric study was planned using a design-ofexperiments (DOE) model. Such a DOE model allows for investigation of the influence of chosen parameters on the HAZ size over a wide range of values with a decreased number of experiments. For the experiments, a nanosecond-pulsed disk laser emitting in the near-infrared range was used as a laser source. The laser source allowed for independent manipulation of pulse duration, repetition rate and average laser power as laser parameters. The influence of specific process parameters on the extent of the HAZ can be clearly determined by evaluating optical micrographs. Based on these results, corresponding parameter windows for further process developments can be deduced.