Optimising process efficiency during remote laser cutting of CFRP by utilisation of a double-scan-head

Abstract

A double-scan-head was developed combining two pairs of galvo-mirrors into one device. One pair controls the laser beam's position, while the other in this setup is used for a pyrometer. Thus, a pyrometer's optical path can be controlled independently from a laser's path as well as being locked to the same geometrical path during CFRP processing. Using such a double-scan-head, a comparison between locked pyrometry and independent scanning pyrometry is performed during multi-pass laser cutting on multiple geometries. Carbon fibre reinforced epoxy and PPS are cut with pre-selected threshold surface temperatures ranging from T = 80-120°C to interrupt and optimise the process in order to reduce the material's thermal strain. Both locked and scanning pyrometry are compared based on total processing time, heat affected zone, and the influence of fibre orientation. The study shows a double-scan-head allows improved process monitoring strategies leading towards more efficient laser material processing in terms of quality and time.