Reducing the taper and heat-affected zone in nanosecond laser drilling of CFRP plate using backside sacrificial layer

Owing to the anisotropic and heterogeneous properties of carbon fiber reinforced plastics (CFRP), laser drilling processes often lead to substantial heat-affected zone (HAZ) and taper formation. The introduction of a medium to facilitate heat conduction during laser processing has emerged as an efficacious strategy to mitigate these challenges. In this study, a sacrificial layer was added to the back of the CFRP plate to reduce the taper and HAZ produced by laser drilling. The effects of laser power, scanning speed, and pulse frequency on hole surface morphology and HAZ evolution were investigated. By adding a sacrificial layer, the taper was reduced by 4.6 % to 31.4 %, the exit roundness im-proved by 1.11 % to 2.56 %, and the HAZ on the exit surface decreased by 47.6 % to 61.9 %. The sacrificial layer had minimal impact on the entrance diameter and HAZ. This study provides a reference for improving the quality of laser drilling in CFRP plates.