Flow speed of the ablation vapors generated during laser drilling of CFRP with a continuous-wave laser beam

摘要

The hot plume of ablation products generated during the laser drilling process of carbon fiber reinforced plastics (CFRP) with a continuous-wave laser beam was analyzed by means of high-speed imaging.The formation of compression shocks was observed within the flow of the evaporated material,which is an indication of flow speeds well above the local speed of sound.The flow speed of the hot ablation products can be estimated by analyzing the position of these compression shocks.We investigated the temporal evolution of the flow speed during the drilling process and the influence of the average laser power on the flow speed.The flow speed increases with increasing average laser powers.The moment of drilling through the material changes the conditions for the drilling process and was confirmed to influence the flow speed of the ablated material.Compression shocks can also be observed during laser cutting of CFRP with a moving laser beam.