Residual heat during laser ablation of metals with bursts of ultra-short pulses

Abstract

Abstract The usage of pulse bursts allows increasing the throughput, which still represents a key factor for machining with ultra-short pulsed lasers. The influence of the number of pulses within a burst on the specific removal rate is investigated for copper and stainless steel. Furthermore, calorimetric measurements were performed to estimate the residual energy coefficient as well as the absorptance of machined surfaces for copper to explain the reduced specific removal rate for a 2-pulse burst and the similar or even higher rate for a 3-pulse burst compared to single pulse ablation. Based on the measurements, a description of the process using single pulses and pulse bursts with up to three pulses is presented.