Cut quality assessment of CO2 laser cutting of twinning-induced plasticity steel sheets

Abstract

In this study, the effects of the main process parameters involved in CO2 laser cutting of 1.5-mm twinning-induced plasticity steel sheets have been investigated by means of experimental tests. The quality of the cut edges of the sheets was evaluated by analyzing the kerf width, kerf deviation, roughness of the cut surfaces, and dross attachment. The process parameters used were the laser power, cutting speed, oxygen pressure, and pulse frequency of the CO2 laser beam. The optimal settings of the process parameters were predicted using the Taguchi parameter design approach with an L27(313) orthogonal array and calculating the average effect of both the laser parameters and the signal-to-noise ratios. Analysis of variance was performed to evaluate the statistical significance and the contribution of the laser process parameters to the examined kerf features and roughness. On the basis of the Taguchi approach, the predicted optimal settings of the process parameters were verified through confirmation tests. The results show that the selected process parameters, as well as their interactions, can have a remarkable effect on the cutting quality of twinning-induced plasticity steel sheets. The laser power is the main process parameter that affects the kerf width on both sheet sides, while the pulse frequency and its interaction with the laser power are the main factors that influence the kerf deviation, followed by the cutting speed. The roughness of the cut surfaces is mainly affected by the oxygen pressure and the interaction between laser power and cutting speed. Dross attachment was primarily observed in the specimens cut with high laser power and low cutting speed.