The effect of power density, scanning velocity, and pulse frequency on residual stress in laser grooving process

Abstract

The purpose of this study is to present three-dimensional (3D) simulations using the finite-element (FE) method of thermo-mechanical stresses developed in the laser cutting process. The CO2 laser beam is assumed to be in Gaussian mode and the calculation for prediction of material removal rate and stress values in the target was done on St.37 steel. The analysis allows the investigation of groove depth and stress field for a variety of laser power, cutting speed, and pulse frequency. The laser that is used for this study is 0.15 mm in beam radius with a 10.6 µm wavelength at an intensity range of 200–1000 W and repetition rate of 5000–10 000 Hz. The pulse duration is 10 μs and cutting speed varies from 1 to 2 m/min. Thermal properties of the material are assumed to be temperature dependent and the birth and death technique of elements was employed for simulation of material removal. Therefore, during the cutting process, if the temperature of any element is greater than the melting point, then the element is deactivated and does not participate in the calculation. Applicability of the thermal model under consideration was verified by comparing the result of simulation with experimental data in the relevant literature. The results show the validity of the simulation and applicability of the developed FE model for modelling of the laser cutting process.