An Investigation of Groove Depth and Thermal Stress Developed During the Pulsed Laser Grooving Process
S. Shamsaei and M. Ghoreishi
This article outlines the details of a numerical model that is used to estimate groove depth and stress field in CO2 pulsed laser grooving by employing the finite element method (FEM) to solve the threedimensional (3-D) heat conduction equations. The laser was in Gaussian mode and the calculation for prediction of material removal rate and stress values in the target was conducted on the St37 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 used for this study was 0.15 mm in beam radius with a 10.6 mm wavelength at an intensity range of 200 to 1000 W and repetition rate of 5000 to 10000 Hz. The pulse duration was 10 ms and cutting speed varied from 1 to 2 m/min. Thermal properties of the material was assumed 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 was greater than the melting point, then the element deactivated and did not participate in the calculation. Applicability of the model under consideration was verified by comparing the result of simulation with experimental data in the relevant literature. The good agreement of results show the validity of the simulation and applicability of the developed finite element (FE) model.
Keywords: CO2 laser, pulse, laser grooving, ST 37 steel, finite element method (FEM), groove depth, thermal stress