A model for prediction of dimensional tolerances of laser cut holes in mild steel thin plates

Dimensional variation in laser cutting of sheet metals depends on two factors: the accuracy and repeatability of the positioning system, and the thermal effects of the laser beam on the workpiece material. In this work, a physical model was formulated to estimate the dimensional accuracy of holes produced with laser cutting. The model included the assumption that the layer adjacent to the hole is plastically deformed and contains residual stresses up to the yield strength. The model was used to calculate the size of the hole and cut-out disk of varying radii in steel plates with thicknesses of 3.2 mm and 6.4 mm. The model-predicted data were verified with the experimental data obtained using a 1 kW continuous wave CO2 laser. Results indicated that there is an excellent correlation between the model and the experimental data especially for smaller diameter holes. (C) 1997 Elsevier Science Ltd. All rights reserved.