Nanosecond laser for polishing of 316L stainless steel: numerical simulation and optimization

Abstract Laser polishing is increasingly recognized as an effective post-machining technique for surface quality enhancement, especially when applied to materials exhibiting good mechanical performance. However, the optimization of the laser polishing process remains a challenge because of the numerous interdependent processing parameters that require precise control. This study addressed the complexity of parameter optimization for the pulsed laser polishing of 316L stainless steel using a strategy that integrated simulation modeling and experimental optimization method. A two-dimensional simulation model was developed in COMSOL Multiphysics using the Heat Transfer in Solids interface to investigate the thermal response of the polishing surface under nanosecond pulsed laser irradiation. The model was then used to predict the effects of pulse width, laser power, repetition rate, and scanning speed on surface roughness. The simulation model demonstrated the reliability for the laser polishing of 316L stainless steel with complete parameters related to processing, laser source, material and initial surface roughness corresponding to semi-finish surface by the ISO 21920 standard. A series of experiments was conducted to validate and optimize the effects of laser parameters on surface roughness. The good agreement between simulation outcomes and experimental data verifies the accuracy and applicability of the proposed model. The validation results revealed a significant average surface roughness reduction of 81%, from 2.92 to 0.552 µ m. The integrated strategy of simulation and experiment successfully identified optimal surface finishing conditions and established a systematic methodology to improve process stability, reduce experimental costs, and achieve superior surface quality in 316L stainless steel components.