Polycrystalline diamond has great potential for power-device heat dissipation and precision manufacturing owing to its exceptional hardness, excellent thermal conductivity, and superior wear resistance. However, the challenges of material removal and controlling thermal damage hinder high-quality machining. In this study, a three-dimensional transient temperature field model is developed for multi-pulse nanosecond laser ablation of polycrystalline diamond. The model incorporates the Gaussian spatial distribution of laser energy, Lambert–Beer depth-dependent absorption, multi-pulse energy superposition, and three-dimensional heat conduction. The heat conduction equation is numerically solved using MATLAB, and lateral and longitudinal temperature gradients are introduced to characterize thermal accumulation and material removal behavior. The model is validated by comparing the predicted ablation depths with experimental measurements, which show consistent variation trends. The results indicate that increasing the number of scans, single-pulse energy, and pulse frequency enhances thermal accumulation, expands the microgroove width, and increases the ablation depth, whereas increasing the scanning speed weakens thermal accumulation and reduces the ablation depth. In addition, a shorter pulse width increases the instantaneous power density and strengthens near-surface thermal concentration. This study provides theoretical guidance for controlling the heat-affected region and optimizing process parameters in precision laser machining of diamond.
Wang et al. (Mon,) studied this question.