Thermal Field Modeling and Experimental Analysis in Laser-Assisted Machining of Fused Silica

Fused silica, a high-strength brittle material, is widely used in optical, aerospace, and laser industries. However, a high-efficiency and high-quality machining method for fused silica is widespread demand in the industry. In this paper, based on the three-dimensional cylindrical transient heat transfer model and cutting experiments, the cutting performance of fused silica in laser-assisted machining (LAM) is studied. The finite element method is adopted to simulate the temperature field in the LAM of fused silica, and the temperature distribution of the workpiece surface is obtained. The results show that the material softens sufficiently under high laser power, low feed rate, low rotational speed, and preheating process. The verification experiments were then performed based on the range of parameters selected from the thermal model analysis. The cutting performance with different parameter combinations was compared, such as cutting force, surface roughness, machined surface integrity, and chip morphology. The results show that the smaller surface roughness, the lower cutting force, the smoother surface topography, and the large-size semi-continuous chips are obtained under the optimal combination of parameters, further demonstrating that the thermal model can provide a practical guide to improve the machinability of fused silica.