| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 104 === This study is to simulate the 3D transient gas-assisted laser cutting for ultrathin glass by COMSOL Multiphysics software. The research purpose is to use the simple model to understand the relation between gas-assisted cutting and the rough crack (heat affected zone depth) produced by the thermal stress. This study continues previous works of our lab team to consider the reflection and absorption coefficient of material and phase change of cutting process in order to obtain the real temperature distribution. The main jet-assisted parameters are nozzle diameter, the distance between nozzle and material, Reynolds number. In addition, the different cutting parameters, including laser spot diameter, laser energy are also investigated.
In this study, Al2O3 is chosen as the cutting material. The simulation result shows that the smaller diameter of the nozzle or the smaller distance between nozzle and material or the larger Reynolds number makes heat affected zone depth smaller, and has better cutting quality.
For the examination of jet-assisted cutting parameters, the results show that with larger spot diameter or laser power, the depth of the heat affected zone reduces more, so that the enhancement of jet-assisted becomes more obvious.
Finally, the simulation results also show that using jet-assisted cutting can increase cooling rate to improve the cutting. Besides, it also reduces the surface temperature gradient in depth and improves the cutting quality.
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