Thermal Simulation on Carbon Dioxide Laser Cutting for Ultrathin Glass

Abstract

According to previous works of our lab team laser heat source on the ultra-thin glass will result in a high temperature that might cause the phase change on the surface The temperature distribution was simulated by using COMSOL Multiphysics In the process of heating glass the phase change was considered The temperature distribution should be closer to the real value The purpose of the thesis uses a simple physical model to explore the influence of laser heating on ultrathin glass Combining the previous research analysis the simulation of laser heating can be closer to the real behaviors Then a numerical simulation method can be applied to the analysis of laser cutting on ultra-thin glass In this study Al2O3 is chosen as the cutting material After comparing the result of experiment with simulation several variable parameters play very important roles The phase change and heat transfer coefficient are especially significant and cannot be ignored Moreover the reflectivity is important as well It will reduce the power density directly The smooth surface has a reflectivity of 0 25 Although it is difficult to accurately get the reflectivity of the rough surface an estimated value by comparing the simulation with experiment can be obtained The reflectivity is about 0 0744 on the rough plane in melting case Finally a more suitable simulation method is found to provide a precise temperature prediction of glass In the melting case the deepest rough crack produced by the influence of heat exists between the temperature of 1196 8 K and 1248 7 K Therefore the simulated temperature distribution can be used to estimate the depth of rough crack By decreasing the energy density the proper set of parameters can be found to reduce the depth of rough crack It will be helpful to assess the laser cutting quality before processing

Date of Award	2015 Aug 11
Original language	English
Supervisor	Alex Chang-Da Wen (Supervisor)