Research On The Technology Of Glass Cutting With Double-Beam CO₂ Laser

The major problem of CO₂ laser glass cutting is producing uncontrolled cracks. Thereby, it is significant and valuable in theory and engineering applications to find a new way of glass cutting. Numerical simulations have been done to explore the heat transfer and stress distribution of cutting plate glass with laser beam in this article, to analyze the mechanism how the cracks form during the glass cutting and to find the measures to avoid the forming of cracks. The main contents in this thesis are as follows:(1) A 1-D heat transfer mathematical model of glass cutting with laser beam has been developed, and then an equation for cutting-curve has been set up. The relationship between the limited velocity and the laser power has been obtained via solving the curve equation. The analytical results have been compared favorably to the presented experimental data, which shows that the theoretical analyses are correct.(2) The three-region heat and stress coupled mathematical model of glass cutting with single CO₂ laser-beam has been developed. The whole geometry model has been divided into three regions according to the heat affected zone, and the stress models caused by the temperature difference in the three regions have been obtained in addition to the heat transfer models. Later, a finite element method has been selected to solve the problem.(3) The numerical simulation has been executed to explore the process of cutting glass with single CO₂ laser-beam. At first, temperature distributions and thermal stress distributions have been analyzed in large geometry models. Later, numerical simulation has been done in the facula of the laser beam to observe the thermal stress distribution and to analyze the mechanism of crack appearing.(4) The four-region heat and stress coupled mathematical model of glass cutting with double CO₂ laser-beam has been developed, and the coupled of temperature distribution and stress distribution has been analyzed by both the effect of the cutting laser beam and the aided laser beam. Numerical simulations on the 3-D geometry model cut with double laser beams have been executed to observe the temperature distributions and stress distributions. The differences of numerical results of models between double CO₂ laser-cutting and single CO₂ laser-cutting have been compared, in which the affect on the thermal stress by the aided laser has been analyzed. Later, an optimized way has been put up to design the assignment of the power of the two lasers.(5) Based on the Non-Fourier heat conduction effect, the heat transfer and stress mathematical model of the laser glass cutting has been rebuilt. A three-region"instantaneous thin layer"model has been developed based on the presented"instantaneous thin layer"model.At the end of this thesis, a summary has been made to the whole thesis, together with the looking forward to doing the next work.