Numerical Simulation Of Molding Stage Of 3D Glass Hot Bending Machine And Experimental Analysis

With the development of information and electronic technology,the demand for mobile phone and electronic accessories is increasing.3D curved glass screen has become the favorite of the mobile phone market because of its many advantages.The3 D optical glass screen needs to be formed by heating,molding,annealing and cooling,but the molding quality and contour deviation are affected by the molding stage.In this paper,finite element analysis software is used to simulate the molding process of glass screen.Through the simulation results,the distribution of residual stress and the reasons of contour deviation after glass forming are analyzed and the optimum process parameters are selected.Firstly,by introducing the microstructure of glass material and the variation of thermodynamics with temperature,the optimum temperature range of molding is given and the viscoelastic constitutive equation suitable for describing glass at high temperature is studied.Then the constitutive equation parameters are obtained by normalized processing according to the experimental data provided by the supplier,and then input into the analysis software to complete the definition of glass material at high temperature,which is the mathematical basis for simulation and simulation.Secondly,According to the size of 3D curved glass produced,the corresponding molding die is designed and the temperature rise process of graphite mould containing flat glass is simulated and analyzed.Based on the simulation results,the distribution of the temperature field of the mould and the glass preform is analyzed,and the process of thermal stress generated by the thermal distribution of the glass preform is given and the reasons are explained.Then,based on the viscoelastic constitutive equation of high temperature glass and the simulation results of heating stage,the molding stage of 3D optical glass screen is numerically simulated.By setting different molding temperature and different molding rate,the flow characteristics of glass,the stress distribution of glass screen and the profile deviation of molding size were obtained.In view of theuneven distribution of stress and the size of contour deviation,a method of sectional control of moulding rate and the optimal temperature range of moulding are proposed.Finally,according to the simulation boundary conditions,the 3D glass screen thermal bending experiment is designed.By measuring the size data,it is determined that the third generation of Kangning glass is suitable for the temperature range of thermal bending molding.The experimental results show the correctness of theoretical analysis and the feasibility of the piecewise control method of moulding rate.In this paper,the method of combining analysis and experiment is used to obtain the optimal process parameter scheme,which not only provides guidance for 3D optical glass production and processing,but also provides certain theoretical and data support for the subsequent improvement of 3D thermal bending machine tool.