Study On The Heat Transfer Process In Preheating Stage Of 3D Curved Glass Hot Bending Process

With the advent of the intelligent era,the consumer electronics industry has developed rapidly.3D curved glass which is conducive to 5G communication and fits AMOLED display technology can greatly improve the performance of mobile phones.Now it has gradually begun to be applied on a large scale.However,the production process of 3D curved glass is complicated,and the hot bending process is one of the most core and difficult processes.The unreasonable temperature strategy in the preheating stage of the hot bending process is likely to cause uneven heating of the glass,and excessive thermal stress,which will affect the accuracy of the product.This article establishes a finite element analysis model based on the heating conditions and process in the preheating stage of the hot bending,analyzes the heat transfer process and thermal stress distribution of the mold and glass,and explores the influences of temperature process parameters on the glass temperature and thermal stress after preheating.The main contents are as follows:First,according to the actual working conditions of the hot bending process,a theoretical analysis of the heat transfer process between the heating plate,mold,and glass in actual production is carried out.According to the theoretical analysis,based on ABAQUS,a finite element analysis model of the temperature field of the glass and the mold during the preheating process was established,and the history of the temperature field of the glass and the mold was calculated and predicted.It was found that: there is a difference of about 35 °C between the glass temperature and the preset temperature after the preheating,and the temperature at different locations of the glass is extremely different by about 15 ° C.According to the temperature field data,the thermal stress changes of the glass during the preheating process are analyzed.The results show that the maximum thermal stress is mainly concentrated in the part that is not in direct contact with the mold,and the maximum thermal stress value mainly appears in the preheating station one heating stage.Then,according to the conditions of the hot bending machine to perform the hot bending process,a custom thermocouple and a self-designed experimental mold were used to carry out the hot bending process mold temperature test experiment,and the simulated temperature data and the experimental test data were compared,and the error was found to be within 10%.The effectiveness of the simulation model was confirmed.Finally,based on the finite element analysis model,the influence of the single-factor change of the hot bending temperature process parameters on the glass temperature and thermal stress was first analyzed,and then the orthogonal test method was used to explore the effect of the cross change of the temperature process parameters on the glass temperature and thermal stress.The research shows that the temperature of the glass is mainly affected by the preheating temperature;the difference between the preset temperature and the glass temperature is mainly affected by the heating time;the maximum thermal stress of the glass during the preheating is mainly affected by the preheating temperature;the residual thermal stress of the glass after preheating mainly affected by the temperature difference between the upper and lower molds.