The Basic Research On Numerical Simulation And Experiment Of Optical Glass Precision

Precision glass molding technology is a high precision,high-efficiency,low-cost and green hot forming method of glass optical element,in which a glass gob who is heated to the between transition and softening is directly pressed by high-precision mold and special molding machine to create the finished lens shape.It is a hot issues of research concern in the field of optical glass components manufacturing.During the glass molding process,the glass lens occurs the profile deviation and residual stress,which seriously effect the imaging quality and service life of the lens.In the paper,the work maily utilized numerical simulation method to investigate the process of optical glass precision molding.Firstly,the heating efficiency and temperature distribution of the glass under different boundary conditions and heating loads were studied,and the corresponding relationship between temperature and time of glass and mold was obtained.Besides,we analyzed the change law between glass internal tissue and thermal stress/residual stress at different temperature during isothermal molding process,and the suitable molding temperature was obtained.Furthermore,studies have deeply investiagted the response relationship between the stress,shear stress,residual stress and profile deviation at different molding force and molding velocity.And,it analyzed the temperature gradient of glass under different cooling rate,revealing strong relationship between residual stress and temperature gradient.The appropriate glass molding process parameters were obtained.In addition,the work investigated deformation characteristic and stress state of the glass during non-isothermal glass molding,elucidating the temperature effect-viscoelastic model,and explaining the change relationship between temperature gradient and stress/profile.Finally,we investigated the friction coefficient how to influence the deformation and stress of the glass,and revealed that the relationship between the deviation of glass lens and process parameters.In order to decrease the profile deviation of molded lens,a iterative method of mold compensation was proposed.Finally,in order to elucide the physical properties of temperature effect-viscosity-deformation characteristics during glass forming process,the glass molding experiment were carried out by using precision moulding equipment.Furthermore,the mold damage mechanism and surface defects of the lens during the forming process were investigated,and the molding quality control strategy were obtained.The interface friction coefficient between glass and mold were investigated by using the high temperature vacuum friction wear machine.Revealing friction dynamic synchronous response characteristic of high temperature.Besides,in order to analyze the wear mechanism of WC mold without Co element,the wear zones on the WC molds are scanned by the SEM for analysis.The last but no least,the study results can provide a theoretical basis for glass precision molding.