Research On Precision Molding Technology Of Optical Lens

As a new type of plastic lens processing technology,optical lens precision molding technology has great advantages in the production of multi-variety and small-volume products compared with traditional injection molding technology,and also has low production cost,it has greatly promoted the development of plastic lens industry.Based on the method of finite element analysis,the process parameters of PMMA lens molding are studied and analyzed.Based on the study of the optimal parameters,a design scheme of low-cost small PMMA lens molding equipment suitable for experimental research is proposed.In order to obtain the better process parameters of the molding technology quickly and at a lower cost,based on the characteristics of the lens material PMMA,establishment of Finite Element Simulation Model of PMMA Material.Then the process of lens molding is simulated under different molding temperature and speed,and the effects of different processing parameters on the stress of the molded lens are compared.The results show that,on the one hand,as the molding temperature increases,the maximum stress of the molded lens decreases,and after the temperature reaches 125?,the falling speed is gradually gentle;on the other hand,as the molding speed decreases,the maximum stress is decreasing,and when the molding speed is less than 0.05 mm/s,the speed of the drop is gradually gentle.Suitable molding temperatures and molding speeds for PMMA lens molding are 125? and 0.05 mm/s.According to the optimal parameters of research and analysis,the key technology of plastic optical lens precision molding equipment was analyzed and studied.The key system of die pressing equipment includes four parts: die structure,frame structure,transmission system and heating system.According to the technical index,the material and accuracy guarantee of die,the selection of transmission mode,the installation layout of frame and the structure of heating system are designed.Finally,according to the actual situation,the frame structure and mold structure of optical lens molding equipment are analyzed,the force analysis of the frame structure and the mold of the optical lens molding equipment under the working condition is as follows.The maximum deformation of the frame structure is 7.2229 ?m,the maximum stress is 2.7869 MPa,and the first-order vibration frequency is 84.772 Hz.The structure has good rigidity and work stability.The maximum stress of the mold structure is 2.4047 MPa during high temperature molding and the influence can be neglected.The maximum deformation is 27.877 ?m,which is mainly caused by temperature and has certain influence on the lens shape.For this reason,a method of mold surface correction compensation is studied and verified by experiments.At this time,the surface accuracy of PMMA lens is 6.1251 ?m,and the error is small.The experimental results show that the modified method can effectively improve the surface quality of PMMA lens.