Numerical Simulation Of Ultraprecision Glass Molding For Aspherical Glass Lens

Aspheric glass lens manufacturing is a difficult problem in advanced opticalmanufacturing field, which is also an important symbol to appreciate R&D level ofscience and technology of a country. With improvement of the performance of opticalsystem, demand for high-precision aspherical glass lens of market have increasedsharply. Traditional processing methods of aspherical glass lenes have manydisadvantages, such as long processing cycle, high cost, and not suitable for massproduction.Glass molding process (GMP) is a new processing technology. It can notonly obtain higher accuracy, but also overcome shortcomings of traditional processingmethods. Currently, there are still many technical problems of GMP to be solved.These technical difficulties prevented this technology from being applied tolarge-scale manufacture of molded glass lens. Therefore, this research on thesetechnical problems has important theoretical and practical significance for promotingits engineering applications, shortening the development cycle and savingdevelopment cost.Based on the literature review, research situation of GMP have beenpreliminarily analyzed in this paper. In view of the current challenges in GMP, usingthe nonlinear finite element software MSC.Marc, Glass Molding Process of two kindsof different diameter of aspherical glass lens were simulated.The researching iscarried out as following:1. Studied suitable material constitutive model of GMP, established the relevantconstitutive equations, the constitutive relation of glass materical is added to thefinite element simulation program with FORTRAN lanuage, and the conditions ofverifying the constitutive relation are given.2. Based on the GMP numerical simulation for a glass lens with diameter Ф11mm,the minimum heating time, the thermal deformation of mold and the H-FK61glass,the change of thermal stress in the glass were obtained. The minimum heating time ofH-FK61glass heated to520℃is260s. Forming properties of lens, under differentmolding temperature, different molding rates, different friction coefficients, has beenstudied. The law of flow characteristics of glass materials, the stress and straindistribution of the lens were obtained, molding temperature, molding rate andglass-mold conditions of exposure were optimized.the optimal molding temperature of H-FK61glass is520℃, molding rate is0.1mm/sec, glass-mold conditions of exposureis0.1.3. Based on the GMP numerical simulation for a glass lens with diameterФ30mm, the large-diameter glass lens have similar processing properties as asmaller-diameter glass lens. Difference is that the friction coefficient has a greatereffect on the forming performance of lens.4. Contraction deformation of glass lenses in different diameters were studied,deformation curves of the molded lens were obtained. Through the research, it can befound that the larger diameter of the lens, the bigger shape error will be gotten.