Numerical And Experimental Research On Precision Molding Of Small Diameter Dual Aspherical Chalcogenide Glass Lens

With the wide application of small diameter dual aspherical chalcogenide glass lenses in the fields of military,civil and medical applications,mass production of small diameter dual aspherical chalcogenide glass lenses has become imminent.The conventional grinding and polishing methods can only process the lenses individually,which have high cost and low production efficiency.The precision molding technology can be used to press glass preform into a final lens at one shot under molding temperature conditions,so this technology has gradually become the best method for mass production of small diameter dual aspherical chalcogenide glass lenses.However,there are some problems that need to be solved in the precision molding technology:Firstly,determination and optimization of process parameters'ranges;Secondly,design and manufacture of precision molds for molding;Third,the impact of cooling gap on the quality of molded lenses.In this paper,in order to solve the above problems,the method of simulation analysis and experiment was used to study the precision molding of chalcogenide glass IRG205.The main research works and corresponding conclusions of this paper are as follows:1.In the simulation analysis of chalcogenide glass precision molding,the thermal expansion coefficient and specific heat capacity of the glass required for the simulation analysis were measured.The stress relaxation and structural relaxation parameters of the chalcogenide glass were calculated by sample test datum and related formulae.2.Through the simulation,the molding process of the chalcogenide glass IRG205 was analyzed,and the three parameters range of the molding temperature,pressure load and maintenance force were determined.Then,through orthogonal molding experiments,the influence of process parameters on the quality of molded lenses was studied.The optimized molding process parameters were:molding temperature is 345?,pressure load is 0.05Mpa,and maintenance force is 0.02Mpa.3.Based on the optimized process parameters,simulation analysis was used to perform profile deviation compensation analysis of the molds.After the upper and lower molds were compensated twice and three times respectively,the maximum profile deviation of the molded lens obtained from the simulation analysis were all less than 0.25?m.The mold was fabricated using the fitted aspheric curve parameters,then the molding experiment was carried out,and the profile deviation of the lens obtained from the simulation and the experiment was compared and analyzed.114.The cooling gap between the upper die and the molded lens during the cooling stage of small diameter dual aspherical chalcogenide glass was studied,and its influence on the molding quality was revealed.Firstly,the effects of different cooling gap conditions on the internal temperature distribution,stress distribution,and profile deviation of the molded lens were analyzed by simulation.Then,through molding experiments,the effects of different cooling gap conditions on the surface form error(PV),surface roughness(Ra),and profile deviation of the molded lens were analyzed,and the experimental results were compared with the simulation.