光学玻璃精密模压成型设备模具研制

发布时间：2018-04-15 11:17

本文选题：玻璃模压机 + 模具设计与制造　；参考：《深圳大学》2017年硕士论文

【摘要】：光学玻璃精密热压成型技术是一种新兴的快速有效加工光学元器件的成型工艺。在该工艺过程中,首先将经过预成型的玻璃坯料放入下模具中,同时将模具和玻璃坯料加热到转化点温度附近合适的温度区间内,在无氧的环境下,通过闭合上下模具,将模仁上的面型形状复制到玻璃预制件上,然后通过通入氮气调整不同温度区间的冷却速率直至冷却至室温,直接得到可用的光学玻璃镜片。该技术的特点在于将传统的研磨、抛光等工艺都省略掉,直接加工出光学元器件,特别是非球面、微透镜阵列和衍射光学器件等,具有高效率、适合大批量生产和环保等优点,是现在市场上较为主流的光学玻璃镜片的生产方法。本文的目标是研制一套供光学玻璃精密热压成型设备用的光学模具,要求加工得到的模仁面形精度误差小于5μm,表面粗糙度小于10nm。研究中,首先对各种模具结构、模压工艺过程及模具材料特性进行充分调研分析,然后在此基础上,对光学模具进行了初步的设计。通过对比模具钢、碳化钨、碳化硅的材料特性,确定了使用碳化钨为模具材料。然后对比冲压模具、注塑模具和压铸模具的工作特点,确定了本文的光学模具结构采用导柱定位,模仁装配在模座中的结构。在此基础上,通过ABAQUS软件,对设计好的模具进行仿真,验证其在加热到玻璃软化点温度附近的变形情况,分析其应力应变是否满足模压要求,得出WC模具在模压温度下的应力应变情况远远优于H13模具。然后选择粘弹性模型,设立边界条件,构建有限元仿真模型。用该模型仿真玻璃在加热、模压、退火和冷却时候的温度、应力应变变化。仿真结果表明应力较大部分主要出现在玻璃预制件与模具型腔的拐点处,透镜底部中心处应力几乎为零,玻璃透镜在经过退火后,应力释放相较于未退火有所下降。随后仿真了模压参数对玻璃应力的影响,表明在模压阶段,随着温度的增加,最大等效应力减小;随着模压速率的增加,最大等效应力增加。在退火冷却阶段,残余应力随着保持压力和退火速率的增加而增加,但是退火速率对残余应力的影响更大。根据仿真结果提出了一套最合适的工艺参数方案。最后再通过加工出模具并装配到设备上后,通过实验制作出来的光学镜片对模具的设计进行改进。
[Abstract]:Optical glass precision hot pressing technology is a new technology for rapid and effective processing of optical components.In this process, the pre-formed glass billet is first put into the lower mold, and the mould and the glass blank are heated to the appropriate temperature range near the transformation point temperature. In the anaerobic environment, the upper and lower mold are closed.The surface shape of the kernels is copied to the glass prefabricated parts, and then the cooling rate of different temperature ranges is adjusted to room temperature by nitrogen transfer, and the available optical glass lenses are obtained directly.The characteristic of this technology is that the traditional grinding and polishing techniques are omitted, and optical components, especially aspherical surfaces, microlens arrays and diffractive optical devices, are directly machined. It has the advantages of high efficiency, suitable for mass production and environmental protection.Is the current market more mainstream optical glass lens production methods.The aim of this paper is to develop a set of optical mould for optical glass precision hot pressing equipment. The precision error of kernel shape is less than 5 渭 m and the surface roughness is less than 10 nm.In the research, various die structures, molding process and die material characteristics are investigated and analyzed, and then the optical mould is designed preliminarily.By comparing the characteristics of die steel, tungsten carbide and silicon carbide, the use of tungsten carbide as mould material is determined.Then comparing the working characteristics of stamping mould injection mould and die casting mould the structure of the optical mould in this paper is determined which is located by guide post and assembled by die kernel in die base.On this basis, through the ABAQUS software, the designed mold is simulated to verify its deformation near the temperature of the softening point of glass, and to analyze whether the stress and strain of the mold can meet the requirements of mold pressing.The results show that the stress and strain of WC die is much better than that of H 13 die at molding temperature.Then the viscoelastic model is selected and the boundary condition is set up to construct the finite element simulation model.The model is used to simulate the temperature, stress and strain of glass during heating, moulding, annealing and cooling.The simulation results show that the large part of the stress mainly occurs at the inflection point between the glass preform and the mold cavity, and the stress at the center of the bottom of the lens is almost zero. After annealing, the stress release of the glass lens is lower than that of the unannealed one.The results show that the maximum equivalent stress decreases with the increase of temperature and the maximum equivalent stress increases with the increase of molding rate.At the cooling stage of annealing, the residual stress increases with the increase of holding pressure and annealing rate, but the effect of annealing rate on residual stress is greater.According to the simulation results, a set of most suitable process parameters is proposed.Finally, the mold design is improved by the experimental optical lens after the mold is manufactured and assembled to the equipment.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ171.63

【参考文献】