基于广义Maxwell模型的非球面光学镜片成型模拟

Simulation of Compression Molding Aspherical Glass Lenses Based on Generalized Maxwell Model

介绍了玻璃材料模压过程及其存在的问题,针对玻璃模压仿真过程中所表现粘弹性力学特性,提出了采用广义Maxwell模型来模拟,分析了模压过程中的热传递形式及其模型。采用MSC.MARC软件对玻璃L-BAL42圆柱模压实验进行仿真,结果表明,广义Maxwell模型能够较好地模拟实际模压中的粘弹性力学特性,在600℃时利用此模型得到的松弛曲线与理论上的松弛曲线十分吻合。通过对非球面光学镜片的模压成型过程进行模拟,发现玻璃的最大应力出现在与上下模接触处的侧边,随着温度的降低,最大应力变大、模压力逐渐升高,在上下模闭合时,模压力快速上升,通过分析得到了透镜边缘处最易破碎失效的结论,实际透镜模压结果证实了结论。最后对非球面的形状偏差进行了预测,表明随着中心距离的增加,偏差变大,偏差最大值超过了5μm。研究的结果对玻璃模压建模及非球面透镜的实际加工具有一定的指导意义。

A aspheric optical glass molding technology was introduced briefly and the problems of the technolo- gy of compression molding aspherical glass lens were pointed out. Combined with related theories, using MARC soft- ware, compression molding process of glass was simulated, results show that the generalized Maxwell model can well simulate the actual molding of some phenomenon, relaxation curves attained from this finite element model and theore- tical model were fit well. Based on forming process simulation of aspherical optical lens, it was found that maximum equivalent stress appeared in the side of upper and lower die contact. As the temperature decreased, the maximum resi- dual stress became larger, pressure gradually increased, when the upper and lower mold was closed, pressure increased quickly, result that lens edge most easily broken failure through the analysis, actual molding results confirm the conclu- sion. At the same time, it was found shape deviations become larger with the distance from the center increasing, maxi- mum value exceeds 5 μm. The results of the research has certain guiding significance to the actual processing.