Molding Analysis of Multi-Cavity Aspheric Lens and Mold Designing

The key of qualities of optical lens created by injection molding are geometric errors and distribution of residual stress. This study analyses a mobile phone camera lens with aspheric optical lens created by one mold and 16 cavities. Mold flow analysis was used to simulate geometric shapes of different gates and design cooling systems to control mold temperatures. Mold temperature was controlled during the actual injection process and simulation results were used as the basis for mold design. The effects of cold-wall-mold on lens residual stress are discussed. The experiment result showed that higher mold temperatures are helpful to reduce residual stress. An aspheric mould measurement system was used to measure both the mold and the product. The results showed that the replicating capacity is satisfactory with a molding error of 3.604μm.