Experimental Study During Injection Molding Process Of Optical Elements With Microstructures

The surface with microstructures which is more and more widely used has become a new hotspot in processing areas because of its structural characteristics and certain functions. There are many processing methods for the surface with microstructures. In comparison to the mechanical processing technology, replication processing technology especially the injection molding technology has the higher efficiency and lower cost and it can handle the processing of some complex structures which attracts attention of most researchers. The microscale effect makes the filling and flow of the melt more complex, and seriously affects the replication of the microstructures. This thesis designs the injection mold for a V-type microstructure optical element, which is used to study the effect of processing parameters on the replication of the microstructure through simulation and molding experiments. Moreover acoustic emission technology is used to monitor the injection molding process and study the effect of processing parameters on the AE signal.Firstly, a set of injection mold for the optical component with microstructures is needed and can replace the type of microstructure. The processing and assembly of the mold, especially the microstructure core are completed.Then Moldflow is used to research the effects of process parameters on warping of microstructure optical element injected by two materials PMMA and COC. The obtained results show that the melt temperature and holding pressure are the major factors affecting the warpage of microstructure.Next the Injection Molding experiments are carried on to study the impact of injection speed, injection pressure, holding pressure, mold temperature and melt temperature on the replication of the microstructure of PMMA. The orthogonal experiments with four factors of PMMA and COC are completed to study the changes of the impact of process parameters with the reduction of the microstructure size.Finally, the injection molds of the secondary lens and microstructural elements is used to carry on acoustic emission technological experiments and study the effect of process parameters on the AE signal. And defect-line monitoring of injection molding is achieved.