Research On The Dynamic Evolution Of UV Curing Injection Molding And Pricision Control

For the limiting of some factors, tradition injection molding was hard to applied in products with large aspect ratio and micro structures. UV curing injection molding was a new method of injection molding which was put forward by our team. This method applied the UV cured resin into the injection molding to make the curing process controllable. This method greatly improved the filling effect of injection molding process. Using the UV curing injection molding, micro or nano products could be well filled and copied, which was suit for producing precision products such as Micro fluidic chip, micro optical elements, micro actuator, et al.For the UV curing injection molding products’ curing process was with intense and complex shrinkage, this process would lead to various defects and greatly influence the accuracy of products. The shrinkage process in UV curing injection conditions had not been ascertained. To obtained the accuracy evolution in UV curing injection molding and to know the reasons of various defects. Some works had been done and many results were obtained:1. Based on polymer PVT testing instrument developed in our lab, a device to measuring the shrinkage evolution during UV curing molding was designed and manufactured and the measurement process could achieve real-time. Using the device, the effects of the light, temperature, pressure, material and color parameters on shrinkage rules were studied. The results showed that:light, temperature and pressure as the molding conditions affected the dynamic evolution of the accuracy of products. In the high light intensity, high temperature and high pressure conditions, products had higher final shrinkage and shrinkage rate. In the high light intensity, product had smaller late shrinkage. Type and color as the materials’properties also had impact on the dynamic evolution of UV curing injection molding products’ accuracy. Products with high transmittance and high functionality had higher final shrinkage and shrinkage rate. The study also found that non active pigment will have a negative influence on the curing process of products. Based the research the method to design the parameters was carried out.2. In order to meet the requirements of ultra precision UV curing injection molding.a set of micro UV curing injection molding machine was designed, the electrical control system and control program of micro injection molding machine was also designed. Experimental results show that the key parameters of the instrument was precision controllable, it was automation and has the advantages of simple operation, low energy consumption and other advantages. Using the injection molding machine, many researches had been done. In the light of 4 kinds of typical defects in UV curing injection molding was found--Injection bubbles, Accompanied bubbles, Incomplete curing, Shrinkage bubbles. Based on the shrinkage research in injection molding and the visualization technique, the reasons of the defects were proved, and these defects were eliminated by improving the injection molding process.This was the first study to achieve a true new method of UV curing injection molding, the key problem of shrinkage was also solved in the study. This study was important in the application and popularization of the new method of UV curing injection molding, and would play a great role in the field of micro injection molding products.