The Study On Plastic Injection-Compression Precision Molding Technology And Molding Equipment

Since 1930's, plastic injection molding (PIM) technology has been developed, and become a kind of very important, representative plastic processing method. Plastic parts are used widely. At present, plastic injection molding is the highest efficient processing method in the plastic processing field, especially in the optics plastic field. But the surface precision and surface roughness of the produce is bad, so the employment of the plastic injection molding machine (PIMM) is limited. To improve the product quality, many countries invented plastic injection-compression molding (PICM) machines which didn't appear in China. The price to import a type of PICM machine is so high that most company couldn't afford. The author designs a kind of equipment used in common PIMM which can finish injection/compression processing and produce better plastic parts. Thus the employment of PIMM will be wider.The main contents of the paper are listed as follows:1.Formulate the development history and status quo of plastic precision injection-compression molding technologyIn exordium, the author briefly reviews development of PICM. The author believes that increasing demands for plastic parts and appearance of new material are the motive force of PICM. Although many foreign countries developed plastic injection- compression molding (PICM) machines, we couldn't find anyone in China. So if we can use the PICM technology on PIMM, we would save much money.2.Analyze PICM technologyThe author introduces the PIM technology and its problem and difficulty. Then the author analyzes PICM technology , lists its varieties and discusses its merits and demerits. The result is useful for the next investigation in studying PICM technology for PIMM.3.Design PICM equipment for PIMMDesign machine system, hydraulic pressure system and servosystem for PICM equipment. The common PIMM is widely used in China, so the author designs a kind of equipment for PIMM. Then we can finish injection-compression processing on PIMM. The servo control system can control the molding accurately, so the produce quality is improved greatly. 4. Design injection processing system and injection-compr- ession system suited for PIMM and produce plastic partsThe author designs two sets of moldings to validate PICM technology on PIMM. The method to design injection molding is common, so the author only tell us its technics and how to select the best technical parameter. The PICM molding is designed to process the produce of PIM for the second time. We validate PICM technology by comparing the produce of the two kinds of processing.5.Compare the two kinds of produceThe author compares the two kinds of produce in birefring- ence, surface roughness and surface form deviation. We measure the birefringence through polarized microscope at orthogonal polarized light condition and observe the surface roughness at parallel light condition. The surface form deviation was measured through INTERFEROMETER V-100 made in Germany. The results tell us the produce of PICM gets lower birefringence, better surface and lower surface form deviation. It is visible that the quality of PICM produce is improved greatly.Many experimental results tell us that the quality of PICM produce is improved greatly and could satisfy the customers. At the same time it will broaden the employment of PIMM because it makes full use of the resource at hand and keeps up with the development of plastic.