Optimization Research On The Wall Thickness Distribution Of Extrusion Blow Molding Products

Extrusion blow molding are widely used in the molding of various hollow containers and many complex parts, because of its characteristics such as lower production cost, more superior in forming performance and stronger in adaptability. However, the problem of wall thickness nonuniformity, which is common in the extrusion blow molding products and affected the quality of products and the service performance seriously, has become the biggest bottleneck that restrict the development of extrusion blow molding.The thesis by taking an extrusion blow molding product, an 1p65 oil tank which made in Zong Shen company, as the main research object, analyzed the main factors that affecting its wall thickness distribution and offered an optimization scheme about the design of allotype die. At the first, studied the flow behavior of the polymer, which provided theoretical foundation for the design of the die. Secondly, based on the basic parameters of the groove such as the shape, size, position and amount, we made some different experimental dies and did a lot of contrast experiment, to compare the condition of the extruded parison and forming parts that formed by different dies. By analyzing the effects of different design parameters on the forming,we had gotten the feasibility of the design scheme, as well as provided guidance for the design of allotype die for the 1p65 oil tank. Thirdly, we obtained the relative relation between blow-up ratio of products and the wall thickness distribution of the products, as well as the corresponding relation between corner of the products and the position of the groove by measured the wall thickness of the parts and simulated its process of the forming. Through mathematical analysis, we completed the key position design of the allotype die such as the depth, the width and the relative position of the groove, designed and made the allotype die. Then, we determined the best optimization scheme through test mould and optimization. At last, we analyzed and compared the condition of the products which made by the old die and the innovated allotype die, studied the effect and enormous functions of the innovated allotype die in the optimization of the wall thickness distribution. According to the research mentioned above, we offered effective measures to optimize the wall thickness distribution of the extrusion blow molding products.