Study On Development Of Special Injection Screw For POM And Its Properties

Recently,there is a steady increase in the demand of Polyoxymethylene(POM) injection products.While in the POM injection molding,POM products are molded by conventional injection screw,which has poor plastication and restricts the improvement of molding process in efficiency.At the same time,the poor products cannot meet the expectations of high performance.Therefore,it is significant to study on special injection screw for POM .There are two aspects in this study.On the one hand, by compounding glass bead(GB) with polyoxymethelene(POM),the influence of GB content,diameter on the mechanical properties,the rheological behavior and dispersion morphology of POM/GB composites were investigated. On the other hand,we designed 13 combination injection screws,and did experiment by the novelty injection screw with three formulas.There were three kinds of properties tested,including effect of distributive blending,effect of dispersive bending and mechanical propertied.By compounding glass bead(GB) with polyoxymethelene(POM) The results show that the major factors of effecting the properties are the GB dispersion morphology in matrix and the interfacial adhension. A better properties effect was observed when the dispersion of particles ishomogenous and the adhension between the filler and matrix is strong.When the slenderness ratio is 17,it is reasonable that the length of feed zone extraction zone and pump zone is 8D,5D and 4D respectively.lt is indicated that perfect mechanical properties and excellent microscopic morphology were gotten after POM compound materials molded by pineapple injection screw,and the clearance of Maddock injection screw played an important role in POM plasticizing efficiency.In addition, the models in homogenizing zone were established to analysis the movement of melt POM in common screw,pineapple screw and Maddock screw.Fundamental reasons that influenced the plastication were carried out.