Study On Plunger Stamping Injection Molding Process Of Ultra High Molecular Weight Polyethylene

Pre-forming of UHMW-PE is a worldwide problem. The traditional process methods'production efficiency is low and its quality of molding products is not high. These methods only produce these materials which molecular weight is low. So these disadvantages hinder its use.Plunger stamping injection molding machine is a novel mechanical plunger injection molding machine which was developed based on hydraulic plunger pushing injection molding machine and forge principle. It pushes power into barrel by the ram of small cross-sectional area. The materials melt under a certain temperature. Then materials are poured into mould through spreader and nozzle. By the comparison with traditional methods, it has some advantages:good melting plasticization, stable material flow, excellent performance of molding products, sample equipment and process.In this paper, plunger stamping injection molding process is discussed. The process is divided into solid conveying part, melting part, split-flow part and injection molding part. Physical model of every part is built. And then temperature and pressure formula of solid conveying part and melting part is derived. Finally, with the help of fluent, temperature and pressure distribution of melting part and split-flow part is simulated. The data and graphs of temperature and pressure in different barrel diameter, material flow velocity, space and length of spreader are drawed. The paper makes conclusions by analysis of these data and graphs:(1) Viscosity of UHMW-PE is special high. Loss of the pressure is very great. When flux flow in the circular runner which its diameter less than 20mm, the loss of pressure is above at 0.7MPa with flowing though 1mm. (2) Pressure drop got larger with the increase of flow velocity. But the augmentative range is smaller. (3) By the comprehensive analysis of relationships among the pressure drop, barrel diameter and melting section length. (4) The data obtained from simulation provides important reference for structure design and practical operation. At last, simulated datas are reliable by verification of experiments.