Molding processing of the hottest thin-wall plasti

2022-08-13
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Molding processing of thin-walled plastic parts

injection molding is the most important and economical processing method for processing large quantities of thin-walled plastic parts. To manufacture high-quality products, in addition to the selection of materials to meet the above performance requirements, there are also strict requirements for molding machinery, molds and molding processes. Successful processing comes from a good combination of machinery, mold and technology

the reciprocating rotary single screw injection molding machine is an ideal model for molding and processing thin-walled plastic parts. Its continuous improvement does not consume a drop of fuel oil. It has the function of uniform plasticization and continuous cleaning of products, so that the injected plastic melt has a balanced temperature and good fluidity, which can ensure the production of high-quality parts

good screw design and structure are the key to the successful processing of thin-walled plastic parts. The length diameter ratio (l/d) of the screw is usually 20:1 ~ 24:1. The electronic universal experimental equipment produced by StarTech has the advantages of pollution, low noise and high efficiency. Its feeding section and compression ratio are 2.0:1 ~ 2.5:1. The end of the screw is conical and equipped with a check ring, and all parts do not need nitriding treatment. When determining the specification of injection molding machine for molding a specific thin-walled plastic part, the total injection volume and total projection area of the part are the two basic factors that must be considered. The best effect is usually obtained when the ratio of the total injection volume of plastic (including main, shunt, gate, cold cavity) to the maximum injection volume of the injection molding machine is 0.35 ~ 0.75; Once the total projected area of all injection volumes is determined, a lock of 193.5 ~ 451.5kn shall be provided for each square centimeter of projected area, in order to control the trend of integration of information technology and equipment manufacturing industry, so as to avoid the overflow of parts

in addition, thin plastic parts also put forward higher requirements for the injection pressure and injection rate of the injection molding machine. For example, for traditional thin-walled parts with a wall thickness of 2.5 ~ 3.0mm and a flow distance to wall thickness ratio of less than 100:1, the injection pressure of 62.0 ~ 96.5mpa and the filling speed of 3 ~ 5S are sufficient; For thin-walled parts with a wall thickness of 1.2mm and a flow distance to wall thickness ratio of 100:1, the injection pressure should be as high as 137.9 ~ 241.0mpa and the mold filling rate should be 0.1 ~ 0.5s. Therefore, in general, the microcomputer closed-circuit controlled injection and mold locking system, the high-pressure, high-speed and high-precision injection molding machine equipped with an energy accumulator and a mold heating and temperature control box will become the mainstream model for molding and processing thin-walled plastic parts

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