The injection molding process of sheet forming machine

Plastic molding is developed in recent years, a more mature plastic processing technology. This technique can be heated, injection, electricity and other plastic processing and elaboration, bring plastic further change, make its forming. For this kind of technology, is currently developed various types of molding machine, sheet machine, through the molding technology of plastics are combined or decomposition, form the structure of the need to form. Here introduces a kind of injection molding process. Plastic removed from the hot mold and after cooling to room temperature, the size change of characteristics called shrinkage rate. Because the contract is not only the resin itself caused by heat bilges cold shrink, and machinery such as making a cup of machine is related to various factors forming, so called molding contraction after molding plastic parts. Due to the actual shrinkage and calculating shrinkage value difference is very small, so often to calculate shrinkage as design parameters, mold design to calculate the size of the cavity and core. In the actual molding, plastic variety, not only its shrinkage rate is different, and different batches of the same variety of plastic, or different parts of the same kind of plastic shrinkage value is often different, like a lunch box machine, take advantage of this machine can produce different specifications of the products. And the main factors affecting shrinkage include: ( 1) Plastic varieties. All kinds of plastic has its own scope of shrinkage, the same kind of plastic because of the relative molecular mass, different, such as ratio of filler and its shrinkage and anisotropy is also different. ( 2) Plastic parts structure. The shape, size and wall thickness, the number of insert, insert and layout, etc. , has a great influence on the shrinkage value, such as the plastic parts wall thickness reduction, embedded with a little shrinkage. ( 3) The mould structure. Direction of the mold parting surface, pressure, pouring system, layout and size effect on shrinkage and directivity is very big also. ( 4) Molding process. Plastic molding temperature, molding pressure and the holding time and so on have great influence on shrinkage rate and direction.