塑料部分答案（The plastic part of the answer）.docVIP

塑料部分答案（The plastic part of the answer） 2. injection molding, compression molding, injection molding process, and the characteristics are different from each other Injection molding process: (1) molding preparation: raw material inspection, dyeing and drying; insert preheating; barrel cleaning; cleaning mold (2): the process of injection feeding; plasticization; filling; pressure; flow; cooling; release (3) forming postprocessing: annealing; humidity Compression molding process: (1) preparation: pre press molding; preheating and drying (2) molding process: feeding; mould; exhaust; pressure and curing; release (3) postprocessing: molding mold cleaning; plastic stress; special treatment; modified polishing Injection molding process: (1) preparation: pre compression molding material or pressure plastic mold cleaning powder; (2) molding process: mold; feeding; melt; extrusion; curing; mold; mould (3) postprocessing: molded products Features: (1) injection molding has the advantages of screw injection molding machine) (1) to the complex shape and high precision and various plastic parts with embedded parts. (2) the molding cycle is short, high efficiency, can realize the automation of production process (3) heating cylinder material retention less, poor thermal stability of the materials are rarely retained decomposition. (4) by means of rotation of the screw, the material is heating, uniform plasticizing plasticizing capacity. (5) due to the pressure loss of the heating cylinder is small, with low injection pressure can be formed. 2) compression molding characteristics The plastic directly into the mold cavity feeding chamber is extended cavity The mold is in the plastic molding is completely closed end The pressure through the punch directly to plastic Is not easy to get the size precision especially plastic parts with high precision, not easily broken, pressing with fine inserts and more plastic pieces. Is conducive to forming good liquidity to fiber filler for polymer