塑料特性成型工艺等（The characteristics of plastic molding technology）.docVIP

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塑料特性成型工艺等（The characteristics of plastic molding technology）.doc

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塑料特性成型工艺等（The characteristics of plastic molding technology）

塑料特性成型工艺等（The characteristics of plastic molding technology） The characteristics and forming process, use two PMMA PMMA The chemical and physical properties PMMA, commonly known as organic glass, with optical properties and weatherability good. The white light transmittance is as high as 92%. PMMA products with very low birefringence, especially suitable for making DVD etc.. PMMA exhibits room temperature creep. With the increasing load, time grows, can cause stress cracking phenomenon. PMMA has good impact properties. Injection molding processing conditions Drying PMMA is hygroscopic and dried before processing is a must. Suggested drying conditions for 90C, 2~4 hours. Melting temperature: 240~270C. Mold temperature: 35~70C. Injection speedmoderate Typical use The automobile industry (signal equipment, instrument panel, etc.) the pharmaceutical industry (blood storage containers), industrial applications (DVD, light scattering device), consumer goods (drink cup, stationery, etc.). PE-LD low density polyethylene The chemical and physical properties Commercial use of PE-LD material density is 0.91~0.94 g/cm3. PE-LD is permeable to gases and water vapor. The thermal expansion coefficient of PE-LD is high in processing products is not suitable for long-term use. If the density of PE-LD in the 0.91~0.925 g/cm3, then the shrinkage rate between 2%~5%; if the density in 0.926~0.94 g/cm3, then the contraction rate was 1.5%~4%. The actual shrinkage depends on the injection molding process parameters. PE-LD can resist a variety of solvent at room temperature, but aromatic hydrocarbons and chlorinated hydrocarbon solvents can make its expansion. Similar to PE-HD, PE-LD is prone to environmental stress cracking phenomenon. Injection molding processing conditions Drying: generally do not need to Melting temperature: 180~280C Mold temperature: 20~40C In order to achieve uniform cooling and more economical to heat, cooling channels suggest a diameter of at least 8mm, and from the