Polyethylene (PE) and injection molding process

PE for the crystalline material, moisture absorption is extremely small, not more than 0.01%, so no need to be dried before processing. PE molecules associated chain flexibility is good, key interactions among small, low melt viscosity, excellent mobility, so no high pressure molding can be a long process of forming a thin-walled products. PE shrinkage range, shrinkage of large, clear direction, LDPE shrink rate of about 1.22%, HDPE shrinkage rate of 1.5%. So easy deformation warpage, mold cooling conditions on the shrinkage rate greatly, it should be good control mold temperature, cooling to maintain uniform and stable. Crystallinity of PE high mold temperature on the plastic parts of the crystalline state has a greater impact. High mold temperature, melt cooled slowly, plastic parts with high crystallinity, high strength also. The melting point of PE is not high, but the specific heat capacity, so the plastics still need to consume more when the heat, and called plastination to have a larger heating power plant in order to improve production efficiency.