HDPE injection processing performance parameters

2020-12-07 21:31:11

1) HDPE is a crystalline material with low moisture absorption and excellent fluidity. Fluidity is sensitive to pressure, so high pressure injection should be used in injection molding. The material temperature should be uniform, the filling speed should be fast, and the pressure should be fully maintained. However, direct gates are not suitable to prevent uneven shrinkage, obvious directionality and increased internal stress. In general, care should be taken when selecting the gate location to prevent shrinkage and deformation of plastic products.

2) The cooling rate of HDPE injection molding is slow, and the injection mold should be equipped with cold material cavity and cooling system.

3) The shrinkage range and shrinkage value are large during HDPE injection molding, and the directionality is obvious. Easy to deform and warp. The degree of crystallinity and the cooling conditions of the injection mold have a greater impact on the shrinkage, so the mold temperature should be controlled during the injection molding process to keep the cooling uniform and stable.

4) The heating time should not be too long during HDPE injection molding, otherwise decomposition and burns will occur.

5) When HDPE is a soft plastic part with shallow side grooves, it can be demolded forcibly.

6) Melt fracture may occur during HDPE injection molding, so it should not be in contact with organic solvents to prevent cracking.