1. Oxygen-sensitive at high temperatures, it should be avoided to have the melt come into contact with air, as well as to prevent contact between the melt and copper.

2. Low mold temperature results in quick melt cooling and low crystallinity, leading to products with good toughness and transparency, but prone to internal stress. High mold temperature with slow cooling ensures stable crystallization and low internal stress, but the products have a high shrinkage rate during shaping, along with reduced transparency and toughness.

Due to the high shrinkage rate, the mold should have a certain demolding slope, typically ranging from 0.5° to 1.5°. For more complex shapes, a larger value should be chosen, and appropriate exhaust holes should be set to prevent poor exhaust.

The viscosity of PP melt is more dependent on shear rate than on temperature, so the flowability can be increased by raising the injection pressure during molding (typically 70-120 MPa).

5. Polypropylene (PP) has a low glass transition temperature, which can cause post-shrinkage after demolding (usually completed within 24 hours after molding processing), with the amount of shrinkage increasing with the thickness of the product. For products with high dimensional stability requirements, heat treatment (80-100℃/1-2 hours) should be conducted.