What are the characteristics of PP
1. Crystallized material, small hygroscopic, easy to melt rupture, long-term contact with hot metal easy to decompose.
2. Good liquidity, but the shrinkage range and shrinkage value is large, easy to occur shrinkage hole. Dents, deformations.
3. The cooling speed is fast, the pouring system and cooling system should dissipate heat slowly, and pay attention to control the molding temperature. When the material temperature is low temperature and high pressure, it is easy to Orient. When the mold temperature is below 50 degrees, the plastic parts are not smooth, easy to produce poor fusion, flow marks, and easy to warp and deformation above 90 degrees
4. Plastic wall thickness must be uniform, avoid lack of glue, sharp corners, to prevent stress concentration.