1. Metering area: The screw groove has a fixed groove d […]
1. Metering area: The screw groove has a fixed groove depth, and its main function is mixing, melt transfer, and metering. It must also provide enough pressure to maintain uniform melt temperature and stabilize the flow of molten plastic.
2. Compression zone: Taper screw groove tooth depth, the function of plastic raw material melting, mixing, shear compression and pressure exhaust. The plastic will dissolve completely in this section and the volume will shrink, so the design of the degree of compression is very important.
The general length is: amorphous (AS, ABS, PS) about 25~35% L, crystallinity (PA, POM, PE, PP, CA) about 22~32% L, plus glassiness about 28~40%L , heat-sensitive (PVC) 100% L
3. Feeding area: The groove depth of the screw groove is fixed, and its function is responsible for preheating and plastic solids conveying and pushing. It must be ensured that the plastic begins to melt at the end of the feed section—that is, it is preheated to the melting point.
The general length is: amorphous (AS, ABS, ps) about 48 ~ 58% L, crystallinity (PA, POM, PE, PP, CA) about 48 ~ 58% L, plus fiberglass about 45 ~ 55% L.