a, consider the compression of material, filling level, back and other affected products to be dense, heat and exhaust;
b, the appropriate compression ratio can increase the density of plastic, so that the molecules and between molecules more closely to help reduce the air absorb and reduce the stress generated due to temperature rise and affect the output of the difference, inappropriate compression than would destroy the physical properties of plastics;
c, the higher the compression ratio, the plastic tube in the plastics material produced during the higher temperature, the plastic in the plastics results in better mixing uniformity, greatly reduced relative to the fluxes.
d, high compression ratio for easy melting plastic, especially a low melt viscosity, thermal stability of plastics; low compression ratio suitable for fusible plastic, especially with high melt viscosity, heat-sensitive plastic.