a, increase the back pressure can increase the screw on the work done by the molten resin to remove the plastic particles without melting, increasing raw material tube density and uniformity;
b, back pressure is being applied to improve the barrel temperature, the effect is most significant;
c, back pressure is too large, the higher the heat-sensitive plastic decomposition, the low viscosity of the plastic may cause salivation phenomenon, back pressure is too small, injection molding of the finished product may be air bubbles.