The structural form of the feed mouth material directly affects the feed effect and the feed capacity of plasticized parts. Most of the injection molding machines feed the material by the hopper, and the commonly used feed mouth body form is: symmetrical mouth body, as shown in FIG. 8(a), which is simple to make but unfavorable to feed; Now the use of asymmetric mouth body, this feed mouth due to the material and screw contact Angle, contact area is large, domestic brand injection molding machine is conducive to improving the feed efficiency, not easy to open in the hopper.

The thickness of the cylinder wall requires sufficient strength and heat resistance to the cylinder wall, because the cylinder is subjected to molten material and air pressure, and the long diameter of the cylinder is relatively large, requiring the cylinder to have sufficient heat capacity, so the cylinder wall must have a certain thickness, otherwise the cylinder is difficult to ensure temperature stability; However, if the cylinder is too thick, it will cause material waste, large thermal inertia, slow temperature rise, and large temperature lag.

Barrel gap refers to the single-sided gap between the inner wall of the barrel and the outer diameter of the screw at the gap of the barrel. If the gap is too large, the plasticizing capacity will be reduced, the injection displacement will be increased, and the injection time will be prolonged, resulting in partial degradation of the material in this process. If the gap is too small, the thermal expansion will aggravate the friction between the screw and the cylinder, increase the energy consumption, and even get stuck, and the gap Δ=(2~5)ds.