What is the role of the bimetal screw barrel in the injection molding machine?

Update:30-11-2018
Summary:

When the screw rotates to push the extruded material fo […]

When the screw rotates to push the extruded material forward, the heat is transferred from the outside of the barrel to the raw material, and the volume of the screw thread groove is gradually reduced, so that the raw material is squeezed, flipped and sheared in the forward movement. After a variety of forces, it is uniformly kneaded and plasticized into a molten state to complete the plasticizing work on the plastic.
Injection molding machine screw barrel classification
The application of the structural form of the barrel is divided into: integral, segmented, bushing, casting, and bimetal layered barrels.
Integral barrel: In the case of injection molding machines and extruders, the most comprehensive ones, especially small and medium models, basically adopt this type of structure. The barrel is generally used for 38CrMoALA. Moreover, the temperature control is accurate and easy, and the machining accuracy is relatively easy to ensure.
Segmented barrel: Mainly used in larger format extruders and exhaust type extruders. Since the total length of the barrel is divided into several sections, the machining of each barrel is convenient, and the temperature control of heating and cooling is relatively large.
Rubber screw barrel classification
The barrel is generally designed as a one-piece, and the multi-section combination barrel is rarely used.
In the solid matter delivery theory, it has been discussed how to increase the solid transport capacity problem, mainly from the rational selection of the structural parameters of the screw to analyze the structural parameters, but the improvement of solid transport capacity is not significant, the efficiency is only 20% -40%.