About the definition of the barrel and its structure?

The barrel is the same as in the extrusion compression molding system and is an important part of the extruder. The barrel and the screw work together, the barrel contains the screw, and the screw rotates in the barrel. When the screw rotates and pushes the plastic to move forward in the barrel, the outside of the barrel heats and transfers heat to the plastic in the barrel. In addition, the volume of the screw on the screw is gradually reduced, so that the plastic in the screw groove is squeezed, turned and cut. After the action of various forces such as cutting, it is uniformly mixed and plasticized. As it moves to the front of the granulation screw barrel, it gradually melts into a viscous fluid state, completing the plasticization of the plastic. The normal cooperation of the barrel and screw ensures the continuous extrusion of raw materials for the extruder.
structure
The structure of the barrel is relatively simple. In a large extruder, the structure of the barrel can be composed of several sections. Since the barrel is divided into several sections, the length of each section of the barrel is reduced, which brings convenience to the machining barrel. However, for such a barrel composed of several sections, the inner diameter size after machining and the concentricity accuracy of the inner holes of the barrels of several sections are difficult to achieve the same; in addition, the section barrels are connected by flanges to provide heating and The layout of the cooling equipment will also bring some difficulties, and the temperature control will not be too uniform. In order to save more expensive alloy steel, the barrel of some large extruders adopts the method of inner hole lining or casting wear-resistant alloy layer. The outer casing of such a barrel can be cast from ordinary steel to achieve the purpose of reducing the manufacturing cost of the barrel.