It is obviously different between extruder screw barrel and injection screw barrel from the appearances.
The extruder is to extrude plastic through a fixed shape extruder outlet, which is under the effect of the screw. The screw is cut after water cooling and shaping under the effect of a traction machine, which is mainly used for continuous production of products with the same cross-section, such as pipe, bar, profile, etc. It can also be used for plastic modification granulation.
An injection molding machine is to inject plastic into the mold after cooling is the product. The process is known as the injection molding process.
The structure of the two types of machine screws is different. The extruder screw thread is generally bent and narrow, while an injection molding screw barrel is required for plastic materials to flow in the mold.