The screw head group of injection molding machine is composed of three parts: 1. Rubber head; 2. Rubber ring; 3. Meson. They play an important role in the whole screw group, such as rubber sealing, mixing and plasticizing. Many quality problems of plastic products are closely related to the three parts of screw head. Often due to many of the three components of the details of the problem did not dispose of plastic products so that the waste rate increased significantly, and even forced to stop maintenance.

The function of the rubber ring is to check. It is a part to prevent the plastic melt from leaking after injection. In operation, the contact between the rubber passing ring and the glued meson forms a blocking structure to prevent the leakage of the plastic melt. The precision level of the weight of an injection molding machine has a lot to do with the speed of the check action of the over rubber ring and over rubber meson. The speed of the reaction of a rubber passing ring is determined by its check action stroke, sealing and pressing time, separating the rubber passing head time and other factors. Good separation of the tip, ring and meson can achieve high precision injection control. Especially in the forming of transparent products and fine products, the three functions are shown.