The screw is a key component in the plasticizing part. It is in direct contact with the plastic. The plastic passes the effective length of the screw groove. After a long thermal history, the three-state (glassy, viscoelastic, viscous flow) transition is required. The length, geometry, and geometric parameters of each functional segment will directly affect the plastics delivery efficiency and plasticization quality, which will ultimately affect the injection molding cycle and product quality.
Injection screw can be divided into general-purpose screw and special screw according to its adaptability to plastic. General purpose screw, also known as conventional screw, can process most thermoplastic plastics with low and medium viscosity, crystalline and non-crystalline civilian plastics and engineering plastics. It is the most basic form of screw.
Corresponding to this, there is a special screw, which is used to process plastics that are difficult to process with ordinary screws, such as thermosetting plastics, polyvinyl chloride, and high-viscosity PMMA screws, which can be divided into routines according to the characteristics of the screw structure and its geometry. Screw and new screw.
Conventional screw, also known as three-stage screw, is the basic form of the screw. There are many types of new types of screw, including separate screw, split screw, corrugated screw, horizontal screw, non-metering screw, two-stage screw, strong mixing screw and so on.