Common Materials and Material Requirements for Cylinder Screw of Injection Molding Machine

Injection molding machine barrel screwIs an important part of the injection molding machine. Its function is to transport, compress, melt, mix and apply pressure to the plastic. All of this is done by rotating the screw in the cylinder. WhenInjection molding machine barrel screwWhen rotating, the plastic will produce friction and mutual movement between the inner wall of the barrel, the bottom of the screw groove, the edge of the screw and the plastic.

The basic working principle of the injection molding machine can be understood as the plastic material is uniformly plasticized in the cylinder, and then the injection products are obtained by injection, filling, holding pressure, cooling and so on. InInjection molding machine barrel screwUnder the action of, the granular plastic stored in the funnel moves continuously along the screw groove. Due to external heating andInjection molding machine barrel screwThe combined effect of shearing, the plastic is continuously heated and softened to form a viscous flow state of the melt, and the melting force of the screw head pushes the screw back. By changing the screw back pressure (working oil return resistance) to adjust the screw oil return speed, changeInjection molding machine barrel screwThe plastic flow state in the groove achieves the purpose of controlling the plasticizing performance of the plastic.

Injection molding machine barrel screwCommon materials and material requirements:

Commonly used and commonInjection molding machine barrel screwMaterials are45No. steel,40Crnitrided steel and38CrMOAlWait. The following describes the performance requirements of these materials, as follows:

1,45Steel is relatively cheap, cost-effective, processing function is also good, the only deficiency is: wear resistance and corrosion resistance function is poor.

2,40CrThe function is stronger45No. steel, but we often have to plate it with a layer of chromium to improve it.Injection molding machine barrel screwCorrosion resistance and wear resistance. However, it has high requirements for chromium plating. If the coating is too thin, it is easy to be worn, and if it is too thick, it is easy to peel off. After peeling, it accelerates its corrosion, so it is currently used less.

3nitrided steel,38CrMoAlThe comprehensive functions are relatively excellent, and their application functions are also extensive. General nitride layer up0.4-0.6mm. However, the ability of this material to resist corrosion is relatively low, and the price is relatively expensive.

Injection molding machine barrel screwIt is operated under high temperature, certain corrosion, strong wear and high torque.Injection molding machine barrel screwIt is necessary to meet the following requirements:

1High temperature resistance, no deformation under high temperature;

2Wear resistance, long life;

3Corrosion resistance, the material is corrosive;

4High strength, can accept large torque, high speed;

5Good cutting function;

6After heat treatment, the residual stress is small, and the thermal deformation is small.