Functional characteristics of plastic extrusion molding

Plastic extrusion molding refers to the molding method in which the plastic is melted and plasticized by the shear force and pressure of the rotating screw in the heated barrel of the extruder, and then passed through the extrusion die to become a continuous long product with a certain cross-sectional shape. The process includes raw material mixing, extrusion, cooling and setting, pulling and cutting, etc. Let's take a look at the functional characteristics of plastic extrusion molding.

Functional characteristics of plastic extrusion molding:

1. It can realize stable extrusion, improve the dimensional accuracy of extruded products, and reduce the scrap rate. During the extrusion process, it is unavoidable to avoid the phenomenon of uneven feeding amount, fluctuation of barrel and head temperature, and pulsation of screw speed. The use of the melt gear pump can eliminate the feeding error of the feeding system, greatly reduce the fluctuation of the upstream process transmission, quickly enter a stable working state, improve the dimensional accuracy of the extruded product, and reduce the scrap rate.

2. Increase output, reduce energy consumption, realize low-temperature extrusion, and prolong the life of the machine. Since the extruder is equipped with a polymer melt pump, the decompression function of the extruder is transferred to the gear pump to complete, the extruder can work at low pressure and low temperature, the leakage flow is greatly reduced, and the output is increased. Compared with the extruder, the gear pump can effectively build the head pressure, and can reduce the back pressure of the extruder, reduce the axial force on the screw and prolong the service life.

3. With linear extrusion characteristics, it is convenient for upstream and downstream equipment to coordinate work. Since the leakage flow of the gear pump is less, the delivery capacity of the pump is basically in a linear relationship with the rotation speed. After the rotation speed of the gear pump is changed, the flow rate can be known exactly. The pressure, temperature and other information collected at the entrance and exit can realize the online monitoring and feedback control of the entire extrusion process.

The above content is the functional characteristics of plastic extrusion molding introduced by Xiaobian. Its main process parameters include extrusion temperature, extruder screw speed, traction speed and so on. Mainly used to produce tubes, rods and profiles. With the necessary auxiliary machinery, it can produce thicker plates, especially special-shaped plates such as corrugated plates, and products compounded with other materials, such as wires, composite films, etc. Products such as nets, bamboo tubes, and corrugated tubes can also be produced with special machine heads and shaping equipment.