Injection molding processing speed and quality of products

The most important process conditions in the process of injection molding are the temperature, pressure, speed and the corresponding action time that affect the plasticizing flow and cooling. These factors influence each other and restrict each other. For example, increasing the temperature of melt and mold can reduce the injection pressure and speed, etc.; otherwise, it is necessary to increase the injection pressure and speed. The core of the influence of various process conditions is the change of plastic viscosity, which is very important for the reasonable selection of parameters during the injection process and the influence of each other.

The characteristics of high and low injection speed

Adopting high-speed injection in the injection process has the following advantages:

(1) Reduce the injection time, shorten the molding cycle; (2) improve the process of plastic, is conducive to the formation of thin-wall parts; ⑶ improve the surface gloss of products; (4) can improve the strength of the welding wiring, so that the welding lines are not obvious to prevent cooling deformation, etc.

The low-speed injection has the following advantages in the injection process:

(1) to prevent forming products from producing flaps; (2) prevent the generation of jet lines and flow lines; (3) to prevent the production of burning marks; (4) To prevent the phenomenon of air entrapment in plastic melt; Prevent the formation of molecular orientation deformation and so on.

Injection processing speed and product quality is closely related to high speed, the advantage of injection is also the disadvantage of low speed injection, and vice versa.

Therefore, the combination of high speed and low speed in the injection process can make full use of their advantages and avoid their disadvantages, so as to ensure the quality of the product and the economy of the process. This is what we usually refer to as the multistage injection technology, which is commonly used in modern injection molding machines.

At present, most of the medium and above injection molding machines have five to six levels of injection pressure and speed changes as well as three to four levels of pressure holding pressure changes (because of the pressure holding stage, the melt has filled the cavity, at this time the melt through the pressure holding pressure into the cavity feeding material has been limited, so the pressure holding speed has little influence).