Injection molding process, temperature control of each process!

1. Barrel temperature.

The melt temperature is very important and the injection cylinder temperature used is only a guide. The melt temperature can be measured at the injection nozzle or by using the air injection method. The injection cylinder temperature setting depends on the melt temperature, screw speed, back pressure, injection volume, and part cycle. If you are not experienced in processing a particular grade of plastic, start with the lowest setting.

Injection cylinders are divided into zones for ease of control, but not all are set to the same temperature. If operating for long periods or at high temperatures, set the temperature in the first zone to a lower value, which will prevent premature melting and shunting of the plastic. Make sure that the hydraulic fluid, hopper closers, molds, and injection cylinders are all at the correct temperature before starting to inject parts.

2. Melt temperature.

Melt temperature plays a major role in the liquidity of the melt, as the plastic does not have a specific melting point, the so-called melting point is a temperature band in the molten state, the structure, and composition of the plastic molecular chain is different, and thus the impact on its liquidity is different, rigid molecular chain by the temperature is more obvious, such as PC, PPS, etc., and flexible molecular chain such as PA, PP, PE, and other liquidity by changing the temperature is not obvious, so the temperature of the injection molded parts should be adjusted according to the different materials to a reasonable.

3. Mold temperature.

Some plastic materials due to high crystallization temperature, slow crystallization, the need for higher mold temperature, some due to control the size and deformation, or the need for mold release, to a higher temperature or lower temperature, such as PC generally requires more than 60 degrees, and PPS to achieve a better appearance and improve fluidity, mold temperature sometimes requires more than 160 degrees, so the mold temperature to improve the appearance of the product, deformation, size, rubber mold has an inestimable role.

4. Injection pressure.

The melt to overcome the required resistance to advance, directly affect the size, weight, and deformation of the product, different plastic products require different injection pressure, for materials such as PE, PP, etc., increased pressure will make its flow significantly improved, the injection pressure size determines the density of the product, that is, the appearance of glossy. It does not have a fixed value, and the more difficult the mold is filled, the pressure of the injected part increases.