Injection molding process and each process temperature control

1, mold temperature

Some plastic materials due to high crystallization temperature, slow crystallization speed, need higher mold temperature, some due to control size and deformation, or the need for demoulding, to higher temperature or lower temperature, such as PC generally requires more than 60 degrees, and PPS in order to achieve a better appearance and improve fluidity, mold temperature sometimes needs more than 160 degrees, Therefore, the mold temperature has an inestimable effect on improving the appearance, deformation, size and mold of the product.

2. Injection pressure

Melt to overcome the resistance required to advance, directly affect the size of the product, weight and deformation, different plastic products need different injection pressure, for materials such as PA, PP, increase the pressure will make its fluidity significantly improved, injection pressure size determines the density of the product, that is, the appearance of luster. It has no fixed value, and the more difficult it is to fill the mold, the pressure of the injection part increases.

3. 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 nozzle or by air injection. The temperature setting of the injection cylinder depends on the melt temperature, screw speed, back pressure, injection volume and injection part cycle. If you do not have experience working with a particular grade of plastic, start with the lowest setting.

For ease of control, the cylinders are divided into zones, but not all are set to the same temperature. If operating for a long time or at high temperatures, set the temperature in Zone 1 to a lower value, which will prevent premature melting and diverting of plastics. Ensure that the hydraulic oil, hopper sealer, mold and injection cylinder are at the correct temperature before the injection parts begin.

4. Melting temperature

Melt temperature plays a major role in the flow performance of the melt, because the plastic does not have a specific melting point, the so-called melting point is a melting state of the temperature segment, the structure and composition of the plastic molecular chain is different, so the impact on its fluidity is different, rigid molecular chains are affected by temperature more obvious, such as PC, PPS, etc., and flexible molecular chains such as: PA, PP, PE and other fluidity by changing the temperature is not obvious, so should be adjusted according to different materials to reasonable injection molding parts temperature.