In plastic processing, mold temperature is an important variable that needs to be controlled. Perfect temperature control can reduce unit cost of injection molding. Improve the quality of products and ensure the correct reproduction of plastic parts. Ensure uniformity of shrinkage. Therefore, mold temperature control must be optimized. A hot mold surface keeps the plastic surface liquid for a long time to form pressure in the cavity. If the cavity is filled and before the frozen skin hardens, the cavity pressure can press the soft plastic onto the metal, then the cavity surface duplication is high. On the other hand, if the plastic that enters the mold cavity at low pressure is suspended, no matter how short the time is, slight contact with the metal can cause stains, sometimes referred to as gate stains.

For each plastic and plastic part, there is a limit to the surface temperature of the die, beyond which one or more undesirable effects may occur (e.g. components may overflow the brim). Higher mold temperature means less flow resistance. In many injection molding machines, this naturally means faster flow through the gate, gate and cavity, because the injection flow control valve used does not correct this change, faster filling will cause higher effective pressure in the runner and cavity. May cause spillage. Since the hotter model does not freeze the plastic that enters the spill area before high pressure is formed, the melt can spill the brim around the ejector rod and spill into the splitter gap. This indicates the need for good injection rate control, and some modern flow control programmers can do this. ​

Usually, the increase in mold temperature will reduce the amount of plastic in the cavity with a condensation layer in the morning, making the molten material flow more easily in the cavity, resulting in greater part weight and better surface quality. At the same time, the increase of mold temperature will increase the tensile strength of parts. Many molds, especially engineering thermoplastic, operate at relatively high temperatures. If the mold is not kept warm, the heat lost to the air and the injection molding machine can easily be as much as the heat lost from the injection cylinder. Therefore, mold and machine plate insulation, if possible, the mold surface insulation. If a hot runner mold is considered, try to reduce the heat transfer between the hot runner part and the cooled injection molded part. This method can reduce energy loss and warm-up time. Necessity of temperature control

1. The purpose and action of temperature control for formability.

The appearance, physical and physical properties, forming cycle of molded products are significantly affected by the temperature of die. Generally speaking, the mold core temperature is kept at a low level, which can improve the injection times. However, the forming cycle related to the shape of the mold core and the type of the finished product depends on the need to increase the mold core filling temperature. ​

2, in order to prevent stress, temperature control.

This is the material problem of forming materials, which requires only cooling rate. The cooling time is short, and even if part of the hardening part is still soft, the stress caused by inhomogeneous shrinkage can be avoided. That is, proper temperature control can improve the properties of cooling stress. ​

3. Temperature control for the adjustment of the crystallization degree of the forming materials.

Crystalline materials such as polythiamine (nylon), polyacetic acid ester, polypropylene etc. generally require higher mold kernel temperature to adjust the degree of crystallization and improve mechanical properties. ​