Usually, an increase in mold temperature reduces the condensation layer of plastic in the mold cavity, making it easier for molten material to flow in the cavity, resulting in larger part weight and better surface quality. Meanwhile, the increase in mold temperature will also increase the tensile strength of the parts. Many molds, especially thermoplastic materials used in engineering, operate at relatively high temperatures during plastic mold processing. If the mold is not insulated, the heat lost to the air and injection molding machine can easily be as much as the heat lost to the injection cylinder.

So it is necessary to insulate the mold from the machine board, and if possible, insulate the surface of the mold. If considering using a hot runner mold, try to reduce the heat exchange between the hot runner section and the cooled injection molded part. This method can reduce energy loss and preheating time.

The necessity of temperature control:

(1) The purpose and function of temperature control on formability

The appearance of the formed product, physical properties of the material, and forming cycle are significantly affected by the temperature of the mold core. In general, the temperature of the mold core is kept low during molding, and plastic mold processing can increase the number of shots. However, the forming cycle related to the shape of the formed product (mold core structure) and the type of finished material also depends on the need to increase the temperature of mold core filling.

(2) To prevent stress, temperature control is applied

This is a material issue with the formed product, and the only requirement for this is ※ cooling speed. The cooling time is short, and even in situations where some parts are hardened and some parts are still soft, it can still avoid stress caused by uneven shrinkage. Proper temperature control can improve the cooling stress properties.

(3) Temperature control for adjusting the degree of crystallization of forming materials

Crystalline materials such as polysulfide (nylon), polyacetate ester, and polypropylene generally require a higher mold core temperature to regulate the degree of crystallization and improve mechanical properties.