There are three ways of heat transfer: radiation, convection and conduction. In the mold, the heat generated by the plastic brought into the mold accounts for 95% of the heat absorbed by the mold, and about 5% is emitted into the air by radiation and convection. In the process of processing, the change of temperature is the most important influencing factor, and it has a great influence on the quality of the finished product and indirectly affects the production efficiency.
The mold temperature control method is to cool the mold with liquid flowing in the cooling pipe. Since water is quite cheap, water is used as a primary coolant to cool the mold. Water can shorten the rapid cooling time by guiding the mold. Often more efficient than cold molds, as this allows for faster cycle times. However, this is not necessarily true, as some materials are too cold to have the opposite effect.
Beryllium copper inserts are often used in molds to improve mold cooling
The mold can also quickly transfer the heat to the cooling water flowing through it through the beryllium copper material with good thermal conductivity in the parts where the heat dissipation is not good (such as the part wrapped around the plastic parts), so as to achieve the cooling effect.
There are also plastics with high melting temperature that need to be heated and injected into the mold, such as using a resistance wire heating rod embedded in the mold plate to heat the mold.
The liquids used for mold cooling are water and oil; the common ones are water, ice water, and water plus antifreeze.
Conversely, when the mold temperature needs to be increased, hot water is used to heat the mold.