During the die-casting process, hot molten metal is pressed into the mold cavity and cooled through heat exchange with the mold. The die-casting mold absorbs the heat from the hot molten metal and dissipates it through the die-casting machine. Generally, the amount of heat absorbed exceeds this natural heat dissipation, so the mold temperature gradually rises as the die-casting process progresses. Excessive mold temperature affects casting quality and mold life. Maintaining a relatively constant mold temperature is essential for proper die-casting production.

Common cooling methods include extending the die-casting cycle, spraying release agents or coolants, or running cooling water through cooling channels in the mold. Extending the die-casting cycle reduces production efficiency, and spraying release agents or coolants is limited in effectiveness. Therefore, water cooling has become the primary method for mold cooling.

Currently, water cooling of die-casting molds mostly involves directly connecting cooling water to the mold to exchange heat with the mold. Foreign die-casting companies often use specialized water chillers to cool large, complex die-casting molds, achieving high temperature control precision. In contrast, domestic die-casting companies typically use tap water for cooling, resulting in poor temperature control accuracy. While direct water cooling is effective, the direct heat exchange between the water and the mold creates a significant thermal shock, which can easily lead to the formation of fine microcracks within the mold. If these microcracks penetrate the mold surface, they can negatively impact casting quality and mold life. While embedded cooling pipes avoid direct contact between the water and the mold, the gap between the pipes and the mold creates an insulating layer, significantly impacting heat transfer and resulting in poor cooling. This is the primary reason why direct water cooling is currently the predominant method for die-casting molds.

Currently, cooling pipes are used in several ways: fixed-point cooling, linear cooling, and circulating cooling. Generally, fixed-point cooling is used at the casting inlet, diverter cones, core pulls, and areas with thicker walls. Linear and circulating cooling methods are often used to cool the entire mold. The ideal cooling method for the core pins on a mold is to use fixed-point cooling using high-pressure circulating water. The advantages of this fixed-point cooling process are: ① Simple structure, excellent cooling performance, low processing costs, and easy processing and maintenance. ② It is extremely effective for adjusting the temperature gradient after mold trialing, allowing for additions and position adjustments at any time. ③ It effectively controls the distance between the cooling point and the mold cavity surface, thereby effectively controlling the mold temperature.