Die casting mold considers the coordination of die casting molding
The design of a die-casting mold must fully consider coordination with the die-casting process. This coordination runs through every step, including mold structure design, process parameter setting, and production flow scheduling. The goal is to ensure that the mold is compatible with the die-casting machine, molten metal properties, production rhythm, and other factors, achieving efficient and stable die-casting production. If the mold design is not coordinated with the die-casting process, problems such as poor filling, increased casting defects, and low production efficiency may result, and even affect the service life of the mold and die-casting machine. Therefore, a systematic concept should be established during the mold design stage, taking the entire die-casting process into consideration.
Coordination between mold structure and die-casting machine parameters is essential for ensuring smooth die-casting. Parameters such as the mold’s maximum dimensions, projected area of the parting surface, and mold opening stroke must match the specifications of the die-casting machine to avoid molds that are too large or too small, resulting in installation problems or inadequate utilization of the die-casting machine’s performance. For example, the mold’s projected area should be compatible with the die-casting machine’s clamping force. Generally speaking, the machine’s clamping force should be greater than the product of the projected area and the die-casting pressure ratio to prevent flashing during the die-casting process. Furthermore, the mold’s ejection mechanism must coordinate with the die-casting machine’s ejection device to ensure synchronization and reliability, avoiding damage to the casting or difficulty in demolding due to uncoordinated ejection.
The coordination of the mold runner system and the characteristics of the molten metal has a direct impact on the filling and molding results. Different metal materials have different fluidity, solidification temperatures, and shrinkage rates, and the mold runner design needs to be adjusted according to the characteristics of the molten metal. For example, for zinc alloys with poor fluidity, coarser runners and larger gates should be used to reduce the flow resistance of the molten metal and ensure that it can smoothly fill the mold cavity. For aluminum alloys with better fluidity, the runner size can be appropriately reduced to avoid defects such as flow marks and insufficient pouring. At the same time, the runner length and turning angles must also be coordinated with the solidification rate of the molten metal. For molten metal with a faster solidification rate, the runner length should be shortened and the number of turns should be reduced to prevent the molten metal from solidifying prematurely within the runner.
Coordinating the mold’s temperature control system with the die-casting process parameters is key to ensuring stable casting quality. The mold temperature affects the fluidity, cooling rate, and shrinkage of the molten metal, and must be precisely controlled according to the die-casting process parameters. For example, when die-casting thin-walled parts, the mold temperature must be kept at a higher level (e.g., 180°C – 220°C) to improve the fluidity of the molten metal. When die-casting thick-walled parts, the mold temperature must be appropriately lowered (e.g., 120°C – 160°C) to accelerate cooling and reduce defects such as shrinkage cavities and porosity. The mold’s cooling channel layout should be coordinated with the die-casting process’s holding and cooling times to ensure that the temperature of each part of the mold can be quickly adjusted according to process requirements, achieving a uniform temperature distribution.
The coordination of the mold’s exhaust system and the gas exhaust during the die-casting process can effectively reduce porosity defects in castings. During the die-casting process, the gas in the cavity mainly includes air, gas generated by the volatilization of the coating, and gas contained in the molten metal itself. These gases need to be discharged in a timely manner through the exhaust system. The position and size of the mold exhaust grooves need to be coordinated with the filling speed and direction of the molten metal. Exhaust grooves should be set at the last place where the molten metal arrives, the corners of the cavity, and other places where gas is likely to accumulate, to ensure that the gas can be discharged before the molten metal fills the cavity. At the same time, the exhaust capacity of the exhaust grooves must also match the injection speed of the die-casting machine. When the injection speed is fast, the gas exhaust time is short. The size of the exhaust grooves needs to be increased or the number of exhaust grooves needs to be increased to improve the exhaust efficiency.
Finally, coordinating mold life with production batch size is also a crucial aspect of die-casting coordination. Mold material selection, heat treatment processes, and structural strength must be designed based on production batch size to ensure the mold maintains optimal working condition throughout the planned production cycle. For large-scale die-casting production, molds should be constructed of high-strength, high-wear-resistant materials (such as H13 hot-work die steel) and undergo rigorous heat treatment (such as quenching and tempering) to maximize mold life. For smaller batches, mold material requirements can be appropriately lowered to reduce production costs. Furthermore, mold maintenance cycles must be coordinated with production batch size. A reasonable maintenance plan should be developed to promptly repair mold wear and damage, ensuring consistent coordination between the mold and the die-casting process. Comprehensive coordination between the mold and all aspects of the die-casting process maximizes mold performance, improving die-casting quality and production efficiency.
