Die casting injection speed
In die-casting production, the injection speed is one of the core parameters that determine the quality of the casting. It refers to the movement speed of the die-casting machine’s injection punch in the process of pushing the molten metal into the mold cavity. The setting of this parameter is directly related to the filling state of the molten metal, the solidification process, and the mechanical properties of the final casting. Different alloy materials, casting structures, and mold designs have significantly different requirements for injection speed. For example, for thin-walled complex castings, a higher injection speed is required to ensure that the molten metal can fill the cavity in a short time to avoid insufficient filling due to rapid cooling; for thick-walled castings, if the injection speed is too high, it may cause problems such as molten metal splashing and air entrainment, affecting the density of the casting.
Injection speed control requires precise manipulation based on the die-casting machine’s performance and process requirements. Modern die-casting machines typically feature a multi-stage injection speed control system, enabling segmented speed adjustment during the injection process. In the initial injection phase, a lower speed helps the molten metal enter the runner smoothly, reducing turbulence and air entrainment. As the molten metal approaches the ingate, increasing the speed enhances its fluidity, ensuring rapid cavity filling. At the end of the injection phase, appropriately reducing the speed prevents the molten metal from violently impacting the mold, extending mold life. This segmented speed control method is a key technical approach for balancing casting quality and production efficiency.
The injection speed has a decisive influence on the flow pattern of the molten metal. When the speed is too low, the molten metal cools faster during the filling process, making defects such as underfill and cold shut more likely to occur. These problems are particularly prominent in the corners and complex structural parts of the casting. Conversely, if the injection speed is too high, the molten metal will form turbulent flow within the mold cavity, entraining a large amount of air to form pores. At the same time, the high-speed flow of molten metal may also scour the mold surface, causing increased mold wear and even sticking. Therefore, finding the appropriate injection speed range requires repeated process experiments and optimization based on the structural characteristics and alloy properties of the casting.
In actual production, the injection speed setting also needs to consider the mold’s exhaust capacity. If the mold exhaust is poor, even if the injection speed is within the appropriate range, gas in the cavity cannot be promptly expelled, resulting in porosity defects. In this case, it is necessary to coordinate the injection speed and the mold exhaust system. For example, appropriately reduce the speed during the initial filling phase to allow time for gas to escape, and increase the speed in the middle and late stages of filling to ensure full cavity filling. This coordinated adjustment can effectively improve the qualified rate of castings.
With the advancement of die-casting technology, intelligent injection speed control systems are gaining increasing adoption. By real-time monitoring of parameters such as the flow of molten metal and mold temperature, the system automatically adjusts the injection speed for dynamic optimization. This intelligent technology not only improves the stability of casting quality but also reduces reliance on operator experience, providing strong support for more efficient and refined die-casting production. In the future, with the in-depth integration of technologies such as artificial intelligence and big data, the control accuracy and adaptability of injection speed will be further enhanced, driving the die-casting industry towards higher quality.
