In the production process of aluminum die casting products, deformation problems will directly affect product quality and subsequent use. Controlling deformation needs to start from multiple links. First of all, mold design is a key factor affecting product deformation. Unreasonable mold structure will lead to uneven filling of aluminum liquid, which will cause uneven stress distribution inside the product. For example, if the gate position is improperly set, the impact force generated by the aluminum liquid when flowing in the mold is different, and the cooling shrinkage degree of the first filling area and the later filling area is different, which will easily cause the product to deform. Therefore, when designing the mold, it is necessary to fully consider the flow path of the aluminum liquid, optimize the gate and runner layout through simulation analysis software, ensure that the aluminum liquid fills the mold cavity smoothly and evenly, and reduce the deformation caused by filling differences.
The temperature control of the mold also has an important influence on product deformation. If the mold temperature is too high, the aluminum liquid cools slowly, and the product is prone to shrinkage deformation due to internal residual heat after demolding; if the mold temperature is too low, the aluminum liquid fluidity becomes poor, the filling is insufficient, and the product surface is prone to defects such as cold shut and insufficient pouring. It may also deform due to local stress concentration during subsequent processing. Therefore, the mold temperature must be strictly controlled during the production process. The mold must be preheated before die-casting to reach the appropriate working temperature, and the temperature must be kept stable through the cooling system during the production process to avoid product deformation caused by temperature fluctuations.
The selection of die-casting process parameters should not be ignored either. Parameters such as pressure, speed, and holding time during the die-casting process will affect the solidification process of the aluminum liquid in the mold. If the die-casting pressure is too high, a large residual stress will be generated inside the product, and the stress release will cause deformation after demolding; if the die-casting speed is too fast, the aluminum liquid will easily be drawn into the air to form pores, and at the same time increase the flushing force on the mold, affecting the filling uniformity. If the holding time is insufficient, the aluminum liquid will be demolded before it is completely solidified, and the product will also be deformed due to defects such as internal shrinkage and looseness. Reasonable adjustment of these process parameters and finding the best combination of pressure, speed, and holding time according to the product structure and the characteristics of the aluminum alloy material are important measures to control deformation.
The characteristics of the aluminum alloy material itself are also closely related to product deformation. Different grades of aluminum alloys have different shrinkage rates and thermal expansion coefficients. If the selected aluminum alloy material has a large shrinkage rate, the volume change during the cooling and solidification process will be large, which is more likely to cause product deformation. In addition, if the impurity content in the aluminum alloy is too high, it will reduce the mechanical properties of the material and make the product more likely to deform when subjected to force. Therefore, before production, the quality of aluminum alloy materials must be strictly controlled, and materials with stable shrinkage and low impurity content must be selected. The die-casting process parameters should be adjusted according to the material characteristics to reduce deformation caused by material factors.
The demolding process of aluminum die casting products may also cause deformation. During demolding, if the ejection mechanism is not designed properly, the ejection position is uneven, or the ejection force is too large, the product will be subjected to uneven external forces, resulting in deformation. For example, if the ejector pins are too concentrated in a certain area of the product, the area will be subjected to excessive force and cause dents or warping. Therefore, it is necessary to optimize the design of the demolding mechanism, arrange the ejector pin position reasonably, ensure that the ejection force is evenly distributed, and adjust the ejection speed according to the product structure and size to avoid product deformation due to improper demolding.
The impact of the cooling process on product deformation should not be underestimated. After the product is demolded, if the cooling speed is uneven and the shrinkage of various parts is inconsistent, deformation will also occur. For example, during the natural cooling process, the heat dissipation speed of the product surface and the interior is different. The surface cools and shrinks first, and the interior cools and shrinks later, which is easy to cause warping deformation. Forced cooling can be used, such as using fans, sprays, etc., to speed up the cooling speed of the product and make the cooling more uniform, reducing deformation caused by cooling differences.
Controlling deformation during the production process of aluminum die casting products is a systematic project, which requires comprehensive consideration from mold design, temperature control, process parameter selection, material control, demolding operation to cooling links. Only when each link is strictly controlled can the problem of product deformation be effectively reduced and the quality and production efficiency of aluminum die casting products be improved.
