In the automobile manufacturing industry, casting molds are important equipment for the production of high-quality automobile parts, and their performance directly affects the quality of the final product. However, during the casting process, defects such as shrinkage often occur on the mold surface, which not only affects the appearance of the product, but may also have far-reaching negative effects on its performance and reliability.

Analysis of causes of shrinkage
Sink is a common defect in automobile casting molds during the casting process, which appears as smooth dents on the surface of the casting. The causes are complex and mainly include the following aspects:
Mold design defects: During the mold design stage, if the wall thickness and shape of the casting are not fully considered, uneven shrinkage of various parts of the casting may occur during the cooling process. For example, the transition design between thick-walled and thin-walled areas in the mold is unreasonable, causing shrinkage due to differences in cooling rates.
Improper cooling system design: The cooling system has a significant impact on the cooling rate and shrinkage rate of the casting. If the design of the cooling system is unreasonable, such as improper number, location and size of cooling pipes, the temperature difference of the casting during the cooling process will be too large, which will lead to shrinkage.
Molten metal composition and temperature control: The composition and temperature of the molten metal directly affect the shrinkage rate of the casting. If the impurity content in the molten metal is too high or the temperature is improperly controlled, it may cause large shrinkage stress in the casting during the solidification process, leading to shrinkage.
Improper mold preheating and temperature control: The preheating temperature of the mold and temperature control during the casting process are crucial to reducing shrinkage. Insufficient preheating or excessive temperature fluctuations during the casting process will cause the casting to shrink unevenly during cooling, causing shrinkage.

Collapse solution
In order to effectively solve the shrinkage defects of automobile casting molds during the casting process, companies can take the following measures:
Optimize mold design: In the mold design stage, the wall thickness and shape of the casting must be fully considered, and the structure and size of the mold should be designed reasonably. For the transition area between thick and thin walls, it is recommended to use rounded corners or bevel designs to reduce cooling rate differences and shrinkage stresses. At the same time, the wall thickness of the mold should be kept as consistent as possible to avoid excessive wall thickness differences.
Improve the cooling system: Optimize the design of the cooling system and rationally arrange the number, location and size of cooling pipes. For large or complex-shaped castings, zoned cooling is recommended to reduce temperature differences between parts. At the same time, the operating status of the cooling system should be checked regularly to ensure that its cooling effect is good.
Strictly control the composition and temperature of molten metal: The composition and temperature of molten metal should be strictly controlled to ensure that its quality meets casting requirements. Metal liquids with too high impurity content need to be purified. At the same time, the pouring temperature and pouring speed of the molten metal should be reasonably controlled to reduce the shrinkage stress generated by the casting during the solidification process.
Strengthen mold preheating and temperature control: Before casting, the mold should be fully preheated to reduce the temperature difference between the mold and the molten metal. During the casting process, the temperature fluctuation of the mold needs to be strictly controlled to ensure the uniformity of the cooling process of the casting, thereby reducing the risk of shrinkage.