Causes of mold damage in fully automatic low pressure casting machines

Causes of mold damage in fully automatic low pressure casting machines：

 

      1. Mold temperature: The mold must be preheated to a certain temperature before production. Otherwise, when high-temperature molten metal is filled, cooling will occur, causing the temperature gradient between the inner and outer layers of the mold to increase, forming thermal stress and causing the mold surface to crack or even crack. During the production process, the mold temperature continues to rise. When the mold temperature is overheated, it is easy to cause the mold and moving parts to fail, resulting in damage to the mold surface. The low-temperature Casting Machine should be equipped with a cooling temperature control system to maintain the working temperature of the mold within a certain range.

　　2. The fully automatic low-pressure casting machine is filled with molten metal, high pressure and high speed, which will inevitably cause severe impact and corrosion to the mold, resulting in mechanical stress and thermal stress. During the impact process, molten metal, impurities and gases will also have complex chemical interactions with the mold surface, accelerating corrosion and cracks. When the molten metal is filled with gas, it will first expand in the low-pressure area of ​​the cavity. When the air pressure rises, it will cause an inward explosion, pulling out the metal points on the surface of the cavity, and causing damage and fracture due to cavitation.

 

　　3. During the core pulling and mold opening processes, the deformation of some parts will also produce mechanical stress.

 

　　4. Production process of fully automatic Low Pressure Casting Machine. During the production process of each die casting, due to the heat exchange between the mold and the liquid of the fully automatic low pressure casting machine, the surface temperature of the mold will change periodically, causing periodic thermal expansion and contraction. , resulting in periodic thermal expansion and contraction. Thermal stress. For example, when a mold is cast, the surface of the mold is subject to compressive stress due to rising temperature, and after the mold is ejected from the casting, the surface of the mold is subject to tensile stress due to temperature. decline. When the alternating stress cycles repeatedly, the stress accumulated inside the mold becomes larger and larger. When the stress exceeds the fatigue value of the material, cracks will occur on the surface of the mold.

 

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