With the different complexity of casting shape, aluminum alloy gravity casting dies are also different. Even if the same part adopts different casting processes, the mold forms are often different, but in any case, the aluminum alloy gravity casting mold still has its commonness.
First of all, the appropriate casting process must be selected. The quality of the casting process is directly related to the casting quality and process yield. Some domestic mold manufacturers have begun to use solidification simulation to carry out casting process aided design. Through the computer simulation of mold filling and solidification process, the hot junction parts prone to casting defects are found and overcome, which is very important and effective to improve the reliability of casting process design and effectively prevent unnecessary rework of molds during commissioning.
Secondly, the mold should have good heat capacity. The thicker mold base and module aluminum alloy casting that meet the requirements is not only an effective guarantee for the service life of aluminum alloy casting mold, but also plays a very important role in regulating the temperature field in the continuous working process of the mold. In order to reduce costs and materials, some mold factories blindly reduce the effective thickness of the mold to achieve the purpose of reducing weight. However, this not only greatly reduces the service life of the mold, but also makes the castings easy to deform, affecting the dimensional accuracy of the castings. In serious cases, it will lead to the batch scrapping of the castings, causing losses to the foundry, and more seriously, it will damage the reputation of the foundry.
Third, the mold should have a more reliable cooling system and air extraction system. By cooling, not only the labor productivity can be effectively improved, but also the casting temperature field can be adjusted and the casting cooling rate can be controlled, so as to affect the internal structure and grain size of the casting and realize the purpose of effectively controlling the mechanical properties of the casting. As the name suggests, air extraction in aluminum alloy casting means that the air inside the mold cavity is artificially discharged outside the mold cavity to reduce the possibility of porosity defects in the casting. At the same time, the mold temperature in local small area can also be adjusted by installing exhaust plug, which plays an important role in preventing and overcoming the cracking and shrinkage of aluminum alloy.
Fourth, there must be a mold positioning device matching the casting machine and a convenient mold installation system. The positioning device is not only the key to ensure the size of the casting and reduce the cracks and burrs, but also the key to ensure the normal operation of the casting machine. It can be said that without a good positioning device, there will be no good and qualified casting. The mold must be easy to install and disassemble. Because of the gravity casting of aluminum alloy, the mold must be removed every certain time to spray paint and repair the mold. If the disassembly is not convenient, it will increase the labor intensity of workers, occupy more labor time, and reduce the output and efficiency.
