Aluminum Alloy Gravity Casting Mold And Use Steps
While advanced equipment is an essential factor in ensuring product quality, the role of molds in casting is equally important. Especially for aluminum alloy auto parts manufacturers, the accuracy and durability of the mold have a significant impact on product quality.
For ferrous metal casting, the mold is more for the formation of the mold cavity. In general, the mold itself is not directly in contact with the molten metal, especially for the non-metal mold castings with complicated shapes, and the contact with the hot metal liquid is the shape. The material, mainly the molding sand, makes the modeling material a major factor affecting the quality of the casting.
The aluminum alloy gravity casting is different. Because the melting point of the aluminum alloy is low, the casting performance is good. In the mass production, the shape of the casting is generally formed directly by the mold, such as the aluminum alloy cylinder and the cylinder head of the engine. This not only helps to improve labor productivity, but more importantly, it controls the structure and grain size of castings by adjusting the temperature distribution of different parts of the mold, improves the quality of castings, and avoids the environment caused by the large use of modeling materials. Pollution has improved the working conditions of the workshop. As the shape of the casting is different, the aluminum alloy gravity casting molds are also different. Even in the same part, different casting processes are used, and the mold forms are often different, but in any case, aluminum alloy gravity casting molds have their commonalities.
First of all, it is necessary to choose a suitable casting process. The quality of the casting process is directly related to the quality of the casting and the production rate of the process. Some mold manufacturing factories in China have begun to use the solidification simulation to carry out the casting process auxiliary design. Through the computer simulation of the filling and solidification process, the hot junction parts which are easy to produce casting defects are found and overcome, which is reliable for improving the casting process design. It is very important and effective to prevent the mold from being reworked unnecessarily during the commissioning process.
Second, the mold should have good heat capacity. The thicker formwork and modules that meet the requirements are not only an effective guarantee for the life of the mold, but also have a very important role in the adjustment of the temperature field during continuous working of the mold. In order to reduce the cost and save the materials, some mold factories blindly reduce the effective thickness of the mold to achieve the purpose of reducing the weight. However, this not only greatly reduces the service life of the mold, but also makes the casting easy to deform and affects the dimensional accuracy of the casting. It will lead to the scrapping of castings, causing damage to the foundry and, more seriously, the reputation of the mold factory itself.
Third, the mold must have a more reliable cooling system and a gas extraction system. Through cooling, not only can labor productivity be effectively improved, but also the temperature field of the casting can be adjusted, and the cooling rate of the casting can be controlled, thereby affecting the internal structure and grain size of the casting and achieving the purpose of effectively controlling the mechanical properties of the casting. As the name implies, the gas is extracted artificially to discharge the gas inside the cavity to the cavity to reduce the possibility of pore defects in the casting. At the same time, the mold temperature can be adjusted in a small area by adding a vent plug, which plays an important role in preventing and overcoming the cracking and collapse of the aluminum alloy.
Fourth, there must be a mold positioning device that matches the casting machine and a convenient mold mounting system. The positioning device not only ensures the casting size, reduces the crevice and burr, but also ensures the normal operation of the casting machine. It can be said that there is no good positioning device without a good positioning device. The mold must be easy to install and disassemble. Because of the gravity casting of aluminum alloy, it is necessary to remove the mold to re-spray the paint and repair the mold at regular intervals. If the disassembly is inconvenient, it will increase the labor intensity of the workers and take more labor time and reduce. Yield and efficiency.