Casting Method

Metal casting method means the casting processes, which make the metal materials into designed metal products. Casting is the most basic and the most commonly used metal manufacturing technology. 

According to the different casting materials, casting methods can be divided into black metal casting (including cast iron, cast steel) and nonferrous metal casting (including aluminum, copper alloy, zinc alloy, magnesium alloy, etc.). 

According to the different mold materials, casting methods can be divided into sand mold casting and metal mold casting. 

Casting methods can also be divided into gravity casting and pressure casting according to the different process theories. 

Gravity casting is the casting process that pours the molten metal into the mold by the Earth's gravity, also known as pouring casting. Gravity casting method includes sand casting, metal mold casting, investment casting, lost foam casting and die casting. 

Sand casting is a kind of metal casting method, whose main material is quartz sand. Sand casting is a traditional casting process. Sand casting is usually gravity casting, but if there are special requirements, it also may be low pressure casting or centrifugal casting process. 

Sand casting has a wide adaptability, such as producing small castings, large castings, simple parts, complex parts, single casting, large quantities of castings. The casting patterns of sand casting can be divided into wood pattern, resin pattern and metal pattern.  

Metal mold casting method uses the heat-resistant alloy steel patterns as the casting molds, and the melted metal will be poured into the steel patterns directly. Metal mold casting methods can also be divided into gravity metal mold casting and pressure metal mold casting. The steel patterns of metal mold casting can be used repeatedly, each time pouring can get a casting, the steel patterns have a very long lifetime, and the production efficiency is high. 

Metal mold casting method is not only a good dimensional accuracy, surface finish, and the casting strength is higher than the sand castings, but also not easy to damage. Therefore, metal mold casting method is usually used for producing non-ferrous metal castings. 

However, the metal mold casting method also has some disadvantages: The heat-resistant alloy steel patterns are very expensive, so for small batch production, the share to the cost of each product is too high on the mold, generally difficult to be accepted. Moreover, because the steel patterns have size limitation, so it also limit the size of castings. Therefore, for small quantities or large size castings, generally do not use metal mold casting.

Die casting method is a kind of metal mold casting process, but the melted metal is injected by pressure from die casting machines. Die casting machines are divided into hot chamber die casting machines and cold chamber die casting machines. Die casting machine has a high degree of automation, less waste of materials, and higher efficiency than the cold chamber die casting machine, but because of the mechanical heat capacities, the hot chamber die casting machines are only for producing zinc alloy, magnesium alloy and other low melting point materials casting. Today's widespread use of aluminum die casting, due to high melting point, only produced in the cold chamber die casting machines. 

In short, all metal casting methods have their own advantages and disadvantages. According to the difference of the product materials, applications and requirements, buyers should choose the suitable casting method.

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