What is the metal casting process in the foundry?

By definition, you may think it is just a piece of cake but once you step into a certain foundry nearby you will know how skillful and ingenious this casting work is. Casting any product in a foundry all involves many steps and each step requires careful and exactly working spirit.

Summarized speaking, the general metal casting process involves pattern making, molding, pouring, cooling, shaking-out, sand-blasting, fettling, and inspection. The further machining step applied CNC precise machine for milling, turning, lathe etc. is upon request and depends on each foundry’s capacity.

In the first step, pattern making is very important in the metal casting process. The pattern is a replica of the project to be cast. It is commonly made from wooden or metal (aluminum is widely used). These patterns can be reused to create as much mold cavity as needed.

An aluminum pattern of lamppost base in VIC foundry

Among the molding techniques, sand molding seems like the most favorite and widely applied molding process in the foundry due to its low cost. The sand mold technology can apply for either small and large foundries; and is very easy to process in comparison to other manners.

In the sand molding technique, green sand is most commonly features wet-content and naturally high bonding ability. Basically, the worker presses the pattern into the sand flask and the mold cavity is created after the pattern withdrawing. This step can do either by automatic line or manual.

The cavity features the shapes as the pattern does and includes a few holes and lines for the pouring step. By pouring the molten metal into these cavities, the casting is formed.  Nowadays, melting metal mostly is processed by an electric furnace, whereas coal furnace can find in a few small foundries.

After pouring, it requires a few hours to allow the casting to be cool down. Roughcasting is collected by the shaking-out process and goes through cleaning remain sand.

Sand molding casting part

Depending on requirements, the fettling can be simple, complicated, and hard work. It could be applied treatments for surface defects such as pinhole, crack, rough skin, etc. The inspection will be carefully processed before shipping to the customer.