Casting technology has played an important role in creating the products for automobile, machinery, or automatic fields. Some of daily everyday items we use daily such as cookware, pots, hotplate, pans, toast rack…are produced by casting technology. However, if you are not a specialist, you may not understand about what is casting, process, material…Therefore this article is written to introduce basic information of casting. There are a lot of methods of casting green sand, furan, gravity, investment casting…but the same point of these methods is a sand mold. We will introduce the knowledge of green- sand casting, this is a method with long history.

1. Definition

Casting technology is pouring molten metal into the mold to create to the desired shape. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. The casting can be machined to drill or polish. The used metal is very various cast iron, steel, aluminum alloy, stainless steel,…

2. Classification

- Classifying based on mold: green-sand mold, metal mold

- Classifying based on pouring method: pressure casting, centrifugal casting

-Classifying based on mold making: green-sand casting, lost foam casting, investment casting, shell casting

3. Green-sand casting

Green-sand casting is made in a sand mold boned with clay to harden the sand. Sometimes, the hardening can be effected by mixing sodium silicate into the sand to create chemical bonds. The sand mold is used one time only.

The ejected casting will have a rough surface, low accuracy, and an excess material. The mold sand is suitable to be made big casting or low quality.

4. The process of sand casting

- 3D/ 2D design, designer team create the casting drawing included surface, core, casting slope, tolerance, mechanical directives, the shrinkage of metal when solidifying.

- The mold, template and core box are usually made into 2 parts can joint by pins.

- Metal melting parts

- Assembly the mold to pour molten metal

- After solidifying, the casting is formed in the mold

- Break the mold to take casting out

- Check measurement, shape, tolerance and quality.