subject: Sand Casting Process - Green Sand, Resin Sand, Shell Molding, Dry Sand [print this page] There are many types of casting methods, such as die casting, lost foam casting, permanent mold, continuous mold, lost wax investment casting etc., but sand casting process is still the most common casting process.
Sand casting process means the main molding material is "sand". According to the different sand materials, it can be divided into green sand, resin sand, dry sand and shell molding processes. Herein, we will try to elaborate them.
1. Green Sand
Green sand casting uses a kind of humid sand mixed with black clay. This sand is cheap, and can be used repeatedly. So, it is suitable for manual molding and automated machine molding. Green sand is the cheapest sand casting process, and is also mostly used casting process in China. This process is suitable to produce iron castings with rough weights less than 100kg.
2. Resin Sand
Resin sand casting process uses furan resin sand as the molding material. After burning, the resin sand can become hard sand, so it is also called as hard mold casting process. Resin sand can be used repeatedly either, however, it needs to replenish new furan sand constantly. In 2011, the furan resin material became very costly, so the resin sand castings became more costly. Resin sand casting process is suitable to produce large iron castings with weights from 50kg to 2000kg.
3. Shell Molding
Shell molding process uses a kind of yellow phenolic resin sand. This sand is more costly than furan resin sand, and phenolic resin sand can not be used repeatedly, so it is one time molding sand. Therefore, this process is more costly than furan resin sand.
However, shell molding process can meet higher requirements to the rough casting surface quality, more complex inside structures, and higher casting dimensional tolerances. So, it is widely used for producing small iron castings with high requirements. In China, we normally do not use shell molding process to produce steel castings, however, in other countries, they do.
4. Dry Sand
Dry sand is mixed with water glass. This type of sand has better air permeability, but worse surface smoothness, so it is used for producing middle and large steel castings.
This article was from Dandong Foundry. For the whole article, please check Dandong Foundry Blog.
