What is the technological process of sand casting?

Casting is a process in which liquefied material is poured into a specially designed mold cavity and allowed to harden. After solidification, the workpiece is removed from the mold and then undergoes finishing treatment to finally form the finished product.

There are various casting methods. According to the characteristics of the mold, they can be classified into one - time casting, semi - permanent casting, and permanent casting. Casting methods can also be divided into two major categories: sand casting and special casting. In the casting industry, sand casting accounts for 80% because of its short production cycle and low cost, so it has become the most widely used casting method in casting production.

1. Characteristics and technological process of sand casting

Prepare molding sand - molding - mold assembly - pouring - cooling - shake - out - cleaning - inspection - heat treatment - inspection - obtain casting

Molding sand - A mixture made by mixing raw sand or recycled sand with a binder and other additives.

Mold - The cavity made of molding sand that forms the outer contour of the casting is called the mold.

Core - The solid made of core sand that forms the inner cavity of the casting.

Molding - The technological process of making a sand mold.

Core making - The technological process of making a sand core.

2. Classification of sand mold making

In the process of sand mold making, according to its strength and other characteristics, the manufacturing methods can be divided into three categories.

(1) Mechanically bonded core - The bonding produced by the clay core sand with clay as the binder.

(2) Chemically bonded core - In the process of molding and core making, the core sand hardens according to the physical and chemical reactions of the binder itself, thereby establishing strength and firmly bonding the sand grains into a whole.

(3) Physical consolidation - It refers to the consolidation of the raw sand without a binder by the force generated by the physical principle.

3. Principle of sand casting

The principle of sand casting is actually very simple. First, a model is made for the part needed. This model is divided into two parts, the lower half - mold and the upper half - mold. First, place the lower half - mold on a flat plate, then place a sand box and fill it with molding sand. After compacting and scraping it flat, turn the sand mold 180 degrees and remove the lower half - mold to form a cavity, which is the lower sand box. Make the upper sand box in the same way, and then combine the two to make a complete sand mold, waiting for pouring. This is the basic principle of sand casting.