1. Ordinary sand mold casting uses sand as the mold material, also known as sand casting and sand turning, including wet sand mold, dry sand mold and chemical hardening sand mold, but not all sand can be used for casting. The advantage is lower cost, because the sand used in the mold can be reused; The disadvantage is that the manufacturing of the mold is time-consuming, and the mold itself cannot be reused. The finished product can be obtained only after it is destroyed.

1.1 sand mold (core) casting method: wet mold sand mold, resin self hardening sand mold, sodium silicate sand mold, dry mold and surface dry mold, full mold casting and negative pressure molding.

1.2 manufacturing method of sand core: it is selected according to the size, shape, production batch and specific production conditions of sand core. In production, generally speaking, it can be divided into manual core making and machine core making.

2. According to the molding materials, special casting can be divided into special casting with natural mineral sand as the main molding materials (such as investment casting, mud mold casting, shell mold casting, negative pressure casting, full mold casting, ceramic mold casting, etc.) and special casting with metal as the main molding materials (such as metal mold casting, pressure casting, continuous casting, low-pressure casting, centrifugal casting, etc.).

2.1 metal mold casting method

The mold is made of metal with high melting point. It is subdivided into gravity casting method, low-pressure casting method and high-pressure casting method.

The metal that can be cast is also limited by the melting point of the mold.

2.2 dewaxing casting method

This method can be outer film casting method and solid casting method.

First copy the object to be cast with wax, then immerse it in the pool containing ceramic (or silica sol [2]) and let it dry, so that the copy made with wax is covered with a layer of ceramic outer film, and repeat the steps until the outer film is enough to support the casting process (about 1 / 4 inch to 1 / 8 inch), then melt the wax in the mold and pull it out of the mold. After that, the mold needs to be high-temperature for many times, and can be used for casting after enhancing the hardness.

This method has good accuracy and can be used for the casting of high melting point metals (such as titanium). However, due to the high price of ceramics and the need for multiple heating and complex production, the cost is quite expensive.