8 Basic Steps of Sand Casting

Because sand casting has the following characteristics: it is not restricted by the shape, size, complexity, and alloy types of parts; short production cycle and low cost. Therefore, sand mold casting is still the most widely used casting method in casting production, especially for single or small batch castings!

The basic process of the traditional sand casting process has the following steps: sand matching, mold making, core making, modeling, pouring, sand falling, grinding processing, inspection, etc.

1. In the sand mixing stage. molding sand and core sand are prepared for modeling. Generally, a sand mixer is used to put the old soil and appropriate amount of clay into it.

2. In the mold making stage. molds and core boxes are made according to the parts drawings. Generally, a single piece can use a wooden mold. Mass production can be made into plastic molds or metal molds (commonly known as iron molds or steel molds), and large scale sand castings can be made into pattern plates. Nowadays, molds are basically engraving machines, so the production cycle is greatly shortened, and mold making generally takes 2 to 10 days.

3. Modeling (core making) stage. including modeling (forming the cavity of the casting with molding sand), core making (forming the inner shape of the casting), and mold matching (put the core into the cavity, and close the upper and lower flasks). Modeling is a key link in sand casting process.

4. Melting stage. According to the required metal composition, the chemical composition is allocated, and the appropriate melting furnace is selected to melt the alloy material to form a qualified liquid metal liquid (including qualified composition and qualified temperature). Smelting generally uses cupola or electric furnace (due to environmental protection requirements, cupolas are now basically banned and electric furnaces are basically used).

5. Pouring stage. use a ladle to pour the molten iron in the electric furnace into the finished mold. It is necessary to pay attention to the speed of pouring molten iron so that the molten iron fills the entire cavity in sand casting process. In addition, pouring molten iron is more dangerous, so pay attention to safety!

6. Cleaning stage. After pouring and waiting for the molten metal to solidify, take a hammer to remove the gate and shake off the sand of the casting. Then use a sandblasting machine for sandblasting, so that the surface of the sand casting parts will look very clean! The casting blanks that are not strictly required can basically be shipped after inspection.

7. Casting processing. For some sand castings with special requirements or some castings that cannot meet the requirements, simple processing may be required. Generally, a grinding wheel or a grinder is used for processing and polishing to remove burrs and make the castings smoother.

8. Casting inspection. Casting inspection is generally in the process of sand casting cleaning or processing, and the unqualified ones are usually found out. However, some castings have individual requirements and need to be inspected again. For example, some castings require a 5 cm shaft to be inserted into the center hole, so you need to take a 5 cm shaft and try it out.

After the above 8 steps, the sand casting parts is basically formed. For castings that require high precision, machining is required. If you have this need, you can contact Yifei, we are a professional manufacturer and factory of die casting, investment casting, sand casting, forging in China, and we can provide you with a variety of customized casting forging services.

With the advancement of casting technology, traditional sand casting is either improved or replaced by other casting methods. Constant innovation is the eternal theme.