Introduction to the Process of Precision Casting

In our lives, there are many alloy materials that are difficult to process, and the shape of the parts is so complex that it is impossible or difficult to manufacture them through other methods, especially in aerospace and other fields. Precision casting, also known as investment casting or silica sol process, is a low-cut or non-cut casting process.

It is an excellent process technology in the casting industry. It has a wide range of applications, not only for various types, but also for casting various alloys. The size accuracy and surface quality of the produced castings are higher than other casting methods. Even complex castings with high temperature resistance that are difficult to process by other casting methods can be produced through precision casting. So, how does the precision casting process work? Here is an introduction to the precision casting process.

Understanding precision casting

Precision casting, also known as lost wax casting, has precise, complex products that are close to the final shape of the parts and can be used directly without or with minimal processing. Therefore, investment casting is an advanced process of forming to near net shape.

The process of precision casting

Make molds according to the different shapes of the products. The molds are divided into upper and lower concave molds, which are completed through comprehensive processes such as turning, planing, milling, etching, and EDM. The shape and size of the pits are identical to half of the product. Since wax molds are mainly used for industrial wax molding, aluminum alloy materials with low melting point, low hardness, low requirements, cheap price, and light weight are used.

Use aluminum alloy molds in precision casting to produce a large number of industrial wax solid models. Under normal conditions, the industrial wax solid model can only correspond to one blank product.

Refine the edges around the wax mold. After removing the burrs, multiple individual wax molds are glued to a prepared mold (also called a group tree). The mold is also an industrial solid model produced by precision casting.

Apply a uniform layer of fine sand (refractory sand, resistant to high temperature, usually silica sand) on the multiple wax molds fixed on the mold with industrial glue. The sand particles are very small to ensure that the surface of the blank is as smooth as possible.

Let the wax mold sprayed with a layer of fine sand dry naturally at the set room temperature (or constant temperature), but it will not affect the shape of the internal wax mold. The natural drying time during precision casting depends on the complexity of the product itself, but it is generally good. The natural drying time of precision castings is about 5-8 hours.