Silica sol casting is a casting process that we often hear at present, and precision casting manufacturers are familiar with it. Precision casting can be divided into three types:

1. Silica sol casting;

2. Water glass castings;

3. Composite casting;

What is the status of silica sol casting in the precision foundry?

The difference between these three silica sol casting methods lies in the different materials used to make the wax and shell. Taking silica sol as an example, a wax mold is made of low-temperature wax and medium-temperature wax, and the shell is made of wrong sand, moying sand, wrong powder, and silica sol. According to the different needs of each product, 4-8 shells can be made; the water glass process is to use low-temperature wax to make wax molds, and then sodium hydroxide, quartz sand, etc. Use silica sol for two or three layers, and use water glass for the last two layers.

Comparing these three processes in terms of size, silica sol is very suitable for small pieces, the surface will be very fine, the fine roughness value can reach between RA3.2-6.4, and the tolerance size control will be better. Moreover, if the silica sol process is used, some places can be molded at one time without processing, and a lot of cost can be saved. The composite technology is not as good as the silica sol technology in surface and tolerance dimensions, but the composite technology can make larger castings, which are better than sodium silicate in size and outer surface, and sometimes can reach Ra6.4-12.5. Compared with the composite process, the silica sol casting is one grade worse than sodium silicate.

So, for precision casting manufacturers, what are the applications of silica sol in precision casting?

Silica sol is mainly used as a binder for silica sol casting, and can be used to make reinforced coatings and surface coatings for shells. Precision casting manufacturers will use small particles of silica sol instead of ethyl silicate in precision casting, which can not only reduce casting costs, but also improve the working environment and conditions. When silica sol is used in thin-shell precision casting, the strength of the shell shape will become higher, and the smoothness and dimensional accuracy of the casting will also become better. The molding quality is better than sodium silicate, and the price is lower than ethyl silicate. For large castings, castings with high surface finish requirements and castings that do not require or have a small margin, it is more suitable to use silica sol casting. Silica sol is used as a high temperature resistant coating in precision casting, which can make the coating have good wear resistance and heat resistance, reduce the loss of molten metal to the mold at high temperatures, and help the castings to be demolded.