Which Investment Casting Shell Making Accuracy is Higher? In the investment casting process, there are 4 shell-making methods. They are water glass shell making, Composite shell making, Silica Sol Shell Making (Low-Temperature Wax), Silica Sol Shell Making (Middle-Temperature Wax). So, which Accuracy is higher in water glass than in silica sol casting? Today, let’s discuss it. Hope it is useful for your investment casting process choosing.
4 Investment Casting Shell Making Process and Features
Water Glass Investment Casting Shell Making
The water glass process has been in production for nearly 50 years in China. After half a century of hard work, the application and research of the water glass shell process have reached a very high level. Due to the improvement of back-shell shell refractories and the popularization and application of new hardeners, the strength of water-glass shells has tripled. Low cost, shortest production cycle, excellent shelling performance, and high gas permeability are still far beyond the advantages of any other shell process.
Composite Investment Casting Shell Making
Compared with the water glass shell, the surface quality of the composite shell casting has been greatly improved. The surface roughness is reduced, the surface defects are reduced, and the repair rate is lowered. It can be applied to high alloy steels such as stainless steel and heat-resistant steel. The production cycle is much shorter than the low-temperature wax-silica sol shell. Similar to the water glass shell.
Silica Sol Shell Making (Low Temperature Wax)
When casting more than 1kg, especially 5kg or more, it has greater adaptability and superiority. It is more stable than composite shells, especially for castings with high dimensional accuracy. Because it does not have water glass, the shell has good high-temperature performance. After calcination at 1000-1200 ° C, the shell has high gas permeability and strong creep resistance. It can be applied to thin-walled parts, small and medium-sized parts with complex structures, and can produce extra-large parts weighing 50-100kgs. Such as water pump, impeller, diversion shell, pump body, ball valve body, valve plate, etc. For thin-walled small or small parts, you can use a fork shell or a lifting shell to cast directly in front of the furnace. More high yields are available.
Silica Sol Shell Making (Middle Temperature Wax)
This is the internationally popular precision casting production process. It has the highest casting quality and the lowest repair rate. It is especially suitable for small and medium-sized parts and extra small parts (2-1000g) with high surface roughness and high dimensional accuracy. However, due to equipment and cost constraints, it is less used in medium and large parts (5-100kg).
Silica sol and water glass are a binder. They are used to formulate investment casting coatings. The different manufacturing processes of the binder are called different precision castings. Such as silica sol precision casting, water glass precision casting.
So, which Accuracy is the water glass and silica sol casting?
In the process of casting, we must not only know its method but also its process and material. The principle of the production process is the same. However, the wax, the surface sand, and the adhesive used in the two are different.
1– The wax of water glass is very soft. The wax of silica sol is very hard. The surface of the silica sol product is better than that of water glass.
2–The two are only different in the quality of the manufactured shell: the type produced by silica sol is more suitable for precision casting. The manufactured product has good surface smoothness, small deformation, a small shrinkage ratio, and precise size. machining.
3– Silica sol products are basically small products. Water glass lost molds are relatively large.
From the above comparison, we can conclude that the accuracy of silica sol casting is greater than that of water glass casting.
But on the others side, the water glass investment casting cost is very cheap than silica sol investment. If you pursue the economic value, water glass investment casting is a good choice.