Silica Sol investment Casting vs. Sand Casting vs. Water Glass Casting
Our foundry is located in Dongying Shandong. We can produce steel castings by process of sand casting process, water glass casting and silica sol precision casting processes. They are also the main process of investment casting. However, some buyers or clients are still confused in of them.Or how to choose it as per their requirement. Here, we briefly introduce their differences, advantages and disadvantages to help you have a reference.
Different 1: Concept different
What is sand casting, water glass casting, silica sol casting?
1. Sand casting process uses wet clay sand as the main molding material, which is cheap.
2. Water glass investment casting process uses water glass quartz sand as the molding material, which can stand temperature up to 1800 degree, but it is more expensive than wet clay sand.
3. Silica sol investment casting process uses silica sol zircon sand as the molding material, which can stand temperature up to 2000 degree. This molding material is very expensive.
Casting surface quality and defects
1. Sand castings will have very rough surface, and more surface and inside defects.
The followings are some photos to show the surface quality of steel castings made by sand casting process.
2. Water glass investment castings have much better surface smoothness, less surface and inside casting defects.
The followings are some photos to show the surface quality of steel castings made by this process.
3. Silica sol investment castings have very good surface quality, very smooth, very less surface and inside defects.
The followings are photos for the steel castings made by this process.
Different 3: Specifications on unit weight and wall thickness differences
Sand casting process can produce very heavy and very large steel castings, but it cannot be used to produce too small, too complex or very thin wall thickness castings.
Investment casting can make casting smaller than 10b, while sand casting can not always make small and complex parts like investment casting.
Investment casting also has restrictions on the size and weight made in sand casting.
The following table could be reference to tell their difference.
Casting ProcessUnit weightSize limitationComplexityWall thickness
Sand casting5 – 3000kg0.1 – 3 meterNot complex>5mm
Water glass investment casting0.1 – 100kg0.01 – 0.5 meterComplex>3mm
Silica sol investment casting0.1 – 100kg0.01 – 0.5 meterVery complex>1mm
The following photos are showing how complex the silica sol investment castings could make.
Different 4: Casting prices
The mould material costs have caused very big difference on their casting prices. The wet clay sand is very cheap, water glass quartz sand is expensive, and silica sol zircon sand is very expensive. The investment casting process always costs higher than sand casting for the complexity and preparation needed.
For example, the sand casting is 1.5 USD/kg, water glass investment casting will be 2.50 USD/kg, and the silica sol investment casting will be 6.5 USD/kg.
Different 5 : Surface Finishing.
Surface finish is another big difference between investment casting and sand casting and Water glass investment casting.
Investment casting can create finished parts showing smooth surfaces and low tolerances under the work of pattern.
After removing the sprue gate and shot blasting, the casting blank is the final part for delivery.
The water glass casting has more goof surface than sand casting
With sand casting, the mold has to be split apart to release the final product. As a result, the parting line will leave outside the finished part. And due to the rough sand, the surface of finished cast parts will be equally rough. So additional cost and time will be required in secondary machining for removing the parting line and a more smooth surface.
Different 6:Ease of design:
In investment casting, ceramic shell mold is created using liquid slurry, so parts by investment casting process can be made almost any shape, giving engineers extraordinary freedom in their designs to add intricate features and complex shapes.
For sand casting parts, to come out the sand easily with less friction, they usually have to be tapered (with draft angles) or shaped. It’s also a challenge for sand casting to make parts with internal voids or cavities. Sand casting requires cores properly shaped and inserted in the mold to form the part’s interior. Sometimes, several cores may be needed, and it also costs time to form and secure them within each mold.