Sand casting is a lost-mold casting process, meaning the casting mold is destroyed in the manufacturing process. With sufficient expertise, cast parts with very complex geometries can be produced through the sand casting process.
How does the sand casting process work?
For the first step of the sand casting process an exact model similar in size, dimensions and details to the final product is created from plastic, resin, wood, hard foam or polystyrene. This pattern is then placed in a molding box filled with silica sand or molding sand. A small path through which the molten metal can later enter into the mold cavity is also formed at this stage.
Next, a hardening agent is mixed into the sand, which enables the molding sand to settle into a solid shape. Once the pattern is removed, the pattern’s impression remains fixed in the sand, forming the cavity for the casting material. The molding box is then closed and sealed firmly to prevent leaking. The casting mold is now finished.
In the following step, the alloy metal is molten. Usually these are alloys with are low smelting temperature, such as aluminium. The molten metal is poured into the mold cavity, where the melt gradually solidifies as it cools down. Depending on the size of the pattern and the metal used, this process can last between several hours and several days.
As soon as the final product is completely solid, the molding box can be removed and the molding sand is hammered away. The sand casting process is a lost-form casting process because the mold does not survive this last step.
What are the advantages of the sand casting process?
The sand casting process requires a fresh mold for each individual product. Because of this the process is best suited for small to medium-sized production run or for the manufacturing of prototypes. The sand casting process
- Can be used for large parts,
- Is suitable for core intensive geometries and also for parts with undercuts,
- Is suitable for the fast production of casting parts,
- Is cost-effective,
- Is ideal for the production of prototypes in the original process.
Which raw materials can be used for sand casting?
Sand casting utilizes a mixture of metals. Metallic and non-metallic components are molten, mixed and poured into the cavity of the molding box. We mainly use aluminium mixtures for the sand casting process.
The most important information at a glance
Component: 0.02–30.0 kg.
Dimensions: Depending on size and weight.
Tolerances: According to BDG directive, VDG code of practice P690 D1-D3.
Quantities: Small and medium-sized batches.