8 Main Steps in Sand Casting

8 Main Steps in Sand Casting

The sand casting process is a traditional casting method where sand is the primary material used to create molds. Sand casting offers significant advantages, such as being versatile in shape, size, complexity, and alloy type, having a short production cycle, and being cost-effective. This makes sand casting the most widely used method in foundry production, especially for single or small batches of castings.

The basic steps of the traditional sand casting process are as follows:

1. Sand Preparation
   Sand and core sand are prepared for molding, typically using a sand mixer to combine used sand with the appropriate amount of clay.
   
   

2. Pattern Making
   Molds and core boxes are created based on part drawings. Wooden molds are used for single-part production, while plastic or metal molds are used for mass production. Large castings often use pattern plates. Modern engraving machines have significantly shortened the production cycle for molds, which can now be made in 2 to 10 days.
   
   

3. Molding
   Molding consists of three main activities: sand molding, core making, and mold fitting.

• Sand Molding: Forming the cavity for the casting from the molding sand.

• Core Making: Producing cores that create the internal shapes of the casting.

• Mold Fitting: Assembling the upper and lower sandboxes after placing the cores inside the cavity. This step is crucial in the casting process.
  
  

4. Melting
   The metal's chemical composition must match the required specifications. A suitable furnace is chosen to melt the alloy material into a qualified liquid metal. Electric furnaces are primarily used due to environmental regulations that have limited the use of cupolas.
   
   

5. Molten Metal Pouring
   The molten metal from the furnace is poured into the mold using a ladle. Pouring speed is critical to ensure the molten metal fills the entire cavity. This step requires careful handling due to the dangers involved.
   
   

6. Sand Removal
   After the molten metal solidifies, the casting is removed by breaking the mold and shaking off the sand. A sandblaster is then used to clean the casting's surface. The casting blanks are inspected before leaving the factory.
   
   

7. Grinding
   For castings with special requirements or those that do not meet surface expectations, grinding is necessary. This step involves using a grinding wheel or grinder to remove burrs and improve the casting's finish.
   
   

8. Inspection
   Although non-conforming castings are usually identified during cleaning and grinding, a final inspection is necessary. For castings requiring assembly, tools or gauges are used to ensure proper assembly and compliance with specifications.
   
   

Conclusion

After completing these eight steps, the castings are shaped and ready. High-precision castings may require additional machining, which is beyond the scope of this casting process description.

Dongrun Casting has 20000 square meters of facility houses and 200 production & test equipment, From quotation and tooling design to casting and finished machining, we can work with you at every stage. We serve a wide range of industries-from Fortune 500 corporations to small and midsize OEMs. Our products include Automotive&trucking, Electric Utility & Communications, Metering Systems, the Hydraulic Industry, Medical Devices,  Lighting, Fuel and Gas Pressure, and Furniture parts.

More Details: www.dongruncasting.com