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Impro is a manufacturer of custom precision parts for a wide range of industries and applications. One of our core services is sand casting, a manufacturing process sought after for manufacturing custom components quickly and efficiently while maintaining low overall costs. At Impro, our team often receives questions pertaining to sand casting. Here are their responses to some of the common questions we encounter.

1. What is sand casting?

Sand casting is characterized by the use of sand-based molds to shape melted metal alloy into pre-designed parts. The process is particularly useful for the production of highly detailed and complex components. The molds themselves are dispensable after production, and the sand casting process is compatible with virtually any metal alloy.

2. How does sand casting work?

Sand retains its shape when exposed to high temperatures, which makes it desirable in metal casting since it can withstand the high temperatures necessary to melt alloys. Molds composed of sand-based materials are also easy to break away without damaging the hardened component once the casting is complete.

The sand casting process follows six basic steps:

1. Create a pattern. A reusable pattern is designed to fit the specifications of the required product. The pattern can be used to make multiple molds for sand casting.
2. Add metal delivery details. These passages in the design allow for the free flow of molten alloy into the finished mold. These gates and risers ensure that the mold is filled completely by facilitating the release of gases and mitigating thermal contraction.
3. Form the mold. Using the prototype pattern, sand is formed into a highly detailed, breakable mold.
4. Pour the casting. Molten metal is poured into the mold using a specialized delivery system.
5. Shakeout process. The molten metal cools and hardens into the required shape. Once cooled, the mold is broken to reveal the fully formed part.
6. Finishing process. Finishing processes remove gateways and risers and smooth the part surface.

3. What are the advantages of sand casting?

Sand casting is highly versatile and may be used to create custom designs in nearly any shape and size. It is particularly useful for detailed parts with complex geometries and internal passageways. The manufacturing process is more efficient and less expensive than other manufacturing methods, and excess material is recyclable.

4. What kinds of materials are used in sand casting?

Sand casting can be used with a wide range of metals, including iron, aluminum, steel, zinc, brass, and bronze alloys.

5. What types of products can be made by sand casting?

Due to its exceptional versatility, sand casting is one of the most widely used manufacturing processes for a variety of applications, including:

• Construction equipment (housings, combustors, manifolds, gearboxes, transmission impellers)
• Engine components (housings, brackets, frames, pistons, cylinders, manifolds)
• Wind energy components (torque arms, rotor hubs, blades, axle pins)
• Agricultural applications (axles, gears, gearboxes, brake drums, pulleys)

6. What types of sand are used for sand casting processes?

Sand casting uses the following types of sand to produce molds:

• Green sand. Also known as clay, green sand molds are created using wet sand. The process is quick and efficient and the sand can be reused.
• Resin sand. Resin sand is shaped using heat and exhibits a smooth surface when formed so less finishing work is required.

7. What are the differences between green sand casting and resin sand casting?

Green sand casting is less expensive than resin sand casting, as it requires less preliminary preparation. Green sand produces fewer solid molds with more potential for collapse during the molding process. Although resin sand casting offers a smoother finish and more durable mold, it is more expensive to produce and cannot be recycled at the same rate.

To learn more about the differences between green sand casting and resin sand casting, here is our blog about the topic.

8. What are the differences between sand casting vs. investment casting?

Investment casting is similar to sand casting in that both methods use prefabricated breakable molds for the casting of finished components from metal alloys. While sand casting uses sand based molds, investment casting uses melted heat-resistant material, often ceramic, coated around a wax pattern to create the mold. While sand casting leaves a rough surface that requires more finishing, investment casting results in a smooth finish with very little machining necessary to produce a finished product. However, investment casting tends to come at a higher cost, as the mold material is more expensive and cannot be reused.

Sand Casting With Impro

At Impro, we pride ourselves on providing high quality sand casted parts and components in the industry. If you have any other questions about sand casting or would like to learn about our sand casting capabilities, reach out to us today.