Sand casting is a metal-shaping process that has been employed for over 3,000 years, and it remains one of modern manufacturing’s most popular metal-casting processes. Throughout the years, advancements have been made to the precision, materials, and the range of specifications that sand casting can handle. However, the foundational principles of this flexible, cost-effective casting technique have largely remained unchanged across the centuries.
What Is Sand Casting?
Sand casting begins by shaping a mold out of compressed sand; this sand is often combined with other materials to increase its strength and structural stability. The sand mold pattern often incorporates sand cores, which are inserts that allow for greater complexity and types of angles in part designs. Once this is complete, molten metal is poured into the mold. The metal cools and hardens within the mold, producing the desired part.
There are many advantages to sand casting:
- Stability: Sand remains stable under extreme heat, making it suitable for shaping molten metal.
- Flexibility: Sand molds can be designed to handle almost any shape or weight, and complex or unusual geometries are rarely a problem. Sand casting is suitable for both ferrous and non-ferrous alloys.
- Affordability:Sand-casting molds are expendable, making the process a cost-effective option for both large and small production runs. In many cases, sand mold materials can be reused or recycled.
- Customizability: Molds can be customized with the specifications and intricacies that specialized applications require.
How Sand Casting Works
Sand casting is a multi-step process – here is how it typically works:
- Designing the mold: Before manufacturing a mold, a pattern must be carefully designed, and a preform of the pattern must be produced. This pattern must meet substantially all the needs of the final product, including the required precision and tolerances. It must also allow for thermal contraction. Once designed, the mold pattern can be used and reused to create as many molds as needed.
- Adding gaters and risers to the mold:The mold design must include passages that will allow metal to flow into it and gas to vent out of it. Risers and gaters assure that the molten metal will fill the mold completely before it starts to cool, so that even complex detailing is fully formed and free of defects. Risers and gaters also help control the amount and location of thermal contraction.
- Making the mold: To make a sand-casting mold, sand is packed around the preformed pattern. Some molds require heating as well. When the two halves of the mold are separated and the preform removed from them, a cavity is left behind where metal can be poured. Green sand is a popular and cost-effective mold material, while resin sand provides greater accuracy, higher surface strength, and the ability to handle greater weights. Sometimes, sand molds will be lubricated before metal casting occurs to make the removal of the final part easier.
- Casting the metal: Molten metal is removed from a furnace and poured into the mold. This must be done quickly, so the metal can fill the entire mold before cooling begins. Pouring can be handled either manually or by automated machine.
- Cooling the metal: The cast metal must be fully cooled before it is removed from the mold. The cooling time varies depending on the design’s complexity, on the type of metal being cast, and on the cooling technique being used. Once cooling is complete, the sand mold is broken and the finished piece removed.
- Finishing: Finally, any excess material is trimmed away, and the metal is smoothed by grinding or sand blasting. The product is inspected, any necessary testing is conducted, and the part is sent on to the client.
Sand Casting for Power Generation Applications
Sand casting is an excellent technique to produce parts for power generation applications and the harsh conditions they must endure – such as humidity and moisture, corrosive chemicals, ultraviolet solar radiation, and more. Power generation types that are compatible with sand casting include:
Sand casting produces parts that are built for excellent durability and strength when it is needed most. Below is a list of particularly good application candidates for the sand casting process:
- Engines for power generators
- Flame and gas detection equipment for oil drilling platforms
- Well-testing and well-drilling equipment
- Steering systems for solar power fields
- Gas and oil pipelines
- Gas turbines
- Engine power systems
Sand Casting Services at Impro
Sand casting is a flexible, economical, and reliable metal-casting technique. It produces high-quality parts suited for a wide range of applications, including power generation equipment.
Impro is a global leader in sand casting, and we are able to produce high-end, geometrically complex castings from high-grade materials. Our state-of-the-art facilities possess the machines and manual casting equipment required for both low- and high-volume productions. Impro can cast parts that weigh anywhere from a half kilogram to twenty tons, and we are committed to excellence and customer satisfaction.
To learn more about sand casting services at Impro or to receive tailored recommendations for your next project, contact us. We look forward to hearing from you!