Sand casting is an age-old process within the metal manufacturing industry and involves pouring molten metal into a sand mold cavity, where it solidifies to form intricate components. Often hailed as the most widely used method in metal casting, sand casting offers unparalleled versatility, making it a preferred choice for various industrial applications.
The Process of Sand Casting
Sand casting begins with heating the material to its melting point and sometimes modifying its chemical composition to achieve desired properties. The molten metal is then poured into a mold with a cavity shaped according to the intended product.
Sand casting employs a two-part mold contained within a flask box—the cope and the drag. The pattern, a replica of the desired object, is made oversized to account for metal shrinkage. Sand is packed around the pattern to form the mold, divided into the cope and drag halves. Molten metal is poured into the cavity, and after cooling, the mold is removed to reveal the casting.
Key Considerations
Manufacturers must carefully consider several factors to produce high-quality sand castings at the right price point. These include draft angle, parting line, undercuts & cores, cross-sections, wall thickness, corners & angles, junction design, and casting allowance.
Characteristics of Sand Casting
- Over 70% of all metal castings worldwide are produced through sand casting.
- Sand casting accommodates a wide range of sizes, from small statues to parts weighing over 100 tons.
- Its flexibility allows for the creation of complex parts in one piece, though with relatively low dimensional accuracy and surface finish.
At Omega Sinto, our Chemically-Bonded Sand Casting (CBS) machines are completely customisable to meet the individual requirements of your foundry. We specialise in designing, manufacturing and installing equipment that aims to make sand casting a flexible and productive process.
Advantages of Sand Casting
- Design Flexibility: Sand casting accommodates a broad spectrum of sizes and shapes, offering unparalleled design freedom.
- High Complexity: It enables the creation of intricate features in components.
- Material Choice: Virtually all engineering alloys can be cast using this method.
- Low-Cost Tooling: Sand casting requires minimal tooling investment, making it cost-effective.
- Short Lead Time: Ideal for short production runs due to its quick turnaround.
Chemically bonded, ‘no-bake’ sand casting focuses on low runs and speciality castings in sectors such as construction and mining. To learn more about the countless benefits that CBS casting offers to many industries, read our article
‘Benefits of Sand Casting’.
Disadvantages of Sand Casting
- Low Material Strength: Parts may exhibit lower strength due to high porosity.
- Defects: Despite advancements, defects such as shrinkage and porosity remain unavoidable.
- Post-Processing: Secondary machining may be necessary for tighter tolerances, increasing processing costs.
Whilst sand casting boasts numerous advantages such as design flexibility and cost-effectiveness, it is essential to acknowledge its limitations and potential drawbacks. By understanding the intricacies of this technique, manufacturers can harness its potential to create intricate components efficiently and effectively.
As a
globally-leading foundry equipment manufacturer, Omega Sinto understands the vital role that CBS casting plays within many large and small-scale operations. Our equipment range aims to recover 80% inorganic and 90% of organic sand – working to save time, costs and align with sustainability goals for the future.