Sand Casting Process

Investment Casting Process
2014-07-26
CNC Machining
2014-07-26

SAND CASTING

 

Sand casting, the most widely used casting process, utilizes expendable sand molds to form complex metal parts that can be made of nearly any alloy. Because the sand mold must be destroyed in order to remove the part, called the casting, sand casting typically has a low production rate. The sand casting process involves the use of a furnace, metal, pattern, and sand mold. The metal is melted in the furnace and then ladled and poured into the cavity of the sand mold, which is formed by the pattern. The sand mold separates along a parting line and the solidified casting can be removed. The steps in this process are described in greater detail in the next section.

 

sand-casting-mold
Sand casting overview

 

Sand casting is used to produce a wide variety of metal components with complex geometries. These parts can vary greatly in size and weight, ranging from a couple ounces to several tons. Some smaller sand cast parts include components as gears, pulleys, crankshafts, connecting rods, and propellers. Larger applications include housings for large equipment and heavy machine bases. Sand casting is also common in producing automobile components, such as engine blocks, engine manifolds, cylinder heads, and transmission cases.

Capabilities

Typical Feasible
Shapes: Thin-walled: Complex
Solid: Cylindrical
Solid: Cubic
Solid: Complex
Flat
Thin-walled: Cylindrical
Thin-walled: Cubic
Part size: Weight: 1 oz – 450 ton
Materials: Metals
Alloy Steel
Carbon Steel
Cast Iron
Stainless Steel
Aluminum
Copper
Magnesium
Nickel
Lead
Tin
Titanium
Zinc
Surface finish – Ra: 300 – 600 μin 125 – 2000 μin
Tolerance: ± 0.03 in. ± 0.015 in.
Max wall thickness: 0.125 – 5 in. 0.09 – 40 in.
Quantity: 1 – 1000 1 – 1000000
Lead time: Days Hours
Advantages: Can produce very large parts
Can form complex shapes
Many material options
Low tooling and equipment cost
Scrap can be recycled
Short lead time possible
Disadvantages: Poor material strength
High porosity possible
Poor surface finish and tolerance
Seondary machining often required
Low production rate
High labor cost
Applications: Engine blocks and manifolds, machine bases, gears, pulleys
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