About This Service
Sand casting is the oldest, most versatile and most widely used metal casting process, in which molten metal is poured into a one-off sand mold shaped around a pattern of the desired part, allowed to solidify, and then released by breaking the sand mold away - yielding the unique ability to produce very large parts in nearly any castable alloy, with low tooling cost, rapid lead time for prototypes and one-offs, and economical production across small batches and medium volumes. A pattern (typically wood, plastic, aluminum or steel) of the external shape of the part is placed in a molding box (flask), and sand mixed with a binder is rammed around it to form the cope and drag mold halves; separately formed sand cores are inserted into the mold to create internal cavities and undercuts, the pattern is withdrawn to leave a cavity in the shape of the part, the two mold halves are clamped together, and molten metal is poured through a sprue, flowing through runners and gates into the cavity, where it cools and solidifies before the casting is shaken out, the sand is removed, the cores are broken out, and the casting is fettled, ground and inspected. Three principal binder systems are used - green sand (clay-bonded), resin-bonded (furan or phenolic urethane) and chemically hardened (sodium silicate or phenolic-ester) - and the process accepts almost any castable alloy, including gray and ductile iron, carbon and low-alloy steel, stainless steel, tool steel, aluminum alloys, copper alloys (brass, bronze), nickel-based superalloys and cobalt-based alloys, an alloy breadth that is one of sand casting's principal advantages over die casting. Sand casting is suitable for parts ranging from a few hundred grams to hundreds of tons, offers low tooling cost compared to die casting because the sand molds are expendable, is economical for small batches, prototypes and one-offs, accommodates complex internal cavities, undercuts and variable wall thicknesses, and delivers rapid lead times when patterns are kept on hand - making it the process of choice for heavy machinery such as pump housings, valve bodies, gearbox cases and turbine components, automotive engine blocks in low-volume and heavy-duty applications, cylinder heads and brake components, construction equipment and mining machinery, marine propellers, rudder frames and shipboard fittings, architectural and artistic castings, and railway components such as bogie frames, couplers and brake shoes.
Three Size Classes: What We Pour
In addition to the regular products that we already produce.
Class A - Small Precision (0.5-5 kg)
Tolerance plus/minus 0.5-1.0 mm. Surface finish Ra 6.3-12.5 micrometer. Common materials: gray iron, ductile iron, aluminum. Pattern type: aluminum or resin. Typical parts: valve components, pump impellers, gear blanks.
Class B - Medium Castings (5-50 kg)
Tolerance plus/minus 1.0-1.5 mm. Surface finish Ra 12.5-25 micrometer. Common materials: iron, steel, aluminum, brass. Pattern type: wood, aluminum, 3D sand. Typical parts: pump housings, valve bodies, machinery bases.
Class C - Large Castings (50-200 kg)
Tolerance plus/minus 1.5-2.5 mm. Surface finish Ra 25-50 micrometer. Common materials: gray iron, ductile iron, carbon steel. Pattern type: wood or resin. Typical parts: heavy machinery bases, large pump casings, machine tool beds.
4 Common Defects and How We Prevent Them
Know these defects before you place an order. They are preventable with proper design and process control.
Sand Inclusions (Hard Spots)
Cause: Sand grains break loose from mold surface and become embedded. Prevention: Apply mold wash, control sand moisture, proper sand compaction.
Porosity (Voids Inside Casting)
Cause: Gas trapped in molten metal during solidification, or shrinkage during cooling. Prevention: Design risers, vent the mold, control pouring temperature.
Cold Shuts (Visible Seams)
Cause: Molten metal too cold or pouring too slow, premature solidification. Prevention: Pour 50-100 degrees C above alloy melting point, pour continuously.
Hot Tears (Cooling Cracks)
Cause: Tensile stress from non-uniform cooling combined with low ductility. Prevention: Uniform wall thickness, fillets at corners, proper riser placement.
Why Choose Our Sand Casting
0.5-500 kg Range
From small precision parts (Class A) to heavy industrial castings (Class C). Few foundries handle this range.
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Sample Products We Make
Click any product to inquire about a similar part for your application.
