Shenzhen Alu Rapid Prototype Precision Co., Ltd.
Industry News
Die casting and sand casting are metal casting processes used to produce metal parts, but they differ significantly in method, materials, precision, and applications. Below is a concise comparison:
1. Definition
Die Casting: Molten metal (e.g., aluminum, zinc, magnesium) is injected under high pressure into a reusable steel mold (die) to form precise parts.
Sand Casting: Molten metal is poured into a mold made of compacted sand, which is destroyed after each casting to remove the part.
2. Materials
Die Casting: Non-ferrous metals (aluminum, zinc, magnesium, copper alloys).
Sand Casting: Versatile; supports both ferrous (steel, iron) and non-ferrous metals (aluminum, brass, bronze).
3. Process
Die Casting:
High-pressure injection (10–175 MPa) into a steel die.
Fast cooling and ejection; dies are reused.
Hot-chamber (low-melting metals) or cold-chamber (high-melting metals) systems.
Sand Casting:
Sand is mixed with a binder, packed around a pattern to form a mold.
Molten metal is poured into the mold, cooled, and the sand is broken away to retrieve the part.
Molds are single-use; new molds are made for each casting.
4. Equipment
Die Casting: Expensive steel dies, high-pressure injection machines, furnaces.
Sand Casting: Simple tools (patterns, flasks), sand mixers, and furnaces; less complex machinery.
5. Part Characteristics
Die Casting:
High precision (±0.02 mm) and excellent surface finish.
Thin walls (1–2 mm) and complex geometries possible.
Potential for porosity, requiring secondary processing.
Sand Casting:
Lower precision (±0.8–1.5 mm) and rougher surface finish.
Thicker walls (minimum 3–5 mm) and simpler shapes.
Fewer internal defects but may have surface imperfections.
6. Production
Die Casting:
High-volume production; fast cycle times (seconds to minutes).
Ideal for thousands to millions of parts.
Sand Casting:
Low to medium volumes; slower process due to mold creation.
Suited for one-off, prototype, or small batches (1–1,000 parts).
7. Cost
Die Casting:
High initial tooling costs (steel dies: $10,000–$100,000+).
Low per-part costs at high volumes.
Higher material costs (non-ferrous metals).
Sand Casting:
Low tooling costs (patterns: $500–$5,000; sand is cheap).
Higher per-part costs due to labor and mold recreation.
Material costs vary (ferrous metals can be expensive).
8. Advantages
Die Casting:
High accuracy and smooth surfaces reduce post-processing.
Fast production for large quantities.
Consistent quality for complex, thin-walled parts.
Sand Casting:
Low setup costs, ideal for prototypes or low volumes.
Handles large parts (up to tons) and a wide range of metals.
Flexible for design changes (patterns are easily modified).
9. Disadvantages
Die Casting:
High initial investment limits use to high-volume runs.
Restricted to non-ferrous metals.
Porosity can affect part strength.
Sand Casting:
Poor dimensional accuracy and rough surfaces require machining.
Labor-intensive and slower for large quantities.
Sand disposal and environmental concerns.
10. Applications
Die Casting:
Automotive (engine blocks, transmission housings).
Electronics (heatsinks, enclosures).
Consumer goods (tool housings, fittings).
Sand Casting:
Heavy machinery (engine bases, pump housings).
Art/sculptures (bronze statues).
Prototypes and large castings (turbine casings, manhole covers).
Summary
Choose Die Casting for high-volume, precise, complex, non-ferrous metal parts with excellent surface finish, like automotive or electronic components.
Choose Sand Casting for low-volume, large, or prototype parts, especially when using ferrous metals or when cost-effective tooling is needed.