Quick Answer
Zinc die casting vs aluminum die casting — zinc has lower melting point, excellent castability, and can achieve thinner walls and tighter tolerances; aluminum is lighter, stronger, and has better thermal properties. For OEM buyers, zinc is for small, high-precision parts with thin walls; aluminum is for larger, structural parts where weight or thermal properties matter.
Material Properties Comparison
| Property | Zinc (Zamak 3/5) | Aluminum (A380/A356) |
|---|---|---|
| Density | 6.6–6.7 g/cm³ | 2.6–2.7 g/cm³ |
| Tensile strength | 300–400 MPa | 220–300 MPa |
| Yield strength | 200–300 MPa | 150–220 MPa |
| Hardness | 80–110 HB | 70–100 HB |
| Thermal conductivity | 100–130 W/m·K | 150–200 W/m·K |
| Melting point | 380–420°C | 580–650°C |
| Corrosion resistance | Good (protective oxide) | Excellent (stable oxide) |
Die Casting Capability Comparison
| Factor | Zinc Die Casting | Aluminum Die Casting |
|---|---|---|
| Tooling cost | $15,000–$80,000 | $20,000–$150,000 |
| Tooling life | 200,000–500,000 shots | 100,000–300,000 shots |
| Tolerance | ±0.05–0.2 mm | ±0.1–0.25 mm |
| Surface finish | Ra 0.4–1.6 µm (excellent) | Ra 0.8–3.2 µm |
| Minimum wall thickness | 0.3–0.8 mm | 0.8–1.5 mm |
| Minimum part size | 0.5 grams | 5 grams |
| Maximum practical part size | 2–5 kg | 20 kg+ |
| Production rate | 150–600 parts/hour | 100–300 parts/hour |
When Zinc Die Casting Wins
Zinc die casting is the right choice when:
- Part is small (under 2–5 kg). Zinc excels at small, high-precision parts.
- Thin walls (0.3–0.8 mm). Zinc’s low melting point and excellent fluidity make very thin walls possible.
- Excellent surface finish (Ra 0.4–1.6 µm). Zinc die casting produces a mirror-smooth surface that needs no post-processing.
- Tolerance of ±0.05–0.2 mm. Zinc can hold tighter tolerance than aluminum.
- High production rate (150–600 parts/hour). Zinc cycles faster because of lower melting point.
- Long tooling life (200,000–500,000 shots). Zinc is gentler on dies than aluminum.
When Aluminum Die Casting Wins
Aluminum die casting is the right choice when:
- Weight matters. Aluminum is 2.5× lighter than zinc; critical for automotive/portable applications.
- Part is large (over 2–5 kg). Aluminum scales better for larger parts.
- Thermal properties matter. Aluminum has much better thermal conductivity — for heat sinks, thermal management parts.
- Electrical conductivity. Aluminum is a good conductor; zinc is not typically used for electrical parts.
- Strength-to-weight ratio. Aluminum’s lower density gives better specific strength.
- Material cost is important. Aluminum raw material cost is usually lower than zinc.
Cost Comparison
| Factor | Zinc | Aluminum |
|---|---|---|
| Raw material cost | $$ | $ |
| Tooling cost | $$–$$$ | $$–$$$$ |
| Per-part cost (low volume) | $$$ | $$ |
| Per-part cost (high volume) | $–$$ | $–$$ |
Raw material costs vary with market price.
Application Fit
Zinc Die Casting Typical Applications
- Consumer electronics housings and frames
- Zippers, fasteners, hardware
- Door handles, window hardware
- Lock mechanisms
- Decorative trim and appearance parts
- Precision gears and small mechanical parts
Aluminum Die Casting Typical Applications
- Automotive engine parts, transmission housings
- Automotive structural brackets
- Heat sinks and thermal management parts
- Consumer electronics enclosures
- Motor housings, pump housings
- Lightweight structural parts
Buyer Decision Checklist
- What is part size?
- Is weight a critical requirement?
- What tolerance is needed?
- What surface finish is needed?
- Does part need thermal or electrical conductivity?
- What is realistic annual volume?
- Is decorative appearance important?
Before finalizing the sourcing decision, many OEM buyers also compare Aluminum Casting Buyer Guide, Gravity Die Casting, and Casting Tolerances to clarify process fit, cost trade-offs, tolerance expectations, and supplier risk.
If you need application-specific guidance, drawing review, or a quotation, you can Contact YCUMETAL.
FAQ
Which is cheaper for small parts?
At high volume, zinc and aluminum are competitive. Zinc has higher material cost but lower tooling maintenance and faster cycle time; aluminum has lower material cost but higher tooling wear.
Can you cast the same part in both zinc and aluminum?
For small parts, yes — but the die design is different. Zinc dies can handle thinner walls; aluminum dies need thicker sections and larger runners.
Which has better corrosion resistance?
Both form stable oxide layers that protect the metal. Aluminum is usually considered more corrosion-resistant, especially in outdoor applications. Zinc also performs well, especially with plating or coating.