Zinc vs Al Die Casting

Heavy + precise.
Light + everyday.
Both hot-injected.

Zinc (Zamak) and aluminum (A380 common) are the two main pressure die casting alloys. Zinc gives finer detail and tighter tolerance. Aluminum gives lighter parts and higher strength per weight. Decide by priority.

Get a Quote DFM guide

01 · At a glance

Side-by-side summary.

Option A

Zinc (Zamak 3 / Zamak 5)

Zinc-aluminum alloys. Lower melt temperature (380-400°C) — longer tool life. Finer detail, tighter tolerance, excellent surface finish. Heavier (6.6 g/cc). Common for hardware, locks, toys.

Option B

Aluminum (A380 / A383)

Aluminum-silicon-copper. Higher melt temperature (650-700°C) — shorter tool life. Lighter (2.7 g/cc), stronger at weight. Coarser detail than zinc. Automotive, consumer electronics, structural.

02 · Detailed comparison

Feature-by-feature breakdown.

Attribute	Zinc (Zamak 3)	Aluminum (A380)
Density (g/cc)	6.6	2.7
Tensile strength (MPa)	280	324
Hardness (HB)	82	80
Melt temperature (°C)	380-400	650-700
Casting tolerance	±0.05 mm	±0.1 mm
Minimum wall thickness	0.5 mm	1.0 mm
Surface finish as-cast	Excellent (Ra 1.6 µm)	Good (Ra 3.2-6.4 µm)
Tool life	500K-1M shots	100K-300K shots
Cycle time	Fast (20-30 sec)	Moderate (40-60 sec)
Cost per kg raw	$2-3	$2.50-4
Specific strength	Low	High
Typical applications	Locks, hinges, toys, hardware	Automotive, electronics, structural

03 · Decision guide

When to choose each.

Choose Zinc (Zamak 3 / Zamak 5) when:

Fine detail required (texture, fine features)
Tight tolerance (±0.05 mm)
Mass-production hardware
Locks and decorative hardware
Parts requiring plating (zinc plates beautifully)
Long tool life needed

Choose Aluminum (A380 / A383) when:

Weight-critical applications
Automotive structural components
Consumer electronics housings
Specific strength needed
Higher temperature service (up to 200°C)
When overall mass must be low

FAQ

Common questions.

Zinc's lower melt temperature allows longer fill time before solidification, better filling of fine detail, less thermal stress on tool. Result: finer features, tighter tolerance, better surface finish. Aluminum's higher temperature means faster solidification, more aggressive tool wear, less fine detail capability. For intricate decorative parts: zinc. For bulk structural: aluminum.

Zinc tools last 500K-1M shots typical. Aluminum tools 100K-300K typical. Tool cost same ($30K-100K+). Per-part tool cost: zinc significantly lower. Over production life of 1M parts: zinc tool cost $0.03-0.10 per part; aluminum $0.10-0.50 per part. Factor into total cost comparison. For very high volumes, zinc economics favor even more.

Per unit weight: aluminum significantly stronger (specific strength 120 vs 42 for zinc). For weight-critical applications (automotive, aerospace), aluminum better. For applications where weight doesn't matter (door hardware, locks, fittings): zinc's density is actually preferred (feels solid, stays put).

Zamak 3 (ZA-3): most common, general purpose. Zamak 5 (ZA-5): 1% copper for slightly higher strength, better creep resistance. Used for more demanding zinc applications. Zamak 2 (older): 3% copper, obsolete. ZA-8, ZA-12, ZA-27: higher aluminum content for bearing applications. Most zinc die casting: Zamak 3 or 5.

A380: most common die cast aluminum. 8-9% Si, 3-4% Cu. Good castability, moderate strength. A383: similar but lower iron — better paint/plating. A360: 9-10% Si, 0.5% Cu. Better corrosion resistance. A383 preferred for decorative applications; A380 for general industrial. All available from die cast suppliers.

Zinc: electroplates beautifully (chrome, nickel, brass). Standard for decorative hardware. Paint/powder coat also works. Aluminum: anodize possible (specify die cast alloy compatibility), powder coat standard, paint with proper primer. For premium decorative: zinc with chrome or gold plating. For industrial/automotive: aluminum with powder coat.