Comparing zinc and aluminum die casting on cost is harder than it looks. The material cost per kilogram is one number, but it is dwarfed by the cycle time, the tooling cost, the finishing cost, and the reject rate. A a plater who buys on material price alone often gets the wrong answer, because the cheaper alloy ends up costing more per finished part.
The right way to compare is on total cost per acceptable part out the door, including material, machine time, labor, tooling amortized over the production volume, finishing (deburring, polishing, plating), and the expected reject rate. Each each line item behaves differently between the two alloys, and the relative weight depends on the volume and the part geometry.
This article walks through each cost line, gives typical industry ranges, and ends with a decision rule. Use it as a sanity check on a vendor quote, not as a replacement for one.
Material Cost per Kilogram
The raw material cost is the easiest line to compare. As of late 2026, the relevant ranges are:
| Alloy | Spot price band | Density | Relative material cost per cm³ |
|---|---|---|---|
| Zamak 3 | $2.80 to $3.40/kg | 6.6 g/cm³ | 1.0× baseline |
| Zamak 5 | $2.80 to $3.40/kg | 6.7 g/cm³ | 1.0× baseline |
| A380 aluminum | $2.50 to $3.10/kg | 2.7 g/cm³ | 0.4× baseline |
| ADC12 aluminum | $2.50 to $3.10/kg | 2.7 g/cm³ | 0.4× baseline |
On a per-kilogram basis, zinc and aluminum are similar. On a per-volume basis, aluminum is roughly 40% the cost because it is so much less dense. For a part where weight matters and volume is constant, aluminum wins on material. For a part where the casting cost dominates, the material line is small.
The material cost per part is usually 10% to 25% of the total cost per part. For a high-volume part, it is closer to 10%. For a low-volume part, it can climb to 30% as machine and labor lines get amortized over fewer parts. The material line alone is rarely the deciding factor.
Tooling Cost
Tooling is the biggest single line on a low-volume program and the line where zinc and aluminum differ most in absolute terms. The rough ranges:
| Tooling type | Zinc mold | Aluminum mold |
| Single-cavity prototype | $5,000 to $15,000 | $10,000 to $25,000 |
| Production 4-cavity | $30,000 to $60,000 | $50,000 to $100,000 |
| High-volume 8-cavity | $60,000 to $120,000 | $100,000 to $200,000 |
| Multi-slide, complex geometry | $80,000 to $200,000 | $150,000 to $400,000 |
Aluminum tools cost more because the steel has to withstand higher temperatures, higher injection pressures, and more aggressive cooling. A a Zamak mold can run on P20 tool steel with a basic cooling layout; an A380 mold needs H13 cavities and often conformal cooling. The steel cost and the machining time both go up.
Tooling life tells the same story. A a Zamak mold routinely runs a million to three million shots before cavity rework. A an A380 mold runs 200,000 to 500,000 shots before similar rework. The amortized tooling cost per part:
| Volume | Zinc ($/part) | Aluminum ($/part) |
| 50,000 parts/year | $0.60 to $1.20 | $1.00 to $2.00 |
| 200,000 parts/year | $0.15 to $0.30 | $0.25 to $0.50 |
| 1,000,000 parts/year | $0.03 to $0.06 | $0.05 to $0.10 |
On every volume tier, zinc tooling amortizes 30% to 50% cheaper than aluminum. For a high-volume program, this line is the single biggest reason zinc wins on total cost.
Cycle Time and Machine Cost
Cycle time for the same part is faster on zinc because of the lower melting point and faster solidification. Typical numbers for a 200 g part:
| Operation | Zinc cycle | Aluminum cycle |
| Injection | 0.05 to 0.1 s | 0.05 to 0.15 s |
| Cooling | 8 to 20 s | 20 to 50 s |
| Eject and reset | 3 to 5 s | 3 to 5 s |
| Total cycle | 12 to 25 s | 25 to 60 s |
Aluminum takes roughly twice as long per cycle. For a high-volume program running 24/7, that difference is the difference between two shifts and three shifts. The machine cost per part reflects this:
| Volume | Zinc ($/part) | Aluminum ($/part) |
| 50,000 parts/year | $0.40 to $0.80 | $0.80 to $1.50 |
| 200,000 parts/year | $0.10 to $0.20 | $0.20 to $0.40 |
| 1,000,000 parts/year | $0.02 to $0.04 | $0.04 to $0.08 |
The machine cost per part for zinc is roughly half of aluminum at every volume. This is the second biggest reason zinc wins on total cost for medium and high volumes.
Finishing Cost Difference
Finishing is where the cost gap reverses for some parts. Zinc is softer and easier to grind and polish. Aluminum is softer still but more prone to smearing, which can hide defects rather than remove them.
For parts that go to bright chrome (bathroom, hardware, decorative):
| Step | Zinc | Aluminum |
| Deburring | Easy, fast | Easy, fast |
| Polishing | Easy, 2 to 3 steps | Harder, 3 to 4 steps, needs special compounds |
| Plating | Standard copper-nickel-chrome stack | Needs special zincate pre-treatment |
| Plating cost | Baseline | 1.3× to 1.8× baseline |
The plating pre-treatment for aluminum is the big difference. Aluminum forms an instant oxide layer that prevents plating adhesion. The plater has to dip the part in a zincate solution to deposit a thin zinc film, then plate on top of that. The extra step adds 15% to 30% to the plating cost and adds a reject risk if the zincate bath is out of balance.
For parts that paint instead of plate (toys, appliance, automotive interior), the gap is smaller. Both alloys paint well with proper prep. The cost difference is mostly the extra paint needed to cover the harder aluminum surface.
Total Cost Per Part
Putting it all together, the total cost per acceptable part (including reject rate) for a typical mid-volume part:
| Cost line | Zinc ($/part) | Aluminum ($/part) |
| Material | $0.40 | $0.15 |
| Tooling (amortized) | $0.20 | $0.35 |
| Machine time | $0.15 | $0.30 |
| Labor | $0.25 | $0.30 |
| Finishing and plating | $0.80 | $1.20 |
| Reject allowance (2 to 5%) | $0.10 | $0.12 |
| Total | $1.90 | $2.42 |
These are rough numbers for a 200 g decorative part at roughly 200,000 parts per year. The exact figures depend on the region, the plating spec, and the part geometry, but the order of magnitude is right: zinc costs roughly 80% of aluminum on a total-cost basis for this kind of part.
For a structural part without plating, the gap narrows:
| Cost line | Zinc ($/part) | Aluminum ($/part) |
| Material | $0.40 | $0.15 |
| Tooling (amortized) | $0.20 | $0.35 |
| Machine time | $0.15 | $0.30 |
| Labor | $0.20 | $0.25 |
| Finishing (deburr only) | $0.15 | $0.15 |
| Reject allowance | $0.05 | $0.05 |
| Total | $1.15 | $1.25 |
For non-decorative parts, zinc and aluminum end up close on total cost, with the decision driven by weight, strength, and corrosion needs rather than price.
When Zinc Wins, When Aluminum Wins
Zinc wins on total cost when:
- The part is decorative and goes through plating or paint.
- The volume is medium to high (above 50,000 parts/year) so tooling amortizes well.
- The geometry is complex with internal features, ribs, and bosses that zinc fills easily.
- Weight is not a constraint and the customer values the metal feel.
- The plating spec is standard — chrome, satin nickel, brass, bronze, or matte black.
Aluminum wins on total cost when:
- Weight matters for the customer — aerospace, portable, handheld.
- The plating spec is exotic — anodizing, hard coat, or specialty finishes that work better on aluminum.
- The part runs hot above 120 °C continuous, where Zamak softens.
- Corrosion resistance matters without plating — aluminum forms a protective oxide layer naturally.
- The strength-to-weight ratio is the spec — automotive structural, aerospace, defense.
The decision rule:
- If the part is decorative, plated, complex geometry, and high volume → zinc.
- If the part is structural, weight-sensitive, runs hot, or needs anodizing → aluminum.
- If the part fits both categories, run the total cost analysis above.
Decision Matrix
For a quick triage at the design stage:
| Question | Zinc | Aluminum |
| Plated finish required? | Yes → Zinc | No → Continue |
| Weight budget tight? | No → Zinc | Yes → Aluminum |
| Volume above 50k/year? | Yes → Zinc | No → Either |
| Continuous temp above 120 °C? | No → Zinc | Yes → Aluminum |
| Anodizing required? | No → Continue | Yes → Aluminum |
| Complex internal geometry? | Yes → Zinc | No → Either |
Three or more “Zinc” answers and zinc wins. Three or more “Aluminum” answers and aluminum wins. Mixed answers mean running the total cost analysis.
Making the Call
Zinc and aluminum are both reasonable choices for die casting, and the total cost gap is rarely huge. The right answer depends on the part’s end requirements, the volume, and the finishing spec. Material cost is the smallest line; tooling and cycle time dominate for high volume, and finishing dominates for decorative parts.
The first step is the same as for any material choice: pull the part print, identify the must-haves (metal feel, plating finish, dimensional accuracy, weight budget, temperature), and pick the alloy that meets them at the lowest total cost. A a 30-minute review at this stage saves a year of cost surprises later.
For plants comparing zinc and aluminum for the first time, the pilot project is the right path. Pick one part, run it through both alloys (or simulate the cost with vendor quotes), and measure the total cost against the part requirements. A a single pilot project answers more questions than a week of vendor meetings.
A Door Hardware Maker’s Alloy Switch
A mid-sized door hardware maker in the Foshan region had been running a decorative lever set in A380 aluminum. The set shipped in six finishes — bright chrome, satin nickel, oil-rubbed bronze, polished brass, matte black, and antique brass. Volume was roughly 400,000 sets per year. The aluminum levers cost $2.10 per set finished, of which $0.45 was plating cost (the zincate pre-treatment plus the standard plating stack).
The maker considered switching to Zamak 5 for two reasons: the plating cost on aluminum was eating margin, and the cycle time on the aluminum tool (32 seconds) was limiting capacity. The maker ran a pilot on the most popular finish (bright chrome) and found the Zamak 5 version cost $1.65 per set finished, of which $0.20 was plating cost. Total saving was $0.45 per set, or $180,000 per year on this finish alone.
The maker switched the full line to Zamak 5 over eighteen months as the existing aluminum tools reached end of life. The plating cost dropped because the zincate pre-treatment was eliminated, the cycle time dropped from 32 seconds to 19 seconds (freeing up machine capacity for other parts), and the reject rate on the plating line dropped from 2.1% to 1.3% because Zamak 5 takes plating more consistently than A380.
The the upfront cost was real: six new molds at roughly $40,000 each, totaling $240,000 in tooling. Payback from the per-set saving was eighteen months, and the maker also picked up an additional 20% capacity on the casting machines that the faster cycle time delivered.
The lesson is that zinc die casting is rarely the wrong answer for a decorative part at committed volume. A a part with uncertain volume stays with the alloy that requires the smallest upfront investment, which is usually aluminum or plastic. A a part with committed volume and a plating finish usually rewards a switch to Zamak within two years of payback.
