# Die Casting: Aluminum and Zinc Parts at Scale

> How die casting works, when it beats machining, and quality points to check.

Source: https://goodsfromchina.com/resources/die-casting-aluminum-and-zinc-parts-at-scale/
Updated: 2026-10-18

## Key takeaways

- Die casting suits complex aluminum and zinc parts in thousands.
- Porosity, flash and machined features are the main quality points.
- Compare die cost plus unit price against machining at your volume.

Die casting forces molten aluminum or zinc into a steel die under high pressure. It produces complex, near-net-shape metal parts at high volume.

## When it makes sense

- Volumes from a few thousand parts upward.

- Complex shapes with ribs, bosses and thin walls.

- Housings, heat sinks, brackets and hardware.

## Quality points

- **Porosity** — trapped gas; critical for pressure-tight or plated parts. X-ray inspection can find it.

- **Flash and parting lines** — removed by trimming.

- **Dimensional stability** — machined features need secondary CNC work.

## Cost structure

Die cost is significant, but unit prices fall sharply with volume. Always compare against machining at your expected quantity.

## Aluminum vs. zinc die casting

- **Aluminum (ADC12, A380)** — light, strong, good heat dissipation; cold-chamber machines; typical for housings, heat sinks and automotive parts.

- **Zinc (Zamak 3, Zamak 5)** — excellent detail and surface for plating; hot-chamber machines with faster cycles; typical for hardware, handles and small decorative parts.

## Secondary operations

Most die castings need trimming, deburring and CNC machining of critical faces and threads, then a finish: powder coating, painting, anodizing (limited on casting alloys) or plating for zinc. Include these steps in the quote so prices are comparable.

## Die cost and life

Die-casting dies typically cost US$5,000–50,000+ depending on size and complexity. Aluminum dies wear faster than zinc dies because of higher temperatures — often around 80,000–150,000 shots for aluminum, several hundred thousand for zinc.

See [die casting in China](https://goodsfromchina.com/manufacturing/die-casting/).

## Checklist

- [ ] Choose aluminum or zinc by function and finish
- [ ] Include trimming and machining in quotes
- [ ] X-ray critical or pressure-tight parts
- [ ] Confirm die ownership and life
- [ ] Agree finish tests before production

## Frequently asked questions

### When is die casting cheaper than CNC machining?

Usually from a few thousand parts per year upward, when the die cost is spread over enough units and the part shape suits casting.

### What is porosity in die casting?

Small gas or shrinkage voids inside the casting. It matters for pressure-tight, structural or plated parts and can be checked with X-ray or sectioning.


## Related services

- [Die Casting](https://goodsfromchina.com/manufacturing/die-casting/)
- [Zinc Alloy](https://goodsfromchina.com/materials/zinc-alloy/)
- [Automotive & Aftermarket](https://goodsfromchina.com/industries/automotive-aftermarket/)