Zinc CNC Machining
Resolute Precision Manufacturing machines zinc alloy components for applications requiring a low-cost, easily machined material with good dimensional stability and compatibility with zinc electroplating and galvanic coating systems. Zinc is lighter than steel, easy to machine, and is the base material for Zamak die casting alloys where CNC machined inserts or secondary machining operations are required. ISO 9001 certified. 24-hour quote response. Request a QuoteWhen Zinc is the Right Material Choice
Zinc as a machined material occupies a specific niche: where die casting is the primary manufacturing process and secondary CNC machining is required for precision features, or where sacrificial anodic protection for steel corrosion protection is needed in a specific geometric form.
Zinc alloys — particularly the Zamak family (Zamak 3, Zamak 5) — are among the most fluent die casting alloys, enabling complex near-net-shape castings with excellent detail. When those castings require precision bores, threaded features, or tight-tolerance mating surfaces beyond the capability of die casting alone, secondary CNC machining brings the casting to final specification.
Zinc Material Characteristics
Zinc’s material characteristics determine its application range:
- Low melting point (787 degrees F for pure zinc; 720 degrees F for Zamak 3) — enables die casting at low temperatures with long die life
- Good machinability — zinc alloys machine readily at moderate cutting speeds with good surface finish
- Dimensional stability — zinc alloys are dimensionally stable after machining and aging; suitable for precision housings and covers
- Corrosion protection — zinc is anodically active relative to steel; zinc-coated hardware protects underlying steel by galvanic sacrifice
- Weight — zinc is approximately 40% heavier than aluminum but 25% lighter than steel
Specifications
| Alloys | Zamak 3 (ASTM AC41A), Zamak 5 (ASTM AG40A), and zinc alloy bar stock and castings |
| Turning | Bar-fed turning for zinc alloy components in production quantities |
| Milling | Vertical CNC milling for secondary machining of zinc die castings |
| Machinability | Excellent; supports high cutting speeds with superior surface finish and extended tool life |
| Tolerances | ±0.001″ standard; zinc die castings machined to ±0.001″ on precision features |
| Coatings | Chrome plating and nickel plating coordinated through qualified outside finishing providers |
| Certifications | ISO 9001:2015 |
Zinc Applications From RPM
Zinc CNC machined components from Resolute Precision serve die casting secondary machining and specialty zinc applications:
- Die cast housing secondary machining — precision bores, threaded features, and mating surfaces on zinc die castings
- Zinc sacrificial anodes — machined zinc anodes for cathodic protection of steel and aluminum structures
- Consumer hardware components — zinc alloy handles, knobs, and decorative hardware
- Automotive zinc die cast components — secondary machining of zinc die castings for automotive interior hardware
- Electrical hardware — zinc alloy connector shells and hardware with chrome or nickel plating
Industries We Serve
CNC Turning Services
CNC Milling Services
Custom Fasteners
Value-Added Services
Frequently Asked Questions
Q: Is zinc appropriate for structural load-bearing components?
A: Zinc alloys have moderate mechanical properties — Zamak 3 has a tensile strength of approximately 41 KSI and a yield strength of 32 KSI. This is sufficient for light structural applications such as covers, housings, and non-critical brackets but is not appropriate for high-load structural components where aluminum or steel is required.
Q: Can RPM machine zinc die castings directly from the casting?
A: Yes. We regularly perform secondary CNC machining on zinc die castings — drilling and tapping threaded ports, boring precision ID features, and facing mating surfaces. Send us a die casting drawing and we will quote the secondary machining operations required.
Q: What coating is most common on zinc machined components?
A: Chrome plating is the most common decorative coating for zinc die cast components — it produces the bright metallic appearance common in automotive trim, consumer hardware, and plumbing fixtures. Nickel plating is used for corrosion protection.
Q: Is zinc compatible with aluminum in an assembly?
A: Zinc is cathodic (nobler) relative to aluminum in the galvanic series. In an assembly with both zinc and aluminum in contact with an electrolyte, the aluminum will corrode preferentially. Proper isolation prevents galvanic attack.