What is aluminum CNC machining?
Aluminum CNC machining is the production of precision parts from aluminum alloys by milling and turning. Aluminum is the most widely machined material: it weighs about a third as much as steel, machines very quickly and can be both protected and coloured by anodizing.
Machine housings, mounting plates, brackets, fixtures, electronics enclosures, heat sinks and automation parts are typical aluminum CNC parts. See our Aluminum page for material properties and our CNC machining page for all CNC options.
Aluminum alloys
| Alloy | Key property | Weldability | Typical use |
|---|---|---|---|
| 6061-T6 | Balance of strength, machinability and corrosion resistance | Good | Housings, brackets, fixtures, general parts |
| 6082-T6 | Similar to 6061, very common in Europe | Good | Machine and structural parts |
| 7075-T6 | Very high strength | Poor | Aerospace, defence, load-bearing parts |
| 2024-T3 | High fatigue strength | Poor | Aerospace structures |
| 5083 | Marine resistant, good weldability | Very good | Marine, tanks, pressure parts |
| Cast plate (5083-based) | Stress-relieved, very flat | Good | Tooling, fixtures and plates needing flatness |
Not sure which alloy fits? Read the Academy guide Aluminum 6061 vs 7075.
Why is aluminum CNC machining economical?
- High cutting speeds: aluminum machines several times faster than steel and stainless steel.
- Low tool wear: long tool life.
- Easy chip control: especially 6061 and 7075 produce clean chips.
- Low weight: easier shipping and assembly.
That is why the same part is usually made faster and at lower cost in aluminum than in steel.
Tolerances and surface finish
| Feature | Standard | On request |
|---|---|---|
| General tolerance | ISO 2768-m | ISO 2768-f |
| Critical dimensions | ±0.05 mm | ±0.01–0.02 mm |
| Hole fits | H8 / H9 | H7 |
| Surface roughness | Ra 1.6–3.2 µm | Ra 0.8 µm |
For how tolerances affect cost, see our CNC tolerances guide.
Surface finishes
| Finish | What it provides | Note |
|---|---|---|
| Anodizing (Type II) | Corrosion protection and colour (black, blue, red, clear) | Slightly changes dimensions |
| Hard anodizing (Type III) | High wear resistance | For sliding and wear surfaces |
| Bead blasting + anodizing | Uniform matte look | Common in consumer products |
| Chromate conversion coating | Conductive corrosion protection | Electronics and grounding surfaces |
| Powder coating | Thick, durable coloured coating | Outdoor parts |
| Brushing / polishing | Decorative finish | Visible surfaces |
For anodizing types and design tips, see What Is Anodizing?.
Design guidelines
- Keep minimum wall thickness around 0.8 mm in metal; thinner walls chatter.
- Leave internal corner radii of at least 1/3 of pocket depth.
- Aluminum is soft, so consider helicoils or threaded inserts for frequently assembled screw joints.
- Account for coating thickness on precise fits that will be anodized, or request masking.
- State alloy and temper (e.g. 6061-T6) on the drawing.
What drives the price
- Alloy: 7075 and 2024 cost more than 6061/6082.
- Material removal and number of set-ups.
- Tolerances and surface finish.
- Anodizing colour and masking needs.
- Quantity: set-up cost is spread across the batch.
What we need for a quote
- 3D model in STEP format
- PDF drawing with tolerances and threads
- Alloy and temper (e.g. 6061-T6, 7075-T6)
- Quantity, surface finish and anodizing colour
- Any material certificate requirement
Frequently asked questions
Which alloy should I choose for aluminum CNC machining?
For most general-purpose parts, 6061-T6 or 6082-T6 is the right choice. Choose 7075-T6 for very high strength, and 5083 for marine environments or welding.
Can aluminum parts be anodized?
Yes. Clear, black and coloured anodizing as well as hard anodizing are available. As the coating slightly changes dimensions, note it on the drawing for precise fits.
What is the difference between 6061 and 6082?
Both have similar properties. 6082 is more common in Europe and Türkiye, while 6061 is more common in US standards. In most applications they are interchangeable.
Is aluminum CNC machining cheaper than steel?
In most cases yes. Aluminum machines much faster with low tool wear, so the part price for the same geometry is usually lower.