CNC machining
Use sharp carbide with high positive rake and high spindle speeds. T651 plate stays flat when frames are pocketed from one side.
3C electronics sheet guide
6061 Aluminium Sheet and Plate for 3C Electronics
6061 is the default aluminium for machined electronics parts: CNC-milled phone mid-frames, tablet and laptop shells, camera bodies, SIM trays and the fixtures used to make them. In T6 it gives a reliable 276 MPa typical yield strength, machines cleanly and takes a uniform anodised finish, and it is available everywhere. This guide explains which temper to buy, what finish quality to expect and where 6061 stops being the best choice.
- Alloy
- 6061 (Al-Mg-Si-Cu)
- Tempers
- O, T4, T6, T651
- Thickness
- about 0.4 – 12.5 mm sheet
- T6 yield
- 276 MPa typical
Why 6061 is used in 3C products
3C stands for computers, communications and consumer electronics. Aluminium parts in these products have to be light, stiff, precise and good-looking, and most are produced by CNC machining, stamping or a combination of the two followed by anodising.
6061 meets that brief at a low cost. Its magnesium and silicon give a heat-treatable strength that is about twice that of 5052, a small copper addition raises strength further, and chromium keeps the grain structure fine. In T6 or T651 it cuts with short chips and a bright surface, holds tolerance during heavy machining, and anodises to a hard, even film suitable for dyed colours.
For thin, drawn or bent housings, 6061 can be formed in O or T4 and then aged; for milled unibody parts, T6 or stress-relieved T651 plate is machined directly. Where higher dent resistance is wanted, designers move up to 6013 or 7xxx alloys; where the finest cosmetic finish matters more than strength, 6063 is an option.
6061 chemical composition (wt %)
| Element | Limit |
|---|---|
| Silicon (Si) | 0.40 – 0.8 |
| Iron (Fe) | ≤ 0.7 |
| Copper (Cu) | 0.15 – 0.40 |
| Manganese (Mn) | ≤ 0.15 |
| Magnesium (Mg) | 0.8 – 1.2 |
| Chromium (Cr) | 0.04 – 0.35 |
| Zinc (Zn) | ≤ 0.25 |
| Titanium (Ti) | ≤ 0.15 |
| Others each / total | ≤ 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Aluminum Association / EN 573-3 limits. For cosmetic anodising, tighter internal limits on iron and silicon help produce a cleaner, more uniform appearance; agree them with the supplier if colour consistency is critical.
6061 sheet properties by temper
| Temper | Tensile strength | Yield strength | Elongation | Use in 3C |
|---|---|---|---|---|
| O, specified (ASTM B209) | ≤ 152 MPa | ≤ 83 MPa | ≥ 14 – 18 % | Deep forming, then heat treatment |
| T4, specified | ≥ 207 MPa | ≥ 110 MPa | ≥ 14 – 16 % | Bending and drawing, then ageing |
| T6, specified | ≥ 290 MPa | ≥ 240 MPa | ≥ 8 – 10 % | Design minimum for finished parts |
| T6, typical | 310 MPa | 276 MPa | 12 % | Finished parts |
Specified ranges depend on thickness band; the certificate gives the actual values.
Physical properties (T6)
- Density
- 2.70 g/cm³
- Thermal conductivity
- about 167 W/m·K
- Electrical conductivity
- about 43 % IACS
- Modulus of elasticity
- 68.9 GPa
- Hardness
- about 95 HB
Machining, finishing and anodising 6061
Stamping and bending
Form in T4 with radii of about 1 × thickness, then age. T6 needs roughly 1.5 – 3 × thickness for bends.
Surface prep
Bead blasting, brushing or diamond cutting create the texture before anodising. Even grain gives a uniform look.
Decorative anodising
Sulphuric (Type II) films of about 10 – 25 µm, dyed in black, grey, blue and other colours, then sealed.
Hard anodising
Type III films of about 25 – 50 µm for wear-prone parts such as buttons and trays.
Watch points
Coarse grains, iron-rich particles and rolling streaks show after anodising; specify a cosmetic or anodising-quality surface.
3C parts made from 6061
- Phone mid-frames and housings machined from plate, combining stiffness with low weight
- SIM trays, internal brackets and side buttons, often hard-anodised
- Tablet and laptop shells milled or formed and anodised
- Camera parts: lens housings, body shells and mounts
- Production fixtures and test jigs used on electronics assembly lines, usually from T651 plate
- Heat spreaders and brackets where moderate conductivity is adequate
Supply range and tolerances
Typical supply
- Thickness
- about 0.4 – 12.5 mm sheet; thicker T651 plate for machined parts
- Width
- about 600 – 2,100 mm
- Length
- about 1,000 – 12,000 mm, or coil and slit strip
- Tempers
- O, T4, T6, T651
- Standards
- ASTM B209, EN 485, GB/T 3880
- Tolerances
- Standard tables, or precision-rolled thickness tolerance on thin gauges by agreement
- Certificate
- EN 10204 3.1 with chemistry and mechanical properties
6061 versus other 3C sheet alloys
| Alloy | Typical T6 / H yield | Anodised appearance | Notes |
|---|---|---|---|
| 5052-H32 | 193 MPa | Good, slightly yellow | Formable, not heat-treatable |
| 6063-T6 | 214 MPa | Excellent | Best finish, lower strength |
| 6061-T6 | 276 MPa | Very good | Balanced default |
| 6013-T6 | about 340 – 350 MPa | Good, warmer tone | Stronger 6xxx option |
| 7075-T6 | 503 MPa | Fair – good | Highest strength, harder to finish |
References and standards
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- EN 485-2 – Aluminium and aluminium alloys: sheet, strip and plate, mechanical properties
- MIL-PRF-8625 – Anodic Coatings for Aluminum and Aluminum Alloys (Type II and Type III)
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
6061 3C sheet: frequently asked questions
Is 6061 good for phone housings?
Yes. It is strong enough for most frames, machines well and anodises evenly. For thinner, more dent-resistant housings, 6013 or 7xxx alloys are used.
Which temper of 6061 aluminum is used for CNC-machined electronics parts?
T6 for thin sheet and T651 for plate. T651 is stress-relieved by stretching, so parts stay flat when pockets are milled.
Can 6061 sheet be bent before anodising?
Yes. Bend in T4 and age to T6 afterwards, or bend T6 using generous radii of about 1.5 – 3 × thickness.
What anodised colours work on 6061?
Clear, black, grey, blue, red, gold and most dyed colours. Production trials on the supplied sheet are recommended for colour matching.
Can you supply 6061 in coil for stamping?
Yes, as coil or slit strip, as well as cut sheet and plate.
Need 6061 sheet or plate for electronics?
Send temper, thickness, size and quantity. Metline will reply with availability, certification and delivery terms.
