Engineering · Machining guide
How to machine 7075 aluminum.
7075 is the high-strength aerospace aluminum — landing-gear hardware, weapon platforms, drone airframes. The zinc-magnesium-copper alloy delivers ~85% higher tensile strength than 6061 with a small density penalty. Machining is similar to 6061 but with stress-corrosion considerations on T6 and slightly different tooling preferences.
01 · 7075 vs 6061 differences
Same family, slightly different machining.
7075 cuts at similar speeds to 6061 but with somewhat different chip behavior. The higher strength means cutting forces are higher, chip control is easier (chips break more readily), and built-up edge is less of a problem. Tool life is slightly shorter than 6061 due to the higher hardness.
The bigger consideration is temper choice for the application. 7075-T6 has the highest strength but is susceptible to stress-corrosion cracking in chloride-containing environments. 7075-T7351 is overaged for stability — slightly lower strength but much better SCC resistance. AMS 4078 covers T7351 plate; AMS 4124 covers T7351 bar and rod.
For machined parts that experience humidity, marine, or aggressive chemical service, T7351 is usually the right specification. T6 is fine for indoor or coated parts. See aluminum comparison for the broader trade-offs.
02 · Cutting parameters
Numbers that work.
| Operation | Tool | SFM | IPT / IPR |
|---|---|---|---|
| Roughing turn | Uncoated carbide | 800–1500 | 0.010–0.020 IPR |
| Finishing turn | Uncoated carbide | 1200–2000 | 0.005–0.010 IPR |
| Finishing turn | PCD | 2500–4000 | 0.005–0.010 IPR |
| End mill (rough) | Solid carbide 3FL | 700–1200 | 0.004–0.010 IPT |
| End mill (finish) | Solid carbide 3FL | 1000–1700 | 0.002–0.006 IPT |
| Drilling | Solid carbide | 250–400 | 0.005–0.012 IPR |
| Tapping | Spiral-flute HSS | 40–80 | — |
| Reaming | Solid carbide | 120–250 | 0.003–0.008 IPR |
IPT (chip-load) values assume roughly ½–1″ end mills; scale down for smaller tools — see the chip-load chart.
03 · Practical notes
What changes vs 6061.
- Tooling: uncoated polished carbide for best results — same as 6061. PCD inserts for high-volume production where the tool-life payback works.
- Coolant: water-soluble flood. Don’t use chlorinated coolants on T6 material destined for marine or humid service — chloride accelerates SCC on aged 7075.
- Stress-relief: 7075-T6 wrought plate has more residual stress than 6061-T6 because of the higher strength temper. Long, thin parts can move 0.010″+ during machining. T7351 plate (AMS 4078) is stretch-relieved and much more stable.
- Climb milling: mandatory in 7075 — same as 6061. Conventional milling re-cuts chips and creates burrs.
- Anodize: 7075 anodizes well. Type II for cosmetic, Type III for wear. The zinc-magnesium-copper alloying gives a slightly darker natural anodize tone than 6061.
- Common AMS: 4045 (T6 sheet), 4078 (T7351 plate), 4124 (T7351 bar/rod). For stability-critical structural plate, specify T7351.
Keep exploring
Related tools & references
Mechanical properties, UNS, AMS specs, and machinability at a glance.
Convert these SFM and IPT figures into spindle RPM and feed rate.
Recommended chip load by tool diameter for aluminum.
7075 aluminum density for part weight and stock estimates.
Strength, SCC resistance, and cost compared across aluminums.
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