Material Comparison Table
* Cost ratings based on raw material + machining time combination. Actual cost depends on part geometry, quantity, and surface finish requirements.
| Material | Machinability | Tensile Strength | Corrosion Resistance | Typical Applications | Relative Cost | Common Alloys |
|---|---|---|---|---|---|---|
| Aluminum | ★★★★★ Excellent | 270-570 MPa | ★★★★ Good (self-passivating) | Aerospace brackets, automotive, EV battery, enclosures | $ (Low) | 6061-T6, 7075-T6, 2024-T3, 5083 |
| Stainless 304/316 | ★★★☆☆ Moderate | 480-620 MPa | ★★★★★ Excellent | Food, medical, marine, valve trim, fittings | $$ (Medium) | 304, 316L, 303 (free-machining) |
| Stainless 17-4PH | ★★★☆☆ Moderate | 1000-1300 MPa | ★★★★ Excellent | Aerospace fasteners, valve stems, medical instruments | $$$ (Medium-High) | 17-4PH H900-H1150 |
| Titanium Ti-6Al-4V | ★★☆☆☆ Difficult | 900-1100 MPa | ★★★★★ Excellent | Aerospace structure, medical implants, racing, marine | $$$$ (High) | Grade 5 (Ti-6Al-4V), Grade 23 (ELI) |
| Alloy Steel 4140 | ★★★★☆ Good | 655-1020 MPa | ★★☆☆☆ Moderate (needs coating) | Gears, shafts, heavy equipment, automotive drivetrain | $ (Low) | 4140, 4340, 8620 |
| Brass C360 | ★★★★★ Excellent | 340-470 MPa | ★★★★ Good | Fittings, valves, electrical, decorative, plumbing | $$ (Medium) | C360 (free-machining), C464 (naval) |
| Copper C101 | ★★★★☆ Good | 220-350 MPa | ★★★☆☆ Moderate | Electrical, RF components, heat sinks, busbars | $$$ (Medium-High) | C101 (OFHC), C110, C145 |
| PEEK (Polymer) | ★★★☆☆ Moderate | 90-100 MPa | ★★★★★ Excellent | Medical, semiconductor, chemical, high-temp insulation | $$$$ (High) | PEEK 450G, PEEK-ESD, PEEK-CA30 |
| Nylon (PA66) | ★★★★☆ Good | 80-90 MPa | ★★★☆☆ Moderate | Bushings, gears, wear pads, guides, insulators | $ (Low) | PA66, PA6, oil-filled, glass-filled |
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Frequently Asked Questions
Which material is best for CNC machining?
Aluminum 6061-T6 offers the best balance of machinability, strength, cost, and versatility. For high-strength applications, 7075-T6 or 17-4PH stainless. For extreme corrosion resistance, 316L stainless or titanium Grade 5.
What is the cheapest CNC machining material?
Aluminum 6061-T6 is typically the most cost-effective. It machines fast (lower machine time), uses standard tooling, and has excellent chip control. Low-carbon steel (1018/1215) is also economical.
What materials are hardest to machine?
Titanium alloys (especially Ti-6Al-4V), Inconel and nickel superalloys, hardened tool steels, and high-chromium stainless grades. These require specialized tooling, slower feeds/speeds, and rigid machine setups.
Can I mix different materials in one assembly?
Yes, but consider galvanic corrosion when mixing dissimilar metals (e.g., aluminum with stainless). Use isolation coatings or compatible material pairs. Consult our engineering team for guidance.
What surface finish can each material achieve?
Aluminum: Ra 0.4μm. Stainless: Ra 0.8μm standard, Ra 0.4μm with fine finishing. Titanium: Ra 0.8μm. Steel: Ra 0.8μm. PEEK: Ra 1.6μm. All can be improved with secondary operations (grinding, polishing).
How do I choose between 6061 and 7075 aluminum?
6061: better corrosion resistance, easier to weld, lower cost, good for general parts. 7075: ~70% higher strength, lower corrosion resistance, harder to weld, best for highly stressed aerospace/racing components.