At a glance
- Aluminum (6061-T6 / 6082 / 7075): Excellent machinability, light, good strength-to-weight. 6061/6082 for general parts; 7075 for high strength (aerospace/robotics).
- Stainless (304/316): Corrosion resistant; 316 for marine/medical environments. Slower to machine than aluminum; great for hygiene and durability.
- Carbon/Alloy Steel (1018/1045/4140): High strength, wear resistance; heat treatable (4140). Heavier; may require coating for corrosion.
- Brass (C360): Very machinable, stable, beautiful finish; ideal for fittings, electronics, optics.
- Plastics (POM/Delrin, Nylon, PEEK, PC): Light, self-lubricating options, electrical insulation. PEEK for high temp/chemical resistance; Delrin for precision gears & bushings.
Selection tips
- Function first: Strength, stiffness, weight, temperature, and environment.
- Tolerances & stability: Metals hold tight tolerances more easily; many plastics creep or absorb moisture (e.g., Nylon).
- Finish & cosmetics: Aluminum anodizes well (Type II cosmetic, Type III hardcoat). Stainless can be bead-blasted or polished. Brass looks premium as-machined.
- Regulatory needs: Medical/food require specific alloys or passivation.
- Total cost: Material price + machine time + finishing + QC. A “cheap” alloy that machines slowly may cost more overall.
Common picks by use case
- Robotics/frames: Aluminum 6061/6082; 7075 for high-load arms.
- Medical/dental fixtures: Stainless 316; PEEK for sterilizable polymer components.
- Aerospace brackets: 7075-T6 aluminum; 17-4PH stainless for high strength.
- Electronics/enclosures: Aluminum 6061 (anodized) or Brass C360 for RF/EMI features.
- Industrial shafts/gears: 4140 (quench & temper) or 1045 with surface hardening.
CTA: Not sure which alloy fits your application? Send your STEP with requirements—we’ll recommend the most cost-effective material.
FAQ
Q1: 6061 vs. 7075—when to use each?
A: 6061 is versatile, cost-effective, and anodizes well; 7075 offers much higher strength for load-bearing parts.
Q2: Stainless 304 or 316?
A: 304 is general purpose; 316 has better chloride resistance for marine/medical environments.
Q3: Can plastics hold tight tolerances?
A: Yes, but expect looser stability than metals. Design for ±0.10–0.20 mm unless otherwise discussed.
Q4: Is brass suitable for structural parts?
A: It’s fantastic to machine and looks great, but it’s not a high-strength structural substitute for steel or 7075.
Q5: Will finishing change dimensions?
A: Yes. Anodize/powder-coat add thickness; define critical faces and masking in your drawing.
