| Material | Density (g/cm³) | Tensile Strength (MPa) | Hardness (HB) | Corrosion Resistance |
|---|---|---|---|---|
| Aluminum 6061 | 2.7 | 310 | 95 | Good, improved with anodizing |
| Stainless Steel 304 | 8.0 | 520 | 200 | Excellent, resists oxidation |
Aluminum is lightweight, which reduces overall part weight and is ideal for aerospace, automotive, and robotics applications.
Stainless steel offers higher tensile strength and hardness, suitable for wear-resistant components like gears, shafts, and structural supports.
Real-world insight: A CNC workshop producing precision gears for industrial robots found that switching from stainless steel to aluminum reduced the assembly weight by 35% without compromising dimensional accuracy.
| Material | Cutting Speed | Tool Wear | Surface Finish | Recommended Coolant |
|---|---|---|---|---|
| Aluminum | High | Low | Excellent | Water-soluble oil or air cooling |
| Stainless Steel | Low | High | Good | Flood coolant or high-pressure lubrication |
Aluminum machines faster with minimal tool wear. Typical milling cycle times are 20–30% shorter than stainless steel for similar geometry.
Stainless steel requires lower cutting speeds and more frequent tool replacement. Real-world data: Milling a 50 mm stainless steel bracket took 3.5 hours, whereas aluminum finished in 2 hours on the same 3-axis CNC machine.
Tips: Use sharp carbide tools for stainless steel and fine step-down strategies to avoid tool deflection.
| Cost Factor | Aluminum | Stainless Steel |
|---|---|---|
| Raw Material | $2.5–3.5/kg | $4.0–5.5/kg |
| Machining Hours | Lower | Higher (due to slower feed and tool wear) |
| Post-processing | Optional anodizing | Often polishing or passivation required |
Aluminum is more economical for high-volume parts due to faster machining and lower material costs.
Stainless steel increases both material and operational costs but provides superior durability for harsh environments.
Aluminum CNC parts: Lightweight housings, aerospace brackets, automotive prototypes, consumer electronics.
Stainless steel CNC parts: Medical instruments, food-grade machinery, structural supports, high-wear components.
Case Study: A CNC prototyping company replaced stainless steel brackets with 6061 aluminum for a drone project. Benefits included 30% faster machining, 40% weight reduction, and easier finishing with anodization.
Performance priority: If your design demands high strength and wear resistance, stainless steel is preferred.
Weight and cost priority: Aluminum reduces weight and processing cost while maintaining precision.
Environmental exposure: Stainless steel is superior for corrosion-prone or high-temperature applications; anodized aluminum provides moderate protection at lower cost.
