Fiber laser cutting machines have revolutionized metal fabrication since the mid-2010s, offering superior efficiency, speed, and precision compared to CO2 lasers. The laser power (measured in kilowatts, kW) is the most critical factor influencing what you can cut, how fast, and with what quality. Choosing the right wattage prevents underperformance or overspending on unnecessary power.

This guide, updated for 2026, explains the key factors, provides practical recommendations, and includes thickness charts based on industry standards from manufacturers like Bodor, Accurl, and others.

Why Laser Power Matters in Fiber Cutting

• Higher power = faster cutting speeds, thicker material capability, and better edge quality on reflective metals (e.g., aluminum, copper).
• Lower power = sufficient for thin sheets but results in slower speeds, more heat distortion, or inability to cut thicker materials.
• Fiber lasers excel at metals because their 1.06μm wavelength is absorbed efficiently by reflective surfaces, unlike CO2 lasers.

Key Factors to Consider When Selecting Fiber Laser Power

1. Material Type
   Different metals absorb laser energy differently:

• Mild steel (carbon steel): Easiest to cut, uses oxygen assist gas for thicker plates.
• Stainless steel: Requires nitrogen for clean edges; slightly higher power needed.
• Aluminum & copper: Highly reflective; need higher power for clean cuts.
• Brass or titanium: Similar to stainless but often require more power.

1. Material Thickness
   The primary driver. Higher power handles thicker stock without sacrificing speed or quality.
2. Production Volume & Speed Requirements
   High-volume shops benefit from more power for faster throughput.
3. Budget & Future Needs
   Start with power for 80% of your jobs. Add a safety margin (e.g., 20-30% extra) for growth or occasional thicker cuts.
4. Assist Gas & Machine Features
   Oxygen for carbon steel (thicker cuts), nitrogen for stainless/aluminum (clean edges). Higher power allows better use of high-pressure gas.

Recommended Fiber Laser Power by Material and Thickness

Here are approximate maximum cutting thicknesses and speed ranges (2025-2026 data). These vary by machine brand, gas pressure, and nozzle design—always test on your material.

Speeds: For example, a 6 kW laser might cut 1 mm mild steel at 40-60 m/min, while a 1 kW does it at 10-15 m/min. Higher power dramatically boosts productivity.

Step-by-Step Guide to Choosing Your Power

1. Analyze Your Workload
   List the materials and thicknesses you cut most often (e.g., 80% of jobs).

• If most work is <5 mm: 2-4 kW is ideal.
• If 5-15 mm: 6-12 kW.
• If >15 mm: 15 kW+.

1. Check Manufacturer Charts
   Refer to your machine's spec sheet. Test cuts on scrap material to fine-tune.
2. Consider Cutting Quality
   Signs of insufficient power: slag buildup, rough edges, slow piercing.
   Signs of too much power: excessive heat distortion or overburn.
3. Budget for Long-Term
   A 6 kW machine costs more upfront but saves time and energy over years. Many fabricators upgrade from 3 kW to 6-12 kW for speed gains.

Common Mistakes to Avoid

• Buying too low: Limits growth and forces slower production.
• Buying too high: Wastes money on unused capacity (higher power also increases electricity and maintenance costs).
• Ignoring material reflectivity: Aluminum/copper need 30-50% more power than steel for the same thickness.

Conclusion

The best fiber laser power matches your most common material thicknesses and production needs. For most small to medium fabricators in 2026, 3-6 kW strikes the perfect balance of capability, speed, and cost. For high-volume or thick-plate work, 12 kW+ unlocks massive efficiency gains.

Always consult your supplier for specific machine recommendations and perform test cuts. If you're upgrading or starting a metal shop, investing in the right power today will pay off in productivity for years to come.