Fiber Laser Power: 6 kW or 12 kW?

The most frequent question in a fiber laser investment is power: is 6 kW enough, or should you go to 12 kW? The answer depends on your product mix, sheet thicknesses and daily cutting hours.

On thin sheet, power affects speed rather than quality

On 1-3 mm sheet, the difference between 6 kW and 12 kW depends more on acceleration than cutting speed. Both give the same cut quality; 12 kW is only somewhat faster. If 70% of your jobs are under 3 mm, a 6 kW machine pays back faster.

The difference is clear on thick sheet

On 12-20 mm carbon steel, 12 kW cuts 2-3 times faster than 6 kW, and bright edges can be achieved with nitrogen instead of oxygen. If a meaningful share of your jobs is above 10 mm, high power pays for itself quickly.

Operating cost

• Electricity: A 12 kW source draws 38-45 kW while cutting, a 6 kW source about 22-26 kW.
• Gas: High power consumes more gas when cutting with nitrogen; pressure and nozzle choice matter.
• Consumables: Protective glass, nozzle and ceramic ring consumption grow with power.

A simple decision framework

1. List last year's sheet consumption by thickness.
2. Extract the thickness distribution of the cuts you outsource.
3. Estimate monthly cutting hours: below 180 hours consider 6 kW; above that with thick sheet dominating, consider 12 kW.

Cut quality and gas choice

Nitrogen is used for bright edges on stainless and aluminum, and oxygen on carbon steel. With high power, cutting carbon steel with nitrogen also becomes possible, but gas cost rises. In plants that use a nitrogen generator rather than gas tanks, the operating advantage of 12 kW is more evident. A cutting head with thickness-sensing focus control also keeps quality constant.

What to include in the investment calculation

When calculating the payback of a laser investment, add not only the machine price but also side items such as the compressor and dryer, chiller, fume filter, nitrogen generator and electrical infrastructure. Also include nesting software and cutting-head consumables per operator in the annual budget.

Do not forget automation

As the laser gets more powerful the machine idles while material loading and unloading becomes the bottleneck. A dual shuttle table or loading tower determines the real productivity of a 12 kW investment.

With our FL-3015 (6 kW) and FL-4020 (12 kW) you can have a demo cut on the same sheet and measure time and gas consumption together.