In short: Choose laser power by the thickness range you cut every day and the throughput you need on thin and medium sheet — not by the thickest plate you cut once a month. Extra power raises maximum thickness, but for most shops its bigger value is faster cutting and the option to cut with compressed air.
What more power actually changes
- Maximum thickness. More power lets the beam cut through thicker plate. As a published rule of thumb, about 3 kW cuts mild steel up to roughly 16 mm and 6 kW up to roughly 25 mm (source 1). For 12–40 kW we will publish measured values per material and gas in our cutting capability matrix.
- Speed on thin and medium sheet. On the same material, higher power generally allows higher feed rates, so more parts per hour — provided motion, loading and unloading keep up.
- Which gas you can use. With enough power, thin-to-medium carbon and stainless steel can be cut with clean, dry compressed air instead of nitrogen. See chapter 2.
Maximum thickness is not production thickness
Brochures usually quote the thickest plate the laser can cut through. Production thickness — the thickest plate cut with consistent edge quality at an economic speed — is lower. Plan the purchase on production thickness for the materials you cut most, and ask for a test cut on your own part at the edge of that range.
12 kW vs 20 kW vs 30 kW: power classes and who they suit
| Power class | Typical role in a shop | What to check before buying |
|---|---|---|
| 6–12 kW | General job-shop cutting, thin to medium sheet, mixed batches | Is the machine limited by power or by loading/unloading time? |
| 20 kW | High throughput on thin and medium sheet; regular thick plate | Production thickness on your materials; air-cutting range |
| 30 kW | Thick plate as daily work; high air-cutting volume | Power supply and chiller sizing; edge quality on thick plate |
| 40 kW | Heavy-plate specialists; maximum throughput | Whether your part mix really uses the extra power; consumable cost |
Qualitative guide by Halcyon Laser. Thickness and speed values per power level: see the capability matrix.
What extra power costs you
- Higher machine price — see chapter 8.
- Larger electrical supply and chiller — see chapter 3.
- More demanding optics and consumables at full power.
A simple way to decide
- List last year's parts by material and thickness, weighted by cutting hours.
- Find the thickness band that covers most of those hours.
- Compare production speed for that band across power levels (matrix or test cuts).
- Put the speeds into the cost per part calculator: the right power is where cost per part stops falling meaningfully.
Frequently asked questions
What laser power do I need for 6–25 mm plate?
As a published rule of thumb, about 6 kW cuts mild steel up to roughly 25 mm (source 1) — but that is a maximum. If 6–25 mm plate is your daily work rather than an occasional job, a higher power gives production-quality edges and much higher speed in that range; compare production speeds at your main thicknesses before deciding.
Is 20 kW too much for a job shop?
Not necessarily. If most of your work is thin and medium sheet, a 20 kW laser mainly buys speed and air cutting. It only pays if loading and unloading keep up, which is why high power and automation are usually planned together.
Does higher power cut thin sheet faster?
Generally yes, up to the limits of the machine's motion system. On very thin sheet, acceleration and contour complexity often limit speed before laser power does.
What is the difference between maximum and production thickness?
Maximum thickness is what the beam can cut through. Production thickness is what it cuts with consistent edge quality at an economic speed. Buy on production thickness.
Sources
- Atomm, “Laser Cutting Machine Price: From $599 to $319,000, and Why” — 3 kW / 6 kW mild-steel thickness guide, OMTech list prices — www.atomm.com (accessed 2026-10-20)