A practical fiber laser thickness guide with power-based ranges, gas choices, and real tested starter settings.

Quick answer 

Thickness chart by power class (industry ranges)

When users search “How thick can a fiber laser cut?” they often mean industrial 2D fiber systems (3kW / 6kW / 12kW / 20kW+). The table below is a practical planning range. Definitions and results vary by cutting head, gas system, and whether the chart reflects “max” or “production” thickness.

Why ranges? Many charts mix “max cut-through” and “production thickness”. The next section separates them clearly.

Max thickness vs practical thickness

A fiber laser may technically “cut” a thick plate, but the outcome can be non-production-ready. In practice, your thickness decision should use two thresholds:

• Maximum thickness: it can complete the cut, but speed is low, piercing is more sensitive, and edge quality can degrade.
• Practical thickness: stable results with acceptable edge quality, repeatability, and reasonable speed (the number that matters for daily work).

Max vs practical thickness (quick comparison)

Oxygen vs nitrogen vs air: which cuts thicker?

Gas choice is one of the biggest reasons two “same kW” systems show different thickness results. Here’s a simple, operational decision logic.

1) Oxygen (O₂): thick carbon steel route

• Why it cuts thicker: oxidation adds heat to sustain the cut in carbon steel.
• Trade-off: oxidized edge (often needs cleanup/secondary process), and quality is more sensitive at the thick end.
• Best for: carbon steel thickness pushing, especially when “cut-through” matters more than “bright edge”.

2) Nitrogen (N₂): clean edge route

• Why people choose it: cleaner/brighter edge (less oxide), especially important for stainless and aluminum.
• Trade-off: higher pressure/flow requirements and higher operating cost at thicker gauges.
• Best for: stainless/aluminum jobs where edge quality matters and downstream finishing must be minimal.

3) Air (compressed air): budget & convenience route

• Why it’s popular: lower gas cost and simpler setup for thin-to-medium thickness.
• Trade-off: edge color/oxidation and consistency can differ from nitrogen, especially on stainless.
• Best for: cost-sensitive cutting, prototyping, and thickness ranges where results remain stable on air.

Real tested results (800W & 1200W)

Below is real tested thickness outcome from six-in-one metal cutting parameter table. This section adds experience-based data rather than generic charts.

Tested max thickness summary (fast lookup)

Starter parameter tables (tested)

Below are the full tested parameter rows from your data sheet. Units are shown in each table: six-in-one table speeds are in m/min, while the handheld scanning table uses mm/s. Keep them separate to avoid wrong copy/paste.

Why thick cuts fail (fast troubleshooting)

If your cut fails near the thickness limit, it is usually one of these causes:

• Piercing instability: the machine can cut once pierced, but piercing becomes inconsistent at thicker gauges.
• Gas delivery is the bottleneck: pressure/flow at the cutting head is insufficient for kerf ejection.
• Nozzle mismatch: nozzle diameter and standoff height are not matched to thickness and gas route.
• Focus strategy is wrong for thick plate: thick steel often needs different focus offsets vs thin sheet.
• Material condition varies: rust, coating, mill scale, or oily surfaces change piercing and edge quality.
• Wrong definition of “cut”: you can “cut through” but the edge is not acceptable for the application (max vs practical thickness confusion).

FAQ (PAA)

1) How thick can a fiber laser cut?

Fiber laser cutting thickness depends on laser power, material, assist gas (oxygen / nitrogen / air), and whether you mean maximum cut-through thickness or practical production thickness.

2) What is the maximum thickness a fiber laser can cut?

“Maximum thickness” usually means the system can pierce and finish the cut, but speed is slow and edge quality may degrade. Always verify with a short test if you plan to quote or produce parts at that thickness.

3) What is practical (production) thickness?

Practical thickness is the thickness you can cut repeatedly with stable edge quality and reasonable speed. This is the thickness that matters most for daily work and reliable delivery.

4) Can a fiber laser cut 1 inch steel?

It can be possible on high-power industrial fiber laser systems depending on steel grade, assist gas strategy (often oxygen for thick carbon steel), and whether you mean max cut-through or production thickness. Capability varies by configuration.

5) What power fiber laser do I need for 1/2 inch stainless steel?

Stainless is commonly cut with nitrogen for cleaner edges, and thickness capability depends heavily on the gas system (pressure/flow), cutting head performance, and edge quality requirements. Use capability charts as a starting point and validate with a test cut.

6) Oxygen vs nitrogen: which cuts thicker?

For carbon steel, oxygen cutting often reaches thicker cut-through capability because oxidation adds heat to sustain the cut. Nitrogen is typically used for clean edges (stainless/aluminum), but becomes gas-demanding as thickness increases.

7) Can you cut stainless steel with oxygen?

It is possible, but oxygen introduces oxidation and typically reduces “clean edge” quality compared to nitrogen. For most stainless applications where appearance or corrosion performance matters, nitrogen is preferred.

8) Is air assist good for fiber laser cutting?

Air assist can be practical for thin-to-medium sheet where cost and convenience matter. Edge color/oxidation and consistency can differ from nitrogen, so validate against your quality standard.

9) Why do fiber laser thickness charts vary so much?

Charts vary because they mix max vs practical thickness, use different assist gas and pressure references, and assume different cutting heads/nozzles and material conditions. Even at the same kW class, configuration changes results.

10) What limits thick cutting more: laser power or gas delivery?

At higher thickness, gas delivery often becomes the bottleneck: pressure and flow at the cutting head determine whether molten metal is fully ejected. Power still matters, but insufficient gas at the head is a common reason thick cuts fail.

11) Why does thick plate cutting fail during piercing?

Piercing time increases with thickness, and the process window narrows. If piercing is unstable, the cut may never start cleanly, causing dross, blowback, or incomplete cut-through even when the same settings work on thinner sheet.

12) Why do I get heavy dross when cutting near the thickness limit?

Dross near the limit usually points to insufficient gas ejection, an unsuitable nozzle/standoff, incorrect focus position, or speed being too high. Start by improving ejection (gas/nozzle/height) before increasing power.

13) What thickness is realistic for handheld or lower-power fiber cutters?

Lower-power systems can be very effective within a realistic thickness window, especially when the right gas strategy is used. Use tested “starter parameters” and validate with your own material and quality requirement rather than relying on generic charts.

14) Does material type matter as much as thickness?

Yes. Carbon steel often cuts thicker with oxygen cutting, while stainless and aluminum rely more on clean melt ejection and gas stability. Copper/brass are more reflective and can require tighter process control.

15) Should I choose a bigger kW just to cut thicker?

Only if your work consistently demands that thickness at an acceptable edge quality and speed. If you rarely cut that thick, it may be more cost-effective to optimize gas delivery, nozzle/focus strategy, or outsource extreme-thickness jobs.