Fiber Laser Cutting Thickness Chart: How Thick Can a Fiber Laser Cut?
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Durmapress specializes in designing, manufacturing, and selling various metal processing equipment, including bending machines, shears, punches, and laser cutting machines. The company was founded in 2014, with years of experience and technology accumulation. DurmaPress has become one of the well-known brands in China's metal processing machinery industry.
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Table of Contents
Fiber laser cutting thickness is one of the first specifications buyers check, and one of the most frequently misunderstood.
Search for the same power class across several manufacturer websites and you will find noticeably different numbers. One supplier states that a 6 kW machine cuts 20 mm carbon steel. Another states 25 mm. A third states 30 mm. None of them is necessarily wrong, because each figure was produced under different test conditions.
This guide provides a reference thickness chart by power and material, explains the difference between a maximum cut and a production cut, and shows how to select laser power based on your actual job mix rather than a brochure headline.
Quick Answer: How Thick Can a Fiber Laser Cut?
An industrial fiber laser can process material ranging from thin sheet to heavy plate. Entry-level 1–2 kW systems typically handle carbon steel in the 6–16 mm range, mid-power 3–6 kW systems commonly reach 16–30 mm, and high-power 12–20 kW systems can cut carbon steel beyond 40 mm under favorable conditions.
Three points matter more than any single number:
- Power sets the ceiling, not the working range. The thickness you can cut reliably every day is normally well below the published maximum.
- Material changes everything. At identical power, carbon steel usually cuts several times thicker than copper.
- The gas defines the result. Oxygen, nitrogen, and compressed air produce different thickness capacity and different edge conditions on the same machine.
If you are unfamiliar with how the beam, cutting head, motion system, and gas jet interact, this explanation of how fiber laser cutting works provides the process background.
Fiber Laser Cutting Thickness Chart by Power and Material
The following thickness ranges are reference values rather than universal limits. Actual cutting capacity depends on material grade, laser source, cutting head, assist gas, gas pressure, focus position, cutting speed, and required edge quality.
| Potência laser | Carbon Steel (O₂) | Stainless Steel (N₂) | Aluminum (N₂) | Copper / Brass |
|---|---|---|---|---|
| 1 kW | 6–10 mm | 3–5 mm | 2–3 mm | 2–3 mm |
| 1.5 kW | 10–16 mm | 5–6 mm | 3–5 mm | 3–5 mm |
| 2 kW | 14–20 mm | 6–8 mm | 5–8 mm | 4–6 mm |
| 3 kW | 16–22 mm | 8–12 mm | 6–10 mm | 3–8 mm |
| 4 kW | 20–25 mm | 10–12 mm | 8–12 mm | 5–8 mm |
| 6 kW | 22–30 mm | 12–20 mm | 12–20 mm | 8–12 mm |
| 8–12 kW | 25–40 mm | 20–30 mm | 18–30 mm | 12–20 mm |
| 20 kW+ | 40–60 mm+ | 30–50 mm+ | 25–45 mm | System-dependent |
Reference range only. Published maximum thickness can vary substantially by machine configuration and test conditions, and the variation is widest at the top of the table. Treat the 20 kW+ row as an indication of capability class, not a guaranteed cutting specification. If your work depends on very heavy plate, request documented cutting data for the exact configuration you intend to buy, such as a large-format high-power laser system rated for that duty.
Maximum vs. Practical Production Thickness
The single most useful distinction in this subject is the difference between what a machine can cut and what it can cut profitably.
| Thickness Type | Meaning |
|---|---|
| Espessura máxima | The machine may cut through, but speed and edge quality may be compromised |
| Practical production thickness | Thickness suitable for repeatable daily production |
| High-speed thickness | Thickness where the machine maintains a relatively high cutting speed |
1. Maximum Cutting Thickness
Maximum thickness describes a successful cut-through under favorable conditions. At this limit, speed drops sharply, piercing becomes sensitive, dross and taper increase, and small variations in plate condition can cause failure.
This figure is useful as reserve capability. It is a poor basis for quoting repeat work.
2. Practical Production Thickness
Practical production thickness is the range in which the machine produces acceptable parts consistently, sheet after sheet, with predictable cycle times and limited operator intervention.
This is the number that should drive the purchasing decision, because it reflects real throughput, scrap rates, and finishing workload.
3. High-Speed Production Thickness
High-speed thickness is the band where the machine delivers its best cost per part. Many fabrication shops find that most of their annual cut length sits in a relatively narrow band, often thin to medium gauge, while heavy plate represents only a few jobs per month.
Sizing a machine for that dominant band usually produces better economics than sizing it for the rare thickest part.
How Material Affects Fiber Laser Cutting Thickness
At identical laser power, different metals produce very different results because they absorb, reflect, and conduct heat differently.
1. Carbon Steel
Carbon steel achieves the highest thickness capacity in most charts because it is normally cut with oxygen. The advantage comes with an oxidized edge that may require cleaning before painting, powder coating, or certain welding operations.
When comparing carbon steel figures between suppliers, always confirm the assist gas. A nitrogen-cut carbon steel figure will be lower than an oxygen-cut figure from the same machine.
2. Stainless Steel
Stainless steel is usually cut with high-pressure nitrogen to keep the edge bright and oxide-free. Because nitrogen contributes no heat to the process, the laser supplies all the cutting energy and the gas must eject molten metal through the full kerf depth.
As thickness increases, gas flow requirements and running costs rise steeply, and cutting speed falls. This is why the stainless row sits well below the carbon steel row at every power level.
3. Aluminum
Aluminum reflects part of the beam and conducts heat away from the cutting zone quickly. Results depend heavily on alloy grade, surface condition, plate flatness, beam quality, and focus stability.
Aluminum capacity should always be confirmed in the specific alloy you buy. This guide to laser cutting aluminum covers alloy behavior and setup in more detail.
H3: Brass and Copper
Brass and copper are the most reflective common metals in this group and produce the lowest thickness figures. Regular processing requires a cutting head with back-reflection protection and careful pierce control.
If busbar, terminal, or electrical component work forms a significant part of your business, size the machine around copper capacity rather than its more impressive steel rating.
How Assist Gas Affects Cutting Thickness
Assist gas is the most underestimated variable in the entire chart. Two identical machines running different gas will show genuinely different capability.
1. Oxygen
Oxygen reacts exothermically with heated carbon steel and adds heat to the cutting process, which can support the cutting of thicker carbon steel. The oxygen does not increase laser output; the oxidation reaction itself contributes energy to material removal.
The trade-off is an oxidized, darker edge and greater sensitivity at the thick end of the range.
2. Nitrogen
Nitrogen is inert and adds no chemical energy. Every joule must come from the laser, and the gas must clear the melt at high pressure and flow.
The result is a clean, bright, weld-ready and paint-ready edge, at the cost of lower thickness capacity for a given power and significantly higher gas consumption on thick material.
3. Compressed Air
Compressed air is the low-running-cost option for thin and medium sheet. Edge oxidation and consistency differ from nitrogen, so it should be validated against your quality standard before being used on visible or corrosion-critical parts.
One practical note: pressure measured at the supply does not guarantee adequate pressure and flow at the cutting head. Undersized piping, regulators, filters, or nozzles can prevent a high-power source from reaching its rated thickness.
How to Choose Fiber Laser Power by Material Thickness
Once you understand that the chart is a reference, the practical question becomes which power class fits your work.
| Typical Daily Thickness | Suggested Power Class | Best Suited To |
|---|---|---|
| 0.5–4 mm, high detail | 1–2 kW | Enclosures, brackets, signage, thin-sheet volume work |
| 3–10 mm | 3–4 kW | General fabrication, mixed job shop work |
| 6–16 mm | 6 kW | Structural parts, machinery components, medium plate |
| 12–25 mm | 8–12 kW | Heavy fabrication, plate-dominant production |
| 20 mm+ daily | 20 kW+ | Dedicated thick-plate production with high utilization |
Work through four questions with your own data:
- Where does most of your annual cut length sit? Sort parts by thickness and identify the band that consumes the majority of machine hours, not the extremes.
- What edge quality do customers require? Nitrogen-bright stainless above 8 mm pushes you toward higher power far more than an oxygen-cut carbon steel requirement does.
- How many shifts do you run? On a single shift with idle capacity, a faster machine mainly produces more idle hours. On two or three shifts, every minute saved compounds.
- What happens to heavy jobs today? If you already subcontract thick plate, you know its annual value. That figure is the cleanest way to test whether extra power pays back.
Buying power you rarely use is an expensive way to avoid quoting a longer lead time on a handful of jobs. Comparing configurations across a range of fiber laser cutting machines is more productive than comparing source wattage alone.
What Factors Affect Fiber Laser Cutting Thickness?
Beyond material and gas, six factors determine whether a machine reaches its rated capacity.
1. Laser Power
Power sets the capacity ceiling and improves piercing and speed. The return is nonlinear: energy is reflected at the surface, conducted into the surrounding plate, and carried away with the ejected melt, so each additional kilowatt adds less depth than the one before it.
2.Material Grade
Grade, alloy content, surface finish, and plate condition all shift results. Rust, mill scale, oil, coatings, and warped stock reduce pierce reliability and edge quality compared with the clean, flat material used for published tests.
3.Cutting Speed
Speed must allow enough interaction time for melting while the gas jet clears the kerf. Too fast leaves uncut sections and bottom dross; too slow increases heat input, widens the kerf, and can burn the top edge.
4.Assist Gas Pressure
Pressure and flow at the nozzle determine whether molten metal is fully ejected. On thick plate, gas delivery — not laser power — is frequently the actual bottleneck.
5.Focus Position and Nozzle
Thin sheet and thick plate require different focus strategies. Nozzle diameter, centering, condition, and standoff height control how effectively gas enters the kerf. A worn or off-center nozzle can cost several millimeters of usable capacity. The main variables and their interactions are covered in this overview of fiber laser cutting parameters.
6.Laser Source and Cutting Head
Beam quality, focus control range, cutting-head power rating, protective-window condition, and back-reflection protection vary between platforms. Machine rigidity and height-control response also matter during the long, slow cuts that thick plate requires.
Fiber Laser Cutting Cost per Part
Thickness capability determines whether a job is possible. Cost per part determines whether it is worth doing in-house.
Cost per Part=(Machine Cost per Minute×Cycle Time)+Electricity+Assist Gas+Consumables+Labor+Finishing+Scrap
Two implications follow.
First, cycle time is multiplied by a machine rate, so cutting near the maximum thickness is expensive twice over: the cut is slow and the machine is occupied. Second, finishing is part of the equation. An oxygen-cut edge that requires grinding may cost more in total than a slower nitrogen cut that goes straight to welding.
Compare quotations on the finished part, including gas package and expected consumable life, rather than on cutting speed alone.
How to Test Cutting Thickness Before Buying a Fiber Laser
A timed sample cut from your own drawing is stronger evidence than any published chart.
Send every shortlisted supplier the same package:
- Nested DXF of a part you actually run
- Material grade, thickness, and surface condition
- Batch quantity and tolerance requirements
- Your edge-quality standard and downstream process
Ask each supplier to report laser power, assist gas type and purity, pressure, nozzle specification, focus strategy, pierce time, cutting speed, and total cycle time.
Request several repeated parts rather than one successful cut, then inspect pierce quality, top and bottom edge, dross, taper, hole accuracy, and consistency between parts. If results near the limit are inconsistent, this guide to common fiber laser cutting problems helps separate a gas-delivery issue from a focus or pierce problem.
Fiber Laser vs. Other Metal Cutting Methods
Fiber laser cutting is not always the lowest-cost process, particularly at the heavy end of the range.
| Method | Best For | Espessura | Main Advantage |
|---|---|---|---|
| Fiber laser | Sheet and plate metal | Thin to medium/thick | Speed and precision |
| Plasma | Thick conductive metals | Medium to very thick | Lower cost for heavy plate |
| Waterjet | Heat-sensitive materials | Wide range | No heat-affected zone |
Plasma becomes competitive when most work involves thick conductive plate, moderate edge taper is acceptable, and secondary machining is already planned. Its speed advantage on heavy sections often outweighs the wider kerf and lower precision.
Waterjet suits parts that cannot tolerate a heat-affected zone, materials that respond poorly to thermal cutting, and very thick sections where laser speed collapses.
For most sheet metal fabricators, fiber laser remains the primary process because it combines narrow kerf, tight tolerance, clean edges, and high throughput across the thickness range where the majority of parts actually sit. The comparison only shifts when heavy plate dominates the job book.
FAQ
Q1:How Thick Can a Fiber Laser Cut?
Fiber laser cutting thickness depends on laser power, material, assist gas, machine configuration, and required edge quality. A 6 kW machine may cut significantly thicker carbon steel than a 3 kW machine, but the exact production thickness varies by machine and cutting conditions. Use the reference chart above as a starting point, then confirm capacity for your specific material and quality standard.
Q2:How Thick Can a 3kW Fiber Laser Cut?
A 3 kW fiber laser typically reaches around 16–22 mm carbon steel with oxygen, 8–12 mm stainless steel with nitrogen, 6–10 mm aluminum, and roughly 3–8 mm copper or brass.
These are maximum reference figures. Daily production normally runs comfortably below them, particularly where a clean, dross-free edge is required.
Q3:How Thick Can a 6kW Fiber Laser Cut?
A 6 kW fiber laser generally reaches approximately 22–30 mm carbon steel with oxygen, 12–20 mm stainless steel with nitrogen, 12–20 mm aluminum, and 8–12 mm copper or brass.
Published 6 kW figures differ noticeably between manufacturers. The practical gain of 6 kW over 3 kW is often speed in the mid-thickness range rather than the extra headroom at the top.
Q4:How Thick Can a 12kW Fiber Laser Cut?
A 12 kW fiber laser commonly reaches around 25–40 mm carbon steel, 20–30 mm stainless steel, 18–30 mm aluminum, and 12–20 mm copper or brass.
At this power class, gas delivery, cutting-head rating, and pierce strategy influence results as strongly as the laser source. Request configuration-specific data rather than relying on the power rating alone.
Q5:Does Doubling Laser Power Double Cutting Thickness?
No. Moving from 3 kW to 6 kW typically adds several millimeters on steel, not double the capacity. Heat conducted into the surrounding plate, surface reflectivity, and the difficulty of ejecting melt from a deeper kerf all reduce the return on each additional kilowatt.
The stronger argument for higher power is usually faster cutting on the thicknesses you run every day.
Q6:Why Do Fiber Laser Cutting Thickness Charts Differ?
Charts differ because the underlying test conditions differ. The main variables are material grade, laser source, cutting head, assist gas, gas pressure and purity, focus position, nozzle selection, cutting speed, edge-quality requirements, and overall machine configuration.
Some charts publish maximum cut-through capability while others publish conservative production ranges. Before comparing two figures, confirm which definition each supplier used.
Conclusão
Fiber laser cutting thickness is a system result, not a property of the laser source. Power sets the ceiling, but material grade, assist gas, focus, nozzle, pierce strategy, plate condition, and machine stability decide how much of that ceiling you can use in production.
For a sound decision:
- Treat every published chart as a reference range, including this one.
- Separate maximum thickness from practical production thickness.
- Define your edge-quality standard before comparing machines.
- Select power for the thickness band that carries most of your work.
- Compare cost per finished part, not cutting speed.
- Verify with a timed sample cut in your own material.
If you are sizing a machine now, send your material grade, thickness range, part drawing, batch volume, and edge requirements to ACCURL. Our engineers will recommend a suitable power class and run an application-specific cutting trial so you can compare documented results instead of brochure figures.
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