What should the power of the fiber laser be—3 kW, 6 kW, 12 kW, 20 kW, or 30 kW?

What is the best fiber laser power for cutting metal? This is one of the most important questions when choosing a CNC cutting machine. In practice, it’s not about “the highest possible power,” but about selecting a laser source that suits actual production needs—the type of material, steel plate thickness, number of parts, expected edge quality, cutting cost, power supply infrastructure, and workflow organization.

3 kW, 6 kW, 12 kW, 20 kW, and 30 kW lasers can be excellent solutions, but under different production conditions. The power rating is selected differently for a compact steel plate laser cutter than for a machine designed for tubes and profiles, and yet differently for a large-format fiber laser. Higher power usually means faster cutting speeds, shorter piercing times, and a wider range of applications. In practice, however, the goal is not to choose “the highest possible power,” but to select a laser source that matches actual production needs: the type of material, steel plate thickness, number of parts, expected edge quality, cutting cost, power infrastructure, and the plant’s workflow. It’s a good idea to start the power selection process by asking: Which parts will be produced most frequently?

What affects the power of a laser source?

The power of a fiber laser primarily affects the amount of energy delivered to the material during the laser cutting process. When selecting laser power for steel plate cutting, it’s important to remember that the higher the power, the greater the potential for faster cutting, more effective piercing, and processing a wider range of thicknesses. However, power alone does not determine quality and cost-effectiveness—what matters is the entire technological system: the laser source, cutting head, optics, nozzle, gas, machine design, CNC control, CAD/CAM software, and experience in selecting parameters.

More power can improve:

• cutting speed within specific thickness ranges,
• productivity in mass production,
• the ability to cut thicker materials and the time it takes to pierce steel plates,
• the cost-effectiveness of air cutting in selected applications,
• the plant’s flexibility in the face of fluctuating order profiles.

At the same time, it requires:

• higher capital expenditure,
• greater energy capacity,
• more efficient cooling and exhaust,
• good production organization to maximize the machine’s potential.

If a facility primarily cuts thin sheet metal in small batches, very high power may not be fully utilized. For large batches, thicker materials, multiple punches, and multi-shift operations, higher power effectively reduces the unit cost of the part.

3 kW Laser — When Is a Lower Power Rating Sufficient?

A 3 kW fiber laser is well-suited for applications that require a precise, compact CNC machine for cutting sheet metal of typical production thicknesses. This is by no means a “weak” power output—in many applications, it delivers a stable, repeatable process with good edge quality, such as for assembly parts, covers, brackets, and structural components of moderate thickness.

A 3-kW laser is worth considering when:

• The plant mainly cuts thin and medium-gauge sheet metal,
• What matters is precision, repeatability, and good edge quality,
• Production does not require high speeds for thicker materials,
• The lower investment cost is important,
• The machine is designed to operate in a confined space or with limited power supply.

In STIGAL’s product lineup, the 3 kW power rating is available, among other things, in compact machines for steel plates and in lasers for tubes and profiles. It’s worth noting, however, that 3 kW is chosen less frequently today—many companies opt for 6 kW or more, considering not only their current needs but also future production growth. A more powerful source can serve as a safeguard against a situation where, after a few years, the machine becomes unable to handle new orders or thicker materials.

6 kW Laser — Versatile Power for a Wide Range of Facilities

A 6 kW fiber laser significantly expands capabilities compared to a 3 kW model—it cuts common steel plate thicknesses faster and handles varying production profiles well. For typical contract manufacturing and diverse orders, 6 kW often proves to be more than enough power, eliminating the need to invest in a significantly larger laser source.

A 6-kW laser is worth considering when:

• Production includes sheet metal of various thicknesses,
• We need a versatile fiber laser cutter for our day-to-day work,
• It is important to work with various materials and part geometries.

As production becomes more intensive—larger batches, tight deadlines, and regular cutting of thicker materials—the difference between 6 kW and 12 kW becomes noticeable. 6 kW is a very good, versatile choice for many facilities, while 12 kW represents a step up in terms of productivity, throughput, and part production cost. 12 kW is also the power level at which a significant leap in productivity is noticeable.

12 kW Laser — Higher Productivity and a Wider Range of Applications

The 12 kW fiber laser is the ideal choice for facilities that need higher productivity, greater flexibility, and a significant increase in cutting speed. This power isn’t “just for heavy plates”—it also significantly increases cutting speed and reduces time for completing projects for thin materials, boosting throughput without the need to purchase additional machines.

A 12-kW laser is worth considering when:

• The machine is expected to operate intensively; production is currently running in a multi-shift mode,
• Production involves larger, repeatable runs,
• The plant wants to reduce the cutting time for standard thicknesses,
• thicker materials or more challenging manufacturing tasks arise,
• A technological reserve is needed to expand production.

With properly selected parameters and compressed-air cutting, a 12-kW laser can achieve speeds of up to 25 m/min—reducing production time while also lowering the costs of nitrogen as a process gas.

30 kW Laser — High Power for Demanding Production

A 30 kW fiber laser is the solution for production that requires very high throughput and high processing speeds. It’s worth evaluating it not only in terms of maximum cutting thickness—high power also means faster cutting of the thicknesses that a facility processes on a daily basis. This is a power rating frequently chosen by shipyards and facilities operating in the offshore sector.

A 30-kW laser is worth considering when:

• Production requires very high productivity and cuts large quantities of material,
• Cutting time is the bottleneck of the process,
• thicker sheets, large formats, and challenging orders are appearing,
• The machine is designed to operate under heavy loads,
• The facility has adequate power supply,
• What matters is high precision and accurate geometry, even with very thick materials.

High power requires a well-prepared process—power supply, gases, compressed air, cooling, material logistics, and efficient part retrieval. In STIGAL’s product lineup, 30 kW is available, among other applications, in large-format laser cutters and advanced 2D/3D configurations with bevel cutting.

Comparison of Fiber Laser Power

The table is not a substitute for a technical analysis—the same power setting produces different results depending on the material, thickness, gas, edge quality, and machine design.

Does more power mean lower cutting costs?

Higher power reduces the unit cost of a part only if it is well-suited to production—that is, if it shortens cutting time, reduces auxiliary operations, lowers gas consumption, or increases the number of parts produced per shift. The key factors to consider are not the maximum thickness, but rather the part cost, cycle time, number of cuts, gas consumption, energy cost, and machine utilization.

Air cutting is an important factor. Compressed air, used as an auxiliary gas, reduces the costs of nitrogen or oxygen wherever edge requirements allow. Higher power increases the cost-effectiveness of air cutting, as it allows for maintaining a high cutting speed without the need for expensive nitrogen. In practice, this can result in very tangible savings—for one of STIGAL’s customers, simply replacing nitrogen with compressed air reduced costs by approximately 30,000 PLN per month. Added to this are savings resulting from cutting speed, such as the ability to eliminate one shift in a three-shift production schedule or to produce a greater number of parts.

How do you choose the right laser power for a manufacturing facility?

When selecting a laser power for metal cutting, it’s a good idea to start by asking a few questions:

• What materials and steel plate thicknesses are most commonly used in production?
• Does the machine cut steel plates, tubes, profiles, or structural sections?
• Which parts of the details are thin, which are medium, and which are thick?
• Is production on a one-off, small-batch, or mass-production basis?
• How many shifts does the machine run?
• Which is more important: the purchase price or the lowest unit cost of the item?
• Are you planning to use plasma cutting and automate loading and unloading?
• Is the plant’s power supply sufficient?

When selecting capacity, you should consider not only current orders but also the company’s future growth. Too little capacity quickly becomes a constraint, while too much capacity becomes an unnecessary cost if it isn’t actually utilized.

How does STIGAL help you choose the right fiber laser power?

STIGAL designs and manufactures CNC metal-cutting machines — fiber laser cutters for steel plates, lasers for tubes and profiles, large-format machines, and 2D and 3D solutions. The FIBER Master series includes, among others, the compact FIBER Master ST, the dual-table FIBER Master DT, and the high-performance FIBER Master HD.

We base our selection of the laser source power on a realistic analysis of production, not solely on catalog specifications: we examine the type of material, the range of thicknesses, the type and number of parts, the number of cuts, the expected edge quality, the possibility of air cutting, energy requirements, planned productivity, and subsequent processes—such as bending, welding, tapping, or assembly. For one facility, a compact 3- or 6-kW laser will be best; for another, a 12-kW model that increases throughput; and for large-scale production—a 30-kW or more powerful configuration with a 3D bevel cutting head and bevel cutting capabilities.

Summary — What Is the Best Laser Power?

There is no single, universal answer as to whether to choose a 3 kW, 6 kW, 12 kW, 20 kW, or 30 kW laser—each of these power levels is suitable for a different production profile. 3 kW: compact machines and thinner steel plates at minimal investment cost. 6 kW: sufficient power for many manufacturing and service companies. 12 kW: versatile power, more intensive production, larger production runs, and a wider range of sheet thicknesses. 20 kW: very high productivity. 30 kW: very high productivity, large formats, and thicker materials.

The most important thing is not to choose the power rating based solely on the maximum cutting thickness. In practice, what matters are the unit cost of the part, cutting speed, edge quality, process gas, the ability to cut with air, the number of piercings, automation, power supply, and the organization of the entire production process. If you’re also torn between the two technologies, check out our guide: laser vs. plasma.

Frequently Asked Questions — Fiber Laser Power