Fiber Laser Metal Cutting Parameters Power, Speed, Focus, Gas & Nozzles Explained

Getting clean, accurate, and consistent results from a fiber laser metal cutting machine depends on choosing the right cutting parameters. Laser power, cutting speed, focus position, assist gas, and nozzle settings all influence how the laser interacts with metal, affecting cutting quality, efficiency, and material consumption.

These settings work together, and their optimal values vary depending on the material, thickness, machine configuration, and desired edge quality.

This guide explains the key fiber laser cutting parameters, how they affect cutting performance, and what to consider when adjusting them. You'll also find links to detailed technical guides, cutting parameter charts, and troubleshooting resources from Thunder Laser.

Quick Answer: What Are the Key Fiber Laser Cutting Parameters?

Additional settings, including piercing parameters, pulse frequency, and duty cycle, may also affect cutting performance, particularly during piercing and pulsed processing.

The best settings depend on the material, thickness, laser source, cutting head, and assist gas conditions. Start with the manufacturer's recommended parameters and verify the results through test cuts.

How the five parameters work together inside the machine: the cutting head delivers the beam, the focus sets where energy peaks, and the assist gas stream through the nozzle clears molten metal from the kerf.

1. Fiber Laser Cutting Parameters Chart: What Should You Check First?

A fiber laser cutting parameters chart provides recommended starting settings for cutting different metals and thicknesses. These settings typically include laser power, cutting speed, focus position, assist gas pressure, nozzle configuration, and piercing parameters.

Before selecting a parameter set, identify three essential factors: the material type, material thickness, and available laser power. These determine which settings are relevant to your cutting application.

1.1 How to Read a Fiber Laser Cutting Settings Chart

A typical fiber laser metal cutting settings chart includes the following information:

These values work together to influence cutting performance, including edge quality, kerf width, dross formation, and processing efficiency.

For example, two stainless steel sheets of different thicknesses may require different cutting speeds, focus positions, and nitrogen pressures, even when processed using the same fiber laser cutting machine.

1.2 Where to Find Recommended Fiber Laser Cutting Parameters

Thunder Laser provides a Metal Cutting Parameters Library containing reference settings for its 1500W fiber laser cutting system. The library covers materials such as 304 stainless steel, carbon steel, aluminum, and brass across different thicknesses. Users can select the relevant material and thickness to explore the corresponding cutting parameters. These settings serve as starting points for testing. Actual fiber laser cutting parameters may require adjustment based on material grade, surface condition, laser source, cutting head, assist gas supply, and required edge quality. For reliable results, begin with the manufacturer's recommended settings, perform test cuts on sample material, and verify cut quality before production. The following sections explain how to evaluate individual parameters and select suitable settings for different metal cutting applications.

2. Assist Gas Selection: Air, Oxygen, or Nitrogen?

Assist gas removes molten metal from the kerf and influences cutting speed, edge oxidation, dross formation, and operating costs. In fiber laser metal cutting, compressed air, oxygen, and nitrogen serve different purposes.

2.1 Assist Gas Comparison and Typical Pressure Ranges

Pressure ranges are general references from Thunder Laser's support center. Actual settings depend on material thickness, nozzle configuration, cutting head, and gas supply capacity.

2.2 How to Choose the Right Assist Gas

• Compressed Air: A practical choice when cutting cost and processing efficiency are priorities. Suitable gas filtration and moisture control are important for consistent results.
• Oxygen: Commonly used for carbon steel cutting. Its oxidation reaction supports material removal at relatively low gas pressure, although an oxide layer remains on the cut edge.
• Nitrogen: Preferred when minimizing oxidation is important, particularly for stainless steel and aluminum. Higher gas flow and pressure may be required for thicker materials.

Gas pressure also affects cutting quality:

For example, Thunder Laser's AccuMetal 1500W test settings use compressed air at 15 bar for 2 mm carbon steel and oxygen at 0.6 bar for 5 mm carbon steel. Both achieved dross-free results under their respective cutting conditions.

For detailed gas pressure optimization, gas consumption, and troubleshooting, see the Thunder Laser Assist Gas Pressure Optimization Guide.

3. Laser Power Selection: How Much Power Do You Need?

Fiber laser cutting power determines the range of metal thicknesses a machine can process. Higher wattage generally supports thicker materials and faster cutting, but the required power depends on the metal type, assist gas, and desired cut quality.

3.1 Fiber Laser Power and Cutting Thickness

The table below shows typical maximum cutting thickness ranges at different fiber laser power levels.

These are approximate market-reference maximum cutting thicknesses, not guaranteed dross-free results. Actual capability varies by machine and processing conditions.

3.2 Maximum Cutting Thickness vs. Clean Cutting Thickness

Maximum cut-through thickness refers to the thickest material a machine can separate under suitable conditions. Clean cutting thickness describes a more practical range for achieving consistent edges with minimal dross.

For example, Thunder Laser lists the following cutting capabilities for its standard 1500W AccuMetal configuration:

Source: Thunder Laser AccuMetal Series technical specifications. Cut-through capability represents a different quality standard from clean cutting.

3.3 How to Select the Right Laser Power

Choose fiber laser wattage based on three factors:

• Material type: Carbon steel, stainless steel, aluminum, and brass have different cutting requirements.
• Regular material thickness: Select a power level that comfortably covers the thicknesses processed most often.
• Production requirements: Consider cutting speed, edge quality, and the need for additional capacity.

For instance, a 1500W system may meet the needs of regular thin-sheet metal cutting, while a 3000W fiber laser provides additional power for more demanding applications.

Thunder AccuMetal uses a 1500W fiber laser as its standard configuration, with an optional 3000W configuration available. The appropriate choice depends on the intended materials, thicknesses, and required processing quality.

For a detailed comparison of 1.5 kW, 3 kW, 6 kW, and 12 kW cutting capabilities, including material-specific limits, see our Fiber Laser Cutting Thickness Guide.

4. Fiber Laser Cutting Parameters Chart by Material

The following fiber laser cutting parameters are taken from Thunder Laser's AccuMetal 1500W test records. They cover carbon steel, 304 stainless steel, aluminum, and brass, including cutting speed, assist gas pressure, focus position, and nozzle size.

4.1 AccuMetal 1500W Cutting Parameters Chart

Source: Thunder Laser AccuMetal 1500W Cutting Parameters, September 2026. All listed records use 100% cutting power. S and D are nozzle designations from the original parameter sheet. Values represent the recorded test conditions and results.

5. Focus Position Explained: Zero, Positive, and Negative Focus

Focus position, also called defocus, determines where the laser beam reaches its smallest spot relative to the metal surface. Adjusting the focal position changes how laser energy is distributed through the material, affecting kerf width, penetration, dross formation, and cut-edge quality.

5.1 Zero, Positive, and Negative Focus

The definitions above use the focal-position convention commonly applied in fiber laser cutting. Confirm the positive and negative directions in the specific cutting head and control system.

5.2 Focus Position Examples from Thunder Laser

Thunder Laser's AccuMetal 1500W test data illustrates how focus settings vary with material thickness and cutting gas.

Source: Thunder Laser AccuMetal 1500W Cutting Parameters, September 2026.

The stainless steel examples show increasingly negative focus settings as thickness increases. The oxygen-assisted carbon steel examples use positive focus positions, reflecting a different cutting process.

5.3 How Does Incorrect Focus Affect Cutting Quality?

An unsuitable focus position may cause incomplete penetration, uneven kerf width, rough cutting edges, or excessive bottom dross.

When switching between materials or assist gases, check the recommended focus position along with cutting speed, gas pressure, and nozzle configuration.

For a more detailed explanation of focal position, defocus adjustment, and its effects on cutting quality, see the Thunder Laser Support Center article Focus Position (Defocus) in Fiber Laser Cutting.

6. Nozzle Type and Diameter Selection

The laser cutting nozzle directs assist gas into the kerf to remove molten metal. Nozzle type, diameter, and cutting height affect gas flow, cutting stability, dross formation, and edge quality.

6.1 Single-Layer vs. Double-Layer Nozzles

Two common nozzle types used in fiber laser metal cutting are single-layer (S) and double-layer (D).

The recommended nozzle type depends on the material, assist gas, thickness, and cutting head configuration.

6.2 How to Choose Nozzle Diameter

Nozzle diameter affects gas flow and the ability to remove molten material from the cutting kerf.

• Smaller diameters are commonly used for thin sheets and processes requiring concentrated gas delivery.
• Larger diameters may be required for thicker materials or cutting conditions that need greater gas flow.

The correct diameter should be selected together with gas pressure, focus position, and cutting speed.

Thunder Laser's AccuMetal 1500W test data provides the following examples:

Source: Thunder Laser AccuMetal 1500W Cutting Parameters, September 2026. S and D are nozzle type designations; the numerical values indicate nominal nozzle diameter in millimeters. The 10 mm carbon steel test result was recorded as Slight Dross, while the other listed examples were Dross-Free.

These settings show how nozzle size and type vary with material thickness and assist gas. Use the complete cutting parameter set when selecting or replacing a nozzle.

6.3 Nozzle Height and Alignment

Cutting height, also called nozzle stand-off distance, is the distance between the nozzle tip and the metal surface.

A suitable cutting height helps maintain consistent gas delivery and reduces the risk of nozzle contact with the workpiece. Incorrect nozzle alignment, contamination, or damage can disturb gas flow and contribute to uneven cutting edges or bottom dross.

Check nozzle condition and centering when cut quality changes unexpectedly, especially after replacing a nozzle.

For additional material thicknesses and matching nozzle settings, refer to the Thunder Laser Metal Cutting Parameters Library.

7. Piercing Parameters: What Changes Before Cutting Starts?

Piercing is the process of creating an initial hole in the metal before the laser follows the cutting path. Proper fiber laser piercing settings help control molten-metal spatter, prevent oversized entry holes, and improve cutting stability.

Unlike continuous cutting, piercing often uses a separate combination of laser power, duty cycle, pulse frequency, gas pressure, focus position, and piercing delay.

7.1 Common Piercing Methods

The appropriate piercing method depends on material thickness, laser power, and the cutting system's available process controls.

7.2 Piercing Parameter Examples from Thunder Laser

The following settings are extracted from Thunder Laser's AccuMetal 1500W parameter records.

Source: Thunder Laser AccuMetal 1500W Cutting Parameters, September 2026. The table shows selected piercing settings. The 10 mm carbon steel record also includes a second piercing stage with separate parameters.

These examples show how fiber laser piercing parameters vary by material and thickness. Thicker metal may require additional piercing stages to control heat buildup and molten-metal ejection before continuous cutting begins.

7.3 How Do Frequency and Duty Cycle Affect Piercing?

• Pulse Frequency (Hz): Determines how frequently laser pulses are delivered during pulsed processing.
• Duty Cycle (%): Controls the proportion of each pulse cycle during which the laser is active.
• Piercing Delay (ms): Defines the programmed timing associated with the piercing process.

These settings work together with laser power, focus position, and assist gas pressure to control piercing energy and entry-hole quality.

For detailed piercing strategies, process stages, and troubleshooting, see Thunder Laser Support Center's Two-Stage Piercing for Fiber Laser Cutting. Complete piercing settings are also available in the Thunder Laser Metal Cutting Parameters Library.

8. Common Fiber Laser Cutting Problems and Troubleshooting

Incorrect fiber laser cutting parameters can cause bottom dross, rough edges, incomplete cuts, and excessive oxidation. Similar defects may also result from nozzle damage, unstable gas delivery, or contaminated optics.

Before changing cutting settings, check the nozzle condition, lens cleanliness, gas supply, and cooling system.

8.1 Fiber Laser Cutting Troubleshooting Chart

These are diagnostic starting points. A single cutting defect may have several contributing causes.

8.2 Recommended Troubleshooting Sequence

For consistent fiber laser metal cutting results, follow this order:

• Check machine condition: Inspect the cutting head, protective lens, nozzle, cooling system, and gas supply.
• Confirm the material settings: Verify the material grade, thickness, assist gas, and selected cutting parameter set.
• Inspect the cut edge: Identify incomplete penetration, bottom dross, rough striations, or oxidation.
• Adjust and retest: Change one relevant parameter at a time and compare the cutting results.

For detailed examples of slag, burrs, and rough cut surfaces, read Thunder Laser's Common Laser Cutting Problems and Solutions.

For gas-pressure-related defects, see the Assist Gas Pressure Optimization Guide.

Conclusion

Selecting the right fiber laser cutting parameters requires balancing laser power, cutting speed, focus position, assist gas, and nozzle configuration. Material thickness, edge-quality requirements, and piercing conditions also influence the final settings.

Thunder Laser's AccuMetal 1500W cutting data provides practical reference settings for carbon steel, stainless steel, aluminum, and brass. Use the Metal Cutting Parameters Library to find complete settings by material and thickness.

For equipment specifications and available configurations, explore the Thunder AccuMetal Series.