Laser Assist Gas Selection Chart

Choose the optimal assist gas for your laser cutting application. This guide covers parameters, costs, edge quality, and safety considerations for oxygen, nitrogen, compressed air, and argon.

5 Gas TypesCost AnalysisSafety GuidelinesUpdated 2025-10-30

Gas Selection Wizard

MaterialThicknessEdge QualityBudgetResult

Step 1: Select Material Type

🌊 Gas Flow Dynamics Visualization

Understand how assist gas interacts with the laser beam and material during cutting.

Select Gas:

Nitrogen: Inert gas prevents oxidation, produces clean edges

Gas Flow Dynamics

Show Labels

Diagram Legend

Laser Beam

Assist Gas Flow

Molten Pool

Material

Ejected Material

Cut Edge

Nitrogen-Specific Considerations

• Inert gas prevents oxidation reaction, producing clean edges
• High pressure required (8-20 bar) to effectively blow out molten material
• Higher gas consumption and cost compared to oxygen
• Essential for stainless steel, aluminum, and aesthetic applications

🔬 Why Assist Gas Matters

Assist gas is crucial in laser cutting - it removes molten material, protects the lens, and can even participate in the cutting process (exothermic reaction with oxygen). The right gas choice significantly impacts cut quality, speed, and operating costs.

Speed vs Quality

Oxygen provides maximum speed through exothermic reaction but oxidizes the edge. Nitrogen is slower but produces clean, oxide-free cuts.

Cost Considerations

Compressed air costs 1/10th of nitrogen but compromises quality. Calculate cost per part, not just gas price.

Material Specific

Stainless steel requires nitrogen to prevent oxidation. Carbon steel can use oxygen for speed. Titanium needs argon.

🎯 Quick Selection Guide

For Carbon Steel

Oxygen:

Maximum speed, oxidized edge, lowest cost

Nitrogen:

Clean edge, slower, higher cost

Air:

Thin materials only, economical

For Stainless Steel

Nitrogen:

Required for oxide-free edges (high pressure)

Air:

Thin materials, acceptable quality

Oxygen:

Not recommended - causes oxidation

For Aluminum

Nitrogen:

Best choice, prevents oxidation

Air:

Acceptable for thin materials

For Titanium/Reactive Metals

Argon:

Only suitable gas, prevents combustion

Others:

Not recommended - oxidation risk

📊 Material-Gas Compatibility Matrix

Quick reference chart showing which gases work best for each material type. Click any cell for detailed information.

Material / Gas	Oxygen	Nitrogen	Compressed Air	Argon
Carbon Steel
Stainless Steel
Aluminum
Titanium
Copper/Brass

Legend

✓✓

Optimal Choice

✓

Acceptable

△

Limited Use

✗

Not Recommended

Assist Gas Detailed Parameters

Filter by Material

Oxygen

1x cost

Formula: O₂

Purity: ≥99.5% (Industrial grade)

Cost per m³

$0.15

2 applications

• Carbon Steel (Mild Steel) (3-20mm)

• Low Alloy Steel (5-25mm)

▶ Click for details

Nitrogen

3x cost

Formula: N₂

Purity: ≥99.99% (High purity) or ≥99.999% (Ultra-high purity)

Cost per m³

$0.45

4 applications

• Stainless Steel (304/316) (0.5-12mm)

• Aluminum (5000/6000 Series) (0.5-10mm)

+2 more...

▶ Click for details

Compressed Air

0.33x cost

Formula: ~78% N₂, 21% O₂, 1% other

Purity: Filtered and dried (oil-free)

Cost per m³

$0.05

3 applications

• Thin Carbon Steel (0.5-3mm)

• Non-Metals (Acrylic, Wood, Plastics) (Any)

+1 more...

▶ Click for details

Argon

16.7x cost

Formula: Ar

Purity: ≥99.999% (Ultra-high purity)

Cost per m³

$2.50

2 applications

• Titanium (Aerospace Grade) (0.5-5mm)

• Reactive Metals (Zirconium, Hafnium) (0.5-3mm)

▶ Click for details

Nitrogen-Oxygen Mix

2x cost

Formula: N₂ + O₂ (various ratios)

Purity: Custom blend (typically 90% N₂ + 10% O₂)

Cost per m³

$0.30

1 application

• Stainless Steel (Compromise) (2-8mm)

▶ Click for details

Cost Comparison

Gas Type	Cost/m³	Relative Cost	Consumption	Cost/Hour
Compressed Air	$0.05	0.33x	10-20 m³/hr	$0.50-1.00
Oxygen	$0.15	1x	8-15 m³/hr	$1.20-2.25
N₂/O₂ Mix	$0.30	2x	12-20 m³/hr	$3.60-6.00
Nitrogen	$0.45	3x	15-30 m³/hr	$6.75-13.50
Argon	$2.50	16.7x	10-20 m³/hr	$25.00-50.00

📈 Pressure vs Thickness Relationship

Understand how gas pressure requirements increase with material thickness. Use this chart to determine optimal parameters for your specific application.

Select Material

Pressure vs Thickness for Carbon Steel

Oxygen

Thickness	Pressure	Flow Rate	Speed
1 mm	2-3 bar	80-120 L/min	80-100 mm/s
2 mm	2-3 bar	100-150 L/min	60-80 mm/s
3 mm	2.5-3.5 bar	120-180 L/min	40-60 mm/s
5 mm	3-4 bar	150-220 L/min	25-40 mm/s
8 mm	3.5-4.5 bar	180-280 L/min	15-25 mm/s
10 mm	3.5-5 bar	200-320 L/min	10-20 mm/s
15 mm	4-5 bar	250-400 L/min	6-12 mm/s
20 mm	4-5 bar	300-450 L/min	3-8 mm/s

1mm

2-3 bar

2mm

2-3 bar

3mm

2.5-3.5 bar

5mm

3-4 bar

8mm

3.5-4.5 bar

10mm

3.5-5 bar

15mm

4-5 bar

20mm

4-5 bar

Compressed Air

Thickness	Pressure	Flow Rate	Speed
0.5 mm	6-8 bar	80-130 L/min	80-120 mm/s
1 mm	8-10 bar	100-160 L/min	50-80 mm/s
1.5 mm	9-11 bar	130-200 L/min	35-60 mm/s
2 mm	10-12 bar	150-240 L/min	25-45 mm/s
2.5 mm	10-12 bar	170-270 L/min	18-35 mm/s
3 mm	11-13 bar	200-300 L/min	12-28 mm/s

0.5mm

6-8 bar

1mm

8-10 bar

1.5mm

9-11 bar

2mm

10-12 bar

2.5mm

10-12 bar

3mm

11-13 bar

📊 How to Read This Chart

• Thickness: Material thickness in millimeters
• Pressure: Recommended assist gas pressure range in bar
• Flow Rate: Gas consumption in liters per minute
• Speed: Typical cutting speed in millimeters per second

Note: These are reference values. Always start with manufacturer recommendations and adjust based on actual cut quality. Thicker materials generally require higher pressure and flow rates.

🔩 Nozzle-Gas Pairing Recommendations

Proper nozzle selection is critical for effective gas delivery. Different gases require specific nozzle types and diameters for optimal performance.

Gas Type	Nozzle Type	Diameter	Pressure Range	Optimal Thickness
Oxygen	Single conical	1.0-1.5mm	2-4 bar	3-10mm carbon steel
Oxygen	Single conical	1.5-2.0mm	3-5 bar	10-20mm carbon steel
Nitrogen	High-flow conical	2.0-3.0mm	8-15 bar	0.5-6mm stainless steel
Nitrogen	High-flow conical	3.0-4.0mm	12-20 bar	6-12mm stainless steel
Nitrogen	Double nozzle	2.5mm	10-18 bar	3-10mm aluminum
Compressed Air	Single conical	1.5-2.5mm	6-10 bar	0.5-3mm thin materials
Argon	High-purity conical	1.5-2.5mm	5-10 bar	0.5-5mm titanium

Important: Larger nozzle diameters (≥3mm) are required for high-pressure nitrogen cutting. Using too small a nozzle can restrict gas flow and reduce cut quality. See our Nozzle Selection Guide for detailed specifications.

💨 Pressure Guidelines

Low Pressure (0.1-0.5 MPa / 1-5 bar)

•Use: Non-metals, thin materials, engraving
•Gases: Compressed air, oxygen (thin carbon steel)
•Advantage: Lower gas consumption, quieter operation

High Pressure (0.8-2.0 MPa / 8-20 bar)

•Use: Stainless steel, aluminum, thick materials
•Gases: Nitrogen (primary), compressed air
•Requirement: High-pressure equipment, larger nozzles

Important: Always start with manufacturer-recommended pressures and adjust based on cut quality. Too low = dross formation; too high = excessive gas consumption and potential lens damage.

⚗️ Gas Purity Impact on Cut Quality

Gas purity significantly affects edge quality and oxidation prevention, especially for stainless steel and aluminum cutting.

Gas	Purity Level	Edge Quality Impact	Cost Multiplier	Typical Application
Nitrogen	99.5% (Industrial)	Slight oxidation possible on SS	1.0x (Baseline)	Carbon steel, non-critical
Nitrogen	99.99% (High Purity)	Clean, oxide-free edges	1.3x	Stainless steel, aluminum standard
Nitrogen	99.999% (Ultra-High)	Perfect mirror finish	1.8x	Aerospace, medical, critical
Argon	99.999% (Ultra-High)	Pristine, contamination-free	1.0x (for Argon)	Titanium, reactive metals
Argon	99.9999% (Six-Nine)	Absolute purity	1.5x (for Argon)	Aerospace, medical implants

Key Insight: For stainless steel cutting, 99.99% nitrogen purity is the industry standard. Using lower purity (99.5%) may result in slight edge discoloration. For critical applications (aerospace, medical), 99.999% purity ensures zero oxidation risk.

💰 Cost Optimization Strategies

Gas costs can significantly impact your bottom line. For high-volume operations, consider these strategies to optimize your assist gas expenses while maintaining quality standards.

Use Oxygen for Carbon Steel When Possible

If edge oxidation is acceptable (structural parts, will be painted), oxygen provides 2-3x faster cutting at 1/3 the cost of nitrogen. ROI improvement can be significant.

Consider On-Site Nitrogen Generation

For high-volume nitrogen users, on-site nitrogen generators pay for themselves in 1-2 years. Reduces cost from $0.45/m³ to $0.10-0.15/m³.

Optimize Pressure Settings

Running nitrogen at 15 bar when 10 bar is sufficient wastes 50% more gas. Test and document optimal pressures for each material/thickness combination.

Use Compressed Air for Thin Materials

For carbon steel ≤3mm and stainless ≤2mm, compressed air provides acceptable quality at 1/10th the cost of nitrogen. Ideal for high-volume, non-critical parts.

🔧 Common Issues & Solutions

Excessive dross on bottom edge

Causes: Insufficient gas pressure, wrong nozzle size, cutting speed too slow
Solutions: Increase gas pressure by 10-20%, use larger nozzle, increase cutting speed slightly

Oxidation on stainless steel (using nitrogen)

Causes: Nitrogen purity too low, pressure insufficient, air leaks in gas line
Solutions: Use ≥99.99% purity nitrogen, increase pressure to 12-18 bar, check all connections

Excessive gas consumption

Causes: Pressure too high, nozzle too large, gas leaks
Solutions: Optimize pressure settings, use appropriate nozzle size, inspect for leaks regularly

Lens contamination/damage

Causes: Insufficient gas flow, wrong gas type, contaminated gas supply
Solutions: Increase flow rate, ensure oil-free compressed air, install gas filtration

🔧 Related Resources

Nozzle Selection Guide

Pair the right nozzle with your gas choice

Cutting Speed Chart

Reference speeds with different gases

Material Thickness Parameters

Complete parameter tables by material

Edge Quality Standards

Understanding cut edge specifications

Power Selection Guide

Choose the right laser power

Troubleshooting Guide

Solve common cutting issues

Safety Operations

Gas handling and safety procedures

Maintenance Schedule

Gas system maintenance guidelines

Cost Calculator

Calculate operational costs by gas type

Data Disclaimer: This assist gas parameter data is compiled from industrial gas supplier technical handbooks and equipment manufacturer guidelines, for reference only. Actual gas parameters should be optimized based on specific equipment, material batch, and quality requirements. Always follow equipment manufacturer recommendations and conduct test cuts. Data last updated: 2025-10-30.