Guide to Laser Cutting Focus Adjustment and Method Selection for Optimal Efficiency and Quality

Introduction

Laser cutting technology has become a cornerstone of modern industrial manufacturing, offering precision and efficiency across a variety of materials and thicknesses. Whether it's for fine-tuning intricate designs or cutting through thick metal sheets, the focus adjustment in laser cutting plays a critical role in achieving optimal results. Proper focus calibration and method selection ensure that manufacturers can improve production speed, reduce material wastage, and maintain the desired cutting quality.

Laser cutting focus adjustment is vital for achieving high-quality cuts, ensuring efficiency, and reducing waste. Methods like the slanted board method, dot method, and blue spark method help pinpoint the precise focal point. Correct focus positioning allows for clean, efficient cuts, and with the right power settings based on material thickness, laser cutting can deliver precise results, whether it’s for thin or thick materials.

In this guide, we will explore the importance of laser cutting focus adjustments and provide practical methods for fine-tuning the focus point. Additionally, we’ll dive into how to choose the appropriate cutting methods based on material thickness and composition.

Laser Cutting Focus Adjustment Methods

The position of the laser cutting machine’s focal point directly influences the cutting performance. A well-calibrated focus ensures that the laser beam is concentrated at the correct spot on the material surface, leading to clean cuts and high efficiency. Below are some common focus adjustment methods:

Slanted Board Method

Steps: Tilt the workpiece (e.g., a metal sheet) by about 10 degrees and move the cutting head to find the smallest focal point on the slanted surface. This method helps confirm the most accurate focal point.

Dot Method

Steps: Place a white cardboard on the worktable. Set the laser cutting head above the cardboard with the focus lens positioned 10mm below the focal length. Move the cutting head along the X or Y axis, raising the Z-axis by 1mm with each step. Observe the laser dot's diameter on the cardboard and identify the smallest diameter, which indicates the focal point.

Blue Spark Method

Steps: Remove the nozzle and blow air to activate the pulse laser on the stainless steel surface. Move the cutting head and find the point where the largest blue spark occurs, which indicates the focal point.

Laser Cutting Focus Adjustment Mnemonics

To simplify the focus adjustment process, here are some helpful tips:

• Distance positioning: Ensure the cutting head is 0.1 times the focal length away from the workpiece.
• Blur Rule: Moving the focus further away results in a wider cut, while bringing it closer creates a narrower cut.
• Monitoring Calibration: If the cutting starts incorrectly with weak lighting, prioritize adjusting the focus.
• Quality Check: When the focus is correct, the laser is bright, the material is focused, and the cut is smooth.

Important Considerations During Focus Adjustment

• Safety First: Always ensure the machine is in a safe state, with the power turned off and necessary precautions taken before making adjustments.
• Equipment Maintenance: Clean the lenses and measuring devices regularly to prevent dirt or damage, which could affect the laser's performance.
• Cutting Head Perpendicularity: Make sure the cutting head is perpendicular to the surface of the workpiece to avoid inaccuracies in focus placement.
• Recording Parameters: Keep track of the settings and focus positions for future adjustments and consistency.

Choosing the Right Laser Cutting Method

Laser cutting technology is highly versatile and provides outstanding precision, making it a preferred choice in manufacturing. The selection of the right laser cutting method depends largely on the material type and thickness. The following sections explain how to select the appropriate cutting power based on these factors:

1. Thin Sheet Materials (0.2mm - 5mm)
   Thin sheet materials such as stainless steel, carbon steel, and aluminum benefit from high precision laser cutting, particularly in terms of speed and clean edges.

• Recommended Power: 500W - 2kW
• Applications: Thin sheets can be quickly and cleanly cut using laser machines with lower power (500W to 2kW). For materials under 1mm, 500W is sufficient; for thicker materials (3mm to 5mm), 1kW to 2kW is ideal.
• Advantages: Fast cutting, fine edges, minimal heat-affected zones, and minimal need for post-processing.

2. Medium Thickness Materials (5mm - 20mm)
   For materials ranging from 5mm to 20mm in thickness, laser cutting remains an optimal choice, requiring higher power for efficient cutting.

   • Recommended Power: 2kW - 6kW
   • Applications: Laser cutting machines with power ranging from 2kW to 6kW can handle these thicknesses efficiently while maintaining high precision and cutting speed. Ideal for stainless steel and carbon steel.
   • Advantages: Moderate speed, excellent control of heat-affected zones, and smooth edges without the need for additional treatment.

3. Thick Materials (20mm - 40mm)
   When cutting thick materials like carbon steel and stainless steel in the 20mm to 40mm range, higher power is essential for maintaining cutting quality and speed.

   • Recommended Power: 6kW - 12kW
   • Applications: For cutting 20mm to 30mm thick carbon steel or stainless steel, machines with at least 6kW power are necessary. For thicker materials (30mm to 40mm), 12kW machines offer more efficient and precise cutting.
   • Advantages: Excellent cutting results, fast cutting speeds, and minimized thermal distortion.

4. Super Thick Materials (40mm and Above)
   Cutting materials thicker than 40mm requires specialized equipment and significant power to ensure clean and accurate cuts.

   • Recommended Power: 12kW and above
   • Applications: For materials like high-thickness stainless steel or carbon steel, a 12kW laser cutting machine or higher can achieve smooth cuts with minimal heat distortion.
   • Advantages: Can handle super-thick materials, with slower cutting speeds but high-quality outcomes.

Other Factors When Choosing Power

In addition to material thickness, other factors must be considered when selecting the appropriate laser cutting machine:

• Material Type: Different materials absorb laser energy differently. For example, stainless steel absorbs more laser energy, so lower power can be used, whereas aluminum and copper require more power.
• Cutting Precision: For high-precision cutting, machines with higher power and stability are recommended.
• Production Efficiency: High-power machines improve efficiency for large-scale production by reducing cutting time.

Conclusion

Correctly adjusting the focus point and selecting the appropriate cutting method for each material and thickness is crucial to achieving high-quality and efficient results in laser cutting. Whether you're working with thin or thick materials, having the right equipment and settings ensures smooth edges, reduced waste, and faster production. By following the methods outlined above and considering material-specific power requirements, manufacturers can optimize their laser cutting processes for maximum productivity and cost-effectiveness. Contact us to get more information.

References:

1. "Comparing Laser Machine Cutting to Traditional Methods.", from Kirin Laser.
2. "Why Fiber Laser Cutters are the Future of Industrial Cutting?", from Kirin Laser.
3. "Why Metal Laser Cutters are the Future of Fabrication?", from Kirin Laser.
4. "How to Choose the Best Metal Laser Cutter for Your Needs?", from Kirin Laser.
5. "Laser Cutting Steel: Techniques and Best Practices", from Kirin Laser.
6. "What Is Press Brake Tonnage Explained", from Accurl.