Views: 0 Author: Site Editor Publish Time: 2026-05-21 Origin: Site
Overburn during laser cutting of sheet metal essentially results from excessive local heat accumulation and inadequate slag removal, which leads to blackened edges, rounded sharp corners, and rough cross-sections. The core solutions lie in heat control, efficient cutting, proper gas usage, path optimization, and equipment maintenance.
Sharp Corners/Right Angles: The laser slows down at turns, causing prolonged and heat concentration, which turns sharp corners into rounded ones.
Small Holes/Dense Holes: Limited heat dissipation space inside the holes prevents heat from escaping, resulting in overburn and slag buildup on the inner walls.
Thick Plates/Long-Term Cutting: Continuous heat accumulation raises the plate temperature, leading to cross-section ablation and obvious streaks.
Oxygen Cutting of Carbon Steel: Exothermic reactions from oxygen combustion can easily cause edge burning if parameters are improperly set.
Thin Plates (≤3mm): Adopt high speed + medium-low power to reduce laser time.
Thick Plates (≥6mm): Use high power + appropriate speed increase to avoid heat accumulation at low speeds; adopt "bright cutting" (high power, fast speed, oxygen).
Rule of Thumb: Cut as fast as possible, use only the power needed to penetrate the material, and avoid blindly increasing power.
Carbon Steel: The focal point should be slightly below the plate surface (0.5–1mm) to concentrate energy and prevent upper edge burning.
Stainless Steel/Aluminum: The focal point should be on or slightly above the plate surface to reduce heat-affected zones.
Material | Recommended Gas | Pressure Reference | Function |
|---|---|---|---|
Carbon Steel | Oxygen (O₂) | 0.3–0.6 MPa | Aids combustion, releases heat, and ensures a bright cutting surface |
Stainless Steel/Aluminum | Nitrogen (N₂) | 1.0–2.0 MPa |
For carbon steel, oxygen pressure should not be too high (>0.6MPa may cause overburn); pressure can be appropriately reduced when cutting small holes or sharp corners.
For stainless steel and aluminum, use high-purity nitrogen (≥99.99%); sufficient pressure is essential to blow away slag and cool the cutting edge.
Perforation: Use high peak value + low frequency pulses to reduce molten accumulation and heat input.
Cutting: Adopt continuous wave + appropriate duty cycle to balance melting and cooling.
Design: Modify sharp corners to small fillets (R0.5–R1) to fundamentally avoid heat accumulation caused by speed reduction at turns.
Programming: Set automatic speed reduction + gas blowing delay (0.1–0.3s) at turns, or use the "circular cutting" function.
First drill a preliminary small hole (≥1mm) before cutting to reduce perforation heat.
Use spiral perforation instead of direct perforation to disperse heat.
Dense Holes/Multiple Graphics: Adopt dispersed cutting and jump cutting to avoid continuous heat accumulation in the same area.
Long Edges: Use segmented cutting and intermittent cooling to reduce overall temperature rise.
Lens Cleaning: Contamination of protective lenses/focusing lenses can lead to reduced power, spot distortion, and local heat accumulation. Inspect daily and clean/replace regularly.
Nozzle Condition: Clogged or eccentric nozzles cause air flow disorder and uneven slag blowing, leading to overburn. Clean regularly and ensure concentricity.
Gas Purity: Oxygen (for carbon steel) ≥ 99.95%, nitrogen (for stainless steel/aluminum) ≥ 99.99%; insufficient purity reduces efficiency, requiring low speed and high power, which exacerbates overburn.
Ensure the plate surface is free of oil and rust to avoid abnormal heat absorption or release.
For long-term cutting of thick plates, stop intermittently for cooling, or use an air-cooled/water-cooled workbench for heat dissipation.
Is the cutting speed too slow? → Increase speed appropriately.
Is the power too high? → Reduce power to match the speed.
Is the focal point offset? → Recalibrate.
Is the gas pressure/purity normal? → Adjust pressure and replace with high-purity gas.
Are the lenses/nozzles dirty or eccentric? → Clean or replace.
Have sharp corners/small holes been optimized? → Add fillets, pre-drill holes, and optimize the cutting path.
By following these professional tips, you can effectively eliminate overburn issues, improve laser cutting quality, and enhance production efficiency. Our team of experts is also available to provide customized parameter adjustment guidance for your specific sheet metal cutting needs.
