Industrial recommendations for pulse cutting of aluminum plates

For aluminum pulse fiber laser cutting, the core is to accurately control the pulse output of the laser (frequency, duty cycle, etc.) and intermittently heat the material to optimize the heat input, so as to balance the cutting quality and efficiency under the high reflectivity and thermal conductivity of aluminum.

Key process parameters and optimization suggestions

The following are recommendations for cutting aluminum plates according to different thicknesses, summarized from academic research:

Process Objectives

High quality cutting (reduce hanging slag, improve section finish)

• Applicable thickness: medium thickness (e. g. 4mm)
• Key parameter recommendations:
• Laser mode: Pulse mode is recommended
• Auxiliary gas: Nitrogen or Argon is recommended
• Key points: increase the auxiliary air pressure to enhance the slag blowing force; control the laser heat input to avoid excessive melting.

High efficiency/thick plate cutting (pursuit of speed or cutting thick plate)

• Applicable thickness: medium and heavy plate (e. g. 10-15mm)
• Key parameter recommendations:
• Laser mode: can use continuous wave or high duty cycle pulse
• Auxiliary gas: oxygen can be tried
• Core points: The exothermic reaction of oxygen can increase energy and improve the cutting ability of thick plates; but the section will oxidize and become rough, and subsequent processing is required.

High-precision/sheet cutting (used in precision fields such as aerospace)

• Applicable thickness: thin plate (e. g. 0.5-2mm)
• Key parameter recommendations:
• Laser mode: high frequency pulse mode is recommended
• Auxiliary gas: Nitrogen is recommended
• Key points: the use of higher cutting speed and appropriate auxiliary pressure; control heat input to reduce the heat affected zone (can be controlled below 20 m).

General high quality parameter reference (4mm 2219 aluminum alloy as an example)

In order to achieve the level 1 cutting criteria (less slag hanging and low roughness), a study found that the optimal parameter range is:

• Laser power:>4.5 kW
• Cutting speed: 3-4 m/min
• Auxiliary air pressure: 1.3 MPa

Core Challenges and Targeted Solutions

The main challenges and solutions for aluminum cutting are as follows:

1. High reflectivity

• Challenge: Aluminum has strong reflection on laser, especially near-infrared fiber laser, and low energy utilization.
• Solution: Use a laser with an “anti-reflection” mechanism; use a high-energy pulse to break down the material in the initial stage of cutting, and the reflectivity will decrease after the initial hole is formed.

2. Fast heat conduction and easy slag hanging

• Challenge: Heat dissipates rapidly, and molten metal at the bottom of the incision condenses to form slag that is difficult to remove.
• Solution: Compared with continuous laser, pulse laser can control heat input more accurately; Increase the auxiliary gas pressure (such as ≥ 1.3MPa), improve the airflow shear force to blow away slag; Optimize the focus position, usually below the surface of the plate.

3. Cutting section quality and subsequent process requirements

• Challenge: The cutting section will form a remelted layer. If subsequent welding is required, it will affect the porosity of the weld.
• Solution: If welding is required after cutting, the process should be strictly controlled, and the thickness of the cutting seam remelting layer should be controlled below 136μm to effectively reduce the porosity of the weld.

List of key points of industrial operation

• Gas selection: the pursuit of high-quality non-oxidation incision (especially the subsequent need to weld), give priority to high-purity nitrogen or argon. Oxygen can be evaluated when cutting thickness and speed are pursued and section oxidation is not a problem.
• Parameter debugging sequence: It is recommended to fix other variables and debug in this order: focus position → auxiliary gas type and pressure → laser power → cutting speed → pulse parameters (if pulse mode is used).
• Equipment and safety: to ensure that the laser has the ability to deal with highly reflective materials; When cutting aluminum plate, the spark splashes are more intense. It is necessary to ensure that the dust removal system is effective and the equipment and personnel are protected.
• Trial cutting and inspection: Trial cutting must be carried out before formal cutting. For quality inspection, please refer to: visual observation of slag hanging at the bottom; contact mode sensing section roughness; microscope measurement of remelted layer thickness (if there are high requirements).

Summary and Final Recommendations

The core of pulsed fiber laser cutting aluminum plate is ”precise heat control”. The following path is recommended:

1. Clear priority: first determine whether your primary goal is section quality, cutting efficiency or subsequent welding performance.

2. According to the thickness of the primary parameters: refer to the previous table, according to your aluminum plate thickness and priority, determine the preliminary laser mode and gas type.

3. Fine debugging and verification: fine debugging is carried out around the auxiliary air pressure and cutting speed, and the trial cutting verification is strictly carried out.