About Laser Cutting Machine

Laser was first applied to cutting back in the 1970s. When a focused laser beam hits a workpiece, the irradiated area heats up sharply, causing the material to melt or vaporize. Once the beam penetrates the workpiece, the cutting process begins: the laser moves along the preset contour while melting the material. This is the basic principle of laser cutting.

Technical Parameters of Laser Cutting

Laser cutting is a precision machining method that uses high-energy-density laser beams to process materials, widely applied to both metallic and non-metallic materials. Laser cutters are the most common equipment for this technology.

Key technical parameters include laser power, cutting speed, cutting thickness and gas flow rate. Other factors such as laser beam quality, lens focal length, defocus amount and nozzle also exert a major impact on cutting performance.

1. Laser Power

Laser power is one of the core parameters of a laser cutter. Generally, higher power delivers faster cutting speed and enables processing thicker materials. The laser power here refers to the output power of the laser generator.

For materials with high surface reflectivity, a large portion of laser energy will be reflected instead of being absorbed for cutting, so higher laser power is required. Materials with good thermal conductivity dissipate heat rapidly, making it hard to raise the temperature of the cutting zone, which also demands increased power. In addition, materials with high melting points need greater laser power and power density to achieve melting or vaporization for cutting.

2. Cutting Speed

Under fixed laser power, cutting thicker workpieces requires the laser beam to penetrate deeper material layers. Research shows the relationship between cutting speed and kerf surface roughness presents a U-shaped curve rather than a simple linear correlation. For materials of different thicknesses and different auxiliary gas pressures, there exists an optimal cutting speed that delivers the smoothest kerf with the lowest surface roughness. Normally, a higher cutting speed requires higher laser power.

Cutting speed refers to the cutting length per minute of the laser cutter. A higher speed means higher production efficiency. It is affected by material type, thickness, hardness, as well as laser power and spot diameter.

3. Cutting Thickness

Cutting thickness indicates the maximum material thickness that a laser cutter can process. The main influencing factors are as follows:

· Equipment power: Higher power generally allows cutting thicker materials.

· Material type: Differences in hardness, density and toughness among materials limit the maximum cutting thickness.

· Cutting technology: Laser cutting, waterjet cutting and plasma cutting have distinct limits on cutting thickness.

· Process parameters: Cutting speed and gas pressure also affect the actual cutting thickness.

4. Gas Pressure

In fusion cutting, the laser heats the material to its melting point. The auxiliary gas blows away molten metal to form a clean kerf. Sufficient gas pressure is essential to remove molten material steadily and ensure continuous, high-quality cutting.

Gas flow is closely related to nozzle types. Different nozzles feature unique gas distribution and flow characteristics, thus matching different gas flow rates. Nozzles and gas flow should be selected and optimized according to actual cutting requirements and material properties.

5. Laser Beam

The beam mode generated by the laser generator plays a vital role in cutting results. For cutting without oxygen assistance, the kerf width is almost equal to the laser spot diameter. The spot size is proportional to the focal length of the focusing lens: a longer focal length creates a larger spot, and vice versa.

A lens with a short focal length produces a smaller spot but a shorter depth of focus, which requires stricter control over the distance between the workpiece surface and the lens. The defocus amount greatly influences cutting speed and depth and must remain stable during operation. Negative defocus is commonly used, which means the laser focus is set slightly below the workpiece surface.

6. Nozzle

The nozzle is a critical component affecting cutting quality and efficiency. Laser cutting mostly adopts coaxial nozzles where the air flow is concentric with the laser beam. The outlet diameter of the nozzle shall be selected based on material thickness. Moreover, the distance between the nozzle and the workpiece must be kept constant to ensure stable cutting.

Quality Evaluation Criteria for Laser Cutting

Laser cutting is widely used for metal processing, yet many operators lack clear standards to judge cutting quality. The main evaluation indicators include kerf surface roughness, bottom burrs and kerf width.

1. Surface Roughness

Due to air flow and feeding speed, vertical or inclined textures will form on the cut surface. Deeper textures mean higher roughness, while shallower textures indicate a smoother surface. Surface roughness affects both appearance and friction performance; lower roughness represents better cutting quality. It can be optimized by adjusting laser power, feeding speed, focal length, type and pressure of auxiliary gas.

2. Bottom Burrs

Laser cutting vaporizes metal instantly with high laser energy, and auxiliary gas blows away molten slag. However, improper material thickness, insufficient gas pressure or mismatched feeding speed will leave solidified slag and burrs on the workpiece bottom. Removing burrs adds extra working hours, so burr and slag residue is a key indicator of cutting quality.

3. Kerf Width

Kerf width reflects machining accuracy. It has little impact on conventional cutting quality, but becomes crucial for workpieces with intricate and precise internal contours. A narrower kerf supports the machining of finer patterns and smaller holes, which is a major advantage of laser cutting over plasma cutting.

Improvement Strategies for Laser Cutting Technology

In practical production, improving cutting efficiency and quality while reducing costs is a constant goal. The effective improvement methods are listed below:

1. Adopt higher-power laser generators to boost cutting speed, narrow the heat-affected zone and reduce material deformation, especially for thick material processing.

2. Fine-tune process parameters including laser power, cutting speed, auxiliary gas type and pressure, as well as nozzle-to-workpiece distance. Conduct repeated tests to determine the optimal parameter combination for specific materials and cutting demands.

3. Equip the machine with an auto-focus system to adjust the laser focus automatically according to material thickness and type, so as to guarantee cutting precision.

4. Reduce non-cutting downtime by enabling the cutting head to move rapidly to the next cutting start point and raise overall working efficiency.

5. Install automatic detection functions to identify material edges and tilt angles, and adjust cutting paths intelligently to cut down material waste and preprocessing time.

6. Apply nesting software to simulate cutting and plan optimized paths, minimizing idle travel and improving material utilization and cutting efficiency.

7. Perform regular equipment maintenance: replace wearing parts, clean optical components and calibrate the machine to maintain stable operation and optimal performance.

8. Keep the working environment clean with proper temperature and humidity, to prevent dust and excessive moisture from damaging equipment and affecting cutting results.

9. Upgrade control systems and software to enhance control accuracy and response speed, supporting complex cutting tasks.

10. Keep track of the latest advancements in laser technology, such as high-efficiency laser sources, advanced optical systems and intelligent algorithms, to continuously upgrade cutting capabilities.