What Are The Factors That Affect The Cutting Quality of The Fiber Laser Cutting Machine?

Fiber laser cutting machine has been rapidly developed and applied in the metal processing industry in recent years. It has the advantages of fast cutting speed, narrow cutting width, wide application range, and high precision. With the development of production and the application of new technology, people have higher and higher requirements for cutting quality of laser cutting machines. However, it is not a simple matter to achieve high-quality cutting. If it is not properly controlled, the cutting quality and precision of the fiber laser cutting machine will be greatly affected.
The cutting quality of the fiber laser cutting machine is comprehensively affected by various factors. This article lists the performance and reasons for the affected cutting quality and provides several solutions to optimize these defects.

What are the defects caused by the improper cutting of the fiber laser cutting machine

If the fiber laser cutting machine is not properly operated or the parameters are set unreasonably during the cutting process, it may cause various cutting defects. These defects directly affect the quality of the cut and the performance of the final product. The following are some common defects caused by the improper cutting of fiber laser cutting machines:

Glitch

After the fiber laser cutting machine cuts metal, the auxiliary gas will blow away the slag. However, when the cutting speed is too fast or the laser power is insufficient, burrs may appear on the cutting edge. Burrs will reduce the appearance quality of the product and may have adverse effects on the assembly and use of the workpiece.

Slag

During the cutting process, if the laser power is too high or the cutting speed is too low, the molten material may solidify and form slag at the cutting edge. This reduces the quality of the cut edge and makes subsequent processing more difficult.

Uneven cut

If the laser beam distribution is uneven or the fiber transmission quality is poor, uneven cutting depth or width may occur during the cutting process.

Cutting Skew

If the cutting trajectory is unstable or the motion control system is inaccurate, it may cause the cutting line to deviate, making the workpiece size not meet the requirements.

Oxidized edges

Some metal materials are easy to react with oxygen during the cutting process, resulting in oxidation of the cutting edge, affecting the appearance and material properties.

The heat-affected zone is too large

During the cutting process, the laser generates heat energy, and an excessively large heat-affected zone may cause melting, deformation, or hardening around the material, affecting the accuracy and performance of the workpiece.

Long-term cut quality change

If the optical system or fiber delivery system is not regularly maintained, it can lead to long-term loss of cut quality, affecting productivity and cost.

Reasons Affecting Fiber Laser Cutting Quality

Many reasons affect the quality of fiber laser cutting, covering materials, laser parameters, optical systems, auxiliary gases, control systems, and many other aspects. Here is a detailed explanation of these reasons:

Material Properties

Different materials have different optical properties and thermal conductivity, which affect laser absorption and heat transmission. Factors such as hardness, thickness, and thermal conductivity of the material will also affect the heat-affected zone and degree of deformation during cutting.

Material Type: Metallic materials generally have higher laser absorption rates, while non-metallic materials (such as plastic, wood, etc.) have lower laser absorption rates. Therefore, it is necessary to increase and decrease the laser power and parameters appropriately according to the material type to ensure sufficient cutting energy.
Material thickness: Too thick material will lead to too slow cutting speed, thus increasing the production cycle; while too thin material is prone to cutting instability or incomplete penetration. Adjust parameters for materials of different thicknesses to achieve the best cutting results.
Material surface quality and optical properties: the poor surface of the material surface, such as oxidation, and oil stains will lead to cutting instability and slag and other defects; in addition, the optical properties of the material, including the absorption and scattering characteristics of the material to the laser, will directly affect the laser transmission efficiency and focus quality.

Laser parameters

Laser parameters are important factors affecting the quality of fiber laser cutting, including laser power, laser frequency, pulse width, and frequency, etc. Different laser parameters will have different effects on the cutting effect.

Laser power: The laser power determines the energy density of the laser. Too high power may cause slag and scorch on the cutting edge, and too low power may cause incomplete cutting.
Laser Frequency: Laser frequency affects the speed and quality of the cut. Higher frequencies increase cutting speed but may reduce cut quality. Proper frequency selection can strike a balance between high-speed cutting and high-quality cutting.
Pulse width: The pulse width determines the laser’s action time on the material, too long pulse width may lead to excessive heat conduction and affect the cutting quality. Shorter pulse widths help reduce the heat-affected zone, resulting in smaller cut widths.
Repetition frequency: The repetition frequency determines the frequency of the pulse. Too high a repetition frequency may cause excessive accumulated heat and affect the cutting quality. Lower repetition rates may affect cutting speed. Choosing an appropriate repetition rate will help optimize cutting results.

Optical system

The optical system is responsible for transmitting the laser light from the fiber to the workpiece and focusing the laser light at the proper focal point. The performance of the optical system directly affects the quality of fiber laser cutting, and the specific effects include:

Beam quality: The laser beam quality of the laser generator, that is, the BPP value, is one of the important parameters to measure the quality of the laser generator. The smaller the BPP value, the better the beam quality, which means smoother sections and higher precision when processing sheet metal.
Focusing quality: The focusing effect of the optical system determines the focal size and depth of focus of the laser. Appropriate focus size can achieve fine cutting, while improper focus may lead to unclear cutting edges and even reduced cutting quality.
Focusing accuracy: The focusing accuracy of the optical system determines the position and stability of the laser focus. The inaccurate focus will lead to cutting line deviation or focus drift, affecting cutting quality and precision.

Auxiliary gas

The auxiliary gas mainly plays the role of cooling, cleaning, and combustion in fiber laser cutting. The impact on the quality of fiber laser cutting is mainly reflected in the following aspects:

Cleaning effect: The auxiliary gas can blow impurities such as slag, oxides, and debris generated during the cutting process away from the cutting area to keep the cutting area clean. This helps to improve the absorption efficiency of laser energy and avoid secondary pollution during cutting.
Gas flow: The flow of auxiliary gas determines the strength of the gas flow in the cutting area, too high or too low gas flow will affect the cutting quality. Proper gas flow keeps the cutting area stable and clean.
Gas purity: The purity of the auxiliary gas is also an important factor affecting the cutting quality. High-purity gas can reduce the impact of impurities on cutting and ensure the purity of the cutting area.

Control system

The control system plays a vital role in fiber laser cutting. It involves the motion control and parameter adjustment of the cutting machine, which directly affects the cutting quality and accuracy. Specific impacts include:

Stability of the motion control system: The motion control system of the fiber laser cutting machine is responsible for controlling the movement trajectory of the laser head on the workpiece. Stability is the key to ensuring cutting quality. If the motion control system is unstable, it may lead to changes in the laser focus position during the cutting process, resulting in skewed cutting lines or uneven cutting.
Cutting speed and acceleration: The control system can adjust the cutting speed and acceleration. A cutting speed that is too fast may result in incomplete cutting, while a speed that is too slow may cause the heat-affected zone to be too large and affect the quality of the cutting edge.

How to optimize the cutting defects of fiber laser cutting machines?

When using a metal laser cutter, you may encounter a variety of cutting defects. Such as burrs, slag, cutting deformation, burning holes, etc. Optimizing the cutting quality of a fiber laser cutting machine requires comprehensive consideration. Here are some suggestions and methods to help improve the cutting quality of a fiber laser cutting machine:

Slag and burrs

Properly adjust the laser power, cutting speed, and auxiliary gas flow to ensure the interaction time and cleaning effect between the laser and the material. In addition, the adjustment and maintenance of the optical system, as well as the reasonable selection of high-quality focusing lenses, can help reduce the generation of slag and burrs.

Cutting line skew

Check and adjust the motion control system to ensure the accuracy and stability of the motion trajectory. Calibrating the focus accuracy of the laser head and ensuring the uniformity of the assist gas flow can also help reduce the problem of cutting line skew.

Uneven cutting

Properly adjust the laser parameters to ensure the stability of the spot in the whole cutting process and ensure the quality of the laser spot. For thicker materials, multiple cuts can be made, cumulatively, for a more consistent depth of cut.

The heat-affected zone is too large

Optimize laser parameters, control laser power, and frequency, and avoid excessive heat transfer to materials. In addition, the cooling effect of the auxiliary gas also helps to reduce the heat-affected zone.

Oxidized edges

Select the appropriate auxiliary gas to ensure a sufficient protective atmosphere in the cutting area and reduce the contact between materials and oxygen. In addition, controlling the flow and purity of the auxiliary gas can also reduce the generation of oxidized edges.

Charring and hole burning

Properly reduce the laser power and increase the cutting speed, control the interaction time between the laser and the material, and avoid scorching and hole burning caused by excessive heating.

Summarize

In general, many factors affect the cutting quality of fiber laser cutting machines. To achieve a higher cutting effect, the selection of process parameters before cutting and the analysis of quality problems after cutting are essential. Analyze quality problems in time, adjust relevant process parameters, and improve the process. Only by fully considering and optimizing these factors can high-quality cutting results be achieved.
The above are the factors that affect the cutting quality of fiber laser cutting machines shared by AccTek Laser. If you want to know more about fiber laser cutting machines, you can follow us, we will regularly update all the content about laser equipment.

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