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What Is CNC Laser Cutting? Everything You Need To Know

CNC laser cutting
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    Laser cutting was first used in the 1970s. In modern industrial production, laser cutting is widely applied to materials such as sheet metal, plastics, glass, ceramics, semiconductors, textiles, wood, and paper.

    In the coming years, laser cutting is expected to see significant growth in the fields of precision and micro-machining.

    What Is CNC Laser Cutting?

    Laser cutting technology relies on the principle of a high power density laser beam irradiating the surface of the material to be cut, which melts, vaporizes, or reaches the ignition point in extremely quick time. This is accompanied by the blowing away of the molten or burnt material through a high-speed airflow, thus accomplishing the cutting process.

    Laser cutting is based on a high-power density laser as a heat source. Through computer-aided design and computer-aided manufacturing technologies, the cutting process is in accordance with the designed path. The laser beam permits the workpiece to melt, vaporize, or decompose into a cut.

    Laser cutting has a wide application in manufacturing fields, including automotive, home appliances, and electronics products.

    How Does It Works?

    Laser cutting can be done in continuous or repetitive pulsed mode. The process involves the focusing of a laser beam into a very small spot with a minimum diameter of less than 0.1mm, where the resulting power density at the focal point is extremely high and can be higher than a certain threshold value. At this stage, the input heat from the beam-already transduced from light energy-is far in excess of that reflected, conducted, or otherwise dissipated by the material. The material is then heated up rapidly to its melting and vaporization temperatures. Simultaneously, a flow of high-speed air, directed either coaxially or non-coaxially, acts to blow the molten or vaporized material out from the bottom of the workpiece.

    When the beam moves relative to the material, a narrow slit (0.1 to 0.3mm in width) is formed, effectively dividing the material. The diagram below shows a schematic of a laser cutting head. In addition to the lens, it also includes a coaxial nozzle for blowing auxiliary gas.

    Laser Cutting Process Steps

    Although laser cutting machines can be different in regard to the model and application, a general laser cutting system normally consists of the laser resonator, mirrors, laser cutting head, laser focusing lens, pressurized gas components, and nozzles. The basic processes involved in laser cutting include: beam generation, beam focusing, localized heating and melting, material ejection, and beam movement.

    Part 1: Beam Generation

    The word “Laser” itself is an acronym for Light Amplification by Stimulated Emission of Radiation, and thus describes in a nutshell the principle underlying the generation of laser light. Besides that principle, the laser resonator makes use also of spontaneous as well as of stimulated emission to produce a high-intensity beam of light which is spatially and spectrally coherent-this is the laser. Part of the light amplified by stimulated emission passes through the resonator without being reflected back into the medium, thus creating the original laser beam. Once the beam has been created it enters the laser cutting head, where it is reflected by internal mirrors and directed towards the focusing lens.

    Part 2: Beam Focusing

    The laser beam reflected onto the focusing lens surface is focused through the nozzle of the laser cutting head onto the work surface. In the process, the beam’s cross-sectional area is reduced through focusing, concentrating the energy on a smaller spot, hence increasing the intensity of the beam.

    Part 3: Localized Heating, Melting, And Material Ejection

    The material, in turn, absorbs the radiative energy of the focused laser beam impinging on the surface, rising in internal energy and generating heat. This is followed by heating, melting, and partial or complete evaporation of the surface layer of the material due to the high-powered laser. This results in progressive weakening and removal of the material within the focused area, leading to the formation of the desired cut. In this stage, the auxiliary gas, commonly referred to as cutting gas, enters the laser cutting head and, flowing coaxially with the focused beam direction onto the surface of the material, performs two functions: protecting the focusing lens and cooling it, and removing the molten material from the cut.

    Depending on the removal mechanism, laser cutting falls into various types of laser cutting systems, which include primarily melt cutting, chemical degradation cutting, vaporization cutting, scribing, and oxidation cutting.

    Part 4: Beam Movement

    When the material surface starts heating up, melting, or vaporizing, the laser beam should travel to other regions of the material’s surface to accomplish the cut. This is typically accomplished by moving the mirrors, controlling the laser cutting head, or changing the position of the material. The system, based on the movement of the beam, can be categorized as follows: material movement, flying optics, and hybrid laser cutting systems.

    Material Movement is the most straightforward method of movement. Here, it involves the machine’s moving parts controlling the movement of the workpiece. This method requires that the laser cutting head maintain a certain distance from the material surface and typically involves fewer optical components.

    Flying Optics has its laser head movable while the target material remains stationary. The laser cutting head, with the flying optics system, moves on both the X-axis and Y-axis to make the required cuts on the stationary material. The flexibility in flying optics is good for the treatment of materials of diverse thickness and sizes that shorten the processing time. Since the beam is in constant movement, the variable length of the latter during all the process must be taken into consideration. The variation in beam length can be controlled by collimation (alignment of optical components), using a constant beam-length axis, or employing adaptive optical components or capacitive height control systems that can make real-time adjustments as needed.

    What Are The Different Types Of CNC Laser Cutting Machines?

    The principle of laser cutting is to apply high power density energy generated from a focused laser beam. Available laser cutter machine types are: fiber laser cutting machines, CO2 laser cutting machines, and YAG laser cutting machines.

    Fiber Laser Cutting Machine

    A fiber laser cutting machine uses a fiber laser generator as its light source. A new type of laser technology, fibre lasers output high-energy density laser beams that are focused onto the workpiece surface. The instant area at which the laser focus spot irradiates the material melts and vaporizes. By moving the focus spot through a CNC system, automatic cutting is achieved. Compared to the large volume of gas and solid-state lasers, fiber lasers have great advantages in many aspects, which have gradually become key candidates for applications in high-precision laser processing, laser radar systems, space technology, and medical lasers.

    CO2 Laser Cutting Machine

    A CO2 laser cutter can stably cut carbon steel within 20mm, stainless steel within 10mm, and aluminum alloys under 8mm. The wavelength of the CO2 laser is 10.6 micrometers, which is relatively easy to be absorbed by non-metal materials. This enables high-quality cutting of materials such as wood, acrylic, polypropylene, and plexiglass. However, the photoelectric conversion rate of CO2 lasers is only about 10%.

    Cutting devices using CO2 lasers are fitted with nozzles at the exit of the beam and blow either oxygen, compressed air, or inert gases like nitrogen, which enables them to enhance their speed and cut surface smoothness. Problems relating to discharge stability of high-power CO2 gas lasers must be overcome in order to work for the stabilization of power sources and the extension of their lives. At present, the laser hazard levels are divided into four categories according to international safety standards, and CO2 lasers are in the least hazardous category, which is level 1. However, the operational cost of a CO2 laser cutting machine is the highest among these three types of lasers.

    YAG Laser Cutting Machine

    The YAG solid-state laser cutting machines boast lower costs and good stability, but they have low energy efficiency and are usually less than 3%. The output power of most products is below 800W. Due to the small output energy, YAG lasers are mainly used for drilling and cutting thin sheets because of the small output energy. Their green laser beam can operate in either pulsed or continuous wave modes. Due to the short wavelength and the high focusing ability, it fits precision treatment, and when working in pulse mode, it is especially effective for hole processing. They can also be used for cutting, welding, and photolithography.

    However, the wavelength of a YAG laser is poorly absorbed by non-metal materials; thus, YAG lasers cannot be used to cut non-metals. In order to enhance their performance, much attention needs to be given to increasing the stability and life span of the power supply when developing YAG solid-state laser cutting machines, especially in the development of high-capacity and long-life optical pump sources such as semiconductor pumps, which are intended to greatly improve energy efficiency.

    What Types Of Materials Can Be Cut With A CNC Laser Cutting Machine?

    Laser cutting is popular primarily because of its versatility. From paper, wood, cork, acrylic, and foam to various metals, it can be cut by laser cutting machines. In laser cutting, it is necessary to know the properties of each material and take extra care during the actual process of cutting.

    Different Metals

    Laser cutting machines can cut all types of metals, ranging from low-carbon steel and stainless steel to non-ferrous metals. Reflective metals, like aluminum, are harder to cut, and in those cases, fiber lasers should be used. Nowadays, even the cutting thickness of metals can be as much as up to 100mm, which would depend on the power of the laser.

    Wood

    Many types of wood (including plywood and MDF) can be cut with a laser, but oils in some woods may cause them to ignite, and extra caution must be taken in using a laser to cut them.

    Paper And Cardboard

    Paper also is a candidate for laser cutting, and we often see very intricate and fine wedding invitations that most likely are made by laser cutting.

    Plastic Products

    Acrylic, PMMA, and Lucite are other names for transparent plastics. The edges after laser cutting are smooth and clean, so that they appear to be cut with a knife.

    Polyoxymethylene (POM)

    Polyoxymethylene is one of the highly utilized engineering plastics. It finds applications in gears, guide and sliding components, medical devices, food packaging, and many more. The possibility of complex cuts through lasers extends the use of POM in general applications in various fields.

    Advantages Of CNC Laser Cutting

    Laser cutting possesses the characteristics of fast speed and good quality compared with other thermal cutting methods. The specific advantages can be summarized as follows:

    Good Cutting Quality

    Laser cutting has high cutting quality because of its small laser spot, high energy density, and fast cutting speed. The kerf of the cut is narrow and parallel-sided, with a very good dimensional accuracy of ±0.05 mm. The cut surface is smooth with minimal roughness, and often no further machining of the surface is required. The heat-affected zone is small, and the material characteristics are minimally changed.

    High Efficiency In Cutting

    Generally, laser cutting machines are fitted with several CNC workstations that help to completely automate the cutting process. Since only a change in the program of the CNC is required, the system could be used for parts of varied shapes and, thus, provide 2D and 3D cutting. This, in turn, makes processing easier and more productive, along with adapting to various materials and designs easily.

    Fast Cutting Speed

    Laser cutting offers impressive speed, with a 1200W laser cutting 2mm thick low-carbon steel at up to 600cm/min, and 5mm thick polypropylene resin at up to 1200cm/min. The material does not require clamping, saving time and eliminating the need for fixtures. This improves efficiency by reducing the loading and unloading time, making the process faster and more cost-effective.

    Non-contact Cutting

    Laser cutting is a non-contact process; the cutting torch does not touch the workpiece, so it doesn’t wear out. No tool changes are required in cutting different shapes as with conventional methods but changes may be made in the output parameters of the laser. The process also generates minimal noise and vibration while it produces no pollutants, making it more environmentally friendly and quieter compared to other cutting methods.

    Variety Of Materials

    The materials that laser cutting can process are metals, composites, leather, wood, and textiles. Due to their thermal properties and laser absorption rates, different materials have different lasercutting suitability. Although the majority of materials are easily cut, there are those that might require special laser systems, such as highly reflective metals, which need fiber lasers to perform optimally.

    Disadvantages Of CNC Laser Cutting

    Other disadvantages of laser cutting include the following:

    Requires Expertise

    To properly utilize a laser cutter, one needs to have a professional operator. Setting it up correctly will guarantee that the quality of cuts produced is as desired.

    Limitations In Metal Thickness

    Relatively speaking, laser cutting is not suitable for very thick plate cutting compared to other thermal cutting methods. The maximum suitable thickness depends on the available machine and expertise at hand. In average practice, metal fabrication companies tend to limit laser cutting thickness to 15 or 20 millimeters.

    High Initial Cost

    Laser cutting machines can be twice as expensive as water jet or plasma cutters. While in the long run, the compensatory operational costs and efficiency make up for this, the initial investment nevertheless remains pretty high.

    Toxic Fumes

    The hot cutting techniques melt the material and therefore emit gases and hazardous fumes. This is the case, especially when the materials involved in the cutting are plastics. Thus, a good but often expensive ventilation system is necessary to provide a safe working environment.

    What Are The Common Applications Of CNC Laser Cutting?

    Laser cutting technology plays a major role in many industries that involve rail transportation, sheet metal processing, car making, steel structure processing, and agricultural machinery due to its features of high cutting accuracy, fast cutting speed, smooth and flat surface, narrow kerf, minimal thermal distortion, flexible processes, and safety without pollution.

    Application In Rail Transit Industry

    High-speed rail construction and rail transit involve cutting various kinds of sheet materials, including track, car body, interior panel, tube material for the manufacture of handrails, bogies, etc. Laser cutting technology enables high-quality processing for every component and improves production efficiency.

    Application In Sheet Metal Processing Industry

    Laser cutters weld and assemble sheet metal parts directly, shifting from “casting” to “welding” procedures. This would definitely optimize the manufacturing workflow, reduce processing time, and lower the difficulty level while reducing labor intensity.

    Application In The Automobile Industry

    Laser cutting finds its application in the automobile manufacturing industry, from surface treatment to cutting and welding. It ranges from car body production, doors, door frames, trunks, roof panels, and much more with precision and at high productivity rates for these complicated operations.

    Application In The Steel Structure Industry

    The need often arises to install bolts or any other attachments in a steel structure, and hence accurate processing of holes becomes very essential. Laser cutting can provide different shapes and sizes according to the design requirement for effective and accurate assembly.

    What Is The Future Technology Trend Of CNC Laser Cutting?

    The development of laser cutting technology has accelerated significantly with the widespread application of cutting technologies. The advancement of laser cutting technology has further highlighted its sophistication in practical applications. From the current development trends, laser cutting technology is evolving in the following directions:

    High-Speed, High-Precision Cutting

    Laser cutting in China is evolving toward higher speed and precision. With advances in laser beam modes and microcomputing, cutting speeds exceed 20m/min, achieving precision with minimal errors, such as cutting 10mm holes in 1mm thick material at 500 holes per minute, reflecting the industry’s move toward high-speed, high-precision capabilities.

    Thick Plate And Large Workpiece Cutting

    Laser cutting is shifting from thin sheets in light industry to thicker plates in heavy industry. High-power lasers, such as 6KW models, can cut up to 32mm thick carbon steel. Additionally, the size range for cutting materials has expanded, with plates up to 6.3m in length and 5.5m in width, improving industrial cutting capabilities.

    3D Multi-Axis CNC Laser Cutting

    China is incorporating 5-axis and 6-axis 3D laser cutting technology to meet the growing demand from industries like automotive and aerospace. This technology provides higher precision and broader applications, enabling more complex and efficient cutting processes for a wider range of materials and shapes, contributing to the precision manufacturing sector.

    Automation And Unmanned Laser Cutting

    The automation and unmanned evolution of laser cutting is driven by advances in computer networking. Many countries have developed unmanned laser cutting machines, and the increasing market demand is pushing the technology toward full automation. This innovation aims to reduce human intervention, enhancing production efficiency and consistency in various industries.

    Conclusion

    In laser cutting, light that is produced by material excitations carrying intense heat is used. In contact with the material, the heat quickly melts the surface and, within the trail or motion of the beam, there is a cut. The gaps are also narrower compared to the traditional way of cutting and minimize the disposal of material. The cutting effect of laser cutting is exact and high quality, inheriting the strong points of laser technology that cannot be matched by conventional cutting methods. Cutting with lasers will be more comprehensible, easier to learn, and ensure high-degree advantages in terms of speed of treatment and results that meet the demands of the market. It is expected that, in the future, machines for laser cutting will be put to intensive use.

    Final Thoughts

    As a professional with 15 years of CNC machining service experience, I fully understand the significance of CNC laser cutting in modern manufacturing. CNC laser cutting uses high-energy laser beams to precisely cut various materials, such as metals, plastics, and wood. Compared to traditional cutting methods, laser cutting offers higher precision, speed, and efficiency, especially for complex shapes and small parts. For example, our company once precision-cut hundreds of intricate metal components for an aerospace client, ensuring high accuracy and efficient production. By adopting advanced laser cutting technology, Ultirapid provides customers with faster production cycles and lower processing costs. If you need custom precision parts or would like to learn more about our solutions, feel free to contact us.

    Faqs

    How Accurate And Precise Is CNC Laser Cutting?

    CNC laser cutting is highly accurate, typically achieving tolerances of ±0.05 mm to ±0.1 mm. The precision comes from the laser’s fine beam, which allows for intricate designs with minimal heat-affected zones, reducing material distortion. This makes it ideal for industries requiring high detail, such as aerospace, automotive, and medical manufacturing.

    How Much Does CNC Laser Cutting Cost?

    CNC laser cutting costs vary depending on factors such as material type, thickness, design complexity, and production volume. Generally, the cost is around $0.10 to $3.00 per minute, with a minimum charge typically ranging from $50 to $100. For simple parts, the cost per piece may range from $1 to $5, while more complex projects will incur higher fees. Unit costs tend to decrease with larger production runs.

    How Long Does CNC Laser Cutting Usually Take?

    The time required for CNC laser cutting depends on factors like material type, thickness, complexity of the design, and the size of the part. For simple cuts on thin materials (e.g., 1-2 mm sheet metal), it may take just a few minutes per part. However, cutting thicker materials or intricate designs can take significantly longer, ranging from 10 minutes to an hour or more per part. Batch production can also reduce individual cutting times.

    When To Use CNC Laser Cutting?

    CNC laser cutting machines are highly flexible and fast, improving production efficiency and shortening product production cycles, widely used for processing plates thicker than 2mm. Laser cutting technology is a revolution in sheet metal fabrication, suitable for cutting low-carbon steel under 12mm and stainless steel under 10mm. The technology has no cutting force, no deformation, and no tool wear, allowing for efficient and precise processing of both simple and complex parts.

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