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Fiber Laser Cutting: A Comprehensive Guide

Fiber Laser Cutting Machine

Fiber laser cutting machines have emerged as a pivotal innovation in the realm of metalworking, offering unparalleled precision and efficiency. This guide is dedicated to elucidating the nuances of fiber laser cutting technology, highlighting its myriad benefits while also acknowledging its limitations. Moreover, it aims to furnish users with actionable insights to enhance the quality of cuts they can achieve with these sophisticated machines.

1. What Is a Laser?

The laser, an acronym that resonates with the marvel of modern science, stands for Light Amplification by Stimulated Emission of Radiation. It is a device that generates a beam of coherent light through the process of optical amplification based on the stimulated emission of electromagnetic radiation.

Diving into the Core of Laser Technology

At its core, a laser is a marvel of quantum electronics, emitting light that is notable for its high degree of spatial and temporal coherence. This coherence lends the laser its unique properties:

  • High Intensity and Brightness: The laser’s light is not only intense but also highly directional. This intensity, a product of photons marching in lockstep, creates a beam powerful enough to cut through steel with the ease of a knife through butter.
  • Monochromaticity: Unlike ordinary light sources that scatter a spectrum of colors, a laser emits light at a specific wavelength. This monochromatic nature is crucial for applications that demand precision and uniformity.
  • Coherence: Laser light waves are in phase both in space and time, which allows them to interfere constructively when combined. This coherence extends over remarkable distances, making lasers ideal for applications ranging from fiber-optic communications to holography.
  • Directionality: Lasers produce a narrow beam in a specific direction, allowing the energy to be focused to a pinpoint. This directionality is essential for tasks that require a high level of control and accuracy, such as surgical procedures or the etching of microcircuits.

The Interaction of Laser Light with Materials

When a laser beam strikes a material, it induces a rapid elevation in temperature, leading to melting and vaporization. This interaction is the principle behind laser cutting, where the beam is focused onto a small area of the workpiece, causing localized heating and subsequent material removal. The quality of the cut is influenced by the laser’s power, the material’s properties, and the precision with which the beam is focused.

The Anatomy of a Laser Beam

A laser beam is not a mere shaft of light; it is a complex interaction of energy and matter. The generation of a laser involves exciting a medium, such as a gas or a crystal, with energy from an external source. This energy excitation leads to the emission of light, which is then amplified and shaped into a beam.

Laser Generating Gases: The Triad of N2, CO2, and He

The composition of laser generating gases is a critical aspect of laser operation. These gases play distinct roles:

  • N2 (Nitrogen): Acts as the initial energy recipient from the RF generator, transitioning into an excited state.
  • CO2 (Carbon Dioxide): The excited N2 molecules then transfer energy to CO2, prompting it to emit laser light.
  • He (Helium): Absorbs excess energy and heat, maintaining the system’s stability and efficiency.

The ratio of N2:CO2:He is typically maintained at 1:4:5, ensuring the optimal generation of laser light.

Comparing Lasers with Ordinary Light

The contrast between lasers and ordinary light is stark. Ordinary light diffuses in all directions and encompasses multiple wavelengths, resulting in a lack of coherence and direction. In contrast, a laser’s beam is a paragon of precision, offering a single wavelength, coherence, and a straight path of travel.

laser cutting machine

2. What Is Fiber Laser Cutting?

Fiber laser cutting stands at the forefront of thermal cutting methodologies, harnessing a high-power density laser beam to slice through materials with remarkable precision. This advanced technique has become the cornerstone of modern metal fabrication, offering a fusion of speed, accuracy, and versatility that traditional cutting methods struggle to match.

The Journey of the Laser Beam

The process begins with the generation of a laser beam, which is meticulously guided through an orchestrated array of optical components. Mirrors and lenses work in concert to direct this potent stream of photons towards the cutting head, where it is finely focused onto the material to be cut.

The Heart of the Machine: The Laser Generator

At the heart of the fiber laser cutting machine lies the laser generator, a marvel of engineering that produces the laser beam. This generator operates on a triad of gases: nitrogen (N2), carbon dioxide (CO2), and helium (He). Each gas plays a pivotal role in the generation and maintenance of the laser beam, with nitrogen initiating the energy transfer, carbon dioxide emitting the laser light, and helium stabilizing the system.

Precision Focus for Optimal Energy Delivery

The focus position of the laser beam is of paramount importance. A precisely focused beam ensures that the energy is delivered efficiently to the workpiece, resulting in a cut that is both clean and precise. This is achieved through the careful alignment of the cutting head, which adjusts the focal length to match the thickness and properties of the material.

The Role of Auxiliary Gas

An auxiliary gas, often high-purity oxygen or nitrogen, accompanies the laser beam. This gas serves a dual purpose: it aids in the ejection of molten material from the cut, and in certain cases, it may also enhance the cutting process by reacting with the material.

Evolution and Advancements in Fiber Laser Technology

In recent years, the evolution of high-power fiber laser generators has been nothing short of revolutionary. These advancements have expanded the applications of fiber laser cutting machines, making them a focal point of industrial innovation. The technology’s maturity has led to its widespread adoption across various sectors, including aerospace, automotive, and electronics.

Why Fiber Lasers Are Overtaking Traditional Methods

Fiber laser generators are increasingly preferred over traditional CO2 and YAG lasers for several compelling reasons:

  1. Enhanced Photoelectric Conversion Efficiency: Fiber lasers boast an impressive photoelectric conversion efficiency of approximately 30%, a significant improvement over the 6-10% efficiency of CO2 lasers and the mere 3% of YAG lasers.
  2. Compact and Agile Design: The diminutive footprint and lightweight nature of fiber lasers allow for unparalleled flexibility and mobility within the workspace.
  3. Consistent Cutting Quality: Fiber lasers employ a flexible light-guiding system that maintains a constant beam transmission distance, eliminating the variability in cut quality that can occur with CO2 laser generators.
  4. Economical Operation: The absence of an external reflected light path system in fiber lasers translates to savings on components such as reflection lenses and protective housings.
  5. Superior Performance in Metal Cutting: With a wavelength of 1.06 μm, fiber lasers are more readily absorbed by metals, enhancing cutting speeds and performance, particularly with reflective materials like aluminum alloys and copper.

The Optical Fiber: The Gain Medium

The optical fiber cable, composed of silica glass, serves as the gain medium in fiber laser technology. When exposed to a high-intensity light source, the light rays traveling through the fiber undergo internal refraction and amplification. Reflectors positioned at the fiber’s terminus further intensify the laser beam, with the wattage of the light source dictating the laser’s strength.

Fiber Lasers in the Manufacturing Industry

The adaptability of fiber laser systems has led to their widespread implementation in the manufacturing industry. These systems are routinely employed for a variety of processes, including cutting, welding, marking, cleaning, and drilling, across a spectrum of materials.

KRRASS RAS-3015 fiber laser cutting machine

3. The Fascinating History of Fiber Laser

Inception: Einstein’s Quantum Insights

The lineage of fiber laser technology unfolds like a captivating scientific saga, woven together by brilliant minds across nearly a century. At its core lies Albert Einstein’s groundbreaking work in 1917, where he delved into the quantum theory of radiation. His revelation—that photons could stimulate atoms to emit more photons—set the stage for all subsequent laser advancements.

Gordon Gould and the Birth of LASER

Fast-forward to the mid-20th century, where physicist Gordon Gould etched the term “LASER” into scientific lexicon. His visionary notebook entry encapsulated the essence of Light Amplification by Stimulated Emission of Radiation. Gould’s conceptual leap paved the way for Theodore Maiman, who, in 1960, constructed the world’s first functional laser.

Elias Snitzer’s Fusion of Fiber Optics and Lasers

Enter Elias Snitzer, a scientist immersed in fiber optics research. In 1963, Snitzer achieved a momentous fusion: he combined laser technology with optical fibers, birthing the first-ever fiber laser system. However, the nascent state of optical fiber fabrication posed challenges—the fiber laser’s potential remained untapped without high-quality cables.

Advancements and Refinements

Over the next three decades, scientific luminaries—including Snitzer himself—fine-tuned the design. High-purity optical fibers emerged, followed by double-clad fibers and rare earth metal-doped cables. These innovations elevated fiber laser performance, inching closer to their gas-powered counterparts.

Salvagnini’s Game-Changer

In the early 2000s, Salvagnini, an Italian company, unveiled the first commercially viable fiber laser cutting machine. This watershed moment marked the ascendancy of fiber lasers. Their agility, precision, and cost-effectiveness propelled them beyond CO2 lasers, revolutionizing material processing.

A Journey of Curiosity and Innovation

From Einstein’s theoretical musings to industrial dominance, the fiber laser’s journey epitomizes human curiosity and relentless innovation. Today, fiber lasers stand at the forefront, etching, welding, and shaping our world with unparalleled precision.

4. How Fiber Lasers Work?

  1. Initiating the Light Source: Semiconductor Diodes

    • The journey begins with the light source. Modern fiber lasers utilize semiconductor diodes as their primary illumination source.
    • Higher wattage diodes result in high-power fiber lasers, but they also generate excess heat. Efficient cooling systems are crucial to manage this concentrated energy.
    • Industrial fiber lasers are exceptionally powerful, surpassing standard light sources commonly used elsewhere.
  2. Pumping Light into the Optical Fiber Core

    • Once the light source is active, it must be directed into the optical fiber cable.
    • Light scatters in all directions upon exiting the diode. To prevent unwanted light escape, the diode is surrounded by opaque materials.
    • The only exit point for light becomes the optical fiber.
    • The process of directing light into a single optical fiber is called pumping.
    • Optical fibers are clad in thin, flexible material to prevent light leakage and improve refractive index. The core of the cable is the optical fiber itself.
  3. Conversion of Light into a Laser Beam

    • Initially, the light entering the fiber cable is weak and unfocused.
    • As photons pass through the fiber, they undergo internal refraction and concentration.
    • The light continuously bounces within the fiber until it forms a coherent laser beam.
  4. Internal Amplification of Laser Light

    • Even after forming a laser beam, the power output remains relatively low.
    • Amplification is essential to enhance beam quality:
      • Doping with Rare Earth Metals: Fiber optic cables contain rare earth metals that get excited by laser light, releasing additional photons. These extra photons boost the laser beam’s energy.
      • Coiling the Fiber: Coiling the fiber increases internal refractions exponentially.
      • Reflective Mirrors: Mirrors at the cable’s end prevent light from returning to the diodes or prematurely exiting the fiber.
  5. Wavelength Management with Fiber Bragg Gratings

    • To optimize fiber laser output, controlling the wavelength (frequency) is crucial.
    • Stimulated emission from molecules occurs at varying wavelengths, affecting laser quality.
    • Fiber Bragg gratings selectively allow desired wavelengths to pass through, blocking unwanted ones.
  6. Shaping and Focusing the Laser Light

    • At this stage, the laser beam is strong enough to melt or cut materials.
    • However, it remains unfocused, with a large spot diameter.
    • High-quality lenses shape the beam into a smaller point (spot) and manage other parameters like focal length.
  7. Electronic Deflectors for Beam Control

    • While the laser beam is ready for applications, controlling its position and direction remains challenging.
    • Electronically controlled deflectors (mirrors) at the beam’s end solve this.
    • A computer-controlled system adjusts the deflector angle, directing the fiber laser precisely.
    • This method keeps the sensitive parts inside the fiber laser cavity stationary while moving only the laser beam.

5. Advantages and Disadvantages of Fiber Laser Cutting

Fiber laser cutting technology has revolutionized the metal fabrication industry with its precision and efficiency. Here, we delve into the advantages and disadvantages of fiber laser cutting compared to other cutting methods, providing a comprehensive analysis based on the key points outlined in the image provided.

Advantages:

  1. Impeccable Edge Quality: The advent of fiber laser cutting has brought forth a paradigm shift in edge quality. The technology’s inherent precision engenders edges that are exceptionally clean and well-defined. This is a direct consequence of the minimal kerf width and the reduced heat affected zone (HAZ), which together ensure that the material is cut with utmost accuracy, obviating the need for additional finishing processes. The result is a product that boasts of a superior finish, right off the cutting table.
  2. Unmatched Precision – Computer Numerical Control (CNC): Fiber laser cutting machines are typically governed by sophisticated CNC systems, allowing for intricate patterns and complex designs to be executed with surgical precision. This level of control is indispensable for applications that demand exacting standards, such as aerospace components and medical devices. The repeatability afforded by CNC technology ensures that each piece is a carbon copy of the last, maintaining consistency across production runs.
  3. Durability of Tools: The non-contact nature of fiber laser cutting means that there is no physical wear and tear on cutting tools. This stands in stark contrast to traditional mechanical cutting methods, where the tools degrade over time, affecting cut quality and necessitating frequent replacements. The longevity of laser cutting tools translates to lower maintenance costs and less downtime, enhancing overall productivity.
  4. Minimized Material Deformation: Fiber laser cutting minimizes the heat input to the material, significantly reducing the likelihood of warping or distortion. This is particularly beneficial when working with metals that are susceptible to heat-induced changes. Maintaining the integrity of the material is crucial in industries where precision is not just desired but required.
  5. Complex Cut Geometries: The capability of fiber lasers to produce features that are challenging or impossible to achieve with other cutting methods is one of its most compelling advantages. The technology excels at cutting intricate shapes and fine details, pushing the boundaries of what can be fabricated from metal sheets.

Disadvantages:

  1. Capital Expenditure: The initial cost of acquiring fiber laser cutting machinery is a significant barrier for many businesses. The investment is considerably higher than that for traditional cutting systems like plasma cutters. However, this is somewhat mitigated by the lower operating costs and the absence of recurring expenses for tool replacement.
  2. Operational Energy Requirements: Despite their operational efficiency, fiber lasers do require a substantial amount of energy, particularly in high-volume industrial settings. This can lead to elevated utility costs, which must be factored into the total cost of ownership.

KRRASS Handheld Laser Welding Machine

6. How to Improve Fiber Laser Cut Quality

In the realm of metal fabrication, fiber laser cutting stands out for its precision and versatility. To ensure the highest quality of cuts, several factors must be meticulously controlled. Here, we explore the elements that influence the quality of laser cutting and how to enhance it.

Factors Affecting Laser Cut Quality:

  1. Laser Source:
    • The laser source is the heart of the cutting machine, providing the energy needed for cutting.
    • Quality laser sources from reputable brands like IPG, Raycus, Max, and JPT ensure consistent performance.
    • A stable and long-lasting laser source is crucial for maintaining high-quality cuts over time.
  2. Laser Power:
    • Laser power determines the machine’s cutting capacity, with greater power enabling stronger cutting force.
    • Different materials and thicknesses require appropriate laser power settings.
    • Excessive power can lead to rough surfaces and burrs, while insufficient power may prevent cutting through the material.
  3. Laser Cutting Speed:
    • Cutting speed must be balanced with laser power to control the cutting process effectively.
    • Too fast a speed results in incomplete cuts, while too slow overheats the workpiece, causing large, rough slits.
  4. Laser Focus:
    • The focus of the laser beam, where energy density is highest, is critical for achieving precise cuts.
    • Users must ensure the laser beam is correctly focused, with adjustments made based on material type and thickness.
  5. Auxiliary Gas:
    • Auxiliary gases like oxygen, nitrogen, and air assist the cutting process and help expel slag.
    • The choice of gas and its purity level, such as a minimum of 99.5% for nitrogen, impacts the cutting outcome.
  6. Gas Pressure:
    • The pressure of the auxiliary gas influences the effectiveness of slag removal and overall cut quality.
    • Optimal gas pressure varies with different materials and must be adjusted to avoid issues like adhesion of molten material or enlarged cutting slits.
  7. Nozzle:
    • The nozzle controls the auxiliary gas injection area and thus plays a role in cutting quality.
    • The structure, size, and height of the nozzle must be maintained, and damage to the nozzle can lead to uneven airflow and subpar cuts.
    • Different nozzle diameters are suited for varying thicknesses, and the nozzle must be coaxial with the laser beam for optimal results.

Enhancing Fiber Laser Cut Quality:

  1. Optimize Laser Source and Power:
    • Regularly calibrate and maintain the laser source to ensure its stability and longevity.
    • Adjust the laser power according to the material type and thickness to avoid excessive or insufficient penetration.
  2. Refine Cutting Speed:
    • Conduct test cuts to find the optimal speed that balances the heat input and material throughput.
    • Monitor the cutting process and adjust the speed in real-time to maintain consistent quality.
  3. Precise Focus Adjustment:
    • Use advanced focusing techniques to maintain a small, intense laser spot for cleaner cuts.
    • Regularly check and adjust the focus position to compensate for variations in material surface and thickness.
  4. Select Appropriate Auxiliary Gas:
    • Choose the right type of gas based on the material being cut to enhance the cutting process and edge quality.
    • Ensure the purity of the auxiliary gas meets the required standards to prevent oxidation and other defects.
  5. Control Gas Pressure:
    • Fine-tune the gas pressure to achieve the best balance between efficient slag removal and minimal kerf width.
    • Avoid too high or too low pressure that could lead to rough cuts or inadequate slag expulsion.
  6. Maintain Nozzle Integrity:
    • Inspect and replace nozzles as needed to prevent uneven airflow and suboptimal cutting performance.
    • Use nozzles with the correct diameter and height for the material and thickness being cut.
  7. Regular Equipment Maintenance:
    • Implement a routine maintenance schedule for the laser cutting machine to prevent unexpected downtime and ensure consistent quality.
    • Train operators on proper machine handling and troubleshooting to maintain peak performance.

7. Advancing Fiber Laser Cutting Technology

The trajectory of fiber laser cutting technology is a narrative of continuous innovation and advancement. The industry’s dedication to pushing the boundaries of what’s possible is evident in the ongoing quest for higher wattage in fiber laser cutters. This relentless drive for more power is not merely a quest for greater force; it represents a paradigm shift in operational efficiency and the establishment of new benchmarks in the realm of precision cutting.

Elevating Power: Beyond the Horizon

The evolution of fiber laser technology is marked by a significant increase in power output. This escalation is not solely focused on raw strength but is intricately linked to enhancing the speed and quality of cuts. As manufacturers strive for more efficient production lines, the ability to quickly and cleanly cut through thicker materials becomes increasingly vital. The industry’s commitment to this power surge is reshaping the landscape of laser cutting, making it a more robust and versatile tool in the arsenal of modern manufacturing.

Crafting with Precision: Aiming for the Apex

In the domain of laser cutting, precision is paramount. The industry’s goal is to reach an apex of accuracy that not only meets but exceeds current standards. This pursuit of perfection is driven by the need to deliver products that stand out in a crowded marketplace. The future of laser cutting technology is poised to embrace this challenge, leveraging advancements in optics and control systems to produce cuts with unparalleled exactness.

Smart Operations: The Dawn of Autonomy

The journey of fiber laser cutters towards becoming intelligent systems is characterized by the adoption of sophisticated features such as automated material handling and robotic cutting. These innovations are paving the way for a future where fiber laser machines transcend their role as mere tools and emerge as autonomous, intelligent entities within the manufacturing process. The integration of artificial intelligence and machine learning algorithms is expected to further enhance the capabilities of these machines, enabling them to make real-time decisions, optimize cutting paths, and reduce waste.

The Future of Fiber Laser Cutting: A Vision of Synergy

Looking ahead, the development trend of fiber laser cutting technology is one of synergy between power, precision, and intelligence. The industry is moving towards a future where machines are not only more powerful and accurate but also smarter. This convergence of advancements is set to revolutionize the way we think about and engage with laser cutting technology, opening up new possibilities for innovation and efficiency in manufacturing and beyond.

8. Selecting the Right Fiber Laser Machine for Your Business

Laser Applications: A Critical Consideration

The primary applications of your fiber laser machine should guide your purchase decision. If sheet metal fabrication is the cornerstone of your business, investing in a fiber laser cutting machine could be a strategic move, offering compatibility with a diverse range of metals and alloys. Conversely, specialized machines like laser cleaners, markers, and welders are designed for singular tasks and may not be cost-effective unless utilized regularly.

Machine Size: Compact Yet Spacious

Despite their compact design, fiber laser machines necessitate ample space for optimal operation. Adequate clearance around the machine is essential to prevent overheating and ensure proper airflow. Additionally, sufficient space should be allocated to prevent accidental contact during operation, especially when processing materials that may emit hazardous fumes, such as plastics, necessitating robust ventilation systems.

Laser Power: Matching Your Needs

The power of your fiber laser should align with your cutting requirements. High-power lasers are adept at slicing through thick metal blocks, but not all industries will benefit from a 10kW solid-state laser. The power needed for laser marking is minimal, while engraving, cleaning, and cutting demand varying power levels based on operational conditions. It’s prudent to avoid high-power lasers if they don’t confer a distinct advantage to your operations.

Cost Over Time: A Long-term Perspective

Solid-state lasers, like fiber lasers, generally command a higher purchase price than CO2 lasers. However, they boast lower operational costs due to their exceptional efficiency, even at high power outputs. Fiber lasers are also considered maintenance-free, with an impressively long lifespan.

Operational Modes: Continuous or Pulsed

Fiber lasers can operate in two modes, depending on the application. Continuous wave mode is suited for constant, uninterrupted cutting, but may lead to burn marks on workpiece edges. Pulsed mode, on the other hand, emits energy in short bursts, reducing the chances of unnecessary melting or warping. The duration of the laser pulses dictates the pulse energy, with longer durations yielding more energy output.

Production Capacity: Size Matters

The bed size of most laser machines dictates their production capacity. Larger bed sizes are necessary for enterprises requiring rapid turnaround times but may be impractical for mass production. Some fiber laser cutting machines also employ coil feed systems, where the main laser body is connected to a sheet metal decoiler, continuously feeding metal into the machine for high-volume, low-complexity production runs.

KRRASS Plate fiber laser cutting machine

9. Conclusion

Fiber laser technology originated from the theoretical thinking of Albert Einstein and has developed into a cornerstone of modern innovation. Characterized by their versatility and compactness, these systems have become integral to many fields, including but not limited to complex metalwork, advanced robotics, and precision surgery. Known for their efficiency and reduced space requirements, fiber laser machines have surpassed what was once a prohibitive cost barrier and are becoming increasingly easier to use.

Additionally, the wide range of materials that fiber lasers can finely process puts them well-positioned as alternative metal fabrication methods. Their adaptability and precision not only simplify the manufacturing process but also open up new avenues for creative and functional applications across a variety of industries.

So if you want to know more about fiber lasers, please contact us.

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