We have found that more and more people are becoming interested in laser engraving and marking, whether from industrial production or personal hobbies.
Some newcomers may be confused when choosing a laser engraving machine. Here, we share some insights on choosing the type of laser, which is crucial in selecting laser machines. This overview covers the five most commonly used types of lasers in commercial applications (there are thousands of known lasers, most of which are used for specialized research), and we hope it will be helpful to those in need.
Related:
What is a laser?
What is a laser marking machine?
We will provide you with detailed information about these different types of lasers used for laser marking systems. They are:
- Fiber laser
- CO2 laser
- UV laser
- Diode Laser
- MOPA laser
Fiber Laser
Introduction
Fiber lasers are a special type that uses optical fibers doped with rare-earth elements (e.g., ytterbium, erbium, and thulium, etc.) as the gain medium.
In 1961, Elias Snitzer invented the fiber laser and demonstrated its use. However, it wasn’t until the 1990s that fiber lasers began to be commercialized and gradually became widespread.
Today, fiber lasers are the most commonly used lasers for marking and engraving.
Features
- High Beam Quality: Due to the waveguide properties of optical fibers, fiber lasers offer excellent beam quality and superior focusing ability.
- High Conversion Efficiency: Fiber lasers have very high electro-optical conversion efficiency, usually reaching more than 30%, making them cost-effective, energy-efficient, and environmentally friendly.
- Compact Structure: Fiber lasers are designed to be compact, with small size and lightweight, making them easy to integrate with other equipment or production lines. This compact design also makes them ideal for mobile applications, such as handheld laser tools or laser heads mounted on robotic arms.
- Excellent Stability: With a simple structure, fiber lasers boast high reliability and long service life.
Fiber lasers are more expensive but offer better precision, engraving speed, control, and longevity. They also require less maintenance and consume less energy.
Engraving Materials
- Metals: Fiber laser marking machines, known for their high precision, efficiency, and excellent beam quality, almost can engrave all types of metals, including stainless steel, aluminum, steel, iron, anodized aluminum, magnesium, lead, zinc, and copper.
- Plastics: Some engineering plastics with good absorption properties, such as ABS, PC, PVC, PE, and PP, can be engraved. The surface of these materials change color or ablate under laser action, and ideal marking effects can be achieved by adjusting laser power and frequency.
Applications
- Automotive Manufacturing
- Aerospace
- Medical Device Manufacturing
- Electronics Manufacturing
- Jewelry
- Consumer Electronics
- Home Appliance Manufacturing
- Instrumentation
- Packaging and Printing
Brands
Today’s market features many popular fiber laser machine brands, such as Linxuan Laser, Omtech, Cloudray, Trumpf, and Coherent.
CO2 Laser
Introduction
CO2 laser is one of the earliest developed and widely used gas lasers, invented in 1964 by C. Kumar N. Patel at Bell Labs in the United States. (Reference)
With the advancement of science and technology, CO2 lasers gradually became one of the laser products with higher continuous output power, widely used in fields such as textiles, medical applications, material processing, and industrial manufacturing. By the 1980s, CO2 laser technology had basically matured and was widely used in industrial processing for over two decades, including metal cutting, marking, and engraving various materials.
CO2 lasers use a mixture of carbon dioxide gas as the gain medium, including carbon dioxide, helium, nitrogen, and possibly hydrogen, water vapor, and xenon. Under discharge, the gas molecules undergo energy level transitions, producing infrared lasers with a wavelength of 10.6 microns.
Features
- High Output Power: CO2 lasers offer output power ranging from a few watts to several kilowatts, making them suitable for various applications, from fine marking to cutting thick plates.
- Significant Cutting and Engraving Depth: CO2 lasers can cut metallic and non-metallic materials with thicknesses up to several tens of millimeters.
- Excellent Absorption for Non-Metallic Materials: The 10.6μm wavelength of CO2 lasers matches the infrared absorption peaks of many non-metallic materials, resulting in very high absorption efficiency. For example, materials like wood, paper, plastics, and leather can achieve absorption rates of over 80% with CO2 laser.
Engraving Materials
CO2 lasers have unique advantages for engraving and marking non-metallic materials:
- Organic Materials: Wood, acrylic, paper, leather
- Plastics: PVC, ABS, PP
- Glass and Ceramics
- Composite Materials: Fiber-reinforced plastics (FRP), carbon fiber composites
Application Industries
- Advertising Sign Production
- Packaging and Printing
- Textile and Apparel
- Electronics Manufacturing
- Medical Device Manufacturing
- Artwork Creation
Other applications: laser cutting, welding, medical cosmetology (e.g. skin treatment), industrial heating, etc.
UV Laser
Introduction
The development of UV lasers dates back to the 1970s. With advancements in ultraviolet light source technology, UV lasers have gradually become an important tool for precision processing.
UV lasers are typically based on solid-state lasers or excimer lasers. The base frequency light is converted into ultraviolet light through nonlinear optical crystals in solid-state lasers, while excimer lasers are gas lasers that directly emit ultraviolet light.
Features
UV lasers (ultraviolet lasers) hold a significant position in the field of microfabrication due to their unique wavelength and high-precision machining capabilities.
Short Wavelength, Small Focus Spot
The typical wavelength of a UV laser is 355 nm (tripled frequency Nd:YAG or Nd:YVO4 lasers). Compared to infrared lasers (such as CO2 lasers, which have a wavelength of 10.6 μm), UV lasers have a shorter wavelength, enabling them to achieve a smaller focus spot.
The focus spot diameter of a UV laser can reach 10 μm or even smaller, making it ideal for micron-level precision processing.
Cold Processing Characteristics, Reduced Heat-Affected Zone
Due to the short wavelength of UV lasers, the energy is concentrated in an extremely small area. After the material absorbs photons, it undergoes direct chemical bond cleavage rather than material removal through thermal conduction.
This “cold processing” characteristic significantly reduces the heat-affected zone (HAZ), preventing thermal deformation, charring, or melting of the material. It is particularly suitable for processing heat-sensitive materials.
Engraving Materials
- Semiconductor materials: Silicon wafers, sapphire
- Plastics: PC (Polycarbonate), PMMA (Acrylic), PET (Polyester), PVC (Polyvinyl chloride)
- Glass and crystal
- Ceramics
Application Industries
- Semiconductor manufacturing
- Electronic component production
- Photovoltaics
- Medical device manufacturing
Other Applications: Micro machining, FPC (Flexible Printed Circuit) board cutting, wafer dicing, biomedical research, etc.
Semiconductor (laser diode)
Introduction
Diode lasers, also known as semiconductor lasers, were first successfully demonstrated in 1962, but their widespread commercial application was not achieved until the late 1980s. (wikipedia)
Diode lasers use the special structure of the semiconductor PN junction. When current is injected, electrons and holes recombine to produce photons, generating laser output. They are typically directly driven by current and feature a compact design.
Features
Miniaturization and Easy Integration
Diode lasers are compact, lightweight, and consume low power, making them ideal for integration into existing optical systems, electronic devices, and other industrial machinery.
High Efficiency and Low Power Consumption
Diode lasers boast very high electro-optical conversion efficiency, typically exceeding 50%. They also have very low power consumption, requiring minimal electrical energy to achieve efficient laser emission.
Wide Wavelength Range
By selecting different semiconductor materials (such as GaAs, InGaAs, GaN), diode lasers can be tuned to emit at various wavelengths. Common wavelengths include 635nm (red), 650nm (red), 785nm (near-infrared), 808nm (near-infrared), and 980nm (near-infrared).
Engraving Materials
- Metal Materials: Stainless steel, aluminum alloy, copper, and copper alloys
- Plastics: ABS, PC, PA
- Ceramics
- Glass
Application Industries
- Consumer Electronics
- Medical Devices
- Jewelry
- Automotive Parts
- Decorative Items
If engraving requirements are relatively simple and power demands are low, diode lasers can be used to engrave metals. These entry-level laser systems are more affordable than other types of lasers (some costing only a few hundred dollars), but they have limited power output and beam quality.
MOPA Laser
Introduction
MOPA Laser, short for Master Oscillator and Power Amplifier, is a type of fiber laser that uses a master oscillator and power amplifier structure.
The master oscillator generates a low-power, high-quality seed laser, which is then amplified by the power amplifier to output a high-power laser beam.
Features
- Adjustable Pulse Width and Frequency: MOPA lasers can generate pulses as short as several nanoseconds to tens of nanoseconds. By precisely controlling factors such as pulse width, operating frequency, and energy, it enables multi-color laser marking and fine processing.
- High Beam Quality: The laser beam quality of MOPA lasers is excellent and can easily approach the diffraction limit, allowing for high precision and quality in laser processing.
- High Peak Power: MOPA lasers can achieve extremely high peak power by adjusting pulse width and energy, making them suitable for deep engraving.
Engraving Materials
- Stainless Steel: The MOPA laser can create high-quality oxidized black or color markings on stainless steel surfaces, with marking depths ranging from 0.01 to 0.05 mm. It is suitable for applications such as medical instruments, kitchenware, and bathroom products.
- Aluminum Alloy: By adjusting the pulse width and frequency, the MOPA laser can achieve fine marking on aluminum alloy surfaces, suitable for automotive parts, electronic product housings, and more.
- Carbon Steel: Suitable for deep or shallow engraving, ideal for permanent marking of mechanical parts, tools, etc.
- Titanium Alloy: Applied in aerospace, medical implants, and other fields.
- Non-Metallic Materials: Such as plastics, PVC pipes, and more.
Conclusion (Fiber Laser VS CO2 Laser VS UV Laser VS Diode Laser VS MOPA Laser)
Fiber laser marking machines are the preferred choice for engraving and marking metal materials due to their efficiency and flexibility.
CO2 laser engravers excel in non-metal materials such as wood, plastic, and leather.
UV laser marking machines are known for their extremely high precision and cold processing characteristics, making them ideal for micro-processing in fields such as semiconductors, electronics, and medical devices, though they are more expensive.
Diode laser marking machines are the most cost-effective, easy to operate, and suitable for individual hobbyists and small businesses for economical marking and engraving, especially for metals and certain plastics.
MOPA laser marking machines offer highly adjustable pulse parameters, making them versatile for various material processing needs, particularly suited for high-precision and multi-material applications like consumer electronics, aerospace, and jewelry.
FAQ about Lasers for Engraving and Marking
How to Choose the Right Laser for Your Project?
- For Production Lines: A fiber laser is often the best choice due to its high efficiency, precision, and ability to handle metal and other industrial materials.
- For Small Businesses or DIY Projects: A CO2 laser or diode laser might be sufficient, as they are more affordable and suitable for engraving non-metal materials like wood, acrylic, and plastic.
What is a Green Laser and a Yag Laser?
Green Laser: A laser that emits light in the green wavelength range, typically around 532 nm. Green lasers have a wide range of applications in medicine, display, lighting and scientific research.
YAG Laser (Yttrium Aluminum Garnet): A solid-state laser that uses YAG crystals as its gain medium, with a typical wavelength of 1064 nm in the near-infrared range. YAG lasers are widely used for industrial cutting, welding, medical procedures (e.g., ophthalmology), and scientific research due to their high power and beam quality.
What Are the Processes for Laser Marking Metals?
Laser Annealing
Laser Engraving
Laser Etching
Laser Color Marking
Laser Coating Removal Marking
Laser Hardening
Best Laser for Marking Metal?
Fiber lasers excel in metal engraving and marking applications and are the best choice.
Can CO2 Lasers Mark Metals?
CO2 lasers can mark some metals but with limited results. When a CO2 laser hits a metal surface, most of the energy is reflected, making it difficult to generate enough heat on the metal to make a lasting mark. CO2 lasers are primarily used for marking and engraving non-metallic materials.
