The Working Principle of Laser Marking Machines

Home >> content-21 >> The Working Principle of Laser Marking Machines

The Working Principle of Laser Marking Machines

1. Introduction
In today's industrial production field, laser marking machines, as high-precision, high-efficiency marking devices, are widely used in various product identification and engraving processes. With their unique advantages, such as non-contact processing, high precision, and environmental friendliness, they have gradually replaced traditional mechanical marking and inkjet marking methods, becoming an indispensable tool in modern manufacturing. This article will delve into the working principle of laser marking machines to help readers better understand the underlying scientific mechanisms.

2. Basic Components of Laser Marking Machines
Laser marking machines primarily consist of a laser source, optical system, control system, and workbench.

1. Laser Source
The laser source is the core component of a laser marking machine, responsible for generating high-energy, highly monochromatic laser beams. Common types of lasers include fiber lasers, CO? lasers, and semiconductor lasers. Fiber lasers offer advantages such as high beam quality, high electro-optical conversion efficiency, and low maintenance, making them suitable for precise marking on metal materials; CO? lasers have a longer wavelength and better absorption effects on non-metallic materials, commonly used for marking on plastics, wood, leather, and other materials; semiconductor lasers are characterized by their compact size and high efficiency, making them suitable for small-scale equipment or specialized applications.
2. Optical System
The primary function of the optical system is to focus, shape, and transmit the laser beam generated by the laser, enabling it to precisely act on the surface of the workpiece. It typically includes optical components such as beam expanders, mirrors, and focusing lenses. Expanders increase the diameter of the laser beam, thereby reducing the beam divergence angle and improving beam transmission quality and focusing accuracy; mirrors are used to change the propagation direction of the laser beam, enabling it to follow a predetermined path to the focusing lens; focusing lenses concentrate the laser beam into a small spot, highly concentrating the laser energy to achieve sufficient energy density on the workpiece surface and realize marking effects.
3. Control System
The control system serves as the “brain” of the laser marking machine, responsible for controlling parameters such as the laser's output power, pulse frequency, and pulse width, as well as the movement trajectory and speed of the optical system. Typically, computer software programming is used to achieve precise control over the marking process. Operators can input the desired marking patterns, text, and other content via the software interface and set corresponding marking parameters, such as marking speed and power. The control system generates control signals based on these parameters, driving the laser and optical system to perform marking operations along the predefined trajectory and at the specified speed.
4. Workbench
The workbench is used to secure and support the workpiece to be marked, and its precision and stability directly affect the quality and effectiveness of the marking. The workbench is typically equipped with precision positioning devices and clamps to ensure the workpiece remains stable during the marking process and can be precisely adjusted in position and angle to meet different marking requirements.

III. Working Principle of Laser Marking Machines
The working principle of laser marking machines is based on the physical interaction between lasers and materials. When the laser beam is directed at the workpiece surface, phenomena such as absorption, reflection, and scattering occur. For most materials, the energy of the laser beam is absorbed by the workpiece surface, causing physical or chemical changes within the material to achieve the marking objective.

1. Thermal Effects
When the laser beam strikes the workpiece surface, the material absorbs the laser energy and converts it into thermal energy. If the laser energy is sufficiently high, it can rapidly increase the surface temperature of the material, causing it to melt, vaporize, or even burn. For example, during the marking process of metal materials, the laser beam causes localized melting of the metal surface, forming concave marks; in the marking of non-metallic materials such as plastics and wood, the laser energy causes localized vaporization of the material surface, thereby removing part of the material to form clear patterns or text. This thermal effect is one of the primary mechanisms of laser marking and is applicable to most materials.

2. Photochemical Effects
In addition to thermal effects, the interaction between lasers and materials may also trigger photochemical reactions. When the wavelength of the laser beam matches the absorption characteristics of the material, molecules within the material absorb the energy of laser photons, leading to the breaking or重组 of chemical bonds and altering the material's chemical structure and properties. For example, in the marking of certain polymer materials, the laser beam can cause photochemical degradation on the material's surface, resulting in color changes or variations in surface roughness, thereby achieving the desired marking effect. Photochemical effects are typically used for heat-sensitive materials or applications requiring precise control over the marking process.
3. Plasma Effect
During high-power laser marking, when the laser energy density reaches a certain level, the material surface instantly generates high-temperature, high-pressure plasma. Plasma is a high-temperature ionized gas composed of a large number of charged particles, characterized by extremely high temperature and energy density. The formation of plasma further enhances the interaction between the laser and the material, causing more intense physical and chemical changes on the material surface. For example, in some high-precision metal marking applications, the plasma effect can create finer microstructures on the metal surface, improving marking resolution and contrast. Additionally, the generation of plasma is accompanied by intense light radiation and acoustic shocks, which can be utilized to monitor the quality and effectiveness of the marking process.

4. Advantages of Laser Marking Machines
1. High Precision
Laser marking machines can achieve extremely high marking precision, with the minimum marking line width reaching the micron level. This enables them to meet various high-precision marking requirements, such as micro-marking of electronic components and fine engraving of medical devices. High-precision marking not only improves product appearance quality and the readability of markings but also meets the strict precision requirements of some special industries for product markings.
2. Non-Contact Processing
Laser marking is a non-contact processing method, where the laser beam does not physically contact the workpiece, thus avoiding mechanical stress and wear on the workpiece. This is particularly significant for workpieces with complex shapes, fragile surfaces, or extremely high precision requirements. For example, in the marking of fragile materials such as glass and ceramic products, laser marking machines can prevent damage caused by mechanical contact, ensuring the integrity and quality of the workpiece.
3. Environmentally Friendly and Efficient
Laser marking does not require the use of any chemical reagents or inks, nor does it produce harmful gases or liquid waste, making it an environmentally friendly processing method. Additionally, laser marking machines operate at very high speeds, enabling the completion of large-scale marking tasks in a short time, significantly improving production efficiency. For instance, on production lines in the food packaging industry, laser marking machines can quickly print production dates, expiration dates, and other information on packaging bags while the conveyor belt is moving at high speed, meeting the demands of large-scale production.
4. Permanent Marking
The marks formed by laser marking are permanent and will not fade due to friction, wear, or chemical corrosion. This is of great significance for product anti-counterfeiting, traceability, and quality tracking. For example, in the identification of automotive parts, electronic products, and other products, the permanent marks created by laser marking ensure that the product's identity information remains clear and distinguishable throughout its entire lifecycle, facilitating quality traceability and after-sales service.

V. Application Areas
Laser marking machines are widely used in numerous industries, including but not limited to:
1. Electronics Industry
Used for marking electronic components such as integrated circuit chips, resistors, capacitors, etc., with information such as model numbers, specifications, and production dates. Their high precision and non-contact processing characteristics meet the requirements of electronic components for small dimensions and high precision.
2. Mechanical Manufacturing Industry
Marking on the surfaces of mechanical parts, such as gears, bearings, shaft components, etc., including serial numbers, trademarks, parameters, and other information. The permanence and high contrast of laser marking ensure that the markings remain clear and legible during long-term use of mechanical parts.
3. Food and Beverage Industry
Used for printing production dates, expiration dates, batch numbers, and other information on food packaging bags, beverage bottles, etc. The environmentally friendly and efficient characteristics of laser marking align with the hygiene and production efficiency requirements of the food and beverage industry.
4. Medical Device Industry
Marking on the surfaces of medical devices, such as surgical instruments and implantable medical devices, including model numbers, production batch numbers, and usage instructions. Its high precision and non-contact processing ensure the surface quality of medical devices and the reliability of markings.
5. Jewelry Industry
Used for marking trademarks, materials, weights, and other information on jewelry. The precision and aesthetic appeal of laser marking meet the high standards of the jewelry industry for markings, without affecting the appearance or value of the jewelry.

6. Summary
As an advanced marking device, the laser marking machine leverages the unique principle of laser-material interaction to achieve high-precision, non-contact, environmentally friendly, and efficient marking results. Its widespread application in industrial production not only enhances product identification quality and production efficiency but also provides robust support for product anti-counterfeiting, traceability, and quality tracking. With ongoing technological advancements, the technology of laser marking machines will continue to evolve and improve, and their application areas will further expand, contributing significantly to the development of modern manufacturing.

.

.

Previous page: No page Next page: The Difference Between Laser Marking and Laser Engraving

Does Laser Marking Damage the Play of Colors in Opal?

How does a laser marking machine mark QR codes?

Mitigating Fire Risks in Laser Marking Machine Exhaust Systems

Achieving Precise Marking on Curved Surfaces with Green Laser Marking Machines

Class 1 Enclosure Airflow Organization Design for 1030 nm Femtosecond Laser Marking of Borosilicate Glass Microfluidic Chips

Risks of High Conductivity in Cooling Water for Water-Cooled Laser Marking Machines

YAG-Picosecond Hybrid Pump Laser Marking Machine: Achieving 50 nm Line Width

Ensuring QR Code Readability with Flying Laser Marking Machines on High-Speed Stainless Steel Pipes

Applications of Laser Marking in Wooden Toys Manufacturing

How Laser Marking Machines Engage with TrueType Fonts

The Working Principle of Laser Marking Machines