What is Laser Marking & How Marking Machines Work
Laser marking is the process of permanently marking a surface using a focused beam of light. It can be performed using different types of lasers, including fiber lasers, CO2 lasers, pulsed lasers, and continuous lasers. The three most common laser marking applications are:
- Laser engraving: creates deep and permanent marks that withstand abrasion
- Laser etching: creates high-contrast permanent marks at a high speed
- Laser annealing: generates marks under the surface without affecting the base metal or its protective coating
Laser marking can mark a variety of materials such as steel, aluminum, stainless steel, polymers, and rubber. It is often used to identify parts and products with 2D barcodes (data matrix codes or QR codes), alphanumerical serial numbers, VIN numbers, and logos.
How Does Laser Marking Work?
To create a lasting mark, laser marking systems generate focused beams of light that contain high levels of energy. When a laser beam hits a surface, its energy is transferred in the form of heat, creating black, white, and sometimes colored marks.
The Science of Lasers Explained
Laser beams are generated by a reaction known as LASER, an acronym for “Light Amplification by the Stimulated Emission of Radiation”.
First, a special material is stimulated with energy, making it release photons. The newly released photons then stimulate the material again, generating more and more photons. This creates an exponential number of photons (or light energy) in the laser cavity.
This energy build up is released as a single, coherent beam of light that is directed at its target using mirrors. Based on the energy level, it can etch, engrave, or anneal surfaces with extreme precision.
Different Lasers to Mark Different Materials
Laser light energy is measured using wavelengths, or nanometers (nm). Specific wavelengths are used for different applications and can only be generated by certain types of lasers.
- Fiber lasers stimulate a rare-earth metal known as ytterbium to generate photons on the 1,064 nm wavelength. This wavelength is ideal to mark metals, as a good quantity of its energy is absorbed by the material.
- CO2 lasers stimulate CO2 gas to generate wavelengths between 9,000 nm and 11,000 nm, covering a wide range of organic materials that require different wavelengths. The most common wavelength for organic materials is 10,600 nm.
Laser Marking Benefits
Laser marking has become the technology of choice for manufacturers looking for high-quality marking, offering a multitude of advantages compared to older marking methods like dot peen marking, inkjet printing, and printed labels.