What is Fiber Laser Marking?

In general, laser engraving is the most subtractive manufacturing process, followed by laser etching, and then laser marking. Fiber laser engravers produce deep-set grooves that maintain their fidelity through extreme conditions and can be fine-tuned to the user’s desired depth. Laser etchings are shallow marks and include so-called laser ablations in which a top coating is lasered off, exposing the underlying material.

Laser marking is a category of its own, as it removes no material but changes its surface properties. The four most common reasons for marking a material are for:

• Annealing: changing the mechanical properties of the material in the laser’s path (this is typically performed with metals)
• Carbon migration: carbon at the material/laser interface chemically bonds to its surface, creating permanent black markings.
• Coloring: specific-colored marks made by heating the underlying material (ex. Titanium can become any desired color given a specific temperature is reached)
• Foaming: creating marks lighter than the underlying workpiece (only possible with plastics)

Most laser marking systems have the capacity to perform engraving, etching, and marking, so this article will not differentiate when speaking about specific models/specifications. However, understand that each term is not synonymous.

Regardless of the type of laser marking system, the chosen laser machine will employ uv lasers, CO2 lasers, and/or fiber lasers. This article will focus on the fiber laser, as it is a good balance between power, speed, and affordability, but know that other types are available. 

Fiber lasers emit high-intensity light at wavelengths that are hundreds to thousands of nanometers in length, placing them somewhere between ultraviolet and infrared wavelengths (typically invisible to the human eye). For fiber lasers specifically, wavelengths of 1030-1090 nm are often chosen as those wavelengths correspond to ytterbium-based fiber lasers and provide the best results on metals. This contrasts with CO2 lasers, which generate high-intensity light at thousands to tens of thousands of nanometers that is more suited for organic materials.

To explain the basic operating procedure of a fiber laser marking machine, the next section will detail how fiber lasers work and how they can produce extremely high-quality marks.