UV Laser Marking

Why another laser technology?

How do lasers differ from each other?

To understand how lasers differ from one another, you first need to understand how wavelengths interact with materials. This is how it works.

In the laser source there is a material whose atoms release energy in the form of light. This material determines what wavelength your laser will produce. For example, some solid-state lasers use Nd: YAG crystals to generate light. These crystals release a wavelength of 1,064 nanometers (or 1,064 micrometers).

Since different materials absorb wavelengths differently, you need different types of lasers for different materials. For example, it is better to use fiber lasers for marking metals and CO2 lasers for marking organic materials (such as plastic materials and rubber).

Different lasers can also release this energy differently. You can use either a continuous wave laser or a pulsed laser. While continuous wave lasers emit the laser beam continuously, pulsed lasers release the beam at a set speed. Pulsed lasers can achieve higher energy density peaks because they charge energy before it is released. They are ideal for laser marking applications as they offer higher manufacturing speeds. Continuous lasers are better suited to other laser applications such as laser cutting, welding, and drilling.

Physic

The wavelength of UV laser light is about a third (355 nm) that of standard wavelength lasers (1064 nm). The name "UV laser marker" comes from its wavelength in the ultraviolet part of the light spectrum.

Marking with these lasers is called "cold marking". This refers to how their incredibly high absorption rate allows them to do marking and processing on a wide variety of materials with minimal heat damage. UV laser marking is ideal for applications that require high contrast or minimal product damage.

Light wavelength distribution diagram

Working Principle and properties of UV lasers

The wavelength of a UV laser is a third of that of standard wavelength lasers, which is why UV lasers are also known as THG (Third Harmonic Generation) lasers. By passing a standard wavelength laser with a wavelength of 1064 nm through a non-linear crystal, the wavelength is reduced to 532 nm. This is further passed through another crystal, effectively reducing its wavelength to 355 nm.

A: 1064 nm standard wavelength B: 532 nm green wavelength C: 355 nm UV wavelength

A: 1064 nm standard wavelength B: 532 nm green wavelength C: 355 nm

Feature: High-contrast marking

Compared to standard wavelength lasers (IR / 1064 nm) and green lasers (SHG / 532 nm), UV lasers generally have a remarkably higher material absorption rate, which enables efficient absorption of the emitted light by the marking surface. This means that the power does not have to be increased in order to produce clearly visible markings.

Absorption rates for various resin materials

Absorptionsraten für verschiedene Kunststoffe

Comparison of markings

Feature: Damage-free marking

Marking with UV lasers uses high absorption rates even with gold, silver, copper and other materials with high reflectivity and thus ensures minimal thermal damage. This minimizes soot and burrs and at the same time prevents damage to the surface, so that corrosion-resistant marking and processing is possible.

Light absorption rate for metal