Laser Marking

Annealing

As already seen for laser engraving, also for laser marking it is possible to exploit the oxides that the molten surface material creates in contact with oxygen to create a color. This method is called annealing laser. By playing with the parameters of the source and with the formation temperature of the oxides (varying up to about 200 ° C) it is possible to obtain colored laser markings ranging from black to blue, from red to green. For temperatures over 200 ° C, on the other hand, the chromatic effect of the marking disappears. The advantage of using the tempering laser marking is that the surface is kept intact (important for example when there are mechanical couplings), excellent readability and resistance to abrasion are obtained. The optimal materials for this technique are steel and titanium, the more difficulties there are for aluminum and all non-ferrous metals in general.

Black Marking

Black Marking is a type of marking based on the principle of Laser tempering but which uses short pulse sources, mainly MOPA or USP sources, to create nanometric structures on the surface. The latter are able to guarantee an effective diffusion of the incident light, returning practically zero reflected radiation. A further advantage of this type of marking is that the short pulses generate very little thermal effect on the surface and this ensures excellent surface integrity and the remainder of a small amount of chromium capable of creating an oxide layer that tends to regenerate and therefore to maintain long-lasting marking over time. This important feature is widely used in the head of surgical instruments that require marking for traceability (UDI code for traceability required by European and FDA regulations) and which must be sterilized cyclically. This type of marking is therefore indelible and resistant to corrosion even in severe sterilization processes.

Another important feature is that this type of sources typically have very small spots and therefore allow very small or watermarked markings.

Night & Day marking (Laser marking for surface layer removal)

A common marking technique is that by removing a surface layer. In this case it can be paint, coatings or treatments such as anodizing which is often removed from materials such as aluminum.

In any case it is a question of using the laser to heat and then evaporate the surface layer leaving the underlying surface intact and clearly visible. This type of marking, called "night & day", is highly visible as the contrast of colors is usually very marked and customizable in the colors and for this reason it is highly used in the automotive and consumer electronics fields for the design of components such as the interiors of car or the control buttons of the dashboards of electronic devices.

Foaming

Laser foaming is a technique used for marking plastics and is based on the fact that the pigments and additives contained in the plastic are heated and evaporated locally, inducing an oxidation of the carbon contained which generates CO2. The gaseous formation causes a surface foaming which creates the color change. Usually dark plastics turn white, while light plastics turn dark colors such as gray or black.

Marking for Carbonization

Laser carbonization is a marking method suitable for plastics and organic materials (paper, wood, leather). In this case, the laser radiation heats the surface, raising the temperature to such a point that the carbon bonds are broken and the natural carbonization process of the material is triggered.

On a visual level, Laser carbonization always leads to a darkening of the material (from gray, dark brown to black).

Laser marking compared to other technologies offers important advantages that must be considered when choosing:

Contactless processing

Laser processing makes it possible not to use parts in contact with the piece, making them ideal for materials or products that require careful processing. Furthermore, having no contact tools there are no relative costs of wear and maintenance.

Respect for Nature (Green)

The marking process is environmentally friendly and does not use inks and chemical material that must then be disposed of.

Modern laser systems for marking consume less than a household appliance and certainly much less than many competing technologies, thus emitting less CO2 into the environment and being more respectful of nature.

Processing quality and precision

Laser marking is characterized by the quality and precision of the processing, as they use beams that can reach a few tens of microns. The details, the high contrasts obtainable and the chemical, thermal and corrosion resistance make the Laser the main technology for high-level and indelible marking applications over time.

Versatility

The possibility of processing any type of material, the easy integration on systems and lines and the digital nature of the Laser management process make it flexible to adapt to any process and suitable for highly customized products.