Considerations for laser marking metals

1. Properties of materials

Considering the material to be marked is an important part of any laser marking lasitlaser.de application. Materials react differently to different wavelengths because they have different absorption spectra. When selecting materials for laser sources, keep this in mind. In addition, the melting point and heat response of the material should be considered. A material’s hardness should also be considered. Since aluminium is a much softer metal with a lower melting temperature than steel, laser marking it will take less time.

2. A laser’s type

Laser marking metals can be done using both continuous wave and pulsed lasers. Due to their ability to deliver a higher intensity beam without overheating samples, pulsed fibre lasers are used more frequently.

Wood, glasses, and plastics are more commonly used with CO2 lasers than metal. Again, green lasers are more commonly used on plastics and glasses than on metals. Metals of all types, from steel to copper, can be marked with fibre lasers. Marking metals generally requires lasers with more than 50W of power. It is possible to design fibre lasers to have higher beam quality than lasers with similar average output power. The beam’s quality determines the beam’s spot size and, therefore, the laser marking’s width or finesse.

3. Laser Marking – The Choice

Different kinds of marks can be produced by laser marking metals using multiple methods. When deciding which method is most suitable for a particular application, durability and time considerations must be taken into account. Here are a few examples:

Engraving with lasers

Metal is sublimed using this method. By vaporising the metal with the laser, it goes directly from a solid to a gas. It is very durable to engrave with lasers Laser marking methods produce very deep markings because they create very deep markings. It is typical for laser engraving to cut between 0.0001″ and 0.005″ deep. For applications requiring traceability of parts, laser engraving provides permanent marks.

Etching with lasers

With laser etching, metal is almost instantly melted. The marks are highly contrasted. In spite of the fact that laser etching and laser engraving are similar, laser etching typically leaves a shallower mark than laser engraving – less than 0.0001″ – than laser engraving. The shallower marks created by etching are also suitable for thinner sheets of metal with a lower requirement for permanent markings.

Using lasers to anneal

Metals such as steel, titanium, and stainless steel can be marked with colored markings using this process. Instead of actually removing material, this method alters the material’s surface chemically, making it ideal for surfaces that cannot withstand damage. A laser beam slowly heats the metal, changing its lattice structure as a result of annealing. When the metal cools, it changes colour due to oxidation. As incident light strikes the surface of annealed metals, some of it is reflected and some is absorbed. Oxide layers absorb or reflect the absorbed light. The darker the colour of the metal is, the thicker the oxide layer.

The use of lasers

Laser ablation involves selectively removing material in a controlled manner from a solid surface. A much quicker and environmentally-friendly method of removing paint or thin films, this method can also be used to deposit films on surfaces, instead of just removing them.

4. Environment of work

Whenever machining is being performed, proper airflow, ventilation, and filtration systems must be in place. Heat is generated by lasers, and lasers are capable of producing vapours and particles when they mark metals. It is therefore imperative to ensure a safe working environment.

5. Expenses

It is important to determine if it makes sense to purchase a laser marking setup or to hire another party to provide the services, and if one is a better investment. Depending on how many products need to be marked and how frequently the laser marking setup is used, this may vary. Additionally, laser marking materials and time should be considered.