Laser Annealing / Heat marks

Laser annealing, heat marks on stainless steel

Annealing / Dark Marking

The marking process of annealing is thermo-chemical reaction. A laser beam applies low heat to the surface of a parts material, slightly altering its properties, creating oxide layers. The result is a visible and permanent mark, but it cannot be felt since the material is not upset, moved or displaced by this marking process. This type of mark is also referred to as a heat mark.

Most heat marks will result in a dark or black mark. Which is why this process is also referred to as black annealing or dark marking. Heat marks can sometimes result in a variety of colors, but only with specific metals based on their composition. Best color results are seen on titanium and steel.

Heat marks on plastic depend greatly on the type of plastic, the material composition and its energy absorption.

What types of material can be annealed / heat marked?

  • Carbon containing metals can be used for annealing and heat marks.
  • Typically best on Titanium, Steel, Stainless Steel, Iron and Carbide.

What type of laser sources are used for annealing?

  • Fiber, YVO4 IR and CO2 laser sources can provide excellent heat marks on metals and some plastics. The material composition will determine which laser source is best.

What Industries or applications use the annealing process?

  • Annealing is very common in the Medical and Aerospace industries.
  • Because material is not moved or displaced in the annealing process, that eliminates the possibility of surface grooves, which prevents the potential for bacteria to grow or for any type of corrosion to occur.