Something you need to know about color marking

Color marking lreally depends on what laser module are you using, what type of metal do you have?

There are a few key parameters that you need to take care of: Firstly, focusing. Then power. Last, speed.

These 3 parameters are available on any fiber or DPSS laser modules.

However, fiber lasers have additional parameters that can be changed, like:

1. Pulse width (pulse duration).
2. Frequency of pulses.
3. The energy of pulses.

Unlike DPSS modules very expensive and advanced fiber lasers have an active Q-Switch that allows you to change these 3 parameters.

When you hear about laser engraving of metals you easily visualize a dainty drawing with slight blackening or ornate calligraphy on gifts and souvenirs. As for color engraving.So it is something new even to those who have first-hand knowledge of the laser equipment. Because this technological process is much more complicated.

So the time consuming and painstaking process of color laser engraving on metal is used to decorate exclusive gifts and souvenirs.

The color engraving is possible on oxygen hungry materials

• titan;
• stainless steel;
• zirconium;
• aluminum;
• nickel;
• brass;
• silver.

Also the color, as such, appears in the result of the light interference in the oxide film. Its hue and intensity depend on several factors:

• pulse duration,
• metal thickness,
• thermophysical parameters of the processed material,
• radiation power,
• oxide film thickness.

The principle of laser engraving on metals is the surface removal of the material with the UV ray. Because the size of the grove obtained at the point of the local heating depends on the lens focusing and radiation power. And a by-effect of the laser interaction with some metals is a physical and chemical reaction called the heat-tint effect, which results in the change of the metal surface color.

Problems:

The main problem of the color engraving of metals involves the correct selection of the above-mentioned parameters and the seamless operation of the laser. This task is quite a challenge since a single pulse lasts only a few nanoseconds. At the same temperature and exposure time, the heat tint will vary for every metal.

Color marking fiber laser marking machine, Mopa laser- Bonnie