MOPA machines are called that because they contain both a master oscillator to produce a beam and an
optical amplifier to increase its power output. This causes Master Oscillator Power Amplifier or MOPA machines
to have greater power and faster speed than a traditional fiber laser. This system also has the added feature of
having an adjustable pulse width. The ability to adjust all of these setting is what gives MOPA lasers the means to
engrave color. However, certain conditions must be fulfilled in order to engrave in color.
1.
Material
MOPA systems can only engrave color in material made of stainless steel or titanium alloy. This is
because the process of marking the material will cause a chemical reaction that will anneal or alter
the properties of the metal. The chemical reaction is what creates the color in the material.
2.
Machine Properties
The coloring process can be affected by many factors such as: the laser source, the lens
used and the focus distance. This is important to keep in mind since even similar models
can produce different shades of color.
3.
Engraving Parameters
The hatching type, the pulse width, the frequency, the line spacing and the power are adjusted according
to the type of color ones trying to engrave.
4.
Only vector objects can be engraved in color. That is because the infill will play an important part in
engraving. Bi-directional or Optimization Two-Way hatching are mainly used for color engraving.
If you wanted to use a rasterized image then the tracing parameters will need to be used.
5.
Do not engrave in high power. The material will not engrave color properly or at all if the material gets
too hot.
In the following pages we will explain in more detail how these properties can affect color engraving.
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Section X. Color Engraving
Color Engraving Overview
