Some Issues using Laser Galvos
High Speed Laser Beam
Scanning Galvanometer
2-axis and 3-axis, Industrial &
Retail and Laser Safety
Laser galvos are famous as supermarket
and other point-of-sale barcode scanners, hundreds of thousands are in use throughout the
world. Applications for industrial laser galvos are marking
IDs & bar codes, etching images in grave stones,
resistor trimming and patterning. The main difference
between the retail and the industrial laser galvos is
laser power which brings up the issue of safety. Retail
barcode scanners are classified Class I safe lasers
without need for shielding. High power industrial laser
machines require shielding to earn a Class I rating.
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Shown here is a 2-Mirror Laser Galvo for
rapid laser beam scanning
The two mirror type is called "XY"
galvo or 2-axis galvo.
Actually, it swings the beam focal point in arcs.
The arc is flattened using a F-theta lens in a
so-called 2-axis or X/Y galvo. The Z is
non-adjustable.
Each mirror is mounted on
a shaft with a servo motor opposite. See the
photo. Laser writing speeds of meters/sec are
possible with a large enough laser spot and a
high enough laser rep rate. Applications include
laser marking, resistor trimming and
patterning--usually not good for machining
because the laser focal length using a galvo is too long,
drastically reducing power density by enlarging
the laser spot diameter..
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3-axis Laser Galvo
An XYZ or 3-axis galvanometer substitutes the
F-theta lens in a two axis galvo by a simple lens moving on a linear track along
the beam axis. This controls the focal point in the Z-axis. A
fast motor driving the lens keeps the focal point in the X-Y
plane and permits adjustable Z for scan fields from about
0.25m up to 1.6m..
Other Issues:
Video (CCTV) viewing of the worksite are
worthy issues to discuss relative to moving beam optics (galvo)
versus fixed beam. Other issues are speed, accuracy and
resolution. Contact us for details.
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