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1.
What does YAG mean?
Yttrium Aluminum Garnet. A
type of solid-state laser material. Actually, a
laser rod. A crystal.
2.
What's Nd:YAG?
The YAG crystal is doped with Neodymium, chemical
symbol, Nd. It is about 2 percent Nd and 98
percent YAG. YAG is the host,
simply there to hold the Nd ions that do the lasing in a crystalline
lattice framework.
3.
What are solid state lasers?
The lasing material is a solid (such as YAG, vanadate, glass
and
ruby). Other types of lasing materials are gases
and liquids. The first working laser was ruby,
developed by Dr. Ted Maiman at Hughes Malibu before
1960. YAG began to replace ruby by 1970. YAG
is energized (pumped) by a lamp, called optically
pumped. If pumped by a diode laser, the crystal can be
vanadate. Rod
Waters, Owner of Laserod, was fortunate to have worked
for Dr. Maiman at his company, Korad Lasers, in Santa
Monica, California.
4.
What are gas lasers?
Some popular gas lasers are CO2, excimer, helium neon,
argon and krypton. They are usually pumped by electrical
discharge through the gas contained
in a glass or metal tube.
5.
Why does Laserod prefer solid state
lasers?
They are far more compact than gas lasers such as excimer and CO2.
YAG, at one micron wavelength, is between CO2
at ten microns, and excimers in the short wavelength UV
region. Wavelength is directly related to laser
cutting width. The shorter the wavelength is,
the more narrow is the cutwidth.
|
|
CO2
Laser |
YAG
Laser |
Excimer
Laser |
|
Wavelength
(microns) |
10.6 |
1.06 |
0.248 |
|
Spot
Size
(microns) |
120 |
12 |
3 |
6.
Trepanning is a curious word. From whence does it
come?
Brain surgeons trepan, or saw, a circular bone segment
out of a skull, do their thing, then replace the segment
and sew up the patient. Laser machinists swing
their beam in a circle, thereby drilling a hole.
As opposed to percussion drilling.
7.
What is the minimum feature size that can be produced by
laser micromachining?
A width of slightly less than one micrometer.
But this is for thin coatings under one micron thickness.
A typical value is 10 microns laser cut width for
deeper beam penetrations.
8.
How "micro" do you expect laser micromachining
can do in the future?
A rule of thumb is about one laser wavelength, or 1
micron for YAG, 0.5 micron for frequency doubled YAG and
0.25 micron for frequency quadrupled YAG. These
numbers are for cut widths in thin coatings.
Multiply by 10 for deeper beam penetrations.
9.
What's the meaning of tolerance, resolution, accuracy
and precision?
Tolerance is the acceptable deviation from
specification.
Resolution is the minimum increment to
which a measurement can be made. For us, this is a
design parameter of the X-Y stage motion encoders or
galvo.
Accuracy is how close a measurement is to
the "true" value. "Truth" is the
traceability of the measurement to a primary standard at
NIST, a USA governmental agency, National Institute for
Standards & Technology. For us, this is
conformance to our customer's metrology.
Precision is repeatability. For us,
precision is half the increase in laser line width or
hole diameter when the laser is run repeatedly over the
same part a number of times.
All are plus/minus numbers except
resolution.
If you have any further questions that
were not answered above, please contact us directly at sales@laserod.com. |
Just the FAQs! 