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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 in a crystalline
lattice framework.
3. What are solid
state lasers?
The lasing material is a solid (such as YAG or glass or 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,
or by a laser diode, called diode pumped. Rod
Waters, Owner of Laserod, was fortunate to have worked for Dr.
Maiman for 3 years.
4. What are gas
lasers?
Some popular gas lasers are CO2, excimer, HeNe, Ar, & Kr. They
are usually pumped by electrical discharge through the gas in
question which is contained in a laser glass or metal tube.
5. Why does Laserod
use YAG?
It's a good intermediate between excimer and CO2. YAG,
at one micron wavelength, is between CO2 at ten
microns, and excimer at 0.25 microns. Wavelength
is directly related to laser cutting width. The shorter
the wavelength is, the smaller the spot.
|
|
CO2
Laser |
YAG
Laser |
Excimer
Laser |
|
Wavelength
(microns) |
10.6 |
1.06 |
0.25 |
|
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. For
more information on these topics, visit http://www.marsh-mcbirney.com/Articles/accuracy_terms.htm
If you have any further questions that were
not answered above, please contact us directly at sales@laserod.com.
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