Two of the most common types
of lasers you hear about are YAG and CO2.
While Altatech uses only CO2 laser systems,
we wanted to give you some information about
the two different types of laser systems and
which one may be right for your application.
Both CO2 lasers and YAG
lasers generate a very concentrated beam of
light, but from there the lasers become very
different in their uses and how they work.
In this article we will first look at the
different uses of the two laser types, and
when each one is right for your application,
and finally break down the benefits of each
system.
What are the
different uses for YAG and CO2 lasers?
YAG lasers and CO2 lasers react
very differently on different materials
because of the differing wavelengths of the
laser beams. The wavelength of a YAG laser
(1.064 microns) is exactly ten times smaller
than the CO2 wavelength of 10.64 microns,
which makes it ideally suited for absorption
in most metals, but this small wavelength
inhibits its ability to be absorbed by many
other materials (wood, acrylic, plastics,
fabrics, etc.)
A CO2 laser beam is not
easily absorbed by metal, but can easily be
absorbed by many organic materials such as
wood, acrylic, rubber, etc, while it tends
to reflect off of most metal surfaces. It's
the different wavelengths of the two beams
that are mainly responsible for the
different types of materials that they will
react with. There are a number of other
differences between the two lasers; thermal
efficiency, heat transfer, minimum and
maximum power output, etc. and these
characteristics all have an affect on the
materials that the beams react with.
Will a CO2 Laser
work on any types of metals?
Yes, the CO2 will work on certain
metals in a couple of different ways.
- Coated Metals
Coated metals include painted
brass, anodized aluminum, or any other
metal that has been coated with a
material that the CO2 laser beam will
engrave away. Even a low powered CO2
laser is very effective at removing
paint from most metal surfaces; with
painted brass being a popular engraving
material because of all the different
colors available and the high contrast
that is generated when it is engraved.
However, some metal surfaces are painted
with exceptionally hard paint coatings
that even a 120 watt laser has
difficulty engraving cleanly. The common
products where you will see this are
ballpoint pens, and anything that is
powder coated.
Another metal that is very popular with
CO2 lasers is most anodized aluminum.
When the CO2 laser beam contacts the
anodize coating, it turns it white and
provides excellent contrast on the many
different anodized colors. Aluminum that
is protected with a gold coating is
probably not anodized (it's probably
protected with a process called chromate
conversion) and will not engrave well.
CO2 laser systems are compatible with
painted metals and anodized aluminum
because of the high contrast, fast
engraving speeds, low power requirements
and the wide variety of projects that
these materials lend themselves to.
- Stainless Steel
Metal Marking
Until recently, marking stainless steel
with a low powered CO2 laser was very
difficult to do. The problem is that
most of the CO2 energy is reflected from
the metal surface and only a small
amount is absorbed, providing a very
faint or non-existent mark. In the last
few years a couple of different
companies have introduced products that
allow low powered CO2 lasers to create a
very dark, permanent mark on stainless
steel. The products are known as Laser
Marking Materials (LMM) and go by the
common name of Cermark, or Thermark. The
LMM is sprayed onto non-coated stainless
steel from a spray can (just like spray
paint!). The LMM is allowed to dry for a
couple of minutes before it is ready to
engrave.
When the laser engraves on the Cermark,
it permanently bonds the material to the
metal, resulting in a permanent black
mark. After engraving, the metal is
washed with water to remove the excess
spray. This simple process is often used
for marking tools, medical instruments,
and industrial parts with bar codes and
serial numbers. LMM will also work with
some other metals, but we suggest you
test out any other material you are
considering using to ensure the mark is
acceptable. It is our experience that
stainless steel is the most predictable
metal for use with LMM.
Will
a YAG Laser work on any types of
non-metallic materials?
Unlike a CO2 laser, a YAG laser is
compatible with only a limited number of
materials. Because of its small wavelength,
a YAG laser can mark many different types of
metal, and a few plastics, but its
effectiveness on standard CO2 products
(wood, rubber, acrylic, etc) is almost
non-existent. You will typically only find
YAG lasers in industrial applications, with
personalization applications limited mostly
to high volume marking of products like
ballpoint pens.
The reason that so many
people are excited about the LMM discussed
earlier is that there are a lot of stainless
steel products that require laser marking
and marking with a YAG laser is very
expensive.
| YAG
Laser Benefits |
|
- Faster than a
CO2 laser system (when set up as
a galvo system)
|
| YAG
Laser Drawbacks |
- Setup time for
artwork can be very lengthy,
especially when engraving
graphics.
|
- Does not work
well on organic materials (wood,
acrylic, etc.)
|
- Expensive to
purchase and costly to maintain
|
|
CO2 Laser
Benefits
|
- Works well on
wood, acrylic, plastic, and many
other materials
|
- Can mark
stainless steel (with LMM) and
most coated metals
|
- Quick set up
for each new piece you are
working on
|
| CO2
Laser Drawbacks |
- Not as fast as
a YAG (but still engraves at 120
inches per second)
|
- Does not
engrave into metal,
but will mark some metals
|
This was a
quick look at YAG versus CO2 lasers. While
both have applications that they are best
for, if you would like us to run a test on a
material and show you how a CO2 laser will
work with it, you can contact us:
Not sure of an application? We will be
happy to run a sample for you. Call today!
Altatech Laserworks
ph: 916.983.3621
or via e-mail:
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