Laser etching anodized aluminium

[Fred Nerk]

G'day
Does anybody know anything about etching onto anodized aluminium? Which is best Co2 or YAG? How does it differ from etching stainless? I am in Melbourne Australia and I am unable to find anyone willing to etch aluminium, they all say it is too reflective and will damage they're machine, yet it can be done on stainless that I would have considered to have been equal to aluminium in reflectivity. I know it can be done, in fact you see it everyday in comon items around home, work etc, but I just cant convince anyone to do it for me.

[ServoGuy]

G'day
Does anybody know anything about etching onto anodized aluminium? Which is best Co2 or YAG? How does it differ from etching stainless? I am in Melbourne Australia and I am unable to find anyone willing to etch aluminium, they all say it is too reflective and will damage they're machine, yet it can be done on stainless that I would have considered to have been equal to aluminium in reflectivity. I know it can be done, in fact you see it everyday in comon items around home, work etc, but I just cant convince anyone to do it for me.

There are sprays and coatings that allow you to laser mark aluminum.
Here's the one I know of, http://www.ferro.com/Our+Products/Gl...s/LMM-6000.htm
I'm sure you can find others....

[plexer]

Laser marking anodized aluminium is excellent. I know our low powered versalaser co2 will mark anodized stuff and not plain without a marking compound.

Ben

[SRT Mike]

When you use this "marking compound", what do you end up with? I assume the mark compound changes the surface reflectivity of the Al and allows the laser to 'bite in'. So, after it marks, you wipe it off? Then you have what? a shiny "marked" area against a dull surface? Do you feel anything if you run your finger over the marking?

I understand that with black anodize, for example, you will see a silver (bare aluminum) area where it was marked - but what do you see with marking compound?

[plexer]

I believe that where you laser the compound it "sticks" so you actually have a dark mark against the item you've marked. Then you wipe off the rest of the compound.

Such as:
http://www.ulsinc.com/versalaser/eng...ser_apps.html#

Ben

[Laser Guy]

Hi Fred
Marking on anodized aluminum is very simple and safe. here's a sample picture of a part I did recently with a co2 Laser.
The photo quality degraded when I uploaded the JPEG. The original part shows crisp and clean marking

[laserboy]

pending what you want to do, if you want to remove the color of anodize or etch down to aluminum.
1. remove color eg: black and have white contrast use Nd:YAG laser marker, with smooth surface
2. if you want to etch to Aluminum the use CO2 marker.

do not try lasing parts with anything shorter than 6 inch focus lens unless you have anti reflective lens in place.

Have fun

[Fred Nerk]

Ok the etching I am after is the type shown in the picture provided by Laser Guy above, I believe it is also called ablating (?). Where the anodic coating is bleached by the laser process as oposed to being removed.
Now the above comment from Laserboy interests me because there seems to be two schools of thought on which laser type is most effective in achieving this finish. As above Laser Boy used a Co2 laser to achieve what I want yet you say that a Yag would be more effective.
I have found this post elsewhere http://www.pfonline.com/articles/cli...5cl_alum1.html
and I also found a contridictory article elsewhere but I cant seem to find it again. So what is best? Yag or Co2 and how do I convince an owner of one these units to trial what I want? Does anyone here live in Melbourne and want to have a go?

[KTP]

I think q-switched YAG will work also, but that type of system costs 5x more than a CO2 laser system.

The q-switched YAG has the advantage of being able to directly mark things like stainless steel, but it can't be used to cut wood/plastics.

[Laser Guy]

Hi Fred
I have compared laser marking on anodized aluminum from a co2 an a Yag. laser. We engraved identical marks on the same part and compare the results . We found there was a difference between the two but it was marginal. Both machines removed the anodizing but the Yag left the aluminum a little brighter. Nothing to split hairs over. One other thing , I did my engraving with a 2.0" FL Lens. Remember my part was black anodized aluminum. Don't even consider bare aluminum with a co2 laser.

[1eyedguy]

"etching" in aluminum is a very easy process , depending on this laser being used, it is matter of switching an assist gas, and a duty cycle. of course i am speaking about a production machine, not a laser designed for engraving

[JWHISTON]

A Q-switched yag, works the best on Anodized Aluminum. Co2 are not the best with Metals. I have marked plenty of this with the YAG lasers I sell and it is all in Frequency control and scan speed. You will mark it extremely fast as in a scan speed of around 1000 to 1250 with about 3 to 5 passes, this with a 10w or 20w laser.