black anodized aluminum

[bryan henderson]

I am have been stamping some tags out of 5052 H32 aluminum and they have been black anodized prior to stamping. I have been having issues with in consistent white text that is laser engraved onto these parts. I am not sure if anyone has any experience with this. Should I be using 6061 T6 aluminum instead. I am also using a Speedy 300 trotec laser engraver 30W at full speed and I have tried almost every configuration in regards to power and speed.

Bryan Henderson

[Mike Null]

I have a Speedy 300 45 watt and I run at 75 power, 70 speed 1000 ppi. 500 dpi.

There are variables in dealing with anodized aluminum: 1. the coating tends to vary even with the same manufacturer. 2. It is very sensitive to focus and power level so be sure your material is flat and in focus and test each batch for power setting. Your finish should be white rather than aluminum colored. If it's aluminum colored you've used too much power and burned through the anodized coating. If it's too dark you haven't used enough power.

[bryan henderson]

Mike

Have you had many problems with your laser machine? How long have you had it? Any issues with any boards, motors etc?

[Joe Pelonio]

I had a job like that that was a custom material, 1/4" aluminum in an odd size that had to be anodized black. The black was very inconsistent, even within the same piece. For text this can be corrected with multiple passes on specific letters as needed, but with photos I found it pretty much impossible to get decent results.

[bryan henderson]

Mike

Do you think that a 30W Speedy trotec mahcine is capable of engraving these parts. I have a fixutre which holds 180 pcs on it and I get inconsistent parts throughout the fixture. It is not always in the smae spots. The parts are completely flat as they have been stamped in a progressive die.

Bryan

[Mike Null]

My machine is just past the 2 year mark and I've yet to have a problem. Make the acquaintance of the Trotec tech people, they're very helpful. My issues have been mostly in the "how to" area.

[Mike Null]

Bryan

You have more than enough machine to do the job.

I've had batches where the aluminum was so bad it wouldn't engrave. The anodizer re-processed the batch and they came out ok.

I do several kinds of aluminum including extrusions so I don't believe it's the type of alum. My largest customer is switching to powder coat from anodized because he can't find a reliable processor.

Is your jig perfectly flat, is your lens clean?

[bryan henderson]

Mike

This is a brand new machine, we changed to a 2x lense hoping that would make it better but still not. My fixture is made from aluminum tooling plate and checked it out with indicators on my surface plate so that is not the issue. I am running this at full power and speed, do you think I should cut down the power and still run at full speed? The lense is completely clean. Some of the parts come out white and others are grey looking. How does powder coating work with a laser engraver or can you do this?

Bryan

[Scott Erwin]

I have had several anodized aluminum jobs where I have had to go back over the lettering to make it come out correctly. The bad part is sometimes it is not in the same location and I (having my head inserted in my 5th point of contact) get the anodized aluminum to burn through the anodizing to the base aluminum. Looks bad and is not a quality job in my opinion. If it is only text, you should be able to fix it easily by going back over the weak areas.

Like Joe said, if it is a picture, you are not going to have much success. You can spend the time in an attempt to only redo the locations where the anodizing has not been removed correctly/completely but that is a lot of time and has to be precise. I have only been somewhat successful at it once and I took several small steps to get it to come out...A 15 minute job that took 2 hours...but the end result was fair to good.

The anodized aluminum is not consistant when it is put on, thus the engraver settings being a constant will come out differently in the inconsistant anodized locations.

Not what you wanted to hear, but that is how it works IMHO.

[Mike Null]

Bryan

Yes you can do powder coated materials very nicely. I find that two passes are necessary and on some even a third. The reason being that the powder coat is not applied uniformly over all surfaces (the thickness varies).

In the case of powder coated materials I think a color fill is better but so far my customers are happy to just burn down to the aluminum. (or steel)

[Albert Nix]

I am engraving anodized flashlights at 15P 100S with a 2" lense on a 40W MII and they seem to turn out nice. Havent tried a photo on anodized aluminum yet but, have practiced on painter aluminum a good bit with decent results.

[Scott Shepherd]

As already mentioned, anodizing can be tricky. It's tricky because it's generally an uncontrolled process. When I say it's uncontrolled, certainly you have steps that have to be taken, but the time of each step, along with how clean the tanks are, and how the power is applied are all things that can vary from batch to batch, operator to operator. Now knowing that each of those can change the outcome, map it across the country, or the world for that matter, and it's impossible to know how what you have was processed or if it will behave like the last batch from the same supplier, or the last batch from a different supplier.

There is no industry standard that everyone follows to the letter when doing it, so there is just a ton of variance. Not that there should be an industry standard, because anodizing isn't a coating process for engraving, it's something we have discovered and try to make it work.

There's also 2 types of anodizing. One is the normal anodizing, which basically just changes the color, and the other method is Hard Anodizing, which provides a VERY hard coating on the aluminum. VERY hard. There are some limits to hard anodizing, where as you can put some dyes in them, so it can look like black, but really be hard black, but I'm told that the dyes don't really work well with hard anodizing, although they are used from time to time.

So many variables, it's a tough product to count on unless it's a company who's shipping you a product and they have tight control on the quality of the anodizing, such as a company like MagLite.

[Mike Null]

here is some tech info if you'd care to learn more.

http://www.ihccorp.com/IHC-Anodize.htm

[Bill Cunningham]

This is a anodized plate I picked up at the Engravers Express booth at a trade show.. It was done on a Epilog TT as a sample. This is .020 Anodized Aluminum One side is done at 400 dpi, and the other at 600 I think.. Both look great..