Anodized Aluminum

[Chase Mueller]

Sorry for flooding the forum with my issues, but I'm having some trouble at work and can think of anywhere else to turn.
My job primarily consists of raster engraving AA pipe, but I seem to have run into a strange issue. I've been doing the same kind of work here with this laser for almost a year and I've never had this issue before. All other AA I work with is smooth sailing, but recently I've come across a batch that simply refuses to engrave, and here's the kicker, it seems to only happen with a certain length of pipe. It looks ever so slightly different as well, almost iridescent with a rainbow type look, while all other pipe has that standard anodized look (matte silver I guess?). The pipe is 6063 t6 satin anodized (201r1). I have attached an image depicting the problem pipe. The pipe resting atop the rest engraves perfectly fine, while the others won't at all. I'm pretty sure it boils down to poor anodize finish but would like input from others, especially if someone could help me explain the issue more uhhh, technically.pipeee.jpg

[Gary Hair]

Are you using the CO2 or fiber? If CO2 then try more power/less speed, if fiber try the same but increase the frequency too. If that doesn't work then bring some to me and I'll try it on my machine(s).

[Chase Mueller]

I keep forgetting you're literally in the same town.. It is the CO2 and I tried it, no progress. Let me check with my boss and see if I can bring some over tomorrow. Here's my work email, contact there with any questions. laser@gaexpoDOTcom

[Scott Shepherd]

Unless it's hard anodized, in which case the CO2 isn't going to mark it. Try the fiber on it. If it marks with the fiber but not the CO2, it could be hard anodized. Why? I don't know, but just something to check.

[Mike Null]

I have run across AA that didn't engrave well because the anodizing process was contaminated. I'm not saying that's your issue but I wouldn't rule it out. I had one customer who tried 3 anodizers before he finally switched to powder coat for his products.

[Kev Williams]

Unless it's hard anodized, in which case the CO2 isn't going to mark it. Try the fiber on it. If it marks with the fiber but not the CO2, it could be hard anodized. Why? I don't know, but just something to check.

I laser etch hard anodized almost daily, it engraves just fine. But these same pieces I can't fiber worth a crap, mostly because the hard is extremely thick...
BUT, there's always a but -- there's a guy in town who personally, from his home shop, hard anodizes these small parts for a sheet metal shop, who brings them to me. Both lasers suck at these parts. The 40 watter I can only hit it with 18-20% power and full speed, and even then it's a dark gray. If I get above 25% power, it goes dark blue. At 100% power the mark is so dark gray it's barely noticeable. And once it's been hit that hard, there's no going back. I DO fiber these parts, but it's a 20-pass marathon to get to bare metal...

While some anodizing marks very little, I haven't found any that simply won't mark. And the stuff that marks darkish, I've found less power works better than more power...

Back to these pipes-- I'm guessing 2 things:

1, those that are anodized are very very lightly anodized, just like many brands of clear anodized sheet stock, 'barely legal' so to speak -but that's all it takes to (a) lighten up when a C02 laser hits it, and (b) resist oxides used to blacken the engraving...

-and-

2, i'm going to guess your non-engravable pipes have been clear chem-filmed, and nothing more.

You can test for this, if you have any oxide solution ("Aloxide" or similar) that blackens engraved lacquered brass or anodized aluminum: The oxide will NOT blacken anodized aluminum, but it WILL blacken chem-filmed aluminum...

[Scott Shepherd]

I have seen some hard anodized capable of being marked, but the mil spec stuff we get, won't mark with the CO2 well at all. I've also seen hard anodized be very inconsistent from batch to batch. We have parts that engrave a beautiful bright white and then the same parts from a different batch, with the same settings, engraving a duller gray. No matter what you do to them, you can't get them to go white.

[Mike Null]

For the most part I don't get acceptable results on hard anodized with my co2 machine.

[Bill George]

For the most part I don't get acceptable results on hard anodized with my co2 machine.

But he also has a Fiber if I am reading his Signature line correctly. For all the support for his job he is getting here, you would think he would be a Contributor.

[Gary Hair]

Just sent you an email.

[Chase Mueller]

I'm gonna try not to miss anything here:
Bill: While I appreciate all the forum does, I'm still waiting for my work to approve the charge for contributor status, if it gets declined, ill just do it myself.

Steve: I use the CO2 daily on all the pipe and never have issues until now. I'm going to assume we would have to order another part for the machine to be able to use the Fiber? I've never tried to and my boss has told me to stick to CO2, for whatever reason. You folks are MUCH more knowledgeable than myself, so if you can think of something I could say to change their minds, by all means, I'm all ears.

Mike: I had my boss send out a piece of the pipe to have it tested as he now believes its the AA finish. I'll keep everyone posted if anyone ever decides to tell me the results.

[Kev Williams]

Steve: I use the CO2 daily on all the pipe and never have issues until now. I'm going to assume we would have to order another part for the machine to be able to use the Fiber? I've never tried to and my boss has told me to stick to CO2, for whatever reason.

That reason may likely be that the marking/etching can't penetrate the aluminum oxide layer, aka bare aluminum not allowed, which is exactly what you'll get via fiber...

[Chase Mueller]

That reason may likely be that the marking/etching can't penetrate the aluminum oxide layer, aka bare aluminum not allowed, which is exactly what you'll get via fiber...

Apparently, I don't have the fiber option because "I don't need it". I'll change my signature. I assumed it was as simple as changing something in the driver settings, but I was wrong. Wish I had the fiber though, wouldn't be having these issues I'd imagine..

[Bill George]

Apparently, I don't have the fiber option because "I don't need it". I'll change my signature. I assumed it was as simple as changing something in the driver settings, but I was wrong. Wish I had the fiber though, wouldn't be having these issues I'd imagine..

So is this a brand new machine and your the first user Chase? Or its been in use a number of years and your the new operator?. It would be interesting to know how many hours is on that tube, maybe its getting weak?

If your company has been using these same poles for number of years or have they changed suppliers?

No its not against SC policy to post your real email address, but its not smart as all the scammers pick it up and you will get so many more junk emails.

[Chase Mueller]

So is this a brand new machine and your the first user Chase? Or its been in use a number of years and your the new operator?. It would be interesting to know how many hours is on that tube, maybe its getting weak?

If your company has been using these same poles for number of years or have they changed suppliers?

No its not against SC policy to post your real email address, but its not smart as all the scammers pick it up and you will get so many more junk emails.

Brand new, purchased in June, started running in July of last year. Aside from the VP of purchasing, who only used it when we were building our sliding jig, I'm the only one who operates it. I talked to my boss and he said we have two suppliers for the pipe, and that he sent a piece of one to be tested.
I'd like to think it's not getting weak, since I'm running it right now on the normal looking pipe, and everything is running smoothly. I've been trying to convince them it's a pipe issue for a while now, maybe they're listening now?
Although I have to admit, this would all be easier if we would have gotten the Fiber..