Engraving anodized tag sort of fizzled out

[jkopel]

I would also try it on another material and see what happens. If it is not visibly curved then the focus should be close enough to engrave through the anodizing. I would second @Jules guess about the anodizing itself being the issue. There is a good chance that the oxide layer is of variable thickness, or that they have applied some kind of sealant that is impeding the engraving in spots.

[dan]

Thanks for the feedback - agree that we should suggest trying again on PG material.

FYI, in my personal experience mucking around, anodized aluminum is extremely sensitive to focus. If the laser is even slightly out of focus, it will not engrave - it will just heat up. It’s so sensitive that a small depression in the metal tray, a bit of detritus under one of the feet, or any number of other problems could cause this. Decreasing power / increasing speed will help widen the margin of error. Good luck!

PS: I don’t check threads in this section so I may not see replies here, even if mentioned by name. I’ll try to remember to check this one.

[henryhbk]

@tobiahjadam

Redo this print on a bit of PG material. If it happens again support will actually help.

Pretty disappointing @dan that issues like this aren’t even looked at by support.

IN fairness, support did get back to me and they suggested using a piece of PG in the background

[soldiercoleman]

So how did that turn out?

[Hirudin]

I doubt it’s a focus issue, we’ve all seen the curved edges of iPads and whatnot marked/engraved with a fixed-focus laser. I guess they might have been done with a longer focal-length lense, but I’m not invested enough to research further. I might be interested enough to just throw a piece of anodized aluminum into my laser cutter at an angle to see what happens though.

I had some gradients show up in some of my very early anodized aluminum engraving attempts, I chalked those up to varied speed as I was cranking it up too fast. The Trotec support rep was all but useless in resolving the issue and said something along the lines of “I’ve never seen that before”… yeah right. Thankfully, running the job multiple times (leaving the material in the machine and hitting “go” again) eventually gave acceptible results.

I also bet this issue lies with the consistancy of the anodize on the tag. I’d take that same tag, rotate it 90°, and rerun the job to see what happens.

[Scott.Burns]

Perhaps it’s a heating phenomenon: as you engrave, the piece heats up and doesn’t respond the same way to the laser?

[henryhbk]

@Scott.Burns

Perhaps it’s a heating phenomenon: as you engrave, the piece heats up and doesn’t respond the same way to the laser?

Except I have some beautiful engraves I have done on similar tags. They look fantastic with none of this effect.

[dan_berry]

I’m betting that the tags suffered from stains (hydrated aluminum oxide) before they were covered black. What you’re uncovering is just the overcoat, revealing the stains below, making it appear that the removal was incomplete or inconsistent. Try scrubbing it with sodium hydroxide or, apparently, oven cleaner.

Also:

Fastest way to clean a stained aluminum pot

[jrnelson]

@dan_berry

Try scrubbing it with sodium hydroxide

lol.

i mean, sure, but you know. carefully.

[henryhbk]

OK, repeat worked appropriately, although I did up the power to 50% so not sure if that made a difference from 30% (which has worked in the past - and don’t beyond the manual this now!).

[chris1]

That alignment