I have been trying my hand at my first anodized aluminum project. I grabbed a sheet of this and followed a lot of the guidance in the forum on settings but nothing I do seems to get rid of these horizontal shadows.
I tried:
I’m totally at a loss. Is this just as good as it gets?
Since we’re discussing settings for non-PG material, I am moving this to Beyond the Manual. I have done a lot of anodized aluminum, but I am usually not worried about fine details. I can say that some anodized aluminum kind of just melts the color, and then it needs a good wipe to clean up the image, but I don’t know if that is your issue. I can only suggest running tests on the material to find your best results.
Take that very same piece of aluminum and turn it 90 degrees and run it again. Do it on the same side and everything.
If you see streaks going in the same direction as they are now (horizontally now) then you know it’s your material.
So that would at least give you an idea of what the issue is. In terms of how to solve it? You may be overpowering it. You don’t necessarily need a whole bunch of laser power to get a good engrave on aluminum.
If I were in your shoes though I would do one thing at a time. I would try the 90° test first, and then I would start messing with settings.
Just to be certain, you’re removing the plastic coating first?
You might also try running the engrave twice. Some of those aluminum anodize sheets just come out like that until you hit them a second time. And some colors or anodize have this problem more than others in my experience (bright blue and black primarily)
Spending twice as long is worth it if you get the print you want in the end.
Thanks for all the tips! I think I’m extremely close now. To answer the questions
It does look like reducing the power is the trick. The L in the attached image was run at 608, power 79, 340 resolution, 2x. The odd thing - the O’s came out white and they were run with the same settings but manually running things twice. I’m not sure why it’s inconsistent or even which version is “right”.
Kept tweaking and so far the best settings I’ve found are the following:
Speed 300, Power 85, 340 LPI, auto-focus, 2x
Some shadowing effect but not so noticable. Possibly I could run it a bit faster but running out of time for today
Speaking of time, I find that higher lpi can be beneficial with aluminum. I posted about it once, let me see if I can find it.
Any more updates?
Still working on it 
I managed to get one sign to look absolutely perfect with a series of passes with the above settings (one with your higher LPI then) the following settings ran and it just suddenly was perfect:
600 speed, 95 power, 340 lpi, autofocus. I’m setting the height of my material accurately.
When I get the settings JUST right, it comes out matte with no horizontal lines, but that seems to be extremely finicky to do. I’m trying now to replicate it with a new design and these settings aren’t hitting that sweet spot any more. I’ll keep at it
Finally got it! I don’t know how many passes are needed since I ran through a few times on subpar settings but this setting worked:
500 speed, 95 power, 340 or 675 res depending on engraving, autofocus
So you can see the difference 100 pts slower made…
Ooh buttery. Nicely done, good job sticking to it.
