[ezflowrider]

Hello,

I am new to laser etching/engraving. I work at a machine shop that has a 40W laser engraver. I have been trying to get a nice crisp logo (25mm x 2mm) on black anodized 6061 and 7075. I can get a pretty good looking logo, but it appears more blue/grey than white. Other parts that I see the laser etching is really white.

I've been playing with the dpi setting, speed, and the power settings. More power seem to turn the etching brown. Too little power and the logo barely appears. Speed doesn't seem to affect it at all.

Any suggestions?

Thanks,

Chris

[PinMan]

This may be an obvious question, but have you tried adjusting the focus of the laser instead of the power?
We have a very similair setup and have run into this issue in the past. That is how we fixed it.

[ezflowrider]

Yes, I have. It seems like the power and the focus are linked. I've been trying to keep one variable constant and changing other to see if I can work this out.

I currently have my lens about 54mm from top of part. This seems to get me the smallest laser point. If I bring the lens closer, say to 52mm, the etching comes out blurry at any power. If I leave the lens at 54mm, more power makes etching brown and blurry.

I'm stumped. Are there more variables I can adjust?

[zax15uk]

First, make sure it is regular black and not 'hard' anodized as that is almost impossible to remove cleanly.

Second, use 2-passes to get a nice clean result. The initial pass will remove 90% and leave it grey but the follow up will clean it up nicely.

Zax.

[PinMan]

First, make sure it is regular black and not 'hard' anodized as that is almost impossible to remove cleanly.

I was just about to ask this as well. I was thinking that maybe the problem lies with the part rather than the machine.

[ezflowrider]

pretty sure these parts are not hard ano.

I'll try two passes

does anyone have any general settings to use for engraving on anodized aluminum? low power high speed? 500 dpi?

thanks