Can't get any depth when engraving aluminum on 20w fiber...HELP!

Community Laser Talk
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I am using an older Epilog Fibermark 20w fiber laser. It belongs to my boyfriends work. They didn’t have anybody to run it and I have experience with CO2s so we worked up an arrangement where the laser is at my house and I can use it for personal things and they will pay me per piece to engrave their items.

The items they need engraved are aluminum gas caps for custom motorbikes. They want a deep engraving thats then filled with black rustoleum with a hardener. Problem is I have been unable to get a deep engraving. My marks are surface level or even raised!?! idk how I’m managing to get raised marks but here we are.

Bc it is an Epilog machine I am stuck using Epilog’s job manager software and print driver. I have tried raster and vector engraving at power levels anywhere from 60-100%, speed settings from 1-30%, and frequencies from 20kHz-55kHz. There doesn’t seem to be a huge difference in the outcomes when trying different settings. I have no focus gauge but through trial and error I’m at around 3" of focal height above my workpiece and have tried changing the focus up to +/- .50 in an attempt to get a better engraving with no success.

The machine is fully cleaned, has an exhaust fan but no air assist.

The photos show some of my tests. Engravings are raised or smooth on the surface.

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Has anyone done the engraving you are trying to do? Aluminum is really hard to laser engrave because the metal conducts heat so well. And heat is what makes the laser do its thing.

Have you tried Cermark or equivalent spray? If you can get that to work, it will be more durable than their hardened paint.

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How many passes are you doing? I typically do 40+ for deeper engraving, with a cleaning pass every 5 or so regular passes.

1 Like
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Lower frequencies Engrave deeper… Higher are more surface marks.

To get a deep etch, you’d need quite alot of passes. Best thing to do is try on a piece of scrap. Max power, low frequency and different number of passes to see what works best.

If the marks are raised, sounds like you are creating aluminum oxide which is thicker than aluminium. Trial and error are your friends. There are plenty of test patterns out there - I’d use one of those and run through some speeds and powers

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Try this. The only thing is I don’t know the frequency range of your laser. Set the frequency yourself. Better a lower frequency.

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