Will laser etching non-anodised aluminium do any harm to machine?

I'm looking for ways to get text and designs on to an aluminium sheet. I've been told that only anodised aluminium can be laser etched, but I wasn't told why exactly. I know laser cutting aluminium can reflect the laser back.

I experimented with putting a sheet of paper on the aluminium, then etching just enough so I could use it as a stencil. However, I went too far and got an image on the aluminium. It's exactly what I wanted, but now I'm not sure if I should do any more for fear of damaging the machine. I honestly can't see any danger, because as far as I know, anodised aluminium just has a coating over regular aluminium

Other ideas are painting the aluminium and etching that off. I've heard of the type of paint that's close to anodising the metal, but I was thinking a more conventional paint.

Should I be worried about damaging the machine  by laser etching raw aluminium? I've been using a 75 Watt Epilog Fusion.

I've been using a 60 watt Trotec laser, and I successfully painted a piece of bare aluminum with ordinary spray paint, then etched the nameplate in the photo. As you can see, this worked very well.

Our makerspace forbids vinyl in the laser cutter, because lasering vinyl may produce chlorine gas, which will eat the silvering right off of the laser's mirrors!

As far as etching bare aluminum, I'm not sure how much of a danger there is if the aluminum is not polished, but I also think you may not get much of an etch with this power class. I haven't tried it.

The sheet of paper sounds like a good idea, too.

DSKY Nomenclature plate (Custom).jpg
petercd1 year ago

You could also use a matt black vinyl wrap and then etch.

The thing about reflective surfaces is that they reflect the laser energy whereas the matt black surface (anodised ) absorbs the energy etching the surafce where the top most layer has been melted off.

In my opinion, the worries about laser cutting on flat reflective surfaces is that almost all of the energy will be reflected back up into the laser diode thereby damaging it, but once the surface has been etched it forms a kind of round bottomed trough with a near negligible return reflection.

No, you'll be OK. You get the best results zapping anodised coatings, because of the nice contrast. MARKING metals works well with Thermark or one of the open-source alternatives.