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Fasttrack
04-16-2013, 11:42 AM
Tapping the brain-trust again: What can you guys tell me about engraving anodized aluminum with a CNC router? My business associate is interested in buying a Torchmate CNC product to cut out aluminum panels via plasma but was thinking about getting the router attachment to engrave text on the panels. We were concerned about the tool lifetime in the anodized aluminum; I believe it is just decorative anodizing so it should be very thin. However, based on past experience, the depth varies quite a bit across a 4 by 8 sheet.

Toolguy
04-16-2013, 12:12 PM
I do engraving on a product I make after it's anodized. With a carbide engraving tool I can do hundreds of parts without any noticeable wear on the tool. This is with coolant. You will probably need to run dry, but should still get a lot of life out of each cutter.

Ken Gastineau
04-16-2013, 10:32 PM
I use a spring loaded diamond drag engraver on pewter. This works great for line engraving. I haven't worked with anodized aluminum, but it should work ok. I do not spin the engraving point, just drag it through the metal.

For pocket milling style of engraving I guess it depends on how small the cutter is. I have done engraving in various materials with single lip cutters as small as .005" and it takes a pretty accurate setup. Larger letters/pockets that can use larger cutters should be able to hold their own with slight variations in thickness. Also pocket milling letters is pretty slow compared to what can be done with a spring loaded diamond drag point for single line or outline fonts.

So I guess it all depends on what size and style of engraving you need to do.

Evan
04-17-2013, 04:45 AM
Drag engraving isn't too satisfactory on anodized material. If the tool is spring loaded the point can skip out of the cut and ride on the surface. Also, the anodized layer may tend to check and flake along the cut line. For that I use a carbide point that is ground to a triangle pyramid tip or a hex tip and spin it fast. That makes a reasonably clean line as long as the tip is well centered. I also use diamond dental burrs which I pick up free at the dentist. They work well on glass too.

Fasttrack
04-17-2013, 10:16 AM
Thanks, guys!

Evan - I'm glad you mentioned the diamond burr. I said something to my colleague about maybe using diamond burrs but I was worried about them getting gummed up once they "broke through" the anodized layer.