Need help engraving aluminum

I need to engrave (I guess) some thin marks and lines into aluminum, but my initial tests have been poor. By thin I mean 1/32 or less. I’d appreciate some tips on how to do this cleanly. Bits, speeds, depth, etc.

I haven’t done any on my 1F but in the industrial setting we use 1 flute or 2 flute V bits

and use a single line font

Can you elaborate on the issues you’ve had?

Sure, here’s a photo that might help explain the problem I’m having, as well as the bit I was trying to use. I’m using Carbide Create to create the toolpath. You can see that there’s a lot of built up aluminum around the edges, so it’s really rough. Everything here is a single stroke/path with no volume, so I used a contour cut with no offset. Should I be using a different kind of toolpath?


Any amount of runout with that style of bit can cause issues.

cutting data for engraves we run at work
6000-8000 RPM
XY Feed 250 mm/min
DOC max 0.2mm

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Thanks Nick. So using the non offset contour path is ok?

I’m not a CC user so I’m not entirely confident on that path selection, but it seems to jive with what I’d do in Fusion.

Do you have an indicator that you could use to measure bit runout? A couple of thou would be more than enough to cause some burrs.

The other thing would be just tweaking with feeds/speeds. @cyberreefguru did a couple of good videos recently showing a good method for determining feeds and speeds for a given material.

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Oh man, I do not. I’m really new to this and had to look up runout! Haha.
So, why the lower speed? Technically, is the aluminum melting and cooling before it can be expelled?

What you are really aiming for is chip load aka inches per tooth.

For the feeds and speeds I mentioned you get a chip load of 0.0357 inches per tooth.

You could also run your router at 18000 rpm and go much faster and get the same chip load.

Cutting with incorrect chip loads isn’t great for the longevity of our bits. Heat disappation is primarily via chips since we aren’t using coolant and if the heat isn’t leaving then it is staying in the bit! It’s possible that excessive heat buildup may cause some gumming up around the edges of the cut like you’re seeing, though I wouldn’t expect that with a shallow engrave.