Trouble cutting thin aluminum sheet


I’m looking to cut about the same thing - 26-30 gauge steel similar to what @wbendick did in a post several years ago . I tried unsuccessfully using the gcode attached and got the picture below. New_0.gcode (42.5 KB)

I am using these 3-flute 1/8" up cut bits. Will these suffice or is there a dramatically better bit?

Biggest issue for me I think is the height (and possibly the bit). I have mine higher for other purposes but will end up making through holes for my corners and cut another set of rails for my tools. For ease of use I might just make an entire new inner assembly. At any rate I realize it needs to be dropped as much as possible. Don’t judge, she’s not done yet. :wink:

I do not have speed control either. Is that a must-do for this type of work? Also what is best to hold sheet metal down other than a pricey vacuum system? Any other tips or tricks one might offer?

Thanks in advance.

I’ve had very good results cutting 1/4 aluminum plate, and milling features into even thicker aluminum billet. I use the single flute, 1/8" spiral upcut bits Ryan has in the shop. The trick for me is using trochoidal (or adaptive) cutting patterns – this really reduces load on the cutter and lets me hog out material very cleanly… I have not tried sheet material as thin as you seem to be trying though.

For holding down sheet material try painters tape on the underside of the material and on the spoiler board, then cyanoacrylate glue to bond the tape together. Holds surprisingly well and is easily removed from both the material and the bed after you’re done.

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Yeah. That Z is way too long. The legs are one part, but the bigger issue is the length the Z has to reach down to get to the work. I wouldn’t expect a machine at that height to have the rigidity to do aluminum. I would be suspect that it could do any good with wood either, honestly. If you managed to get a really rigid thick box to lift the metal up you’d get rid of about 3/4 of the flex.

It’s been surprisingly not sucking with wood. Well for what I’m doing anyway. I’m going to try to drop it and shorten up the Z this week, hopefully finish by the weekend. Thanks sir.

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Great stuff, thanks for the good advice! I tried the Scotch permanent double-sided tape at someone else’s recommendation but no love there.

I’ll pair that with Jeff’s and see what shakes out the bottom.

Right now USPS is so bogged down it’s crazy. I placed an order and it’s been about 8 days now. Of course it shipped immediately and got to Atlanta in a day or so but Atlanta to Augusta… wow.

Thanks again!

Does the machine wobble if you push on the corners? If it doesn’t, might be faster/easier to mount your work to a block or a stack of boards and bring it up to the gantry instead.
As for the sheet metal, I’ve thought about sandwiching it between a couple pieces of softwood or mdf. I mean, you only have to cut a little deeper than the top piece, so if you plan the cuts carefully, might go OK.
But I think I might prefer a downcut bit too keep the metal from lifting and some air to keep it clear.

That’s good stuff Tony, thanks. I went ahead and cut and drilled the new Z rails but haven’t done anything else yet. I’ll try that first but my expectations are low. My first results were pretty weak so I’ll probably have to put the work in to drop it. We’ll see.

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I was able to drill the corner holes and drop the legs, then drop the Z-axis motor down so that the tool is still within plenty of range of the core at working height. I made a test cut in the same material (incidentally it’s steel not aluminum as I had in the original post). I cut at 6mm/s on the F(z) and 8mm/s on the F(xy). Everything looks so much better. This I can work with.

Thanks for the help @jeffeb3, @kizmit99, @turbomacncheese!


Let’s see some pics of the resulting cuts!

Oh it’s bad. Really bad. I just threw this up without measuring. Adhesion didn’t work out as planned. Didn’t even have the vacuum ready. But ok, sure. Everyone needs a good laugh right? I do think I want to try the downcut bits though since something this thin looks like it’ll be a pain.

Not sure if this link will work?


Yo…steel? Say what you want about the adhesion and location, but those are CUTS! I say good job!

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Totally agree with Tony – looks pretty good.
You might want to try a piece of scrap board (say 1/4" mdf?) over the sheet - so the steel is sandwiched between that board and the spoil board. I think you just about have it! :+1: