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Milling 0.08" 2024 Aluminum


Original Post
Gilman Coryell · · Mount Vernon, Maine · Joined Jun 2012 · Points: 65

Looking for advice/experience cutting shapes out of 0.08" 2024 Aluminum sheet. And no, I'm not making pro.

Not springing for waterjet CNC so this is a DIY.

I'm planning on using something like a 2mm Blade Diameter,High Speed Steel,Double Flute,Square Nose End Mill Cutter CNC Router Bit in my table top router setup.

This would be for applications like snow saw, tool handles, and the like.

Anyone out there had success doing this kind of thing at home? What was your setup? What worked well? What didn't work? Things to avoid? Lessons learned?

Thanks for any input.

Gregger Man · · Broomfield, CO · Joined Aug 2004 · Points: 1,320

The hold-down strategy is one crux. You might want to sandwich the aluminum between the table and 0.125" plywood and place screws through the work strategically. The aluminum sticks to the bit. You can spritz with alcohol to help with that. I used a solid carbide 1/8" two flute up-spiral and lubricated by squirting canola oil occasionally when I cut out 1/4" thick 6061 (but the oil makes a big mess.)

BigRed11 · · Unknown Hometown · Joined Apr 2013 · Points: 831

Agreed on fixturing it with something thicker on top - thin sheet is going to want to chatter. A tiny end mill like that is also likely to snap off, so I would either dial your feed down and spindle speed up significantly or use a larger bit. I would also be worried about the final cut-out binding on the end mill as you finish the cut - tabs  would help.

Glass Tupperware · · Atlanta · Joined Jul 2012 · Points: 45

Also agree on the cutting fluid!! Shouldn't matter too much what you use, but that'll be helpful in both clearing debris and keeping the bit cool.

Ryan Swanson · · Pepedidnothingwrong, freejg · Joined Jan 2018 · Points: 50

Hate to say it, but you might be using the wrong tool for the job.  Your cutter is the same diameter as your material.  Either plan on making multiple passes to get to depth, or plan on clogging the cutter up with aluminum and breaking it.  A full width cut with a small diameter cutter sucks. You have to spin it as fast as your machine goes, and cut slow.  My last tiny milling project involved slots 1/16" wide in 6061.  I had to go 4-4.5 IPM, something like 18,000 rpm, and a .01 depth of cut to not keep breaking endmills.  This was also in a 4000 lb mill, not a 400 lb table top cnc router.

If it were me, I would CNC plasma, laser, waterjet, or wire EDM.  In that order (for cost).  I also have a buddy with a 5x10 cnc plasma table in his garage, so that makes it a bit easier for me to burn out any shape I want.

Pray your ass off to the metal gods.  You are going to need their blessing to make it worth your time.

Gunkiemike · · Unknown Hometown · Joined Jul 2009 · Points: 2,800

I think it was my Facebook fed that was semi-spammed with a tool that purported to do this with ease. It's an attachment for any hand drill. Cuts freeform shapes in sheet stock. I suspect it's a "nibbler" type cutting action.

Paul Morrison · · Unknown Hometown · Joined Nov 2006 · Points: 0

I haven't 2D cut 2024 on a 3-axis CNC router, but I have done 3003 of about the same thickness that you're proposing. Work-holding is actually really simple; just buy a roll of 9 mil polyethylene double-stick tape (McMaster-Carr sells a 3M product in 1" wide rolls) and stick your sheets to your spoilboard. It wouldn't hurt to have a screw or two in it just in case your upcut spiral bit shears the adhesive bond (don't ask me how I know about this). Your bigger problem will be chip welding. You'll need to keep misting the tool with something or other. I haven't tried any of the fluids that others have recommended already, but I've used WD40. You'll have to find something that doesn't degrade the adhesive on the tape (see above). You can also play a stream of compressed air over your tool bit to try to keep it cool enough to avoid welding. That, of course, will rather defeat the fluid coolant, not to mention spraying WD40 all over your shop.

Ryan, what kind of business are you in? You always seem to have some interesting and useful information about metallurgy and metalworking.

EDIT: It's 3M 9589. And once you've set your stock down on it, go over it with a dead-blow hammer.

Ryan Swanson · · Pepedidnothingwrong, freejg · Joined Jan 2018 · Points: 50
Paul Morrison wrote: 

Ryan, what kind of business are you in? You always seem to have some interesting and useful information about metallurgy and metalworking.

I'm a mechanical engineer, specializing in machine component design.  I also machine and fabricate various things as my personal projects require, from gun parts/silencers to long travel truck suspension.  I don't design something I can't make.  I'm not an architect. (don't hate me if you design buildings)

Everett · · Nevada · Joined Jul 2016 · Points: 25

For work holding, you can DIY a vacuum table if you want to spend a lot of time. The quick way is to just glue or screw the sucker down to a piece of sacrificial board. Double sided sticky tape can also work.

If you have access to compressed air, use that to clear the chips. If your machine is large enough, you can just hose clamp it to the spindle housing and aim strategically. If no compressed air, WD-40 is also commonly used to clear chips. Don't worry about heat; there's no way thin aluminum is going to overheat a carbide tool.

Buy extra material and bits to sacrifice to those metal gods.

Edit: Now I am become slow typer, accidental parrot of Paul Morrison.

Paul Morrison · · Unknown Hometown · Joined Nov 2006 · Points: 0

 I don't design something I can't make.  I'm not an architect. (don't hate me if you design buildings)



The way I would put it is that I don't start designing something until I have a need to make it, a way to make it, and something that I intend to make it from.

That's not at all the way things are done at my job.

I work in an architecture school.
Jim Titt · · Germany · Joined Nov 2009 · Points: 490

Just use a single-flute copy-router bit at 12,000 rpm with oil mist just like every aluminium door and window company has for the last 50 years or so.

NorCalNomad · · Unknown Hometown · Joined Oct 2011 · Points: 120
Paul Morrison wrote:. It wouldn't hurt to have a screw or two in it just in case your upcut spiral bit shears the adhesive bond (don't ask me how I know about this). 

Lololol Had this experience too.

Also another solution instead of tape is using 3M Super 77 or 3M 90 spray adhesive (and a respirator of course) onto some MDF/ sacrificial board. I personal like this method since a lot of double stick tapes will introduce some slop into your system with foam, textile, or polymer core of the tape flexing/twisting. This way is also a bit more resistant than a lot of tapes to cutting fluids. 
Gilman Coryell · · Mount Vernon, Maine · Joined Jun 2012 · Points: 65

Thanks all. Very helpful information. Just what I was looking for.

Matt S. · · Milwaukee, WI · Joined May 2018 · Points: 0

Pro tip: Don't use a vacuum to suck up any aluminum dust.  You could cause an explosion.  

Paul Morrison · · Unknown Hometown · Joined Nov 2006 · Points: 0

Pro tip: aluminum is a very efficient conductor and won't stay hot enough long enough in your ducts, saw cabinets, or anywhere else to ignite wood dust. 

Sam Sala · · Denver · Joined Oct 2013 · Points: 40

Pro tip: In the time it would have taken you to read this thread, you could have emailed me a DXF file and we could have laser cut it for you.

Matt S. · · Milwaukee, WI · Joined May 2018 · Points: 0
Paul Morrison wrote: Pro tip: aluminum is a very efficient conductor and won't stay hot enough long enough in your ducts, saw cabinets, or anywhere else to ignite wood dust. 

That isn't the problem.  Powdered aluminum itself is explosive.  Its caused some pretty large industrial accidents.  Literally Google it...if OSHA was walking through a factory and they saw someone using a shopvac to suck up Aluminum they'd throw a fit.  Can you get away with it?  Yeah, but to act like it's safe is laughable.

Paul Morrison · · Unknown Hometown · Joined Nov 2006 · Points: 0
Matt S. wrote:

That isn't the problem.  Powdered aluminum itself is explosive.  Its caused some pretty large industrial accidents.  Literally Google it...if OSHA was walking through a factory and they saw someone using a shopvac to suck up Aluminum they'd throw a fit.  Can you get away with it?  Yeah, but to act like it's safe is laughable.

Got it. Thanks for the explanation. I don't think the cautiousness is quite applicable to this case, however, in which the debris would be chips rather than dust.

Kees van der Heiden · · Unknown Hometown · Joined Oct 2016 · Points: 40

How about a jigsaw with a metal cutting blade? Slow, but effective and very cheap.

Edit: I mean, coping saw. The hand powered version.

Mike Brady · · Van Diesel, OR · Joined Jul 2014 · Points: 668
Matt S. wrote:

That isn't the problem.  Powdered aluminum itself is explosive.  Its caused some pretty large industrial accidents.  Literally Google it...if OSHA was walking through a factory and they saw someone using a shopvac to suck up Aluminum they'd throw a fit.  Can you get away with it?  Yeah, but to act like it's safe is laughable.

To think it is dangerous for this project is laughable

Everett · · Nevada · Joined Jul 2016 · Points: 25
Mike Brady wrote:

To think it is dangerous for this project is laughable

Does 2024 produce fine dust if you've got your speeds and feeds set to not shitty?

Guideline #1: Don't be a jerk.

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