First time milling aluminum

[Jim Becker]

Michael, where mechanical hold-down gets dicey is with the thin metal material because it distorts easily. In those cases, the tape method(s) are almost required in order to insure that the material both doesn't move laterally and also doesn't "lift selectively" during the cutting process. Heck, this applies to thin wood, too! It's a different animal for work hold-down just due to its nature.

[John TenEyck]

I almost always zero off the top of the material, so adding the tape underneath is not an issue in that regard. I started using tape and CA for parts that already were cut to final dimensions. Where to put screws (sometimes not an option anyway) or clamps w/o the risk of hitting them? I proved I couldn't do it consistently! When I started milling parts for the clocks, it was pretty much the only solution to hold the little parts needed without using the dreaded tabs. I've used double stick tape, too, and Intertape 591 works very well, it's just a lot more expensive than blue tape and CA. And then as Jim said, tape is about the only way to hold thin, flexible parts. I don't have to worry about deadlines and production, fortunately. I'd be doing something else, for sure, with a different machine.

John

[Michael Burnside]

Michael, where mechanical hold-down gets dicey is with the thin metal material because it distorts easily. In those cases, the tape method(s) are almost required in order to insure that the material both doesn't move laterally and also doesn't "lift selectively" during the cutting process. Heck, this applies to thin wood, too! It's a different animal for work hold-down just due to its nature.

Sure, totally agree in some circumstances it makes sense. I do use the method, just not my favorite. I’ve even taped the top side to the table around the perimeter on thin plexiglass even though I was still using my vacuum table.

[Wes Grass]

Kerosene is an old standby for machining aluminum. I've used WD, smoky but does a good job. By urban legend, kerosene and oil of wintergreen.

But unless you've got something sacrificial neither is a good choice with a spoil board involved. Denatured alcohol, mmm, 30% or so water, probably dries out eventually.

[David Buchhauser]

Thanks, David. As Jim said, I'd have to make some sort of containment tray out of Melamine or similar to keep any kind of lubricant from getting slung off onto the MDF spoilboard. I typically use the blue tape and CA glue method to attach workpieces to the MDF or secondary board, as shown here, and wouldn't want anything to interfere with that, or to stain the next workpiece. So far, alcohol sounds like the first thing to try although, to be honest, I saw no aluminum sticking to the 0-flute end mill.

Maybe your and some other recommendations are targeted more at reducing wear on the bit. If so, that's probably not a major concern for me at this point as I don't need to mill aluminum on a regular basis, or many square inches when I do. But if I do, I have some recommendations on what to try.

Why do I use tape and CA glue? Yes, it takes time and costs money to do it. The advantage for me is I can use parts precut to all or a subset of final dimensions and do the milling w/o worry of cutting into clamps, etc. A vacuum hold down system would be the better approach, but that's not likely to happen unless someone has an economical design that uses something no larger than my 3 cfm vacuum bag pump, can accommodate parts of varying sizes, and holds them securely during milling. Anyone have something like that?

John

John - you might also consider trying compressed air directed at the endmill (bit) while it is cutting. This is more to keep the bit from clogging than to lubricate. Of course the air would blow aluminum chips all over and make a big mess as well. When I did my first milling of aluminum on my Avid Pro 4848 router table dry, I broke a bit. I made a temporary cardboard enclose around the part and used WD40 and it worked great. But after that I decided that I needed an additional table just for doing the aluminum work. So I bought a smaller Avid Pro 4824 and am still working on setting that one up with a full enclosure. I should have had it done by now, but got sidetracked building the atc tool changer along with some other projects. I am intending to use a coolant mister instead of the WD4. Here are a few pictures of the progress.

David

Avid 4824 1.jpg

Avid 4824 2.jpg

Avid 4824 3.jpg