More Aluminium testing

Hey guys,

I have just tried a different grade aluminium that’s supposed to be pretty good with not great success. I was running it at 0.3mm per pass, 15mm/s feedrate and 3mm plunge rate. I tried trochoidal as well and that seems even worse for me.

So it starts off not too bad, then as it gets deeper, the bit starts to drag along and even slightly bend as it tries to keep up with the speed.


I’m now wondering whether it’s because I’m using a spindle rather than a router. My spindle is rated at a maximum 15,000RPM @ 500W. Could this be the issue? Has anyone successfully done aluminium with a spindle? Any advice much appreciated. …And yes I have seen the videos posted here and on the facebook page. It just doesn’t work well for me. Ah and using a 3mm single flute, then tried 4mm 4 flute with same results. Grrrr!!!

Try deeper per pass you might actually just be work hardening your metal. Stick with tricoidal, There are a few threads with recommended settings. I haven’t tested it much but am working up to it soon.

How big is your machine? New bits? Metal can kill them fast if they get hot.

Thanks for your reply Ryan.

I started off with 1.0 mm per pass trocoidal and it was even worse. The 3mm single flute had been used before but about 2 weeks old. The 4mm 4 flute was first time used on this today.

The machine has a usable area of approx 600 x 800

Get a brand new sharp 2 flute, forget the 3 and 4. It might be gumming up and rubbing. If you can see your bit bending then thats a serious problem. Make sure it is the right bit in the first place, and make it as stout as possible. A long and skinny endmill is asking for trouble.

So I ask you guys with a router that can run at 30,000RPM, if you turn it down to half speed, will it still cut through it? Like I said I can only run my spindle at a max of 15,000 RPM.

It just seems to me while I’m watching it cut, that it may have something to do with the speed of the spindle.

What is DOC (depth of cut), 0.3mm or 3mm?

Even with trochodial I never go higher then half of bit diameter. Its easier with a larger bit, try a 6mm for now. 15k should be sufficient, I have a 30k rpm router and I mill alu on the lowest powerlevel (or slightly faster for a finishing cut). I think its about 10k rpm on that level.

I found the attached sheet online, translated it to EN and expanded it alot to cover the most common alu alloys in terms of machinability. This sheet is basically for bigger machines, but as long as you keep your DOC small and use trochodial, it works for me so far.

Although my sheet tells you AlMg3 sucks, thats the main material I’m using right now, and with 40% DOC (of diameter of bit) it still works well.

Try the rpm/feed my sheet tells you, if theres too much vibration with your machine, just reduce DOC and/or increase size (width) of trochodial (I prefer to lower the DOC).

Cutcalc.ods (15.6 KB)