I’m trying to cut some mystery aluminum on my shapeoko 3. It is 1/4 sheet. I was using an 1/8 single flute spiral bit similar to the one from inventables. (though much cheaper seen here
The very shallow cuts seemed ok (maybe .003 deep), at 25 IPM feed, 3 IPM plunge but when it started taking .01 off, I broke a bit.
I lowered the speed from 25 IPM to 12 IPM 3 plunge .01 depth, and it was seemingly melting or rubbing and I broke another bit. I tried varying the RPM of the makita to see if it made a clean cut at any point, but it didn’t seem to make a difference anywhere on the dial.
I was not using coolant but i was doing an air blast. I’m not sure if this is because it isn’t 6061, or the cutters are crap, or my feeds and speeds are off base. I have some of these I could try to if anyone has f/s recommendations.
If you try aluminum, take the time to use a F&S calculator, there is a worksheet based one available from @gmack and one from @Julien for free here on this forum, do a search to find it. For the best results, a ZrN coated endmill is best. As @WillAdams said, however, mistery metal can cause major issues, best to try your first cuts with a billet that you know the characteristics.
It looks like my speeds and feeds were initially within spec for Julien’s calculator. The problem with mystery aluminum, is that it’s free. I may try again with the single flute reducing DOC to .003 to see if it can make it through it so I don’t have to scrap it.
Well, it has cost you a couple of bits and may cost you a chunk to replace something on your Shapeoko. I’m sure that won’t be free. Just my 2 cents, though.
Those endmills have horrible geometry for chip excavation and clog up very easily even with speeds and feeds being on point (I’ve run quite a few of those). I recommend carbide3d or Amana single flutes.
I machine “mystery aluminum” (I am going to steal that phrase) all the time…but you need to know that when warmed, aluminum gets as sticky as peanut butter…so coated end mills are great (ZrN are the best in my opinion) and adding some WD40 as Vince says is great. There is one rare grade that is nearly impossible to machine, Type O, but that’s pretty rare to find, so I doubt you have that . Think Peanut Butter
Yep even 7075 in 0 folds like lead, but when brought up to T6 is super stiff. A lot of formed aluminum parts are made at 0 then heat treated. I remember way back in A&P school making wing ribs with a wooden form and rawhide mallet, then heat treating them and there was no bending without cracking, pretty cool stuff! As mentioned above some grades (5052 comes to mind) that are pretty soft and gummy and can only be work hardened (which they kinda do, while also sticking to your endmill) which leads to some ugly results. If you really don’t know the grade, but it’s cost effective to keep using this material, there’s labs that can test it and tell you what it likely is…for a fee of course. Other than that you can keep trying with hopes of being successful at some point, but aluminum grades are very different and there are many.
Thanks! I changed to the standard carbide3d 2 flute and hit it with wd40. Tiny chips, but not gummy anymore. Had to pause the job, hoping to finish tonight.
The wd40 made a big difference. After switching to the carbide3d 2 flute, it was still not breaking the chips. Hit with wd40, boom lots of tiny chips. This is on the list as a future addon.
I’ve seen that! I love TOT. I’m anxiously awaiting more of his CNC refit on that mill he bought.
The whole purpose here is to distribute the water over the grounds evenly. This does a slightly better job than the stock showerhead, but not as good as i was hoping. I’m considering countersinking some of the holes where it looks like it isn’t flowing because of the waters sticky properties.
