Need Help!- Long Reach Milling On VF2

[akedward]

I have a part (see attached picture) that for various reasons requires me to do some pretty deep side milling (4.31"). The material is 6061-T6 aluminum. I can rough most of it away but finishing the wall will be a pain. My first thought would be to use something close to a 1.0" diameter carbide EM with at least enough neck clearance to get me full depth by doing something like .5" step downs. I'm not worried about how fast I finish the wall, so hopefully I can slow things down enough to reduce the chatter.

I posted this on the Haas forum because this problem does have machine specific variables. Any advice or tips are appreciated!

[Matt@RFR]

I suggest this tool: Reduced Shank .750 Variable flute X .734 shank X 6.0 long MariTool

I've used the same to go 5" deep in 6061 with great finishes. Obviously you'll be roughing with something else (indexable endmill would be great for that). Leave about .015" on the walls, max RPM and around .0025" IPT with a .750-1.000" stepdown and you'll be pleased. No chatter whatsoever with those parameters on my VF-2ss.

Yes I know what coating it has on it. Yes I know it's a 4 flute designed for steels. It's one of the few I've found that are reasonably priced and have the shank undersized by just a tiny bit...not a full 1/16" or 1/8". This will be way more rigid than a 1" endmill with full flute length.

One hint though: Make sure to check runout. Any runout at all with that much hanging out of a collet is going to ruin your day.

[Delw]

look into the garr extra long reach alumstar? carbide endmills
I cut deep box's with a 1/2 endmill and 2.5" deep with no problems I have to run 3000rpm but absolutely no chatter with .100 side cuts. the make bigger dia and long depth of cut ones also. I thought I saw a 3/4" with a 4-5 in flute length where I pick mine up.



Delw

[akedward]

Thanks for the tips Matt and Del! That gives me a place to start. I'll post back on how it goes.

[akedward]

I went with a Mari-Tool .75 X 6" long carbide EM and it worked out great. I finished the 5" deep wall and with a .1875" step down and a .05 radial depth of cut max (pic attached). I just used the the stock speeds and feeds that Mari has on their website.

Thanks for the advice.