Feed rate? Slot cutting with 0.031" endmills?

[Donkey Hotey]

I really should post this to one of the general forums but there are enough Haas guys here that I'm hoping for directly applicable opinions.

I am about to make some parts which need slots cut into 6061. They are 0.031" wide and 0.021" deep. A slitting saw is not an option since the paths will eventually have curves in them (if this prototype succeeds).

I purchased 1/32" flat and ball carbide endmills (to experiment with each). I'm trying to calculate safe feeds.

Starting with a 0.25" endmill, I could safely assume 0.002" chip load. Scaling the diameter down to 0.031", the proportional chip load would be 0.00025. At 10K RPM, that would be 5 IPM--fully buried. By the 'normal' calculations, I'd figure 0.5D (0.016 deep) at 5 IPM

5 IPM just sounds too fast to me for such a small, fragile endmill. Can I use this method of 'scaling' to estimate safe feeds? Time isn't that critical but I don't want to spend days machining the parts either. If I don't scrap anything, I have about 30 inches of aluminum to cut these grooves into (in as many passes as it takes).

Any suggestions?

[Vern Smith]

After soliciting opinions on this forum I ran a .0625 carbide 3 flute EM at 6000 rpm and 7 IPM for two days, over 300 feet on the same EM. This was full width and .045 deep. I don't think you are that far out of the park with 5 IPM.

Vern

[Gary55Ford]

Hi Greg--- I don't have a machining center, I have a cnc bed mill the max. speed is 4,300rpm. I machine 6061 with .031 2 flute carbide center cutting end mill @ around 4,000rpm-2. ipm-.020doc it's pretty slow I know.

[fuzzyracing1967]

I don't think your off on those numbers.I did some small slots like that in golf club heads years ago,and they were about half what your looking at,and they were in steel.Hated the part,but loved the money.

[djr76]

Originally Posted by Donkey Hotey I really should post this to one of the general forums but there are enough Haas guys here that I'm hoping for directly applicable opinions. I am about to make some parts which need slots cut into 6061. They are 0.031" wide and 0.021" deep. A slitting saw is not an option since the paths will eventually have curves in them (if this prototype succeeds). I purchased 1/32" flat and ball carbide endmills (to experiment with each). I'm trying to calculate safe feeds. Starting with a 0.25" endmill, I could safely assume 0.002" chip load. Scaling the diameter down to 0.031", the proportional chip load would be 0.00025. At 10K RPM, that would be 5 IPM--fully buried. By the 'normal' calculations, I'd figure 0.5D (0.016 deep) at 5 IPM 5 IPM just sounds too fast to me for such a small, fragile endmill. Can I use this method of 'scaling' to estimate safe feeds? Time isn't that critical but I don't want to spend days machining the parts either. If I don't scrap anything, I have about 30 inches of aluminum to cut these grooves into (in as many passes as it takes). Any suggestions?

That should work just fine. I would even use those speeds and feeds in stainless.

[AMCTony]

That looks to be good. I just finished running some parts with 0.031" endmills to cut small pockets in O-6 tool steel . Used 0.02 DOC at 2 IPM 6000RPM. You should be just fine at 5 IPM and 10000 RPM in aluminum. Use lots of coolant.