We received a call from a machinist who was using a 1/8 diameter, three-flute, ZrN coated, corner radius end mill on aluminum 6061T6. He wanted to know the appropriate speed and feed for this type of operation on a machine that runs at 8000 RPMs.
Since this end mill runs at approximately 45000 to 55000 RPMs, we suggest milling at 90% of the max RPM or at 7200 RPM. This habit will save your spindle bearings. As for the feeds, we suggest a .0001 per tooth per rev up of the feed by 0.0001 IPT (Inches Per Tooth) until you break one, then back away.
Do you have any speeds and feeds wisdom to share?
I've cut a lot of 6061. No simple answer... too many variables to give a reasonable answer.
1) Is your machine rigid?
2)Is it really capable of 8000RPM? (I've run mine at 8K, hours at a time - for years, but the machines I have - when they say 8000, they mean 8000!)
3) how deep are you cutting?
4) how long (or how far is the endmill sticking out of the holder)?
5) is it 2,3,4,or 5 flute?
6) is your fixture rigid?
7) is your part rigid? ( or - thin wall, sticking up a long ways )
8) full width of cut or "chip thinning"?
9) Climb cutting or conventional?
10) coolant? flood - high pressure flood - mist - none?
11) chip removal - are the chips staying in a groove - plugging up the cutter...?
12) cutter material & style / surface coating?
13) how much cutter deflection is acceptable
14) what required tolerance and surface finish?
I was cutting some 3/16 grooves 3/16 deep - 8000 RPM, stubby 3 flute cutter, HP Flood coolant, running @ 100 inces per minute - When quoting the job I figured 50 IPM. Neved did break an endmill on it.