Cutting Speeds and Feeds

[ctate2000]

Does anyone wish they had a better grasp on speed and feed? How about surface finsh and chip thinning calculations?

[rdoty]

Okay, I'll bite!
I'm dealing with that issue right now. I'm cutting some slots in .25 aluminum, 0.203 wide (x .25 dp), four passes at 0.070 per pass, and currently running at 1800 RPM and 4 IPM. When I consult feed/speed calculators they advise some unbelieveable numbers depending on the calculator. Typ: 11000 RPM @ 70 IPM. Where should I really be to get max thruput? My mill has max RPM of about 3000 and I found if I run more than about 2000 I get either cutter vibration or chip galling or both. The cutter is HSS, 13/64 dia (0.203) and 5/8 cutter length. I'm using flood cooling.

[ctate2000]

How many flutes on your end mill? If you are running a 4 fl then you do not have enough clearance. Try a three flute if you can find it. If not go to a two flute. I really think you could run the full 3000 and feed something like 12 ipm and make two passes instead of 4. I suspect most of the problem is related to chip clearance.

[rdoty]

Thanks cstate2000.

Sometimes it's the obvious that is overlooked. I was running a 4-flute and I have both 2-flute and 3-flute available.

[MFassler]

dont forget you also need to take into account the rigidity of your machine and setup.