[strohkirchw]

Can anyone explain to me the benefit to maximizing one or the other in the below scenario.

A end mill that recommends 600-1200SFM and ~.002IPT, is it better to get closer to chip load or sfm?

4200RPM 15IPM - 275SFM and .0018IPT
6700RPM 15IPM - 439SFM and .0011IPT

[rschultz@asc]

too many missing variables to solve that question like type of material and type of bit. if its carbite i would have to say its better to get closer to your chipload. good luck

[strohkirchw]

high helix coated carbide and 6061

[rschultz@asc]

two flute?

[strohkirchw]

Ya, sorry
1/4" 2 flute

I was curious if one effected tool life more than the other or perhaps something else I should know about.

[rschultz@asc]

theres many ways to go about it in regards to tool life and efficiency. my experience with carbide is to have a lower rpm n a higher chipload. keeps the bit cooler and removes more material.

[Kingjamez]

Bob is the right person to answer this but here is my take on it.

SFM tells you how fast the tool should / can go and retain good tool life. Lowering the SFM (within reason) will increase the life of the tool (especially if it is HSS).

Chipload is also not set in stone, but should be kept fairly close to the recommended levels. Chipload is important in keeping the tool cool because a correct chipload will allow the chips to carry away most of the heat generated by cutting.

If I were choosing, I'd choose the correct chipload first. I almost never run a fast enough SFM as I mostly cut aluminum on my X3 with max RPM of 2000. Running the correct chipload has given me very good tool life and finish.

-Jim

[Chrliev]

It depends more on the material than anything else. In aluminum run your machine at the maximum rpm and multiply this rpm times chip load per tooth and then times the number of flutes.

Most importantly in aluminum there are considerations you must take into account. You cannot exceed your machines RPM and or horsepower limits. This is usually the problem cutting aluminum. IE if you have a 1/16" end mill and need 90,000 rpm this may not work out, or say, if you have a 2" end mill, 90% engagement with a 3" depth of cut that would require 50 hp.

Depending on the depth of cut, a 1/4" carbide em in AL. I would run at about 10,000 rpm and about 60-80 IPM for roughing and I would drop to about 40 IPM for finishing...

[fretsman]

Let's not forget about the coolant needed with some of these speed/feed recommendations.

While dry machining can work, for smaller machines it's mostly trial and error to see what your particular machine can get away with.

Dave