Feed rates seem crazy

CC seems to be giving me crazy feed rates: 60 in/min at 15,000 RPM for soft wood for a 1/4" bit? Seems radically slow, and a low chip load (.002). I’m coming up with 120 in/min for an RPM of 5000 for soft wood. (.01225000= 120)

I would not call them crazy, but they are conservative.
Depends on DOC too, which DOC are you using ?
60ipm @15.000RPM with #201 (3 flute) is 0.0013" chipload.
For a 1/4" endmill in softwood I like to be in the [0.001 - 0.005] chipload starting range.
120 @ 5000 RPM on a 3-flute would mean a 0.008" chipload (assuming 50% stepover or more), definitely doable, and if that works for you great (but @gmack would probably frown at such a low RPM for cutting wood, since cutting forces decrease with increasing RPM)

EDIT: are you using the very latest version of CC ? They changed the feeds and speeds computation.


Please try build 433:


Maybe too loud though? :wink:

Yeah, my spindle only goes to 6000 max. I ended up using 60 ipm at 5000 and it ran just fine. (double flute). Previously, when I tried to divide their 15,000 RPM numbers by 3, my ipm was too slow and it smoked like the devil.

And thanks others, I’ll try the new version once I can get it running. I tried to install, but it threw an error when I had to run it, and I had to revert versions.

What machine? Spindle?

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