Feed rates and times.

[FixitMike]

In a some recent posts I have stated that if there was a Z component in a tool path, the resulting feed rate would be the lesser of the Feed rate and the Plunge rate specified for the tool.
I was wrong!
I tried some combinations of tool feed and plunge rates for a ramped fluting toolpath, compared the calculated times, and it was quite obvious the Feed rate is the controlling number. So, this not the reason some see areas where the cutting is slow.

Illustrating another question that quite often comes up:
I drew a straight line 100 inches long, and a zig-zag line of 100 1" segments, with a 90 degree corner at the end of each segment. I compared the calculated times to profile on each line. The calculated times were essentially identical, which we know doesn't represent reality.
This simply illustrates the fact that when estimating cutting times the program ignores the acceleration and deceleration times at each change of direction, which are dependent upon the machine used. The zig-zag line should take considerably more time.