Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 459)

Programming Feedrates
Chapter 18
18-11
Adaptive Feed Maximum Feedrate
When cutting under low to no load the servo may not be able to reach the
programmed torque without exceeding your programmed F--word. In
these cases, once the maximum servo feedrate is reached, the control
allows the torque to drop below your programmed torque so as to not
exceed the maximum programmed axis feedrate (F). The error “Adaptive
Feed Max Limit” is displayed on the CRT.
Adaptive Feed Minimum Feedrate
When cutting under high loads the servo output torque may not be enough
to keep the axis from slowing down below your programmed E--word. In
these cases, once the minimum programmed feedrate is reached, the
control allows the torque to go above its programmed limit to maintain the
programmed minimum feedrate (E). The error “Adaptive Feed Min Limit”
is displayed on the CRT.
Feedrate Override
Because of the precise feedrate control necessary to maintain a constant
torque the feedrate override switch is disabled for any move that is
programmed using the Adaptive Feed feature. If PAL is written to do so,
you can use this switch only to request a feed hold which will halt axis
motion. Cycle stop will also halt axis motion.
Block Retrace
You can perform block retrace on an adaptive feed block. When an
adaptive feed block is retraced adaptive feed control is made in the
opposite direction of the originally programmed block. Typically since no
cutting is performed on the block retrace the cutting tool will move at the
programmed maximum feed rate (F).
Polar Programming
You can not program a G25 block if the axis being programmed is in the
current plane and the control is in polar programming mode (G16).