Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 471)

Programming Feedrates
Chapter 18
18-23
Figure 18.12
Feedrate Limited Below Programmed Feedrate to Allow Deceleration Time
LINEAR
Deceleration
LINEAR
Acceleration
Programmed
feedrate
Feedrate clamped here to
allow time for deceleration
X5 X5.1
F100
F80
For normal programming, this typically causes no problem. However, in
cases where a series of very short blocks exist, the limitation to the feedrate
may cause finish problems as well as increased cycle time.
To avoid the feedrate limitation, the short block Acc/Dec feature can be
enabled by programming a G36.1. In this mode, the control will assume
that no drastic deceleration is forthcoming and allow the control to raise
the velocity of an axis higher than it could decelerate the axis before the
block ends. This method of programming is only acceptable when:
no sudden changes in programmed feedrate within the short blocks
exists (this includes requesting a feedhold or cycle stop)
no drastic change in programmed direction is present within the short
blocks exists