Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 446)

Programming Feedrates
Chapter 18
18-20
Figure 18.11
Programmed Feedrate Not Reached
Linear
Accel
Programmed
feedrate
Z4.8 Z4.9
F100
F60
Z
F
E
E
D
R
A
T
E
D I S T A N C E
Z5.0 Z5.1
Feedrate clamped here to allow
time for deceleration
Linear
Deceleration
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Normally this causes no problem. However, in cases where a series of
very short axis moves in separate blocks exist, this limitation to the
feedrate can cause finish problems as well as increased cycle time.
Figure 18.12 shows the velocity profile that would result from a series of
short Z axis moves from 4.8 to 4.9 to 5.0 to 5.1 to 5.2.
Figure 18.12
Feedrate Limited Because of a Series of Short Moves
Linear
Acceleration
Programmed
feedrate
Feedrate clamped
Z4.8 Z4.9
F100
F60
Z
F
E
E
D
R
A
T
E
D I S T A N C E
Z5.0 Z5.1 Z5.2
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