Rockwell Automation 1771-QDC, D17716.5.85(Passport) MNL. PLASTIC MOLDING MODULE - Manual (Page 156)

Tune Your Machine for Producing Parts
Chapter 10
10-10
RPM Setpoints
Use RPM setpoints only for the plastication RPM vs. position (or time)
profile to control screw rotational speed and the temperature gradient of
the melt. The resulting shear rate produces a barrel re-fill suited to the
requirements of the next injection phase.
Important: Plastication RPM profiles require one additional RPM setpoint
beyond the last non-zero end-of-position setpoint (or last non-zero segment
time setpoint), so you must program one more RPM setpoint than position
(or time) setpoint, such that
total RPM setpoints = total position (or time) setpoints + 1
If not, screw rotation will stop unless the ram (screw) reaches 100% shot
size before:
reaching the final end-of-segment position
the final time setpoint has expired
EndĆofĆsegment Position Setpoints
Shot size is subdivided into profile segments, the lengths of which are
determined by your end-of-segment position setpoints. Each segment has
its velocity, pressure, or RPM setpoint for controlling the ram (screw).
Important: Avoid multiple adjacent segments having the same velocity,
pressure, or RPM setpoint. For better control, use a constant velocity,
pressure, or screw RPM over a single equivalent length (or time) segment.
For injection and plastication profiles, you must always program one final
velocity, pressure, or RPM setpoint without an associated end-of-position
setpoint that the QDC module uses until it reaches transition (for injection)
or 100% shot size (for plastication).
Time Setpoints
Time setpoints define the duration of each profile segment that applies
pressure to the ram (screw).
Important: Avoid multiple adjacent segments having the same pressure
setpoint. For better control, use a constant pressure over a single
equivalent time segment.
For injection and plastication profiles, you must always program one final
pressure or RPM setpoint without an associated time setpoint that the QDC
module uses until it reaches transition (for injection) or 100% shot size (for
plastication).