Rockwell Automation 1771-QDC, D17716.5.87(Passport) CLAMP AND EJECT MODE - Manual (Page 175)

Tune Your Machine
Chapter 10
10-2
High speed clamp operation. Molders wish to achieve minimal
machine cycle time while achieving repeatable mold positioning and
precise Low Pressure Close control.
Smooth clamp operation. Jerky, abrupt clamp movements can cause
damage to clamp mechanisms as well as accelerate wear on machine
hydraulics.
Ejector Control Objectives
Most molders share the following objectives when tuning their ejector
operation:
High certainty of parts ejection. Parts which are not automatically
and completely ejected can cause machine downtime and equipment
damage.
Part quality protection. Care must be taken not to damage the parts
when ejecting them from the mold cavities.
Repeatable ejection position. The advent of automated part removal
from mold cavities has made repeatable ejector advance positioning a
process necessity.
High speed ejector operation while meeting the above objectives.
Molders wish to achieve minimal machine cycle time while insuring
part quality, achieving repeatable ejector advance positioning, and
positive part ejection.
In previous chapters, all profile execution has been accomplished with the
QDC control algorithms disabled (open-loop). Most finished parts run
much more consistently if the QDC module is allowed to operate the
Clamp and Ejector Profiles using closed-loop control.
Important: With few exceptions, all profiles should be executed utilizing
closed-loop control when running actual machine production.
Use Open-Loop control when:
spanning valves and trouble-shooting machine performance
pressure sensors are not available to use as feedback when running
pressure controlled profiles
Use Closed-Loop control when:
repeatable clamp and ejector performance is required
OpenĆloop or ClosedĆloop?