Rockwell Automation 1771-QDC, D17716.5.85(Passport) MNL. PLASTIC MOLDING MODULE - Manual (Page 18)

Overview of Inject Mode
Chapter 1
1-7
Hold Phase
The QDC module controls the hold phase with a pressure vs. time profile.
You create the profile based on controlling hydraulic pressure against the
ram (screw), or by controlling pressure within the mold cavity resulting
from hydraulic pressure against the ram (screw). You can control either
pressure with up to five time segments. You determine the pressure
setpoints and time durations for the hold profile based on your molding
requirements.
After completing the last segment of the hold phase, the QDC module
either immediately starts the optional Pre-decompression movement, skips
the pre-decompression movement if none is required and immediately
starts the plastication phase, or waits for a command from your PLC
program to continue.
PreĆdecompression Movement
You select a length of pullback for the ram (screw) prior to the plastication
phase to separate plastic solidifying in the sprue from molten cushion
remaining in the barrel.
After completing the pre-decompression movement, the QDC module
either immediately starts the plastication phase or waits for a command
from your PLC program to continue.
Plastication Phase
The plastication phase lets you achieve a melt temperature gradient in the
barrel containing the ram (screw). To do this, you can create the
plastication profile with up to 11 segments of position or time (figure 1.8).
You chose from four plastication profiles:
Backpressure vs. position
Backpressure vs. time
Screw RPM vs. position
Screw RPM vs. time