Rockwell Automation 1771-QDC, D17716.5.85(Passport) MNL. PLASTIC MOLDING MODULE - Manual (Page 19)

Overview of Inject Mode
Chapter 1
1-8
Figure 1.8
Plastication Phase Example
1 2 3 4 5 6 7 8 9 10 11
Position or Time
Mold End Back Point
hotter cooler
Barrel Containing the Melt
Temperature Gradient
Backpressure or Screw RPM
Affects of Profiling a Plastication Phase
Backpressure and/or screw RPM have these affects on plastication:
The higher the backpressure (or screw RPM) during plastication, the
higher the resultant temperature of the melt.
You can accelerate the backup rate by reducing backpressure
(or increasing screw RPM).
You can increase resultant melt temperature by increasing backpressure
(or increasing screw RPM).
After completing the last segment of the Plastication phase, the QDC
module either immediately starts the Post-decompression movement or
waits for a command from your PLC-5 program to continue.
PostĆdecompression Movement
You select a length of Post-decompression pull-back of the ram (screw)
after the Plastication phase to guard against drooling molten plastic into the
open mold during ejection. The QDC module notifies your PLC-5
program when the Post-decompression movement is complete.
Screw Speed
Beginning with the 1771-QDC/C revision of the module, you can control
and monitor screw RPM only when you have configured the QDC module
for the singular Inject mode. None of the other mode combinations allow
for connecting a screw RPM sensor to the QDC module.