Do you have a shut off nozzle? Without it, and without the proper software in some machines, you cannot continue to recover the screw while the mold opens and the parts are ejected; for the absolute fastest cycle times. You leave the nozzle open, while you decompress the screw, shut the nozzle, and you can recover the screw while the mold opens, ejects parts, and even closes back.
To do this properly, you need more than one motor/pump on a hydraulic press (one runs clamp and the other the injection unit) or on a hybrid you need electric screw drive!
Back pressure is a MUST for a stable process AND consistent dimensions!
Rick