Open-Loop Molding Revisited...
I have been asked about the proper use of an open-loop molding machines...
When implementing DECOUPLED MOLDINGsm, how should we best incorporate our open-loop molding machines?
Basically, open-loop molding machines are not capable of this since open-loop molding machines cannot decouple 1st stage filling from 2nd stage packing. These machines lack closed-loop, injection velocity control and inject using pressure control instead. As a result, the screw speed decreases as the screw moves forward, resulting in an inconsistent shear rate from shot to shot. On these machines, the best approach is to fill and pack the part during 1st stage.
More posts about this topic can be found below: