Resin change.

[Horeki]

Yesterday some corporate fool decided that it was a good idea to change production resins, so this morning I received a few tons of formoleme 2550A (pp coopolymer) and not my usual formoleme 4142T (pp homopolymer).

So short tale is that I’m unable to reach any results with the new resin (my line is IML cups) one of the pieces keeps stuck on the core (mobile part), air ejector inflates the piece and it breaks and the nozzle in that cavity (No.2) has leakage.

1.- Tried reducing Back Pressure to avoid over packing and no change.
2.- Tried augmenting Hold Pressure, injection force and reduced cooling to avoid under packing, no change.
3.- Reverted Hold P and Cooling, reduced RPM, reduced Back P and Reduced barrel temp, it worked, but... without a label and as son as I start the IML robot and there’s a label in the cavity the problem is there again.

My job is on the line because of this and I’ve been stuck on this problem for hours.

Mold Diagram 3 zones hot runner:
C1
Z1
C2 (this is the cavity with the problem)

Process details:
Thermal profile - 230, 227, 220, 210, hopper OFF C
Z1- 230, C1- 230, C2- 230 C
Back P: 7kgf
Screw Speed: 150rpm
Decompression: 3mm
Injection speed 210mm/s
Hold P: 550kgf, 0.9s
Injection Force: 1450kgf
Cooling: 2s
Mold temp :15C
Cycle Time: 9.6s