Hi all,

I have big problem during overmolding of some PCB. Main function of molded part is to make part waterproof.
When molding is finished, resaults are good, but after day or so there is separation (picture). We have problem on around 30-50% of total number of parts.
Click image for larger version.  Name: keypad 1.jpg  Views: 15  Size: 148.7 KB  ID: 530

Material for overmold is PA 678 (macromelt), material for PCB is polyamide.

So far I tryed every speed and pack profile, different temperature profiles of tool and resin, increasing of gate, cooling time up to 5min (just for testing), tool opeining profile, material drying on diffenet profiles....
In summary i changed every parameter from lowest point to higest point, and i didnt got any solution.
Anyone have experience or advise what i can try next?

P.S. Tool and parts are cleaned from greasses, worker have clean gloves on hands to prevent transfer of grease to part.