HIPS Inner liner hole/craters

[Aria]

Hai All,

Long time no discussing in here.
I have some Issue on Inner liner HIPS.
After PU injection, some of area at the end of radius, raise a hole/crater like photo at attachment.
Until now not yet find the source problem.

If any information or experienced about this issue, just feel free to reply my post.

Thank you,

Warm Regards,

Aria

[Tycho]

Injection molding?

I know nothing about this, but to me it looks like there might be air bubbles or moisture in the injected PU, or if the molds are cooled/refrigerated there might be condensation formed on the molds between injections.

But I'm just guessing

[Aria]

Not injection mold, but thermoformin/vacuum forming process. After forming process , inner liner assembly with cabinet and then continue to Polyurethane injection (PU).
After PU injection , this hole/crater is raises.

Not sure yet, this is because of thickness material or some chemical reaction during PU Injection.

Thanks,