Plastic/insert interface

[Bvora24]

Hi,

Can anyone suggest how to find out air gap if plastic shrinks internally or lose the contact between plastic & insert.

refer attached image for better understanding.

or ... Is moldflow assumes perfect contact between plastic & insert interface??

Regards,

BV

[JCourter]

Hello BV,

To comment on the Moldflow side regarding the contact.  Moldflow uses default heat transfer values to represent different levels of contact throughout an analysis.

Fill-->5000 W/m^2-C

Pack-->2500 W/m^2-C

Detached Cavity/Core-->1250 W/m^2-C

Where the flow solver automatically detects the instant the detachment occurs based on pressure in 90% of the cavity having decayed to zero.  So there is definitely not perfect contact assumed.

[Bvora24]

Hi Justin,

Many thanks.

I understand your reply of different heat transfer values during the process.

May be I have not put my question correctly.

I'm analyzing insert molding with core shift analysis on.

I can see insert deformation during the process & wall thickness variation as well.

But, practically after molding there is no contact of plastic with metal insert  & insert is free to move inside.This is critical for part performance.

May be this must have happned due to internal shrinkage or difference in co-efficient of expansion or some other factor.

I can't see such condition/plot in my simulation to co-relate. Please help me to atlest zeroing the possible cause.

Regards,

BV