topic Re: warpage of thermoplastic overmolding in Moldflow Insight Forum

warpage of thermoplastic overmolding

Anonymous — Wed, 30 Jan 2019 12:12:02 GMT

Hi,
I'm trying to run a Fill+pack+Overmolding Fill+ Overmolding Pack +Warp analysis.

The 2k geometry is more or less two flat strips one over the other.

What I would expect is a bending final results, heavily conditioned by time/temperature of the first extraction, but even if I increase the cooling time (temperature is lowering at mold setting) results do not change.

The bending is very low (1-2 mm)

On the other hand a "simple" one stage analysis with the first injection set as "part insert", give the "expected" results (final part is bending 15-17 mm)

The problem with this last approach is that insert temperature is uniform (it's not real) and it's more difficult to guess temperature set.

Is there something to set in the 2k analysis in order to take into account 1st stage conditions ?

Any help would be appreciated
Thanks

Alessandro

Re: warpage of thermoplastic overmolding

prakashcheyyar — Tue, 05 Feb 2019 05:25:20 GMT

Hi atomasella

Go through this links

https://autodesk.typepad.com/beyondmoldflowinsight/2014/11/script-for-multi-shot-overmoldings.html

https://autodesk.typepad.com/beyondmoldflowinsight/2016/09/enhanced-script-for-multi-shot-overmoldings.html

Re: warpage of thermoplastic overmolding

LadisR — Tue, 05 Feb 2019 05:40:45 GMT

hi Alessandro,

For the over molding analysis the shrinkage (for the first shot) are calculated from the onset of solidification for each element to RT while when you are running as Insert molding, the Shrinkage (for the "insert") are calculated from the dT from the insert temp to Room temp.

So, depending on the geometries for the 1st and 2nd shot, the process may be better represented by using an insert setup.

If you need more detailed response, please contact your Autodesk Support Representative and send us your model.

Regards

Ladis

Re: warpage of thermoplastic overmolding

Anonymous — Tue, 05 Feb 2019 08:53:46 GMT

Dear prakashcheyyar, thank you for your reply, but I do not need to simulate a 3-4 k overmolding process.
I need to get right warp results from 2k overmolding simulation.

Thank you anyway

Re: warpage of thermoplastic overmolding

Anonymous — Tue, 05 Feb 2019 09:24:09 GMT

Dear LadisR, thank you for the reply.

I've already sent both model with a support case to the Autodesk Customer Support.

My wonder about results is that the difference is so big ( 2-3 mm with 2k overmolding and 17-18 mm with the insert approach )

In order to choose the right approach it would be good to have some information on calculation algorithm and their applicability (long or chunky parts, thin walls ... )

Thank you