Is Shrinkage is given to input CAD before Analyzing it.?

[anmol_kr_singh]

Hello,

I have 1 basic query about Moldflow, regarding the shrinkage that we give to mold, is the same needed given for the analysis in Moldflow...?

If yes, please share some reference document links so I can use them to show my customer.

Thanks

Anmol Kumar

[mason.myers]

Hello @anmol_kr_singh ,

Moldflow will run the calculation on the CAD model provided.  If you use the Part CAD (the desired part shape) and run a Warp analysis, Moldflow can provide you shrinkage rates (Shrinkage Compensation) that could be applied to your mold or tool, in order to obtain that part size.  You would need to apply these shrink rates to the Part CAD to create the Tool CAD model.

If you have a larger Tool CAD model, this would be a more accurate depiction of what is actually happening in the mold since the mold cavity is oversized to address the shrinkage that occurs during the molding cycle.  In this example, you would not want to apply shrinkage within Moldfow since you have already applied shrinkage to the larger Tool CAD model.

Mason

[anmol_kr_singh]

Hello Mason,

Thanks for clarifying my doubt. 

I understand this, but I need any of clarification Document of using the Mold CAD (i.e. With shrinkage) always during Moldflow Analysis for better and accurate results. Because they are using Part CAD and always getting the incorrect results. (Like they are getting Cavity weight always less in Mold flow then that of actual).

So, for correcting it and asking them better practice I have to give then some documentation. If there is any document by Autodesk or by any of scholar on this topic, please share with me.

Thanks

Anmol Kumar

[mason.myers · Accepted solution]

Hello @anmol_kr_singh ,

I could not find anything official aside from a blog post that MF Software makes with some of my Moldflow Monday posts on LinkedIn.

https://www.moldflow.eu/part-cad-vs-tool-cad/?lang=en

Mason

[anmol_kr_singh · Accepted solution]

Thanks, Mason for your support.

This blog will help me.

[PascalGosset]

Hello simulators,

For me shrinkages calculated by Moldflow cannot be applied to the mould.
They are often higher than real shrinkages because they are all free.
While generally, in the mold, they are partially blocked versus the X and Y axes and free versus Z.
Also, depending on the material shrinkage model, you may find values significantly different from reality.

Beware of compensated shrinkages.

These are in fact averages of the warpage.

If a part deforms a lot along one axis, the compensation will be very different from the other 2 whereas it should be close.