Why shrinkage percent of injected model is greater than material shrinkage ?

[nguyenbuulam]

Dear Moldflow Support/ Moldflow user

I would like to inquire your issues:

I run a procedure Fill+Pack+Warp of uniform and simple shape with material Xyron DG040.

Material shrinkage value is as below

I checked shrinkage percent of injected model is greater than material shrinkage.

How can this issue occur ? Why shrinkage percent of injected model is greater than material shrinkage ?

Thank you in advance for your support.

[mason.myers · Accepted solution]

Hello @nguyenbuulam ,

What is the thickness of your part?  The tested shrinkage values we show are an average from our CRIMS test plaque.  This plaque can vary in thickness but the data is usually taken from 1-5 mm thick samples.  If the thickness of your part is greater than our test plaque, you will see higher amount of shrinkage.  If the part is not packed our sufficiently, you can also see high shrinkages.

Mason

[nguyenbuulam]

Thanks to Mr Mason for your prompt support

[h-fujitaDXJU5]

Hi.

Generally, thicker part, lower holding pressure(process setting or far from the gate), hotter temperature(melt and mold) and shorter holding time makes greater volumetric shrinkage.  Flow direction shrinkage is smaller than perpendicular shrinkage value particularly on filled material such you used.(This is already written in "observed shrinkage" table.)

Regards.