Voids in the part

[Bvora24]

Dear All,

Does someone knows how to predict Voids in the part through result plot?

[Brian.Sather]

Hi Bvora,

The best way to determine whether there will be voids is to use the volumetric shrinkage plot. Voids are like internal sink marks - usually occurring in thick regions of the part that shrink more than the rest of the geometry.

One of the traditional cases is the plastic wine glass. Where the stem meets the cup there is typically an area 2-3x the wall thickness where a significant amount of volumetric shrinkage takes place. Here is a link to an image of the result:



As you can see - in that region the average volumetric shrinkage is around 12% whereas in the rest of the part it is much lower. It doesn't necessarily mean that there will be a void there - but now that it's been identified you could easily make a design change to minimize the probability of one forming.



Brian Sather
Product Technical Marketing Manager

[GalSherbelis7635]

There is no easy way to tell if a void will happen from the software results. The problem is that you do not have a volumetric shrinkage threshold criteria to tell you if a void will happen. If you have a part with a void simulate the actual molding conditions and set the predicted volumetric shrinkage as a criteria for testing possible improvements.

Further more high volumetric shrinkage does not necessarily mean a void. In some geometry you could get a void or a sink mark (or surface wrinkles) depending on the molding conditions. Running a hot mold with shorter cycle time can get in some cases a void to become a sink mark/surface wrinkle.

Gal

[madhukeshwart]

high shrinkage is a reason for voids, sink marks .....result in either of them

[madhukeshwart]

If you are using 3D mesh, Check for density plot, time to reach ejection plot, volumetric shrinakge plot to predict voids