Volumatric Shrinkage

[Anonymous]

For thermoplastic materials, volumetric shrinkage should be less than the observed maximum value for the material. You can find material shrinkage information in the Thermoplastic material database. Right-click the material in the Study Tasks pane and select Details. The Thermoplastics material dialog is displayed. Select the Shrinkage Properties tab. The observed maximum shrinkage values are in the Observed shrinkage section.

For max number of materials these values are not provided. Where to find an app value of Volumatric shrinkage to compare with the simulation results

[carcarc]

where are you from?

can we communicated in chinese?

because my english is not good enough,



Why you say volumatric shrinkage should less than the observed value in material database? volumematric is also decided by packing?

I think you can fine the volumatric shrinkage from MPL (Moldflow Plastic Laboratory??).

Che

[Anonymous]

volumetric shrinkage should be less than the prescribed values, because volumetric shrinkage shows as a percent of original volume.whereas the shrinkage values in the data sheet is with respect to dimensions. so if you have the value of volumetric shrinkage more than shrinkage values, then for sure you part is shrinking more , due to insufficient packing and other parameters.

[GalSherbelis7635]

Hello,


Regarding volumetric shrinkage.

As far as I know, the volumetric shrinkage values listed on the DB under the shrinkage tab are NOT measured values.
MF only measures the parallel and perpendicular shrinkage. The volumetric shrinkage values listed on the DB are PREDICTED values for the shrinkage measurement geometry under the listed conditions.

To properly measure molded part volumetric shrinkage one needs to measure the shrinkage in the thickness direction and that requires accurate measurement since the dimensions are small.

It is possible to estimate the unconstraint volumetric shrinkage from the PVT data but that has to be done with care for two reasons;
1. Almost all data listed on the DB is measured in heating and not cooling.
2. What transition temperature to use? The transition temperature on the PVT data is usually higher than the "transition temperature" listed under the rheological properties tab