Material Subject to Warpage

Warpage

All polymers shrink during cooling. However, if a part shrinks to different degrees in different places, it can warp.

If your part's geometry means that it has a tendency to warp anyway, then using a semi-crystalline material will make the effects of the warpage worse.

Some materials have naturally higher shrinkage than others. In particular, semi-crystalline materials have a naturally higher shrinkage than amorphous materials.

To find out more about polymer crystallinity, read the Material crystallinity topic.

What to do

1. Decrease mold temperature

   Shrinkage and warpage increase as the mold temperature increases, because a high mold temperature slows down the cooling rate of the material. This means that it will take longer for the part to freeze, which makes the crystalline content increase. Therefore, to decrease the proportion of semi-crystalline areas in the mold, decrease the mold temperature.

2. Decrease wall thickness

   Shrinkage increases as the wall thickness increases. This effect is very similar to that of mold temperature. As the wall thickness increases, it takes longer for the section to cool down and freeze. The slower cooling makes the crystalline content in the area increase, causing the shrinkage and warpage to further increase. Therefore, to decrease the proportion of semi-crystalline areas in the mold, decrease the wall thicknesses.

3. Choose a different material

   Use the Select Materials page of the Analysis Wizard to search for a material with similar properties, but which is not semi-crystalline. Click to see a list of Semi-crystalline material families.