Scaling Factor and Draft in Mold Design

Scaling Factor

When you create a mold you must account for the scaling factor. The scaling factor is the amount the material in the mold shrinks or expands as it solidifies. The scaling factor depends on the type of material used and the shape of the mold, and is expressed as a percentage of the linear size (not volume) of the design part.

The software scales the cavity by the specified scaling factor, using this formula:

Cavity size = part size * (1 + scaling factor/100)

For example:
Desired adjustment Scaling factor in % (enter this number)
2% material shrinkage (cavity larger than part) 2.0
2% material expansion (cavity smaller than part) -2.0

Creating Drafts for Molds

You may need to add draft angles to molded design parts to make it possible to remove the finished part from the mold.

If you have a SOLIDWORKS model, you can use the Split Line tool_Split_Line_Curves.gif tool to split faces and the Draft tool_Draft_Features.gif tool to add draft. You can also used the Rule Surface tool_Ruled_Surface_Mold_tools.gif tool with either SOLIDWORKS or imported models to add draft, correct flawed surfaces, or create interlock surfaces.