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)
|
Resulting
cavity size
|
|
2% material shrinkage (cavity larger than part)
|
2.0
|
part size * 1.02
|
|
2% material expansion (cavity smaller than part)
|
-2.0
|
part size * 0.98
|
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 to split faces and the Draft
tool to add draft. You can also used the Rule Surface 
tool with either SolidWorks or imported models to add draft, correct flawed surfaces, or create interlock surfaces.
Related Topics
Interlock surface
Split Lines
Ruled Surface
Draft