Hello.

As part of a course I'm trying to model a real life object and have encountered a problem which I'm not sure if it is expected or not. Let me describe/motivate the steps I have performed and what I find strange:

- Created a sheet metal part from a sketch which consists of a 175 deg arc, i.e. not a complete half circle. Note that the sketch defines the outer diameter.
- Unfolded the part to add a cutout which I wanted to dimension when the part is in an unfolded state.
- Folded the part and realized that the measurement isn't applied as I expected as the distance I have set is used as shear chord line instead of arc length.

Is this expected behavior?

File is attached for reference.

Best regards

David

David,

This is how most all parametric CAD software works in regards to sheet metal. One thing that will clarify this is that the fold/unfold features calculate the bend allowance for each feature. So if you unbend, it calculates the material to remove to show an accurate flat pattern, and the fold feature calculates the material to add when it is stretched. It is not just a simple visualization of the part with no calculations. So this is really not a limitation of the software, just a misunderstanding of how these two features work.

You are correct that you will need to use a formula to calculate the correct length in the flat to determine a precise value for the arc length.

Please see this page of the help for the formula and explanation when using a K-Factor for the bend allowance.

2019 SOLIDWORKS Help - K-Factor

Regards,

Jeff Parker