Reverse Engineering a Bend Allowance in SOLIDWORKS Sheet Metal


When beginning to use sheet metal, you'll often have the dimensions of a folded part and dimensions of a flat (found through years and years of trial and error). However, when you go and build your part in SOLIDWORKS, your folded part is correct, but your flat is wrong. This is due to an incorrect bend allowance. So to find it, you need to reverse engineer a part. For this example I'll be using the part below.

So we built our part using the following parameters:
Thickness: .100in
Bend Radius: .050in
K-Factor = ??? (start with .5)

We also know our flat boundary should be 27.270" x 14.770"

Now we're going to flatten out our part and take measurements of the bounding box.

27.214 is shorter than the 27.270 we're aiming for, so I'm going to "Edit Feature" on the Sheet Metals properties and increase the K-factor from .5 to .6.

SolidWorks SolidWorks

Still too small, keep increasing. Once you get close, start increasing and decreasing the K-Factor more finely.

SolidWorks SolidWorks

Once you have it for one dimension, it's time to measure all of them.

So we found our nice K factor of .6775


Christian Maldonado, CSWE
Computer Aided Technology, Inc.