- Cut out a rectangle of material that you want to fold, say 100mm x 50mm. Measure accurately, and record, length and thickness.
- Mark a bendline across the centre of the rectangle and form a 90 degree fold with a press-brake or whatever you are using to do your folding.
- Measure, with a vernier caliper, the length of each side and record these (I’ve called them “Leg 1 Length” and “Leg 2 Length”
- Measure and record, using a radius gauge, the Inside bend radius.
- Plug these numbers into the calculator I’ve created here, and voilà, you have your k-Factor to put into your sheetmetal style in inventor.
To check your result, create a sheetmetal style in inventor that has the measured bend radius, k-Factor (from the calculator), and measured thickness, and create a sheetmetal part using this style. Sketch a rectangle, create a face from it, put another sketch line across it in the center, create a 90 degree bend and using the measure command, compare it with your real sample. They should be pretty close. If not, maybe your bend radius is not quite right as it’s a very difficult thing to measure accurately. You can fine tune the k-Factor if necessary.
Note that you will need to repeat this process any time you change material, thickness, tooling etc.