Sheet Metal Bend Line Position?

[changedsoul]

I am confused on how Fusion does sheet metal bending. When creating a bend, the option to select Start, Middle, and End change where the bending takes place, but it seems "End" is not like I would expect it to be.

See linked file.

For example, this part needs to have this tab bent where the inside edge is a certain distance from the center thru hole. I have created a sketch that places a line where the part needs bent with the location set with a dimension.

In the file, the bend is set to the "Start" which visually looks like its the start of the bend, but this is not where the bend is supposed to be at. It should be bent so that the sketch line matches up with the inside bent face. So I tried selecting "end" for the bend line position, but then it makes the bend to far in towards the center.

And even then, the sketch line shows it outside the bounds of the part completely.

Where are these bend locations actually being taken from?

Are they taken from the start and end of the bend radius when laid flat? If so, this doesn't make sense to me why it would be this way.

What would be a good way to know where these bends will lie so I can create a bend and have it be located where it actually needs to be?

I do not think I can use the flange method, unfolding, then cutting the profile out, then refolding.

My goal is the be able to draw flat what I need and then bend it, relying on the k factor of the material to adjust the bend lengths so I know if the flat patterns are the correct size.

Thanks In advance.

https://a360.co/3FU5XJi

[Warmingup1953]

There are only the three options in the bend dialogue. In my example (A workaround) , I simply extract the delta measurement from the bendline to face and then create a new construction line to select. 

[changedsoul]

I like the way you created that offset line. Much more elegant than what I was doing.

Is this a bug in where the bend options are being created from? Seems Start Middle End are pretty straight forward, but the results dont seem to match the meanings.

[jhackney1972 · Accepted solution]

If you are going to use Bending instead of Flanges, calculation of sketch location will be a challenge depending on your material, bending process and K-Factor.  I would recommend a free application called BendWorks to assist you.  If you would like to see how this application makes your job easier, take a look at this Blog Article and Video.

[changedsoul]

I originally thought the flange option would not work for me, but after watching the video, I re-thought my approach and it seems it works far better than what I was previously doing.  I can also now adjust the k-factor and it maintains the proper locations.

Thanks for the input, this helped a great deal.