[longgo]

Before I set some questions, here is the file I will talk about: https://longgo.eu/cnc/cone-loft.sldprt
It is made on SW2015. Also, need to point that is just for my learning curve. Nothing to be manufactured as serial parts. Just for education.

Material for the part is normal 2mm steel. Just for start and test I use K-factor of 0.5
The bending will be made in real test with air bend, and tool is R1 mm. All that are things we have in the company.

What is my issue? The sum of all bend angles per side are not equal to 90°..
My first try was with simple 180° arc. By that I mean sheet arc with radius 55mm divided on 10 equal segments. Roughly that should be about 18° per bend.
When Solidworks produce unfold, it come up with 15,1° and when tested on real 2mm steel it was waayy off the target.

Here, in that file as you see all summed angles for each side are 71.68° and if I subtract it from 90° it leave me with 18.32° remain.
If that is tested with bending machine with 2mm steel plate will produce wrong bend.
From other hand, If I divide that 18.32 on 8 bends that leave me with 2.29° per bend. So, if test once again but add that 2° per each bend, it actually come quite close to the real 90°...

Yes, I try with different K-factors from 0,25 up to 0,48. Also try with calculated Bend Allowance same results.. Also when found some ready excel table with data prepared in it, I select it in SW and the unfold end up with same angles..
Obviously there is something very wrong in my way of doing the things, but what it is?
There are tons of videos how you make loft, how you just unfold the part but didn`t manage yet to find right help tutorial to find my mistake.

If someone have the good will to pass me some tips, or link to good guide will be great!

Thank you