Sheetmetal "Unfolding is failing" Problem

[mermaldad]

I am new to the sheetmetal workbench, so I apologize in advance if I have done something stupid, but I have been working on a sheet metal design of moderate complexity and I just can't seem to get it to unfold. I am designing a bracket that will be riveted together. I start with the PartDesign workbench, making a rectangle sketcch and extruding it by my material thickness. Everything else is bends. Because it will be riveted, i am overlapping surfaces, but I have been careful to include gaps between all surfaces, per https://forum.freecadweb.org/viewtopic.php?t=34269.

When I try to unfold the design, it gives me the "Unfold is failing. Please select a different face to unfold your object." message. Using a different face makes no difference. Can someone tell me what I am doing wrong?

Overview of part:

Screenshot from 2019-11-28 13-19-47.png (231.85 KiB) Viewed 2256 times

Close-up of rear corner, showing gaps:

Screenshot from 2019-11-28 13-18-27.png (219.18 KiB) Viewed 2256 times

OS: Ubuntu 18.04.3 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4.
Build type: Release
Python version: 2.7.15+
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

[chrisb]

The gap in Bend002 is too small; it is reaching into the next bend:

Snip macro screenshot-2b9ffc.png (5.14 KiB) Viewed 2237 times

this leaves a thin stripe of material, which makes it impossible to unfold. Increase the gaps to 0.8 and the unfold works. The same issue occursin later steps again. If you search yourself for issues delete subsequent steps from the end until you find the first bend where unfolding fails.

[mermaldad]

Excellent, thanks!

[chrisb]

You're welcome.

Shaise, can this be avoided?

ping

[jaisejames]

Manually You have to check the condition, relief width ['reliefw'] should be equal or less than gap[say gap1 or gap2]. In attached file, reliefw = 8mm, so it is cutting at 8mm even gap 0.61. Pls adjust to reliefw = 0.61 to get it correctly.

[papyblaise]

Hi Marmelad , and don't pedal in the jam
When you use Gap1 or Gap2 f,FC generat automatiquely ReliefD and ReliefW , you have to modify it (if necessary)
and if you need unfold the job , becare never scratch the radius of bend

[t hauthaler]

Hello I have a problem with unfolding my model with metal sheet I m new of working with free cad could anybody give me advice how to solve the problem please.
thank s a lot

[forte]

Take into account, please!!!
There will be an error when deploying this detail.
On the details of the bends in opposite directions.
The zero plane is one for the whole part.
Thus an error occurs.
K-faktor is always from the first closer bend !!!

[t hauthaler]

Take into account, please!!!
There will be an error when deploying this detail.
On the details of the bends in opposite directions.
The zero plane is one for the whole part.
Thus an error occurs.
K-faktor is always from the first closer bend !!!

So the problem is my zero plane ?

[forte]

Please send a file with detail.