Errors creating a flat pattern

[Anonymous]

I have an assembly of sheet metal parts. Some of them, I have unfolded to fix the edges that aren't normal to the face. This part is one that I was NOT able to select to unfold or create a flat pattern from. I would guess that the issue has to do with cutting or joining along the edges to create the normal cut edges. I already learned that using the fillet command to smooth corners in a bend while flat causes problems, but this part doesn't have those applied before errors start.

I'd like to understand both how to fix this and why it happens to avoid creating this problem next time. I have included a screencast of some of the troubleshooting I have been doing to see if anyone understands what is happening. It shows some unexpected results even before the error message occurs.

Link to the file:  https://a360.co/2q2RYtf

Please help!

[carl.j.barker · Accepted solution]

Extrude 4 and 5 are to blame. They leave a small amount behind which is not connected to the main body thus splitting the component into multiple bodies. You'll see if you move to the end of your timeline that you have 1 sheet metal body and 2 solid bodies which can not be unfolded.

I altered your sketch 4 and extrude 5 to fix.

https://a360.co/2EeOQ2p

[TheCADWhisperer]

I think your technique can be significantly improved requiring only 3 or 4 sketches and features.

If you are interested, let me know - but it might be a couple of days until I can get around to this, so bump the thread back to the top if I don't post a vastly improved "solution".

[Anonymous]

I will wholeheartedly agree that my technique could be "significantly improved". This is my first time working with sheet metal in Fusion and I haven't done much at all in Fusion beyond some of the tutorials. This project felt extremely inefficient. Most of the errors, mostly user error, came from modifying another part in the assembly and that breaking how it interacted with other parts. In this case, leaving little bits of solid floating around and not knowing that they would cause trouble and not just keep floating in relation to the the body they came from.

I appreciate it, but don't worry about making this specific part more efficiently. Working back from the finished individual parts, I think I could recreate them fairly easily. I would be interested in learning the best practice to make a sheet metal assembly more efficiently though. If I were doing this over right now, I would make a solid part, cut out where it interferes with the other parts in the main assembly, clean it up to look pretty and make sheet metal parts on the faces and internally where needed. That would have avoided the modifications to multiple parts along the way and the cutting and joining to correct tapered faces after a cut that needed to be normal and wasn't because of the way I made it. The part I shared is the rear side of this a-arm. I cut the flanges straight back from the front face. I added the slots in the top and bottom plates. Then, I added the tabs on the edges of the vertical parts which weren't normal to the face yet. Basically, I stumbled through and made a mess. The end result, thanks to some help on this forum, is going to turn out nice. It's a good thing I weld better than I use Fusion. 

Thanks,

Scott