How to combine sheet metal bodies and still be able to use flat pattern correctly.

[jefferywilliams308]

G'day Mate,

I am having dramas combining two sheet metal bodies that a want to be on part and being able to maintain the ability to use the flat pattern function correctly. Both parts flat pattern fine before combining, but only the bottom section will flat pattern after combining. I have tried watching a few videos on the subject but I still can't make it work, not sure where I am going wrong. Any help is appreciated. Cheers

[davebYYPCU]

Not a sheetmetal guy, but these 2 sliver faces are showing some sort of misalignment.  The joining fillets - Fusion can see them, and I don't think they should be there.

Might help...

[HughesTooling · Accepted solution]

You have some small height differences between the 2 parts and when combined leaving small surfaces that overlap and stop the unfold.

I can see how these errors are creeping in because the 2 parts have different steps between these 2 faces,

and you're trying to use the last flange to make the 2 parts the same total height.

I don't have time to rebuild your model but try using a sketch like this to build the bend and maintain the correct overall height. You just select the 3 sides for the flange then select the guide rail in the sketch. You can change the step between the faces or angle of the bend and the total height will always be 160mm.

See attached file as an example.

[HughesTooling]

One more tip. You might be better off joining the 2 parts in the middle of the face between the 2 parts rather than in the corner. Or at least drop this flange that is creating 2 overlapping bends, just have the bend on one part.

[HughesTooling · Accepted solution]

Attached is a bodge that allows your design to unfold, I don't like it because it still has the errors for the overall height. 

The 3 things I had to do where, first fully constrain your sketches. You should always try and do this. Then I measured the step between the 2 bodies and adjusted the last flange on one part to get rid of the mismatch.

I also moved the join away from the corner.

After combine.

And flat pattern.

[jefferywilliams308]

Thanks Mate, I really appreciate your assistance. I had previously solved some misalignment errors, so I assumed something like that was cause of my issues but I couldn't work out where. I am quite new at this, both fusion360 and CAD drawing in general, and am yet to master constraints. But thanks to your assistance and direction I will be taking the time to improve my skills using constraints. Cheers