Sheetmetal Folding

I am designing a screen box, and have come across a problem.I want to
fold up the 3 edges of a triangle, and be able to weld the joints. I
start by drawing the triangle, then use the base flange command in
sheetmetal to give a thickness of 8mm. I then try using the edge flange
command to bring out the sides. It will do the fist fold, but none of
the rest. It throws up an error saying the fold will be too complex.

Thanks in advance for any help.

I can email the sheet metal part directly if needed.

The triangle angles are 150, 60, and 60 degrees.

 

In our universe the included angles of a triangle must add up to 180
degrees. But besides that you might try the mitered flange..

Jeff