AnsweredAssumed Answered

form block for sheetmetal rib

Question asked by Tim Mix on Jun 3, 2008
Latest reply on Jun 18, 2008 by Anna Wood
Hello All,
I have been trying to create a form block for a sheetmetal project that our company is undertaking. we are creating all the parts nessecary to put together a tailrotor for a helicopter. The ribs have been a bear to dial in but I am really close. the width of the widest point in the rib has a tolerance of +/- .0025" Now when I put the rib in the middle of the tolerance and create a formblock with a 3 degree draft for springback the block ends up being .003" small below the -.0025" limit. besides making the formblock larger (which I would have to make the rib larger because it (the formblock) is refenced to the rib) is there something I am missing in order to have the finished form part come out in the +/- .0025" tolerance? and to clarify abit...if you take the finished block and add .024" (the total material thickness of both legs) it comes out less than what it appears to be in the rib model. Make sense?

1. I drew the rib to spec
2. created new assy. with rib as base comp.
3. inserted new component (formblock)
4. used the inside face of rib as sketch plane and inside edge of rib legs as profile for FB. Extruded 1.00"
5. did a sweep cut 3 degrees for the draft (.012" 2024-O)
6. installed features such as .03" radii for bend radius all around.

is there something else I need to consider when making the form block or should I just deal with making the ribs larger in order to get the block out to the size that I need.
Any imput is GREATLY aprreciated!
Thank you in advance,
p.s. the screen shot is of the nominal size for the rib and the points of where it needs to be measured to. this rib acutally has a limit of 1.716-1.711.