sheetmetal issue with 2 parts

[vsawye2]

i have a coworker using v5r18 and sheetmetal design to create two parts that are bonded together. when the two parts are shown in their finished state all the holes and tabs line up perfect. but, when he unfolds them in the flat state the features don't line up. if alters the parts so that in the flat the features line up, then in the finished state they wont. does anyone know why this is and if there is a way to correct for this. i'm assuming its because catia is unfolding/folding about the center plane of the material thickness, but not sure on this. thanks

 

[jackk]

are both parts the same size? same wall thickness? same material?
same sheetmetal parameters (such as bend radii)?

If both parts are the same - the results should be same.

 

[vsawye2]

jackk, both parts have the same shapes but are different wall thicknesses. they are joined together in the flat state and then formed into their final shape. i dont know enough about the sheetmetal tool to understand why the parts dont match in one state or the other.

 

[jackk]

With different wall thickness, the thicker part will stretch more than the thinner part (assumming same or similar material), so the different flat patterns is correct.

I would add all the holes and tabs in the final, folded state, with everything in alignment as you want them.

I'm not sure about the actual fabrication of the part, though. Can the two parts be bonded after they are formed? Or maybe just bond the fixed walls before the bending operation, and bond the other walls after?

What are you making?

 

[vsawye2]

actually the two parts aren't even metal. one is rubber the other is a teflon coating for slip. the rubber part is molded in the flat, it then gets coated with teflon, and then wrapped around a tube. this isn't my project here (just trying to help a coworker) but i was thinking we might have to have two assemblies. both with the same rubber part (its the main component) and then each assembly would hold either the teflon coating in the flat state or the final assembled state. one assembly for manufacturing and the other for installed state.