Constraining to holes in curved sheet metal parts

[DavidJ]

Does anyone have a way to tackle this problem?

If I have a sheet metal cylinder which I've made holes in whilst flattened, then re-bent it I can't constrain the parts which should connect to those holes (presumably because the hole isn't cylindrical after the re-bend).

If I make the hole in the rolled up cylinder, I should be able to constrain to it , but then I won't be able to un-bend it.

Best I can come up with so far is to insert an axis either by eye or by calculation through the centre of the re-bent hole, then use that for constraining.

Any quicker / easier methods would be appreciated.

 

[BernardK]

David,

As you know, I am not too familiar with the sheet metal module. Can you place reference geometry in the unbent state, such as an axis or a node at the circle center, that will remain when the part is bent?

 

[DavidJ]

Bernard, unfortunately the inserted reference geometry retains its spatial position relative to the workspace when the re-bend operation is performed; it doesn't stick with the sheet metal.

 

[Jimpulse]

Instead of cutting a circular hole, try cutting polygon with a LOT of sides.
Use an even number of sides an place the Poly Sketch control points so that an edge of the polygon is at 0 and 180 degrees.
Once the tube is "refolded" you can add points at the ends of these edges and then use those points to define the 3rd point midway between the two.

Of course, you can arrange and use the polygon's edges anyway that suits you.


Note: The generation and paramterization of the polygon can be machine intensive, so be prepared to wait a bit if you put too many. I like to use 36 sides for this since 36 is evenly divisible by a lot of different numbers and relates well to the angles of a circle

I did manage to cause a hangup on my home machine, but had no such failure on my more powerful work machine.

Hope it helps-jimpulse

 

[DavidJ]

Thanks - I'll give that a try!