Help with a toroidal bend

[SchiavoA]

Hello everyone,
I'm recently using Creo to model stents, basically
cylindrical scuffolds:

To obtain a stent I basically draw the pattern on a sheet
and then apply a toroidal bend to get the cylindrical
shape. But often an error occurs and I can't figure out
the causes of that.

I sketch a small part of the stent, then I apply a
pattern to it. After that I produce a section with the
command "sweep - protrusion" and then I patternize that
too using the sketch as reference.

After that I apply a 360

 

[design-engine]

cool... teach us!Can you narrow down the problem area (you may already have) by creating a more simplistic model and preforming the toroidal bend to to. Thats how I figure out why things don't work.... narrow it down like your working on a motorcycle or car.
Edited by: design-engine

 

[SchiavoA]

Well of course I started with simple models and gradually
came up with more sophisticated ones, for example this
one gave me this issue with a round section, but if I
change it to a square one it will be automatically
solved.

The only thing I figured out is that this error happens
when the ends of the sheet are not parallel to the RIGHT
plane, I never encountered this in models that had lines
parallel to the main planes, even with very difficult
ones. Sadly not all the stents are like this and if you
have to mesh the model (for FEA) the operation would fail
with that stupid overlap.

 

[solidworm]

if there's an overlap, you can fix that area locally using surfacing features. i can't suggest anything else, because there's no part to work on.

 

[SchiavoA]

Thanks for the hint, I'm new to Creo by the way, so I will
explore some of the surfacing features to find a way, at
least is something new to work on!

 

[solidworm]

if you dont like to upload your design, just cut your part and include only the area of overlap, save as step and upload it here.then i'll have a look and see what i can do.

 

[cpoirier]

Use 3 points on one of the ends to make a plane, sketch on the plane and use extrude to chop off a small bit. Then use the edges and surface the ends together to solidify. Might get you to a shape you can mesh? may not pattern well.

Always sounds simple, if your making this type of geometry I am thinking this has been tried.

Also I don't see the toroid? (curvature on 2 axis) Why not just a spinal bend.

How about a change to part accuracy?


Chris

 

[SchiavoA]

Thanks for all the hints. I solved the problem actually
simply copy pasting the other end (that closed correctly)
over the one that showed the problem and it worked.
Anyway a few of your hints made me understand this
program quite more, since I'm learning on my own and I
just started few months ago I kinda have no idea of all
the features of this editor.
I will definitely try to make a stent using a spinal bend
instead of the toroidal, it should be better now that I
learned how to use it. I chose the toroidal just because
it sounded more like what I wanted and so far it worked
properly.

Thanks everyone, next time I have problems I will
directly upload my part so it would be easier to check
the problem.