Bridge Curves Jumping on Helix Curve NX7.5 1

[SDETERS]

I have this extension spring I have modeled. When I go to expression and change the the length of the spring the darn Bridge curves jump to the other side of the helix. Is there a way to keep this from happening ARRGGHH? We are using NX 7.5. This spring has a little bit of a taper to the coils so it is not just and easy extension spring. If you have any other robust way of modeling I am all ears. Can not wait until we get NX8.5 for the helix funtion update. What is the best way of tying the round ends into the Coil?

 

[JohnRBaker]

OK, the attached version of your part should behave better. While I can't definitely state exactly why what I did solved the problem, the changes that I did make were done to reduce the number of 'objects' which were needed to be referenced by other features, in this case the number of faces of the 'Revolve' which the 'Projected Curve' needed to reference. Making the resulting 'Revolve' a single face reduced the number of segments needed to define the 'Projected Curve', thus reducing the likelihood that it's Object ID's might change during an update, which is why the Bridge Curves got their end-points mixed-up.

Note that since your 'Law Curve' appeared to be a simple 'Helix' I replaced it with a Helix feature. I also removed the Edge Blend since it was no longer needed (these features are still there but have been suppressed so that you can see exactly what I did).

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
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[SDETERS]

Thanks for that Model that really helps out. I was going nuts. I will put your suggestions into our model.

Thanks again

Shane