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Help! Can't sweep an intersect curve?

Forum|Forum|9 years ago
October 1, 2016
20 replies
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Hi!

I'm in a situation where i want to model a torsion spring with an intersect curve for a special reason.

But i can't make CREO complete the sweep feature, only if i choose: Automatic under Horizontal/Vertical control and that ends up in a twisted cross section through the curve which is not want i want to achieve.

Can anybody tell me whats wrong? I have attached the part file with this message.

Best regards

Nicolai

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1_torsion_spring-prt-1.zip

General

Best answer by TomD.inPDX

The logic to letting a sweep like this use the trajectory as normal so that your section is the same as the raw material.

In the case of round wire, you don't see twists, but when you go to square stock wire (typical of magnet wire for high current transformers) you need to manage rotation along the origin. Using an offset curve as a reference lets you manage the rotation.

I suspect that if you were to use a round wire without rotation control, you might send Creo analysis for a loop. This is one area that is not obvious to many nor critical to others. However, I did see "knots" in a helical sweep in the past and that was a s/w bug. Again, not sure if it is really fixed but it was reported fixed. The knot was at every "end" of a 360 degree sweep and they were not continuous.

D

dschenken

1-Visitor

Check out One method to make wound springs. There are others, but I wrote this one.

What I find is that if picking a horizontal/vertical reference causes the sweep to fail it is because at some point along the sweep the direction makes no sense. For example, if a plane is selected as the orientation reference and some part of the spring is perpendicular to the plane.

N

njensen

Author

1-Visitor

What do you mean by "the sweep the direction makes no sense"?

D

dschenken

1-Visitor

Where there is a place where a horizontal reference doesn't determine a horizontal direction.

You skip all of those problems with graph driven curves. If you need control of orientation, then add a second curve that has an increased radius as the reference.

N

njensen

Author

1-Visitor

Thanks for the help guys. I don't remember the specific CREO version I'm using at work, but it's CREO 3.

I'll try to investigate how to sweep with a guided curve and see what happens, I'll return when i have tried.

kdirth

21-Topaz I

Is this something like what you are trying to get. I found that removing the horizontal and vertical constraints was necessary to remove warping.

There is always more to learn.

1_prt0001.zip

T

TomD.inPDX

Answer

17-Peridot

The logic to letting a sweep like this use the trajectory as normal so that your section is the same as the raw material.

In the case of round wire, you don't see twists, but when you go to square stock wire (typical of magnet wire for high current transformers) you need to manage rotation along the origin. Using an offset curve as a reference lets you manage the rotation.

I suspect that if you were to use a round wire without rotation control, you might send Creo analysis for a loop. This is one area that is not obvious to many nor critical to others. However, I did see "knots" in a helical sweep in the past and that was a s/w bug. Again, not sure if it is really fixed but it was reported fixed. The knot was at every "end" of a 360 degree sweep and they were not continuous.

Patriot_1776

22-Sapphire II

Frankly, I never use helical sweeps, for anything. I either use datum curves driven by graphs, or I wrap curves. I feel i have far more control over the outcome.

N

njensen

Author

1-Visitor

I found out how to create the model another way, by leaving the helical sweep as a feature and making the hooks after that.

But now when you guys mention this guided curve option. How do i do that? I can't find out how en CREO and i can't find a guide either.

Thanks for the help so far! 🙂