NX 7.5 - PIPE BEND CENTERLINE 4

[CAD2015]

Hi,

I got a NX file of a pipe, without the curves from which it had been created.
How could I recreate them?
I was able to create the lines for this pipe using: INSERT → CURVE FROM BODIES → EXTRACT VIRTUAL CURVE
How about the arcs, how could I get them as easy as I got the lines?
Is there a specified tool/operation for that?
Thanks


MZ7DYJ

 

[cowski]

I don't know of a specialized tool to get it automatically in NX 7.5, but there are ways to get at it.

If the faces of the tube are B-surfaces, Frank has posted a journal in thread561-331345 to extract the centerline.

However, it appears that your case has only analytical faces (cylinders and tori). To get the centerline of the curved sections you can:
[ul]
[li]Create a datum plane by picking 3 points (the end points of the curved section and the end point of an adjacent straight section). This will give you the plane that contains the center line arc.[/li]
[li]Intersect the plane with the face of the curved section. This gives the ID and OD of the bend.[/li]
[li]Offset either the ID or OD curve by the tube radius to get the centerline of the tube[/li]
[/ul]

Alternately, you can use extract virtual curve to get the axis of rotation for the curved face, intersect the resulting line with the datum plane to get the center point of the centerline arc, and finally draw an arc from the centerpoint to the tube center to get the centerline arc.

Attached is a file showing both approaches.

http://files.engineering.com/getfil...93d-53be1b4b828a&file=CENTERLINE_FINDER_a.prt

www.nxjournaling.com

 

[CAD2015]

Thanks a lot!

MZ7DYJ

 

[JohnRBaker]

There's an easier way than what cowski suggested (see attached model for my results).

First draw lines using Arc Centers as the 'Snap Points', going from Arc-to-Arc for each one of the straight sections. Now go to...

Information -> Objects...

...and select the curved faces only. If you select all of them in a single operation you'll get a list showing the numerical data for each face and since these are all Toroidal faces, one of the bits of info given will be it's 'Major Radius', which is the radius of the 'centerline' arc. Once you know the centerline radius for each curved section simply create fillets between the lines using the appropriate radius for each curved section.

No need to create any Datum Planes.

No intersection curves need to created.

And finally, no offset curves.

In fact, the only curves created using my approach are the actual curves that you're looking for.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[kapmnit123]

Hi,
Although the solution has already been given by experts ...i would like to share one quick (insane though it may be) workaround (but may come quite handy if the labyrinth of tube segments is quite complex....the only drawback of this approach is that it will give you the centerline curve within an accuracy of .001mm (sorry this was the largest i tried but you can try even more stringent values yourself) but it really works fast (if acceptable to you off-course ) One more thing you will be required to measure the radius of the tube (OD) before using step 2 ....I am attaching a ppt herewith depicting the steps followed.
Best Regards
Kapil Sharma

 

[kukelyk]

Kapil Sharma, its a great and smart solution, I will use it.

----
kukelyk

 

[kapmnit123]

Thanks kukelyk,
Please do as much trial cases as possible using this method if possible.Do share your experiences.It will help me understand if it works ok as a generalized tool or not.
Best Regards
Kapil Sharma

 

[CAD2015]

Thanks all for your reply.
I am going to choose John Baker's suggestion.
It seems to be fast, clean and easier to catch .


MZ7DYJ

 

[mmauldin]

I took a little different approach. First I created section curves of the bends using bend face and the specify plane option and selecting the centerlines of the adjacent straight section. Then I offset the section curves by the tube radius and connected them with line segments. Pretty straight forward and associative.

See attached example.

 

[mmauldin]

The second sentence should read " using the bend face".

 

[CAD2015]

Thanks, mmauldin!
A Star for you, too!

MZ7DYJ

 

[CAD2015]

NX 7.5 - Major and minor radius for a bended cylindrical face:

These is a question for Mr. John Baker, but feel free to share....
Please, make the Sketch of the attached NX file active:
“Major and Minor Radius”..........What do they specifically define?
Usually, Major and Minor radius are related to an ellipse, not to cylindrical bend face...........!


MZ7DYJ

 

[cowski]

The "bent cylindrical face" is technically known as a torus (or at least a segment of a torus). It is made by sweeping a circle along an arc: the circle radius is the minor radius, the guide arc is the major radius.

http://en.wikipedia.org/wiki/Torus

www.nxjournaling.com

 

[CAD2015]

Great, thanks Cowski!

MZ7DYJ