Control of thread start

[fighterpilot]

Using the Insert/Design Feature/Threads, is it possible to control the starting point of where the thread cuts into a part?

I wasn't successful using the Extend Thru Start option since the start of my thread didn't cut thru the end of the part. I ended up creating a datum plane offset from the part equal to the thread pitch and using that as the start plane since one revolution should have put me right back to edge of the part. However, it seems like the start is a few degrees off where I expected.

Using NX6.0.5.3

Thanks...

--
Fighter Pilot
Manufacturing Engineer

 

[JohnRBaker]

Can you provide some kind image or picture showing what it is that you're attempting to do? Better would be a simple example part file showing the geometry that you're working with and what your desired goals are.

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

http://www.siemens.com/plm

UG/NX Museum:

http://www.plmworld.org/p/cm/ld/fid=209

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

 

[fighterpilot]

John,

Image below.

Part OD: 4.50"
Part width: .50"
Internal thd: 3.5-12 UN


There are other features to add but they are really dependent upon the location of the thread start. I'd like it to start at the 6 o'clock position but at this point in the part construction it doesn't really matter. I can put a point at what appears to be the thread start but it never ends up where I expect it.



--
Fighter Pilot
Manufacturing Engineer

 

[fighterpilot]

Suppose it would help of the image got linked.

--
Fighter Pilot
Manufacturing Engineer

 

[JohnRBaker]

OK, so you're talking about detailed threads and you want them to cleanly 'run-out' at both ends, correct?

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

http://www.siemens.com/plm

UG/NX Museum:

http://www.plmworld.org/p/cm/ld/fid=209

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

 

[fighterpilot]

Yes, detailed threads. I'm going to make a plastic rapid prototype model eventually and these threads are large enough to get good detail in the prototype.

I think I can get the 'run-out' at each end I've been using a datum plane spaced off one pitch length from my actual part as the starting surface of my thread. Then, I make the thread length the part width plus two pitch lengths.

What I show is not the best example because there are no other orienting features. I just want to know how to control the point (the angle) at which the thread enters the parts. I think I know how UG does it but what ends up in my part is not what I expect.

--
Fighter Pilot
Manufacturing Engineer

 

[Walterke]

I've been using a datum plane spaced off one pitch length from my actual part as the starting surface of my thread

Wild guess here: try moving your starting surface a quarter pitch length and see if the thread starts 90° away from where it used to start.

NX 7.5.5.4 with Teamcenter 8 on win7 64
Intel Xeon @3.2GHz
8GB RAM
Nvidia Quadro 2000

 

[pencilgeek]

I know this may be old school, but I would model the threads manually. Create a profile in sketcher and sweep it along a helix curve. That way you KNOW where the tread start is. the helix curve will control how many turns, centerline, etc. The location of the sketch in relation to the end of the part will be controlled by the sketch.

 

[fighterpilot]

pencilgeek,

I had thought it might come down to that hoping i would get full control of it. I'll have to look back at my modeling books to figure out how to create that feature.

thanks...

--
Fighter Pilot
Manufacturing Engineer