How can I design a thread in a nut? I always get problems with overlapping geometry.

[TS_10556454]

Using the spiral tool and the threat geometry from the standard. In addition to that start and end of the thread are always not realistic.

[StephenW]

I have accurately modeled acme threads specifically for 3d printing. Accurately may not be the correct word, I modeled male and female threads that worked for my purpose of demonstrating the parts threads. 

I've modeled other threads in the past for specific purposes (usually for visual presentation) but in general, I expressly avoid modeling threads and simply add my thread requirements as text on my engineering drawings along with applicable manufacturing specifications for that thread form.

[tbraxton]

Assuming you actually need to model the threads. Creo is fully capable of creating geometry for functional threads compliant with many specifications. Use a reference such as the Machinery’s Handbook to get the thread specifications and create the geometry in your model. Helical sweep functionality is the main tool used to create threads. One approach to get the proximal and distal end geometry of an internal thread is to use a boolean subtract operation of a solid (of the thread profile and pitch) that extends beyond the thread depth. This mimics an actual tapping operation for through holes as an example.

I have even had to model double lead thread geometry (Luer-Lok) that is injection molded.

[TS_10556454]

Hi, Thanks for the answer. I want to model the thread because I want to print it. I used the helical sweep and subtract the solid from the nut. But creo has obvious problems creating the solid because the helix is overlapping. I could only create surfaces. It works if I try to avoid overlapping geometry but then it remains a thin rim (2nd pic).

I also plan to model a luer lock shortly. Therefore I am happy about any advise.

Kind Regards, Thomas

[MartinHanak]

Hi,

if you pack your part into zip file and upload this zip file, then user community can open your model and give you some advice.

[TS_10556454]

Here's the zip file. The geometry still shows the thin rim.

[MartinHanak]

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@TS_10556454 wrote:

Here's the zip file. The geometry still shows the thin rim.

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Hi,

thread geometry exactly corresponds with your definition of sweep. You set pitch value to 0.5 and section height is 0,493057. I think you have to redefine section somehow.

[MartinHanak]

... also you can refine model accuracy in case of regeneration problems.

[TS_10556454 · Accepted solution]

Hi Martin, I redifined the section. There was an error in my first definition. Thanks a lot for the support. Regards, Thomas