Yet another thread/sweep question

tom_auger

Hi team! I've been successful in the past creating custom threads using a helix, a profile and the Sweep tool. This time however, the sweep renders correctly but shows as an error / invalid geometry. What should I check to make it generate properly?



Here's a link to the doc if it helps: https://cad.onshape.com/documents/a5f19813ce860ebb82e3c708/w/c1be84698e0b059e94123117/e/c33c0951bc3805731dfcd90c

(I'm going to still be working on it and presenting it in a tutorial in 30 mins so it might change)

john_mcclary

Rotate your helix 90 deg.

You should start your profile in the same plane as your helix start point.

john_mcclary

Rotate your helix 90 deg.

You should start your profile in the same plane as your helix start point.

tom_auger

Ah @john_mcclary right you are m8! Thank you so much. I'll try to remember this tip for the next time I encounter a sweep error (which I'm sure will be the next time I attempt a similar operation!)

tom_auger

@john_mcclary Thanks again. When I implemented your suggestion 90 degree on the helix or -90 in my case, you can see how the resulting 3D shape is raised up above the actual position of the helix, which doesn't make a lot of sense to me.

Do you know what's going on? And what the mitigating technique might be? Obviously, I don't want the threads to extend beyond the "shaft"...

john_mcclary

You're welcome.

Yes, I'm sure you may encounter more issues with sweep and helix.. The accuracy is a little low and can cause issues now and then.

Let me know if that happens to you. I've learned a few tricks from Onshape support with replace face to repair bad faces.

john_mcclary

That (I immagine) is because your helix is above your profile. It is filling in the entire helix in both directions.
Try modifying your helix start position or just make the sweep "new" and split the thread where you want it to stop. then boolean add the thread you want to merge with the shaft

tom_auger

Man alive it's been 5 months and I had to come back here for some refreshers on almost exactly the same use-cases! That helix / profile / sweep workflow sure is finnicky!