topic Re: Coil with profile up to axis - thread modeling in Inventor Forum

Coil with profile up to axis - thread modeling

dthompsonPHSGY — Thu, 30 Mar 2023 00:13:28 GMT

I'm using the coil command to model threads for 3d printing. I draw my thread profile and wrap it with the pitch and length using coil. This works just fine, but the problem I have is when I draw my thread profile up to or over the axis of rotation, I get an error. If I leave my thread profile sketch short of the axis of rotation then it works fine, but I'm left with this annoying floating cylinder in the middle of my thread which I need another sketch and extrusion to get rid of.

So I'm trying to find a way to get the coil command to completely core out the middle of the thread so I can do it with a single operation. I realize I'm complaining about something that takes 2 extra clicks to get rid of with a simple extrusion but it bugs me and feels like it should be able to be done in a single operation

I've used coolorange, its OK, but I prefer to do "manually" without any add ins as I use multiple workstations and its tedious to load add ins on every one. I also have more control over the thread this way for adjusting clearances, working with unconventional thread profiles, and using tapers for some parts where I want an increasing amount of interference as a screw is threaded in.

Sketch in the first picture works, but leaves the cylinder in the middle shown in the second picture. Sketch in the third picture I would think would clear out the cylinder but it throws the shown error. Draggin the profile past the axis of rotation also gives an error "invalid geometry: axis intersects profile"

Re: Coil with profile up to axis - thread modeling

kacper.suchomski — Thu, 30 Mar 2023 00:17:22 GMT

If the sketch is touching the axis, the inner surface cannot be generated.

Re: Coil with profile up to axis - thread modeling

johnsonshiue — Thu, 30 Mar 2023 01:58:53 GMT

Hi! There are other ways to model it. I would use Solid Sweep to get the precise geometry. In your case, the simplest thing to do is to use Delete Face -> Lump select to remove the rod in the middle.

Many thanks!

Re: Coil with profile up to axis - thread modeling

Wayne.peacockSF88J — Thu, 30 Mar 2023 06:03:03 GMT

Have you looked at free ThreadModeler app from the AutoDesk App Store?

Just click on the shopping trolley in the top right corner of the screen and do a search.

Re: Coil with profile up to axis - thread modeling

JDMather — Thu, 30 Mar 2023 12:24:38 GMT

https://www.youtube.com/watch?v=57t7E7lOdvM

Re: Coil with profile up to axis - thread modeling

WillL84 — Thu, 30 Mar 2023 18:12:35 GMT

That only works on 2019 and before and is incompatible with 2020 and later. You have to upload your model to their website which will do it. Or just open it in Fusion 360 since that has an option for modeled threads.

Re: Coil with profile up to axis - thread modeling

dthompsonPHSGY — Thu, 30 Mar 2023 19:59:34 GMT

Thanks All

The delete face tool is quicker, thanks for that suggestion. I haven't used solid sweep much but will play with it

Yes I've used the coolorange thread modeler, but I use different workstations which don't always allow/have add ins, and I sometimes have specialized thread profiles which need to be drawn manually (nonstandard lead screw types)

I had seen the CAD whisperer video, he is basically doing the opposite of what I am doing, he cores out the middle first (and includes the chamfers) and then adds the thread. Still 2 separate operations, but I guess a bit cleaner as each operation has a purpose other than just cleaning up leftover junk...and yes making a library of punch tools like he does could streamline even further

I still think the software should be smart enough to allow a sketch which touches the axis of rotation, but it seems not. Thanks again