Dimensioning or constraining a coil center point?

[mjdionne]

I'm using a coil to define parametric threads on a body that can be varied in OD by a user parameter. In general that part is working fine.

However, when the center of the cylinder the threads are placed on is shifted (as a part of the user controlled design variables), it all breaks because there appears to be no way to dimension or otherwise constrain the center point of the coil. This is frustrating because it appears that Fusion effectively creates an "internal" sketch to build the coil, but doesn't let the user interact with that sketch.

I'm thinking that this is a limitation of the software, but I wanted to query the hivemind to see if there is something I'm missing.

I also thought to just create a 3D sketch of the path to sweep the thread profile, but it appears the AutoDesk recommended way to achieve a 3D coil sketch starts with a coil which puts me back where I started. Maybe I need to figure out how to create that 3D coil sketch myself parametrically.

[jhackney1972]

I would suggest making your Coil a component, then add a point as a center point handle to then, using a Joint, place it anywhere you desire.  Model is attached.

[jhackney1972]

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[mjdionne]

Thanks for the input here and the video was also amazing.  I'm still working through perhaps a parametric timeline issue where the joint isn't moving when the user variable is adjusted that moves the sketch (or component I tried both) that the joint was based on.  Are there some rules of thumb to follow when setting up joints so they will move dynamically as the joint point is moved?

[TheCADWhisperer]

@mjdionne 

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[mjdionne]

The file is attached. I'm trying to find a way to reference the coil feature, which defines the parametric threads, such that it's center point is tied to either:

1. The center point of the outlet tube feature

2. A sketch

Both of which are able to be moved along the Z-axis via the User Parameter OutletTube_Depth.

The threads are working well parametrically for the OD of the outlet tube (adjusted by the Grommet_ID user parameter), but when the OutletTube_Depth is shifted, the coil feature (or component as I tried that) doesn't seem to be able to shift with the user parameter.

Thanks.

[jhackney1972 · Accepted solution]

It is not the prettiest timeline but I simply suppressed the extrusions for your coil threads and created a new Thread Coil Component as I outlined before.  It is attached to the duct using a Rigid Joint and will move with the duct when the parameter you mentioned is changed.  Model is attached.

[mjdionne]

Thanks John.  I'll take a look at it later today when I have a moment.

I'm not really a pro at this and I'm still working on maintaining a clean timeline.  I'm realizing that I should have created my components, duct and shroud, much earlier in my process to have the sketches for each associated with the component.

This is my first part where I'm aiming to have the design be highly parametric and controlled by user variables, so big learning curve.

[mjdionne]

I jumped in early.  I see there is a solution there.  Just need work out my order of operations to get the threads squared off and filleted.  Thanks again for the assistance.

[etfrench]

You may have more parametric success with a helix created in the Surface workspace plus a sweep of the thread profile.