Creating a round wave guide with a rectangular base

[Anonymous]

I am trying to create a 152mm dia. x 2mm thick round conical wave guide for a speaker that instead of coming to a point at the bottom, turns into a 30mm x 60mm base. So instead of a round hole through the middle, it's a rectangle.

I can't get the 152mm circle to parabolically connect to the rectangular base.  It's just ends up being a saucer with a 30 mm high rectangular block attached to the bottom.

If I do a revolve, it just revolves a circle.  I obviously can't do a revolve that would go into a rectangular shape.

Any ideas?

[blair]

Loft

[JDMather]

Attach your file here if you can't figure it out.

[Anonymous]

Loft got me closer but I need it to curve parabolically from the top to the bottom, so I'm assuming I will need rails that I can adjust but I'm not having any luck with creating the rails to get them to work.

[JDMather]

You can adjust the weight on the tangency curvature as needed.

 

Are you sure you don't want to simply cut a rectangle out of a Revolve?

[Anonymous]

Great.  We're on the right track now.  Any idea how to get this angle to be 60 deg or to make a perfect parabolic flare top to bottom?

[Anonymous]

I could cut a rectangle out of a revolve as long as it gives me the same result - a circle that slopes down the middle to meet up with it.  I was trying a revolve in the beginning but not getting the shape I was looking for.

[CCarreiras · Accepted solution]

Hi!

You can draw some sketches with the path you need between the two profiles, and add those sketches (guide rails) to the loft as guide rails.

[Anonymous]

I did try that and it kept saying unable to do loft when I would add the sketches. Something about them interfering with each other.

[CCarreiras]

Place here your attempt and we will see that...

[Anonymous]

I'm not sure why I can't get the rails to attach to the top and bottom pieces.

[CCarreiras · Accepted solution]

Hi!

You have to project the geometry from sketch 1 and sketch 2 to the sketch's rails. This way you can attach the rails in the proper place.

Check the file.

[Anonymous]

Thanks!  Once I remembered how to and got a little help with the project geometry, that worked.  Now I just have to figure out how to make a parabola between the top and bottom to get the right angle I need.  Guess I'm gonna have to research some math!