How do I make a solid spiral on a cone with smooth transitions on top and bottom?

kjell_kaivosoja

Hello!

How do I make a solid spiral on a cone with smooth transitions on top and bottom? 

I have made a solid cone with a helix on the surface and swept a triangle sketch along the helix to make the spiral, and also a solid 6mm cylinder in the middle of the cone, like a shaft. I would like to extend  the solid spiral into the shaft with a smooth transition. And the spiral should also end smoothly at the bottom. I have no idea how to do this... any suggestions?

https://cad.onshape.com/documents/e1fad23b60bb6f8d749bb993/w/a4cd9352eff70880616cb539/e/4e4bb6adaaaec85340a7c595

Sorry about my bad english

Best regards
Kjell

daniel_splawski

Depends exactly what you mean by "smooth transition".  For the bottom transition, if you just extrude the bottom of the object up and choose "intersect" it will chop off all the extra spiral stuff.  As far as continuing the spiral on the shaft, you'll just have to create a second helix on the surface of the shaft and monkey with the settings until the transition looks decent.  

What exactly are you trying to model here?  

mahir

The general procedure for creating a spiral of any shape is to create a swept spiral surface using a simple line as a profile and a helix for the path. That surface can then be split using a second surface that has the desired overall shape - in your case, a cone. The edge of the resultant split surface is a helix laying on a cone. To generate a lead-in/out, just modify the cone surface to have the desired lead-in/out.

This isn't exactly what you're trying to do, but it might be useful.

https://cad.onshape.com/documents/57acdfaae4b005c413ed9b6f/w/3fd585a46d3af1b3ba413c53/e/396546bb7d9f32aab9f2fd41

MichaelPascoe

This is an old discussion, but in case you need to make a solid body spiral again, I made a feature that will help! Spiral

daniel_splawski

Depends exactly what you mean by "smooth transition".  For the bottom transition, if you just extrude the bottom of the object up and choose "intersect" it will chop off all the extra spiral stuff.  As far as continuing the spiral on the shaft, you'll just have to create a second helix on the surface of the shaft and monkey with the settings until the transition looks decent.  

What exactly are you trying to model here?  

mahir

The general procedure for creating a spiral of any shape is to create a swept spiral surface using a simple line as a profile and a helix for the path. That surface can then be split using a second surface that has the desired overall shape - in your case, a cone. The edge of the resultant split surface is a helix laying on a cone. To generate a lead-in/out, just modify the cone surface to have the desired lead-in/out.

This isn't exactly what you're trying to do, but it might be useful.

https://cad.onshape.com/documents/57acdfaae4b005c413ed9b6f/w/3fd585a46d3af1b3ba413c53/e/396546bb7d9f32aab9f2fd41

kjell_kaivosoja

Thanks a lot! I finally made it Using both methods above. It could probably be solved in a better way but the part look almost as I imagined. Is it possible to make the part solid? Now I have surfaces that I thickened.
Here is the part now

https://cad.onshape.com/documents/264200ec474192e326599120/w/b2d5e12920e5c4d03f3c88a9/e/de4908b5648295d1c4269e34

mahir

To make the part solid you just need to add material where it's currently missing. Perhaps revolving a triangle to create a cone base for the spiral?

MichaelPascoe

This is an old discussion, but in case you need to make a solid body spiral again, I made a feature that will help! Spiral

kjell_kaivosoja

Thanks! That works great. I think I can fix the transition at the bottom someway.