Spherical Helical Path with Solidworks

[snorthcott]

thread559-241904

In the reference thread a user said to " Intersect a helical ribbon with a sphere and use the resulting edge".

Can anyone help explain how to go about this? I need to make a helical path along a hemispherical head.

Thanks ahead of time for any help that can be provided.

 

[ericnutsch]

This guys method is a little inefficient, but just regard the comment;"Why dont you just sweep the circle at? 0:55?" while you watch it:

http://www.youtube.com/watch?v=5rK6vA3qZO0

 

[Eltron]

Is this what you're looking for?

Dan

http://www.eltronresearch.com

Dan's Blog

 

[snorthcott]

It was not exactly what I was looking for but it did turn on a light bulb for me. What I was looking to do was to create a helix on a hemispherical head for a vessel design.

What I ended up doing was creating a variable pitch helix and adjusting each turn to wrap around a transposed arc. It took a lot of trial and error but eventually worked out

But if there is a better way of doing this I am always open to suggestions.

Here is what I am working on:

http://files.engineering.com/getfil...17e-4850-b7a4-3d201871dca0&file=dome_coil.bmp

 

[CorBlimeyLimey]

Does this help?

 

[snorthcott]

That is exactly what I am trying to accomplish. I will try tailor that method to fit my application and let you know how it works out.

 

[snorthcott]

I apologize CorBlimeyLimey at first glance that looked like what I needed to do. But I need to hold a consistent amount of surface (in my case half pipe) around the dome. Thanks for trying to help though.

 

[CorBlimeyLimey]

"I need to hold a consistent amount of surface (in my case half pipe) around the dome"

Can you explain that further?

 

[snorthcott]

I need to lay out half pipe (literally 1/2 of sch.40 pipe) around a domed surface in a helical fashion similar to that of a peeled orange. What I meant by "consistent amount of surface" is that I am doing a revolve of a full pipe around a variable pitch helix and then making an in assembly revolve cut to "halve" it. The problem that I am having is that the helix does not provided a consistent means of keeping half of the on the outside surface of the dome.

 

[CorBlimeyLimey]

Is this closer?

 

[snorthcott]

You are the man Limey! Thanks for all your expertise, I really appreciate it!

 

[CorBlimeyLimey]

I'm curious to know how the pipe will be formed?

 

[snorthcott]

It's actually not pipe at all. The company (not sure of the name) has a machine that actually takes sheet metal and simultaneously forms it into half pipe and coils it to the desired pitch. This is the first I've heard of the process so there isn't much else I can tell you but i'm curious to see the end result when it comes in to our shop