6 Replies Latest reply on Dec 19, 2012 6:23 PM by Jerry Steiger

# Simplify This Spiral Funnel

I have been struggling with this for days. I finally have basiaclly what I need, but there has to be a simpler approach. It is what I call a spiral funnel. The problem is that I need to be able to vary things like size of the opening at the base, the pitch, the width, potentially a lot fo things and with my complicated way of getting from point a to point b, making changes is a challange. Please help with other ways I can produce this part. Thanks in advance.

• ###### Re: Simplify This Spiral Funnel

without getting into what and how you want to vary the part, it would be difficult to suggest much.

one thing that will help the model behave more predictably to change is if you fully define your sketches.

• ###### Re: Simplify This Spiral Funnel

Hi Jeremy, thanks for the reponse. I have started over on the part (see attached) and have also included a VERY ROUGH sketch of what I am trying to do. Basically I want to come off of the red edge of the surface with a tanget surface that consistently spirals down (Consistent pitch) to the Blue Circle. I want the spiral to not exceed the boundries of the Green and Purple sketches. The spiral surface will have 1/2" tall vertical walls (see sketch). When complete, my goal is to be able to change the distance of the blue circle from the edge of the surface with the red edge in all directions by as much as maybe an inch while still maintaining the bouundries.

• ###### Re: Simplify This Spiral Funnel

Mike,

I can't open your part (and don't really have time to do so, anyway), but from youj sketch, it seems like using the surfacing tools would make the job relatively easy. You could Extrude your green and purple sketches to generate surfaces from which you could make your side walls. You can use another surface generated from a spiral to make a constant pitch. I think you would use a Radiate surface, but I'm not sure. Search for "Rectangular Spring" or "Elliptical Spring" to find out how it is done.) Use the Intersection Curves from the Spiral and the inner and outer surfaces to establish the edges of your ramp.

You say you want a consistent pitch, but the outside pitch is always going to be different than the inside pitch. I'm guessing that you mean a constant pitch at some position on the ramp, either the inside edge, the center, or the outside edge.

Jerry S.

Oh, I forgot: once you have the ramp and side walls the way you want them, then Thicken to get a solid model.

Message was edited by: Jerry Steiger

• ###### Re: Simplify This Spiral Funnel

Hi Jerry,

Thanks for your input. I did figure out how to make it a little simpler and it was indeed to basically build it using surfaces, Thanks Again..

• ###### Re: Simplify This Spiral Funnel

Jerry Steiger wrote:

You say you want a consistent pitch, but the outside pitch is always going to be different than the inside pitch. I'm guessing that you mean a constant pitch at some position on the ramp, either the inside edge, the center, or the outside edge.

Jerry

The pitch of a helix is the distance per turn. As you move radially, the angle will change but the pitch won't.

Dwight

• ###### Re: Simplify This Spiral Funnel

Dwight,

Glad one of us is awake! I was thinking pitch of a roof, not pitch of a screw. What a bozo!

Jerry S.