helix: variable pitch tapered

[cadman777]

Has anybody created a Variable Pitch Tapered helix?

If so, would you please share w/me your work-flow for making it?

It's flights for a cement mixer drum, and the flights will be thin plate.

To complicate matters, the flight height must be variable from one end to the other, and the shape of the helix must conform to the varying profiles of the drum cross-section.

My main interest is in knowing you you parametrically make a Variable Pitch Tapered helix with control points in IV.

Keep in mind I'm using IV2010.

Thanx ... Chris

[smokes2998]

is this what you are trying to do in IV2010 ?

https://community.plm.automation.siemens.com/t5/Solid-Edge-Blog/Creating-Custom-Shape-Springs-in-Sol...

You really on a hiding for nothing with IV2010 I would either get a cad system that is capable of achieving the task or upgrade to iv2016 reduce the number of hours you will speend trying to make software do something that it has no functionality for.

[WHolzwarth]

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cadman777 schrieb:

Regarding your offset curve and pattern, in my dataset, I tried using a spline as the 'offset curve' by overlaying it on the offset curves. Is it possible for you to do that and then array along that spline?

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I didn't try it with 2016, but I think, an array along an unsegmented spline can be done without problems.

[Daniel248]

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See what I got so far in 2010. I could create an offset curve  on the flight surface and place an elliptical body there. But I couldn't pattern it along this curve in 2010 (File attached).

In 2016 pattern could be done, but only along a short segment of the whole offset curve. See picture.

Therefore, we urgently need a join option for 3Dcurve segments.

Walter

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In 2016, it is possible to join 3D curve segments by using an Interpolation Spline with Smooth G2 constraints – can’t remember if this was available in 2010.

Using that, I’ve managed to join smoothly the 3D sketch curves (3D Sketch19, in part attached) and pattern along that.

Unfortunately, there is a sharp change in this model’s geometry (see below snapshot, at the end of 3D Sketch19), so I didn’t try to go past that (sorry, too much work for me to try & fix it).

Still, (model attached, 2016, roll down EOF) might help giving some ideas, if someone wishes to take it further… 

[cadman777]

Smokes,

Great idea.

Wanna front me the bux to buy IV2017?

Regarding your link:

I want a combination of "conical" + "variable pitch".

Still think I need to upgrade?

[cadman777]

Thanx Daniel, that's what I wanted to know.

The "sharp change in geometry" is due to the software failing to be have to commands to create a tapered variable pitch helix (= 3 helices, of 1 rev each, being tangent at their ends where they join each other). If the program could do THAT (which Rhino CAN do), then that abrupt change would not exist. I need to rely on the fitters to make those 2 transitions smooth when they weld this thing together inside the drum.

If I had IV2016, what I would do is make one continuous spline along the o.s. edge of the entire involute, and then do the same thing you did.

You can see I tried that in IV2010 with the flight (I forget which 3d sketch), but it failed when I tried to Sweep using multiple profiles that are normal to the spline @ various vertices.

Rhino can only approximate the helix that I want, but I can get it close enough. However, since Rhino is not bi-directionally associative, it becomes a 'red headed step child' in the process, esp. when updates are needed during the design (which occur all too frequently).

Once we tackle that, then what I would need to do is gradually shrink the size of the Ellipse from one fixed size at one end, and then down to another fixed smaller size at the other end of the flight. But while getting gradually smaller, the frequency of the Ellipse needs to increase gradually as a function of quantity per revolution. There are only 3 revolutions.

So you can see that this isn't a simple challenge.

Incidentally, I already made a solution for this which was 'good enough', even though IV forced me to use Rhino to make the flat patterns for the burn table. Also, I put the Elliptical holes on the flat pattern, b/c it was 'stupidly complex' to do it on the formed parts.

Cheers ...