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Rectangular helical sweep feature

Re: Rectangular helical sweep feature

Thanks to Antoni for the Creo 2.0 version.

Here is a short description and some screenshots.

1. Datum point (offset coordinate system)

2. Curve through pionts

   - straight line

   - add fillet radius

3. Sweep

    - Selection plane control >> Normal to Projection ( Direction reference in this case "bottom side" )

Re: Rectangular helical sweep feature

I really like the way this turns into a Fresnel lens if you leave the default projection.

All you need is a guide curve to manage orientation of the section.

The true beauty behind this is that if you come up with some very weird shapes.

The challenge with this is to maintain a constant pitch.

If you can manage the math in a spreadsheet properly indexed, the only limit becomes the single radius entry.

Edit:  the attached creo 2 file uses 2 curves allowing for orientation control.  This helps manage the flair on the corners.

It also brings your computer down to its knees if you lack horsepower.

If you play with it, you will also see some of PTC's shortcomings in Sweep.

Re: Rectangular helical sweep feature

Thanks for sharing. This provides another alternative with less steps to model the rectangular coil  . I like it !

For my application, the shape may be quite irregular/odd and inputting the coordinates of those points may be challenging. One example of the models is shown below:

Capture.JPG

The strip (flex) needs to be able to flatten in sheet metal  to illustrate its 2D geometry. Any idea how to simplify the point input?

Re: Rectangular helical sweep feature

Don't forget that if you can flatten it, you can extrude-cut the diagonals and bend-back to get this result. ...no?

Re: Rectangular helical sweep feature

Not sure what's your idea. Can elaborate further?

Re: Rectangular helical sweep feature

Something like this but I must not be holding my mouth right...

Another brew helped

Re: Rectangular helical sweep feature

OK, got it. Thanks,

The strip needs to be continuous and I guess the sweep is still needed.

Re: Rectangular helical sweep feature

Or you'd be stitching several fragments together to get the full part

In keeping with the idea, however, remember that you can scribe a sketch onto a face while flat.

This could help in selecting an intent curve.

Re: Rectangular helical sweep feature

Hello Heiko,

The key to the solution to this problem is the need to understand that for any helix of a given fixed constant pitch the helix angle will vary with increasing or decreasing diameter. This is the reason for the dip in the helix angle at the intersection with the long flank of the rectangular surface. To succeed with this you will have to use a curve from equation and unless you are absolutely brilliant at mathematics you will need an accomplished maths guru to accomplish this; but it can be done. There is a very slim chance it could be correctly achieved with geometry and most likely with a very complex pitch graph. I would be fascinated to see the construction of a successful model that is absolutely correct.

Regards Michael.

Re: Rectangular helical sweep feature

Hello Heiko

I have created an example using Curve from equation I would say it is approximate but you will get the Idea. Someone with good skills in Calculus would easily be able to make this perfect.

Sorry but the part was created in Creo 4.0 hope you can open it.

Regards Michael.

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