Nearly a wave spring washer ...

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chrisf
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Nearly a wave spring washer ...

Postby chrisf » Thu Mar 20, 2014 5:41 pm

I'm trying to model a single turn wave spring washer using six rectangle sketches at 60 deg intervals round the washer with every other one displaced to give the free height. Well, seven sketches in all to give one to end on.

The loft tool very nearly does a good job of joining them all together but the angle at the start and end is all awry - see attached. I was expecting the loft to pass perpendicular to each sketch but it doesn't.

Does anyone know of a work-around or should I file under 'pointless things to try to model in the first place' :)
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springwasher.fcstd
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quick61
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Re: Nearly a wave spring washer ...

Postby quick61 » Thu Mar 20, 2014 6:38 pm

I'll take it your trying to do an actual wave spring washer - "S" shape - and not a bowed washer - "U" shape?

I think your answer will be found more with Sweep than Loft. It will take me a bit to get back with an example, other things going on...

Mark
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chrisf
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Re: Nearly a wave spring washer ...

Postby chrisf » Thu Mar 20, 2014 7:13 pm

Hi Mark,
Not sure I'd call it an 'S' washer but one of these http://www.springmasters.com/sp/wave-sp ... ers-4.html.
I'll have a play with sweeps. Not sure how to draw the wavy path ... it's just playing anyhow.
Chris
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quick61
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Re: Nearly a wave spring washer ...

Postby quick61 » Thu Mar 20, 2014 7:46 pm

It's hard to tell for sure from that drawing, looks like it's rotated a bit. This is what I went from - http://hubbardspring.com/all-category.p ... ve-washers

I didn't get to the sweep yet, but I did knock something out with a few Pads 'n Pockets.

Have a look and see if it's close. The model should have some resiliency as I avoided using any external geometry on this one. Oh, and I didn't constrain the little helper Pad. ;)

Mark
WaveSpring_Washer.fcstd
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chrisf
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Re: Nearly a wave spring washer ...

Postby chrisf » Thu Mar 20, 2014 8:13 pm

Thanks a lot. I like that.

What's with the 'helper pad'? I deleted it because I thought it wasn't doing anything and that broke it.

Your model has two highs and two lows. The one I was trying to model has three highs and lows so won't be possible with your pad and pocket route. Yours is much better than my loft attempt though.
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quick61
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Re: Nearly a wave spring washer ...

Postby quick61 » Thu Mar 20, 2014 8:39 pm

chrisf wrote:Thanks a lot. I like that.

What's with the 'helper pad'? I deleted it because I thought it wasn't doing anything and that broke it.
That "helper pad" is used to provide a face to map to for the last 2 pockets. Once the "S" shape is pocketed from the cube, there is no planar surface on which to map the next sketches for the ID and OD of the washer. This thread explains the concept.
chrisf wrote:Your model has two highs and two lows. The one I was trying to model has three highs and lows so won't be possible with your pad and pocket route. Yours is much better than my loft attempt though.
OK, so there is a difference. I think that will need to involve a sweep then. I'll give that a go a bit later on this evening, if your not in a real big hurry for it, or someone else doesn't get to it first. ;)
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chrisf
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Re: Nearly a wave spring washer ...

Postby chrisf » Thu Mar 20, 2014 8:56 pm

quick61 wrote:That "helper pad" is used to provide a face to map to for the last 2 pockets. Once the "S" shape is pocketed from the cube, there is no planar surface on which to map the next sketches for the ID and OD of the washer. This thread explains the concept.
Ahhh. I've been working around that with separate (non-parametric) constructs for months. Useful trick.
Chris
ulrich1a
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Re: Nearly a wave spring washer ...

Postby ulrich1a » Thu Mar 20, 2014 10:12 pm

I tried the sweep approach, but was a little bit dissapointed.
I made half of the sweep path with a macro. The sweep path was made with Draft.makeBSpline. But the sweep was not as smooth as I did expect. It does contain 10 points.
spring_washer.png
Spring_washer mirrored from one half
spring_washer.png (30.29 KiB) Viewed 2014 times
Here is also the python code. I called it with execfile("your_path") in the python console.
spring_washer.py.zip
python file to create sweep path and two profiles
(1.33 KiB) Downloaded 45 times
It seems the loft-approach but with more profiles will give a better result. Or I need more points in the B-Spline

Regards
Ulrich
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quick61
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Re: Nearly a wave spring washer ...

Postby quick61 » Thu Mar 20, 2014 10:56 pm

Hi Ulrich, I am being rather disappointed by the sweep as well. Every time there is a transition in the curve, the sweep wants to fold up, (M's and W's) like the loft did at the end point with Chris. Hummm.... Going to take a bit more looking into.
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tanderson69
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Re: Nearly a wave spring washer ...

Postby tanderson69 » Fri Mar 21, 2014 3:00 am

here is a couple files I played with. In the first file I had to use makehalfspace from the python console to make the 2 toolbodies.
Attachments
springwasher_ta2.fcstd
(57.71 KiB) Downloaded 53 times
springwasher_ta1.fcstd
(197.25 KiB) Downloaded 53 times