FreeCAD Challenge 2019-06 June - Hole Punch

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kisolre
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Joined: Wed Nov 21, 2018 1:13 pm

Re: FreeCAD Challenge 2019-06 June - Hole Punch

Postby kisolre » Tue May 28, 2019 5:54 pm

ppemawm wrote:
Tue May 28, 2019 5:25 pm
I almost always try to locate planes of symmetry of the assembly at the global origin irrespective of the drawings. It seems easier to mirror bodies. And, I prefer to locate each body first before starting the model so as to design in context of the assembly.
I usualy do something similar - find what will mate with what, around what axis will it rotate, will some sketches be referenced/reused,... In the Lever Arm I based it around the axle opening. But for the other parts it felt more natural that way when recreating a model and not designing from scratch.
ppemawm wrote:
Tue May 28, 2019 5:25 pm
The sketch should be normal to the helix sweep path in order to have a true spring shape
I see your point and will take that into account for future proper springs. Here it was intentionally simplified so it does not really matter :) Usually I use helix for threads and there we have the profile of the tool that is along the thread axis so normal to helix is not correct.
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ppemawm
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Location: Manhattan New York

Re: FreeCAD Challenge 2019-06 June - Hole Punch

Postby ppemawm » Tue May 28, 2019 6:06 pm

Boneshaker wrote:
Tue May 28, 2019 2:15 pm
here is my FreeCAD model
Thanks for sharing. Nicely done.
A question:
How did you create the wire for the spring sweep path? I have not found a good way to eliminate the 'kink' in the end coils where the cylindrical portion joins the helix. See also my previous comment about attaching the sketch normal to the helix basefeature rather than an origin plane.
"It is a poor workman who blames his tools..." ;)
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Boneshaker
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Location: Emden, Germany

Re: FreeCAD Challenge 2019-06 June - Hole Punch

Postby Boneshaker » Tue May 28, 2019 8:41 pm

You're welcome.
I fiddled around with part wb / helix and wanted the spring parametric to the punch. That works as kisolre shows.
Then I wanted flat ends and added arcs with draft wb / arc. (also tried sketches)
Unfortunately part design / additive pipe didn't sweep the upper arc, as long sweep paths were separate elements.
Tried other angles, slightly other helix parameters ... no luck ... gave up and combined arcs and helix with draft wb / upgrade.
Parametric gone and no way back, but flat ends with a 'kink'. :D

Do you know macro FCSpring?
https://www.freecadweb.org/wiki/Macro_F ... x_Variable
Attachments
spring path.FCStd
(13.99 KiB) Downloaded 9 times
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ppemawm
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Location: Manhattan New York

Re: FreeCAD Challenge 2019-06 June - Hole Punch

Postby ppemawm » Wed May 29, 2019 12:19 am

Boneshaker wrote:
Tue May 28, 2019 8:41 pm
Do you know macro FCSpring?
I do. It seems to have the same problem with the discontinuity, unless I am not using it correctly.
If you try to increase the smoothing it runs too slowly for my short patience.

Here's my take on one solution that is a bit of trial and error to obtain a smooth transition using
basic PartDesign tools:

Picture1.png
Picture1.png (198.81 KiB) Viewed 191 times
spring_mods2.FCStd
(169.76 KiB) Downloaded 13 times
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.16824 (Git)
Build type: Release
Branch: master
Hash: 81ae5688d48fe9037f431b5cb8e1c9cee07f22b9
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)
"It is a poor workman who blames his tools..." ;)