Hole in gear

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bonny
Posts: 36
Joined: Tue Feb 25, 2014 9:04 am

Hole in gear

Postby bonny » Mon Jul 15, 2019 8:05 am

Hello...
I have problem how to create hole for axis in gear. The "body" seems to screw up my knowledge. (using freecad 0.18)

What is "corect" workflow to create involute gear from gear workbench and add hole (with key) (probably partdesign workbench) for axis?
In old freecad *0.16" is easy but on 0.18 I fail.

Please help.
chrisb
Posts: 19487
Joined: Tue Mar 17, 2015 9:14 am

Re: Hole in gear

Postby chrisb » Mon Jul 15, 2019 8:25 am

If you want to use PartDesign you can do the following:

- create the gear
- select it in TreeView
- create a body; this will create a BaseFeature of the gear (some kind of a clone) in the body
- add a sketch with a circle in the appropriate plane to the body
- make a hole through all, you may have to check the "Reversed" option
Attachments
gearHole.FCStd
(101.08 KiB) Downloaded 15 times
bonny
Posts: 36
Joined: Tue Feb 25, 2014 9:04 am

Re: Hole in gear

Postby bonny » Mon Jul 15, 2019 9:43 am

Ok with this I get gear outside of body. I was thinking that should be inside body and that bother me.
bonny
Posts: 36
Joined: Tue Feb 25, 2014 9:04 am

Re: Hole in gear

Postby bonny » Mon Jul 15, 2019 10:01 am

Hello...
Actually doesn't work either.
I do suggested steps and got gear with hole. But the trouble is that I can't change gear itself. (number of teeth ,,,)
What I do wrong?
test.FCStd
(365.34 KiB) Downloaded 13 times
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papyblaise
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Location: France

Re: Hole in gear

Postby papyblaise » Mon Jul 15, 2019 11:12 am

Hello
2 quick questions to Chrisb : 1st: Where comme from your profil because I can't see it when I try to open yours involutegear , so I can't modify it

2cd: How to do the helicoildal pad ? I don't know ths option
chrisb
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Re: Hole in gear

Postby chrisb » Mon Jul 15, 2019 1:03 pm

papyblaise wrote:
Mon Jul 15, 2019 11:12 am
2 quick questions to Chrisb
Bonny uses the Gear workbench. You have to install it with the Addon manager.
looo
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Re: Hole in gear

Postby looo » Mon Jul 15, 2019 1:42 pm

bonny wrote:
Mon Jul 15, 2019 10:01 am
I do suggested steps and got gear with hole. But the trouble is that I can't change gear itself. (number of teeth ,,,)
I guess this is because of topo-naming issues. I have seen this too, but somehow this issue doesn't occure with the file posted by @chrisb. The pocket is sometimes jumping to a wrong face (see attached image)

With the 0.18 appimage from @realthunder this is also failing:

Code: Select all

No planar Face in AttachEngine3D::calculateAttachedPlacement()!
Attachments
Bildschirmfoto von 2019-07-15 15-34-47.png
Bildschirmfoto von 2019-07-15 15-34-47.png (36.79 KiB) Viewed 222 times
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papyblaise
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Re: Hole in gear

Postby papyblaise » Mon Jul 15, 2019 2:43 pm

Thanks Chrisb
bonny
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Joined: Tue Feb 25, 2014 9:04 am

Re: Hole in gear

Postby bonny » Mon Jul 15, 2019 3:26 pm

I got cut just to the half...
But few minutes was ok!
Attachments
Ebicikel02.FCStd
(582.49 KiB) Downloaded 5 times
fcad.png
fcad.png (56.18 KiB) Viewed 205 times
looo
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Re: Hole in gear

Postby looo » Mon Jul 15, 2019 8:02 pm

Here is a short video about the behavior:
https://vimeo.com/348236617

I didn't use any part-design features here but it should show the same problem:
As the number of faces of the gear changes, also the naming of these faces changes and at one point the face which is referenced by the sketch jumps to a different position.
The reason why the sketch is not jumping at first is answered by the observation made with @realthunder's FreeCAD version:

Code: Select all

No planar Face in AttachEngine3D::calculateAttachedPlacement()!
This means after changing the number of tenths a non planar face (most likely a part of the involute) is referenced and an error is reported for LinkStage3-branch. Master simple use the previou location of the sketch.

So we have here an example of the topo-naming issue. Maybe @realthunder can give some better explanation what is going on here.
Also I am still wondering what is different in the version @chrsib made. The posted file seems to work with all different property values.
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