Gears in FreeCAD: FC Gear

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abdullah
Posts: 3174
Joined: Sun May 04, 2014 3:16 pm

Gears in FreeCAD: FC Gear

Post by abdullah » Sat Mar 10, 2018 4:14 pm

I am learning about gears.

I was looking for a way to integrate gears in FreeCAD in a more straightforward way than using the PartDesign involute wizard and then doing lots of boolean operations and I found looo's Gears WB. I did not know it existed:

https://github.com/looooo/FCGear

Then I decided to fork the project and enter the Python realm to create a herringbone gear... I did most of it, until I realised that FCGear already allows you to do HerringBone gears using an involute gear and setting beta to the helix angle you want for your herringbone, and "double_helix" property to true.

I am not sure this subforum is the right place, but I wanted to make an entry to create awareness...
Herringbone_gear.png
Herringbone_gear.png (52.99 KiB) Viewed 9759 times
Thanks looo for this workbench :)
triplus
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Joined: Mon Dec 12, 2011 4:45 pm

Re: Gears in FreeCAD: FC Gear

Post by triplus » Sat Mar 10, 2018 4:53 pm

Looking good.

P.S. Usually that happens indeed. Trying to achieve something in FreeCAD and thinking likely it will take a lot of effort to do that. Only to realize there is already a command for that. ;)
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NormandC
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Location: Québec, Canada

Re: Gears in FreeCAD: FC Gear

Post by NormandC » Sat Mar 10, 2018 4:53 pm

abdullah wrote:
Sat Mar 10, 2018 4:14 pm
FCGear already allows you to do HerringBone gears using an involute gear and setting beta to the helix angle you want for your herringbone, and "double_helix" property to true.
Wow! I didn't know that! I hadn't updated FCGear in some time. Thanks for the tip! :)

O/T in the CAD program I use at work, default colour for surface and shell objects is almost the exact same green as in your screen capture. When I see that green, I automatically think that the shape is not a solid. :D
abdullah
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Joined: Sun May 04, 2014 3:16 pm

Re: Gears in FreeCAD: FC Gear

Post by abdullah » Sat Mar 10, 2018 7:05 pm

NormandC wrote:
Sat Mar 10, 2018 4:53 pm
Wow! I didn't know that! I hadn't updated FCGear in some time. Thanks for the tip! :)
Welcome. I like this WB a lot. Yes, I am a newcomer to gears and I am excited (probably if you are a mechanical engineer and you remember how cool you thought gears were when you studied them... well, I am that excited!).

I am going to print this one. I have used the Bevel gear object as base feature for PDN, and in PDN I have made the shaft, cut the gear to size with an angle, and then I made a connection for a small dc motor. For a while I wanted to see if draft clone worked on bodies, and it does. It is a nice alternative to making clones of the last feature, as seen in the forum.
Bevel_gear.png
Bevel_gear.png (87.59 KiB) Viewed 9669 times
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NormandC
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Location: Québec, Canada

Re: Gears in FreeCAD: FC Gear

Post by NormandC » Sat Mar 10, 2018 7:09 pm

Why do you need a Clone here?
abdullah
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Joined: Sun May 04, 2014 3:16 pm

Re: Gears in FreeCAD: FC Gear

Post by abdullah » Sat Mar 10, 2018 7:15 pm

NormandC wrote:
Sat Mar 10, 2018 7:09 pm
Why do you need a Clone here?
I don't. I only wanted to know if it was possible. Here it is not needed.

I have seen that other users use clones for producing several copies of a part for assemblies. The cool part of using a clone of a body instead of a clone of the last feature of a body, is that if you change the body by adding another feature, the clones will follow automatically.
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NormandC
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Re: Gears in FreeCAD: FC Gear

Post by NormandC » Sat Mar 10, 2018 7:19 pm

FYI,
abdullah wrote:
Sat Mar 10, 2018 7:15 pm
The cool part of using a clone of a body instead of a clone of the last feature of a body, is that if you change the body by adding another feature, the clones will follow automatically.
FYI, there is almost never a good reason to clone the last feature of a Body, or use it in an operation in another workbench. It's a mistake, and it will produce a "Links go out of allowed scope" error. With the introduction of the Body, features inside it should no longer be selected, unless when working within the PartDesign workbench.

EDIT: I wrote "almost", because as usual there are exceptions to the rule.
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sgrogan
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Re: Gears in FreeCAD: FC Gear

Post by sgrogan » Sat Mar 10, 2018 7:21 pm

abdullah wrote:
Sat Mar 10, 2018 7:15 pm
The cool part of using a clone of a body instead of a clone of the last feature of a body, is that if you change the body by adding another feature, the clones will follow automatically.
Nice. For molding this is a good find. I've used draft clones + scaling to account for shrinkage.
abdullah
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Joined: Sun May 04, 2014 3:16 pm

Re: Gears in FreeCAD: FC Gear

Post by abdullah » Sun Mar 11, 2018 5:17 am

NormandC wrote:
Sat Mar 10, 2018 7:19 pm
FYI, there is almost never a good reason to clone the last feature of a Body, or use it in an operation in another workbench. It's a mistake, and it will produce a "Links go out of allowed scope" error. With the introduction of the Body, features inside it should no longer be selected, unless when working within the PartDesign workbench.
I see. Many of us are still to adapt to the "links go out of scope". Thanks for the tip! :D
sgrogan wrote:
Sat Mar 10, 2018 7:21 pm
Nice. For molding this is a good find. I've used draft clones + scaling to account for shrinkage.
Ah moulding!! Another one in my TODO list...
triplus
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Joined: Mon Dec 12, 2011 4:45 pm

Re: Gears in FreeCAD: FC Gear

Post by triplus » Sun Mar 11, 2018 2:41 pm

abdullah wrote:
Sun Mar 11, 2018 5:17 am
I see. Many of us are still to adapt to the "links go out of scope".
Likely at some point in the future things will evolve in this area too.
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