FreeCAD designed 3D printed clock

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FreeCAD designed 3D printed clock

Postby jackfreecad » Sun Feb 14, 2021 4:47 am

Hi Guys

Here is my mechanical clock that I have designed with FreeCAD 0.19
But first, I would like to thank all the developers for this awesome program, as well as the workbenches.
Here is a rendering of the assembly in freeCAD: ... PU6DzSGQZ-
Here is a picture of the 3D printed realisation: ... z5seS_WHdQ
I also want to share the link to the whole file with the following creative commons license: BY-NC-SA ... QHc64cuwZH
Finally here is a link to the latest video of the progress of the clock on my YouTube Chanel:
Checking out FreeCAD, I found the gear workbench with all its options. The cycloid gear is what made me want to experiment more with freeCAD.
I have used Fusion 360 for a couple years and while I am not a clock maker, I already have some experience designing 3D printed clocks.
My first idea was to redo clocks that I already made in Fusion, but then moved on a totally new project, one that can run over 24 hours
I used the Part Design workbench, the Gear workbench, the Assembly 4 workbench and the fastener Workbench
I started with the Assembly 4 to animate two cycloid gears and optimize the meshing
I had to hack into the code to get what I wanted and get something that worked (feature request will follow)
Now I can start with the design with a master sketch to organize the gears, that is for front view, X-Y plan in FreeCAD
I also wanted to limit the size of the frame to 200/200 mm so it could fit easily on my printer
Once I had the layout of the gears, I could start with the back frame.
Once I had a sketch with all major dimension I saved that sketch and duplicated it as a staring point for the all the frames
I then built an new assembly on the back frame, adding gears and extra frames as I went on
At this time I made all the parts in separate documents in part design, then copied the « body » and pasted in the Part folder of the assembly, placed LCS and imported in the model
I made a separate assembly for the front frame
Finally merged both assemblies
Now I could check the sideview and check and adjust clearances in the Z axis.
I already had printed and built a prototype and things where a little tight, I had to increase some dimensions in the Z axis, new side frames, thicker gears

The assembly might not look perfect, gear could turn around to mesh properly, there is no animation, but it fits my need, that is to generate stl files that I could print and then assemble and not have to reprint every parts 5 or 10 times until all fits.
The net result: FreeCAD is perfect for my needs, It did all I wanted to do…Awsome!
Along the way I learned a few things about topological naming issues and learned why attaching sketch to a face is not a good idea.

There are two issues that I can reproduce that I will talk in a separate post, one is trimming circles and tangents that cause an error, another is padding two concentric ellipse caused FreeCAD to freeze
There is one feature request that I have: It is to add a head parameter to the cycloid gear, same as it exist in the involute gear, tried to implement locally, could not get it to work, then hardcoded a short cut using clearance to adjust the length of tooth
This video on cycloid gear explains what I did, how and why

OS: macOS Mojave (10.14)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.23258 (Git)
Build type: Release
Branch: master
Hash: 78c6cc1362c39e3f1f778c52ae2a1c82badeec20
Python version: 3.8.6
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: C/Default (C)
wholePicFreeCAD.png (315.23 KiB) Viewed 1323 times
3DprintedClock.jpg (367.07 KiB) Viewed 1323 times
frontopleft.png (127.7 KiB) Viewed 1323 times
back.png (150.01 KiB) Viewed 1324 times
Last edited by jackfreecad on Sun Feb 14, 2021 1:23 pm, edited 2 times in total.
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Re: FreeCAD designed 3D printed clock

Postby chrisb » Sun Feb 14, 2021 6:29 am

Thanks for sharing! You are welcome to include all images here. so the they will not be lost if you or Google decide to use the space for something else.
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Re: FreeCAD designed 3D printed clock

Postby jbraun » Mon Feb 15, 2021 4:27 am

Very Nice !
I also build clocks But I use purchased plans and wood. Someday I may try my own design but there are so many ways to design it wrong.
That's a good run time for a clock with no weight pulley.
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Re: FreeCAD designed 3D printed clock

Postby A_3 » Tue Feb 16, 2021 9:17 pm

Great job.
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Re: FreeCAD designed 3D printed clock

Postby jackfreecad » Fri Feb 19, 2021 11:28 am

In case you want to get the full Assembly4 file, you can get it here:
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Re: FreeCAD designed 3D printed clock

Postby freedman » Mon Feb 22, 2021 6:34 am

This is very cool. It's a fricken gear ratio nightmare.. :)
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Re: FreeCAD designed 3D printed clock

Postby Kunda1 » Mon Feb 22, 2021 5:48 pm

Amazing :D
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