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Boff

Project Yummy Turtle: 3D Models for Flywheels

Given OldNoob's recent calamity in sourcing flywheels that don't suck, I figured I should probably do something about it. I can't make anything at our end so I've done the next best thing. Below is a fully parametrised OpenSCAD model and associated STL output for push-fit flywheels. The first person who suggests trying to 3D print them gets shot. I'm making these available so that if someone has access to a machine shop and they can get themselves some made then I've taken out a lot of the work.



So I've duplicated the stock flywheels to begin with, it was a simple case of pulling out the callipers and putting them together. I've included the full code and models in the GitHub repository below.

STL File
SCAD Code

GitHub repository is here. You'll be able to make commits and such to the repo if you're so inclined to contribute to the project.

The next step will be to move beyond the push fit stage and progress to grub screw securing so we no longer need rely on the good graces of plastic to fit motor shafts in place.
McRex

Oh, oh me! I want to get shot!

But seriously, is 3D printing not an option? Not even high quality 3d printing with a heated bed?
OldNoob

Try getting a wall thickness that doesn't deform or add too much mass and is perfectly circular.
The whole point is to move forward not be twats and state the obvious, if it was possible for sensible money and as good as a machined alternative, I would have bribed Boff into making me lots of sets. By all means try it through shapeways and see what you get back.
Boff

3D printing isn't an option for a variety of reasons. We use heated beds on all our prints but the risk of delamination and stuff is much greater under high rotational velocities. The other problem with 3D printing is that FDM (the form that we use) is under stepper motor control which can only be done in straight lines. Even turning the steps/mm through the roof you're not going to get a perfect circle. Balancing them is then a pain in the arse...

Then you've got to actually print the buggers. The stock flywheels as modelled above can't be printed without support pegs. Philosophically, I don't use support for my 3D printing because I believe that an assembled alternative is better and lowers the cost of a print failure. Obviously, assembly here isn't an option. If you were to add support then you'd need to remove it in way that reduces the presence of burrs and other artefacts that will result in unbalancing things.

Between the lack of structural integrity and the poor surface finish that comes from printing, the process really isn't suited. It was a remarkable realisation while I was coding this model that it very much a part designed for injection moulding.
McRex

Boff wrote:
words


Thanks for the explanation. Wouldn't flash be a problem with injection though? And what about that little dent you see where the plastic was being injected?

EDIT

Please don't quote entire chunks of text. If your reply is shorter than your quote then you're probably doing it wrong. Smile Thanks, -Boff

Boff

Injection moulding artefacts can be seen on the stock flywheels if you know where to look. To Hasbro's credit they do clean them up fairly well when they break them out. Smile
MarcusH

Boff where did you get the name from? Project Yummy Turtle I am guessing is an obscure reference to something Razz

Certainly a very needed thing though - I might be as good as gone from playing but I can see these being a useful option. Mainly owing to our lack of any kind of reasonable supply of dirt cheap flywheelers like our friends across the pond have with thrifting.
Boff

MarcusH wrote:
Boff where did you get the name from?


Not an obscure reference, it's what GitHub suggested as the repo name for the project. I gave it a slightly more sensible name on system but kept it because I felt bad to let it go to waste. Very Happy

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