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I upgraded two Prusa MK3s to MK3.9, and ended up with a couple of spare boards, stepper motors and a bunch of other things. So I decided to turn them into a Makelangelo clone!
Since the school I work at had these large standing whiteboards, I designed and printed corner brackets to hold the motors, as well as a base for the electronics.
I'm still having trouble with the homing process, but very happy with the results so far!
I'll be posting the firmware and 3d printed files online soon.
It can go further than that, i just limited it to a smaller size for my first real test. I told the software that I was drawing on an A1 sized paper. Drawing this across the full board would have taken forever.
There are a couple of no-go zones close to the corners. Longer belts would allow it to go lower, but then the counterweights would hit the floor when going up high and limit the drawing area there instead.
Would a block and tackle solve that problem? Could 3d print them likely.
Hmmm, only if a second pulley was higher than the motor, I imagine.
You can use multiple pulleys and shackles to take the distance of the rope up.
It’s how they do it inside of machines as far as I’ve seen.
I still feel the distance they travel will stay the same. Except if I use a gear train.
Using #4 would allow you to move the pen 40cm for every 10cm of counterweight travel.
Ah yes, different sized pulleys would work the same as the gear train I had in mind. Thanks for the explanation!
Edit: on second look, it's more complex than that, as the weight is not connected to the end of the rope, but on a pulley.
Likely number 2 would be enough, would double the distance itself. You just need to attach it to the same corner bracket and have a pulley with the weight under it.
Yes. I would need to increase the weight on the pen too, though.
Smaller counterweight may work as well. Can take or add to either side of the equation.
I feel they're too light already 😅
Yeah I think you need to make it lighter?
Using the mechanical advantage for this would be for someone pulling on the rope to be able to lift a weight easier.
Your pen is the one pulling and counterweight is the weight, so you would need more counter weight or lighter weights on the pin. But too light would have its own tensions problems….
Yes, you're right, don't know why I flipped that in my head, it's pretty clear on the diagram you sent me.
neato. Cool project.