Affordable Rock Tumbler - NEMA17 Version

by TimCC Jan 3, 2018
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@TimCC do you have success with this tumbler? I also built my version, and it seems, de abrasive is so heavy, the printed object is so light, it floats on the top of the abrasive pile. Like a boat floats on the waves. I have not noticed any smooting on the surface. Only one side is discolored, that's all. How can I ensure that the things well mixes inside?

Are you using a container with ridges or a hexagonal insert? If the inside of the container is perfectly round there will not be much tumbling going on.

Example of what I mean: https://metaldetectingforum.com/attachment.php?s=f1a2d51a27214b7aa2e58a484d384560&attachmentid=16906&stc=1&d=1217612380

I used the hexagonal insert. Now I mounted aluminum "L" shape extrudes on the inside wall, and it seems it works now. I also put a clear acrylic window on the lid to check what happens in the inside, and to fine-tune the rotation RPM.

This is a really cool design, but wouldn't it be easier to use a DC motor instead of a stepper?

Definitely. But in my case it was easier to adapt the design for what I had lying around instead of buying an appropriate DC motor somewhere.

Congrats! Nice Job :)

May be this is a solution for all the folks that don't want to deal much with stepper electronics: https://www.reprap.me/easy-stepper.html

Very cool. Do you have any shots of your controller setup? I like the molex plug.

I don't have any pictures but it's just an Arduino Uno with an A4988 stepper driver. When I want to use the rock tumbler I can plug it in to the controller. When I don't use the rock tumbler I can disconnect the controller and use it to drive a different stepper in another project or prototype. I'm not a big fan of having to buy/build controllers for every project, unless it is something that I use very often.

How long do you run it for? I am trying to find information on how long the Nema can run continuously but I am coming up short. Also the files are great. Worked perfectly

You can check the datasheet of your specific NEMA17 for the maximum temperature. I think it's usually around 80°C. As long as the stepper does not exceed that it is fine to run it for long periods of time. If it does run too hot you can reduce the stepper current so that the stepper generates less heat.