4th axis on a burly/primo mix + Rumba board

I just managed to change the marlin config of the latest version, so that it:

  • runs on my rumba board
  • supports the full graphics display
  • uses the 6th driver for the A-axis (i-axis in the config).

It all works more less out of the box. I hat to disable laser-pwm support in the config and add a fake pin for i_min.

I use a cheap 4th axis kit from aliexpress, which seems to work fine in dry runs…

I still need to find the correct steps per revolution, etc. and tinker everything toghether… but it looks promising.

I don’t know whether this will prove useful or not, but there are multiple ways to attack the rotation axis math.

The Eggbot from Evil Mad Science labs uses “pixels” rather than distance measurements for the circumference. With 200-steps per revolution and 1/16th microstepping, you end up with 3200 pixels for one full rotation of the item. In Inskcape you then create a template that’s 3200 pixels long by 800 tall (driven by the possible swing of the “pen” axis), and you can plot it on any size physical object, no scaling needed for different circumferences.

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Interesting. I’d like to hear more on the CAD/CAM side once you get up and running.

I’ll keep you posted.
I’m still looking for CAM solutions… I just installed a trialof DeskProto, which seems reasonable… Fusion might be an option too, but I don’t like the subscriptions

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