Squarish Circles

I have a 3d printer I built which is all metal with no backlash.  Recently upgraded the x and y axis with mechaduino closed loop And reflashed the firmware to siut.  The printer runs ok but circles are oval and oblong.  Now I checked the axis movement with a dial test indicator and found that I have a 0.5 backlash in both axis... this was not the case before I fitted the mechaduinos.  When I put the new Repetier firmware, i think that I Enabled Backlash... i am at a loss what is going on... any clues?  Maybe because I gave backlash enabled?


  • Backlash enabled make sonly a difference when the x, y or z value is not 0, otherwise it is ignored. So good for testing if your problem comes from that. Of course having set values while there is no backlash will add lines where not needed making circles not round. Have you not fixed the pulleys on the new motors of the mechaduino? I mean it's idea is to not loose steps but 0.5mm error sounds high.
  • I am appalled with the response I am getting in many forums about the mechaduino.  I also sent a message to Jchurch but nobody bothers to answer.  Is the mechaduino project dead?  I stumbled upon it December 2019 and it immediately crossed my eye as a potential answer to skipped steps.  I realize everything comes at a cost...  I produced a prototype for a quality 3D printer (the linear guides on their own cost around 300euros)  featuring a water cooled hot-end and designed a water cooler to siut.. many features I have worked for months to perfect, but decided to introduce this feature and I found a brick wall.  I have been trying to tweak the PID settings and will be taking on board an engineer.  Nobody better than who designed it can say what they put in.  It seems like an abandoned project.  I have done many searches with discussions going back 2016 and then tapered out...  Am I flogging a dead horse? Can anyone chip in any ideas? maybe there is a much better idea than this mechaduino project.  I look forward to get some comments from this forum and may I  thank every one of us who bothers to help.
  • I once had a user use a expensice trinamic servo (or stepper not sure) motor with step/dir/enable control. That motor has it's own internal control circuit and could be programmed how to behave. Host was 300 euro for motor/electronic combo. Behaves the same as mechaduino just being a professional solution working as supposed.

    But the question is if that is really all worth the costs. If you are not printing very hard to print material that warps up constantly (main problem for lost steps) a print normally succeeds when it stays connected to bed.
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