Zesty Nimble on an Original Prusa i3 MK3
Hi!
I am a big fan of the Zesty Nimble remote direct trive ( https://zesty.tech ) and have been fiddling around to mount one on the Original Prusa i3 MK3. The reason for doing it is not that I don't like the original MK3, it's just that I wanted to see if it could be done.
After some designing and testing I have finally gotten a Zesty Nimble attached to my MK3. This is how it looks:
This modification cut about 250g of the weight of the print head, which I guess is always good as it makes the print head much easier to move around.
I have been printing with it for a while and it works very well most of the time.
Unfortunately it seems like in some occasions the printer seems to get completely stuck when printing, especially when there is a lot of details with a lot of retractions in between.
As the Zesty Nimble have a 30:1 gear reduction, I had to change the "E-steps per unit" for the extruder to a much higher value. The original value is 280, but I had to change it to 5380. This change seems to have done something so the MK3 seems to get stuck completely in some situations.
After changing the E-value down to around 2000 (I am printing without nozzle heating and filament when testing this), it seems like the print always finishes. But as soon as I set the E-value above around 2000, the MK3 seems to get into trouble sooner or later.
Does anyone have any ideas what causes this problem? I know that the MK3 probably never have been tested with such high "E-steps per unit", so maybe it's not that strange that it does not work.
Re: Zesty Nimble on an Original Prusa i3 MK3
Hi there!
I stumbled over this thread because I'm designing something similar to this that's also compatible with the MMU2.0. If you take a look into the Firmware of your MK3 you can see the Extruder is running at 1/32 microstepping whereas the axes have 1/16 microstepping. As far as I know, the TMC2130 is further upscaling these internally so everything runs smooth.
If you don't want to recompile your firmware with adjusted microstepping for the extruder, you could also try to lower your retraction speed and retraction acceleration until everythins works fine without your printer getting stuck.
If you want to change the microstepping so you can set your steps to a value arround 2500 steps/revolution goto https://github.com/prusa3d/Prusa-Firmware , download the sources then change the line with #define TMC2130_USTEPS_E 32 // microstep resolution for E axis to #define TMC2130_USTEPS_E 16 // microstep resolution for E axis in 1_75mm_MK3-EINSy10a-E3Dv6full.h, compile, upload and see if it works :).
Re: Zesty Nimble on an Original Prusa i3 MK3
Hi Andreas!
Thanks for the information! At the moment I have returned the printer to the original state again, so I won't try your suggestions in the near future. But if I decide to put the Zesty Nimble back, I will definitely try it out.
I did get it to work pretty well if I turned down the printing speed a bit. If I printed at around 60-70mm/s, everything turned out really well! But I have to say that the print quality was more or less the same as with the original Prusa i3 MK3 setup. So I'll keep the original setup for now.