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General discussions. For specific printers / electronics / fabrication methods / softwares, please see other sections.
Re: Mechaduino Closed-loop Stepper - 8 years ago
The latest BOM is here: If I remember correctly, C6, C12 and C13 are the only caps that see anything over 5V (I'd use caps rated at least 25V). The only parts where I would really be concerned about tolerance are the sense resistors (R12,R13). Hope that helps.by jcchurch - General
Re: Mechaduino Closed-loop Stepper - 8 years ago
Hi All, I just thought I would let you know that we've launched a Kickstarter for Mechaduino! -Joeby jcchurch - General
Re: Mechaduino Closed-loop Stepper - 8 years ago
We chose to base Mechaduino around stepper motors for a couple of reasons. In addition to the technical specs pointed out by LoboCNC, there was also some consideration of the economics : Most industrial servos use brush-less dc motors. Stepper motors are essentially high-pole count brush-less dc motors. Since stepper motors are mass produced, they are a great way to get a high quality motorby jcchurch - General
Re: Mechaduino Closed-loop Stepper - 8 years ago
As with any servo motor, dynamic positioning error will depend on the load connected to the Mechaduino and how well the Mechaduino's controller is tuned. Static positioning error is forced to zero (there is an integrator in the control loop which forces zero steady state error). I'll have to play around with the phase advance. Those are some pretty impressive speeds for a stepper motor!by jcchurch - General
Re: Mechaduino Closed-loop Stepper - 8 years ago
Thanks LoboCNC! We are using an AS5047 14bit (16,384 counts per rev or 0.022 degree) magnetic encoder from AMS. Be warned: all magnetic encoders that work on this principle suffer from large (~ a degree or so) non-linearities, so we had to develop a calibration routine. Details here. We are very pleased with our calibration routine and we believe our accuracy is at least better than +/-0.05by jcchurch - General
Re: Mechaduino Closed-loop Stepper - 8 years ago
I'm the designer of the Mechaduino, so I thought I'd chime in here: If you use Mechaduino as a drop in replacement for a stepper motor, extrusion will continue and you may see a blob or small defect. Mechaduino will correct for disturbances, but there isn't feedback to the controller on tracking error in this setup. I see this as being most useful for really large prints where a skipped step 8by jcchurch - General