Friday, 11 May 2012

Calibration - Motors (stepper drivers)

As with all calibration steps you should take your time (as long as you need) and try to be as accurate as possible. Calibration will directly affect the quality of your prints.

In order to calibrate the drivers the printer must be powered on, connected to your computer and requires you to be working very closely with the electronic parts. For this reason I highly recommend you take basic electrostatic precautions before doing this (more information in the notes section).


Calibrating the stepper motors is very straight forward and requires only a small flat headed screwdriver and a little time (the fastest calibration step).
However if you miss this step or wing it you can are likely to have issues with overheating (of the stepper drivers) and/or missing steps.


Ok enough of the disclaimers and introductions.

First get your small flat heated screwdriver (you can use a cross head with official Pololu's, but a flat heat works with both Pololu's and stepsticks) and turn the trim pot (the bit highlighted in the below image) counter clockwise until it reaches home.
Now turn it back 1/4, using PrintRun move the motor attached to the stepper driver you just adjusted.
Slowly turn the trimpot until the stepper motor moves. Once its moving stop PrintRun then turn the stepper driver just less then 1/4 more.

Rinse and repeat with each of the stepper motors/drivers.


For the Y and Z you need the carriage on and hotend installed, otherwise the motor will be calibrated excluding this weight.

Electrostatic precautions;
  • Don't touch the electronics directly (use the screwdriver)
  • Don't do the calibration when wearing socks without shoes, especially on carpet
  • Do ground yourself before doing the calibration
  • Above all don't moon walk on a carpet when wearing wooly socks, trousers and jumper before doing the calibration.