Wednesday, January 4, 2012

Some Progress, Still Waiting

I am still waiting for my new pololu boards to arrive but I have managed to make some progress in the meantime. 

It was immediately apparent that my axis were not moving as they should.  The steps/mm were obviously incorrect but it took me a while to figure out what they should be.  I could see that the X and Y were moving in tiny increments and finally realized that I had to multiply by 16 to allow for the microstepping (Duh!).  That worked but then their movement seemed to swing too far in the other direction.  Luckily I found Josef Prusa's online RepRap Calculator (Calculator).  Once I had carefully entered the correct data (gear tooth counts, microstepping settings belt pitch angle, step angles and leadscrew pitch) it spit out settings that seem to be correct for my machine.

I think that the extruder setting is still off.   It seems to be pushing out more than 5mm of extrusion when I hit the jog button but I will wait until I have all three axis working to mess with it further.

I am working on the heated bed while I wait.  I got the PID out and wired it up yesterday.  since it runs on 120v AC I don't want to use it without an enclosure but I will give it a quick power up to confirm that it is working.  I have attached the heater pad to my build plate but I didn't get the thermistor wired up last night.  I should be able to finish it up tonight and give it a try.  Assuming that it works I will finish the enclosure and get everything tidied up.

I expect that the new stepper drivers should be here within the week.  I have ordered some ABS to complement the PLA that I already have on hand so I will be able to experiment with the different materials.


  1. 5mm of extrusion is counting material going _into_ the extruder. :) Read more here:

    Best of luck with the project!

  2. Thanks a bunch Nudel. I had not run across that in any of my reading and I just assumed that it was "extrusion out" that was being measured. It makes much more sense now. My extruder may actually be working correctly.

  3. though i will say that is how repsnapper dose its extrusion, at least there the only ones who are different from what i have seen soo far,

  4. Thanks Mike. I am using Repsnapper for my testing.