RESOLVED: Consistent Bed Leveling Failure on Lower Right Sensor Point
Hello all,
I just finished assembling my Prusa i3 mk3 yesterday and have been trying to get it calibrated. I've been running the full calibration wizard and the printer has passed the self test, XYZ calibration, and Z calibration successfully.
However, when it gets to the point where I am supposed to manually adjust the nozzle offset, it heats the bed and nozzle fine, but when it tries to test the calibration points it consistently fails to trigger on the lower right point (2 of 4 when it does the calibration point searching). This point also consistently takes the longest to find and improve during the calibration phase, so I am wondering if it is a problem with the sensor point on the bed, or something else. The same problem has happened with the base firmware it shipped with, as well as the newest firmware revision.
Any suggestions on how to resolve the problem?
EDIT: The problem was slight Z-axis binding when in the home position.
The zip ties on the extruder "tail" assembly were running up against the RAMBO micro-controller case and causing the z-axis to bind just enough to throw off the z-axis height calibration. I resolved this by redoing the zip ties (again) making sure they were as flush as possible to the bridge piece. I also carefully pushed the door piece of the RAMBO cover such that it resettled itself further inward.
The tolerance between the extruder zip ties and the case is still extremely tight, I put a piece of paper in between the two and still feel some resistance when pulling it out. IMO it would be nice in later revisions to move the micro-controller case and power supply another 2 mm or so away from the extruder, to prevent issues like this (and the related issue of failed x-axis calibration due to zip tie impacting the power supply).