Core One Z Calibration issue
Just finished assembling the Core One Kit. I got everything to boot up and calibrate EXCEPT for Z Axis. I double checked the connections:
- The stepper splitter cable from the splitter card is plugged in to the upper notched corner. The other end is plugged into the ZR port of the Buddy card.
- The Rear ZR motor is on the same side and both the front ZL motors on the opposite side of the splitter card.
During calibration it runs up very smooth and interacts perfect with the Nozzle Touch part of the calibration. On its way down it moves nice other than the last two inches from the bottom the screw shafts shake/rattle a bit but that is expected since the ends are not supported. In the end, when it is back down, it fails the calibration. I have tried at least a dozen times with no success. I took a risk and tried to make a name plate. After the first few layers it lost it position and went haywire. I am at a loss.
I had to battle with getting the X and Y Axis motors to calibrate but only if I loosen the drive belts. I done want to muddy up this post and will deal with that later.
RE: Core One Z Calibration issue
The choice of connectors on the splitter board is arbitrary. All three Z motors are just wired in parallel.
If the Z drive struggles on the lowermost part of its travel, it is likely that there are tensions because the position of the leadscrews (and their black trapezoidal nuts) does not agree with the position of the smooth guiding rods. Move the heatbed all the way down, then loosen the two screws on each of the three trapezoidal nuts. That will let the nuts settle in a position which matches with where the smooth rods want to position the bed. Then retighten the 3*2 screws -- don't overtighten them; you don't want to distort the plastic (POM) nuts.
It may be helpful to also lightly lubricate the leadscrews, using the lubricant from the tube that comes with the kit. The POM nuts are ok to run dry, but several users have reported groaning noises of the leadscrews during longer travel, which went away after lubrication.
RE: Core One Z Calibration issue
Thank you for responding. I appreciate it when people like yourself reach out and help.
First I unbolted one of the trapezoidal nuts to see how much play there is. I was surprised to see there is some, given every bolt hole on the assembly is not much larger than the bolt yet everything lined up dead nuts. So I went ahead and let them settle in and it is fine... no more rattling. Lubed them up as well but still will not calibrate. Yet I can see it go through the procedure - Go up and Touch the nozzle tip/set Zero/go down a few mm's/ go back up to zero/then go all the way back down (264.28mm) nice and smooth. but will not give the green light.
Couple of other observations that may shed light. The only way I got X & Y to calibrate was to have the two belts too loose IMO. I have a CNC Router so I am aware of belt tension. I activated HOMING; It failed and it suggested "Try Tightening the X & Y Belts." So I tightened to what I though is good and X, Y, Z homed beautifully. Yet, despite the WARNING to finish all calibration I tried to make a project (PRUSA Name Tag), the Z was tight right up against the nozzle tip scratching the print sheet.
Something Funky with the electronics saving Z calibration . Have no idea yet about calibrating X & Y with loose belts then tightening afterwards, but if it performs well, I'll pick my fights. I set it up with Wi-Fi. Can Prusa connect remotely with it?
John
RE: Core One Z Calibration issue
Can you check the load cell readings from the printer menu? Check if the values make sense, maybe there is something wrong with the signal or stress applied onto the load cell due to Nextruder assembly.
RE: Core One Z Calibration issue
Hi,
Good news! 😊 Got it to calibrate. But I am not sure how!!!
I could not figure out how to read the Load cell like you asked other than after calibrating the load cell I went to SENSORS and saw the reading flickering between -2.0 to 15.0 Which I think is typical for a pressure sensor due to noise. But you got me poking around the nozzle and I found it must have extruded itself out. I was not sure how tight to make the two thumb screws thinking they would damage to tube but obviously not tight enough. Shoved it back in and the Z calibrated. Looks like the nozzle came out 10mm since after calibrating the Z, instead of 264mm stroke it went to 174mm. Now what the nozzle moving out 10mm has to do with Z calibration is a mystery to me but I'll take it.
The only other mystery is I cannot get both the X & Y to calibrate if I tighten the belts. I'll run it the way it is and see how much layering I get.
Thanks for your help.
John