XYZ Calibration Issue
Hello, my first post so please let me know if you need more information.
I have recently assembled my new i3 mk2 and have been running the tests/calibrations. The selftest (fans, temps, endstops etc.) goes fine. However I am running into an issue with the XYZ calibration.
It runs the initial step over the 4 points without any issues, and moves onto finding the next 9 points. It does does 1, 2 and 3 without issue but when it gets to point 4 it just pushes quite hard into the heatbed, the bed bends and I have to quickly turn it off and manually adjust the Z axis up. I am worried this is going to damage my heatbed.
My PINDA probe is about as low as it can go before it gets lower than the nozzle. If I use the manual axis controls to manuever the extruder over the 4th point (that I can just about see through the heatbed surface) and lower the extruder down slowly, it does trigger the PINDA probe and stop me from moving it into the heatbed. However when the XYZ calibration runs it just ploughs into point 4.
One thing I have noticed is that there is a visible mark where the nozzle has hit the heatbed in my last few calibrations, and this is in a different place to where the nozzle is when I manually position the extruder over what I think is point 4. Its offset by about 5mm in the x and y axis.
Can anybody help?
Re: XYZ Calibration Issue
ehhh... i am sorry to hear it
It sounds like that part of the bed is much much higher than the rest of the bed. Try turning the z screws (by hand) so that the nozzle is pretty close the bed (try to keep the turns in sync and check with some calibers), and move the X cart and bed so you are at home, 0,0,0. While the nozzle is real close, move the x cart to the right side while watching the gap between the nozzle and bed. See if it changes. Do the same for the back right by pulling the bed towards you, always keeping an eye on the gap. Do not allow the nozzle to touch the bed.. obviously. Do all four corners and spot check a few places in the middle. A bump or a completely unleveled bed will be pretty clear, even if your z is out of sync (which will look pretty uniformly sloped on one side).
Turn the printing on the PSU side and check to make sure there are no gaps between the bed nuts and the bed frame. Use a flashlight from behind and look for light bleeding through the cracks. Gently loosen all the bed screws and retighten them, starting at the middle.
Check the bed with a level or ruler. If there are crazy gaps or play in the ruler, let customer service know.
Re: XYZ Calibration Issue
Did you fix your issue as I seem to be having the same problem.
First 4 are fine then it moves on to the 9 points and it rams into the bed at point 4 🙁
Re: XYZ Calibration Issue
Ensure the large threaded rod under that point is as far down into the vertical frame as possible. Loosen the 10mm nut(s) and push the rod all the way down into the groove in the frame.
I got this problem after correcting for x/y skew. When I checked the threaded rod under point 4 (power supply side) it had moved up a bit. When I snugged it down and re-ran the calibration the problem was gone.
DJ Roberts
Re: XYZ Calibration Issue
Do not take your printer apart if it was previously working well.
Ramming the nozzle into the calibration point at about X250 Y100 is a favourite pastime of the Original Prusa i3 MK2. It just wants to tease you a bit. Next time you run the calibration, it might very well go perfectly and end with 'Congratulations!'
Of course many have tried this and that, and then attributed the absence of the slamming into the bed at point 4 of 9 to whatever they did. It probably had nothing to do with it though!
I think it is a software problem, because the same point that gets found just fine as point 2 in the first round of the XYZ calibration is then totally missed in the second round of 9 point calibration.
And if you try calibrating again, maybe after puling the power plug out for a half a minute to show who is the boss, without taking stuff apart first, you will probably find that it completes calibration.