Creeping Live Z value
I’m trying to set my Live Z value using jeffjordan’s method ( https://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/life-adjust-z-my-way-t2981.html ). During the printing of one square, I can lower the Live Z value until the diagonals are firmly attached to the bed and welded to each other. If I let the print complete and immediately print it again, the filament is back to not sticking, exactly as it did the first time. Lower the Z value, rinse and repeat. Each time the print reverts to its unstuck condition, but the Live Z value keeps getting increasingly negative. The only thing I can think of is that the preprinting calibration keeps changing its results to undo the Live Z change from the last print. Is there any way to access the working calibration constants to verify that they keep changing? Thanks.
Latest firmware for MK2MM, 3.0.12, modified only to enable use of a PT-100 thermometer with amp.
Re: Creeping Live Z value
I am afraid I cant tell you a way to read the PINDA values, but I think you are right about that.
Due to the heat of the heatbed the probe will warm up which will result in different measurements.
To prevent that from happening you should leave the Extruder about 10cm above the heatbed while its heating up and before the mesh bed levelling routine is executed. In order to do that, customize your start gcode.
Check out cory.w's start sequence in this thread.
Re: Creeping Live Z value
Unfortunately, I don’t think that can be the problem. As soon as one print finishes, I immediately place the hotend at 10.7mm, not cm, and preheat back to PLA temperatures before anything else. There is no time for the PINDA to cool down.
Re: Creeping Live Z value
Ok, so obviously it would turn out to be pilot error. I was struggling to calibrate the Z axis and lost track of where I was wrt power down/up, resets, calibration steps, etc. Plus the frustration meant that I wasn’t carefully watching the message that popped up on the LCD on reboot. Turns out it was telling me to do the calibration from the beginning, not set the Live Z value. So, of course on reboot it ignored the Z value I had set. Since the Z value lingered in the Live Z Set menu item, it kept getting more negative each time I went around that roundabout, Nevermind. I now have learned a bunch of tricks and calibrated it better than ever.