Z height won't stick after PID calibration?!
Hello all,
I've been fine tuning my printer over the last week, trying to improve my prints, and I'm experiencing a very odd and blocking issue with my printer. When perusing the calibration menu over the weekend I decided to run a PID calibration to help reduce the hot end temperature swings I was experiencing. It worked! My hot end now runs at a very stable temperature. However I'm now experiencing a very odd and maybe unrelated issue? Since calibrating my hot end, I've adjusted my PINDA probe and rerun the Z calibration. After running a calibration squares print and tuning my live z adjust, I ran the print one more time to verify the z height, and this time my nozzle is not even close to where it was before! Live Z adjust reads correctly, it reports that it's still where I set it, but it cant be! I'm so confused. 😕 Is this a firmware issue? I've since updated to the very latest firmware and I'm still experiencing this. I've verified that the PINDA probe is at a reasonable height and isn't loose. I can't continue printing, as I cant even get a passable first layer! Please help! 🙁
Re: Z height won't stick after PID calibration?!
When you say "not even close to where it was before" what exactly do you mean? You state that the Z calibration is the same so I guess you mean the -.xxx number is the same, but the results are different?
If I am correct, I had similar odd issue. My problem was that the grub screw that holds the heater block thermistor in place was loose which was causing temperature swings that were not registered properly because the thermistor was not making good contact and providing proper temp readings. This led to a great first level one print and way off and stringy the next.
Not sure what is happening for you, but it was causing similar problems for me.
Also, could be that you have the extruder idler too loose or firm causing filament feed problems. Also check to make sure the grub screw in the hobbed pully on the extruder is good and tight.
I think the fact that this occurred after your PID calibration is just a coincidence and the calibration has little to do with your problem.
Re: Z height won't stick after PID calibration?!
Sorry George,
I guess I wasn't clear enough. I'm not actually having any issues with over/under extrusion at the moment. My extruder seems to be feeding the filament just fine. My real issue is that after running V2Calibration.gcode or similar and setting my Live Z Adjust to where it needs to be. On the next print, despite what the Live Z Adjust reads, the print head is always several mm in the air. Plastic is being extruded into the air, instead of on the bed, which makes it impossible to print. I haven't actually tried continuing to move my Live Z Adjust in the negative direction, but it appears I would need to move it a mm or more, which can't be correct with my PINDA placement. It seems to be similar to the problem here, which I'm not sure was ever resolved. Anyone have any updates on this?
Re: Z height won't stick after PID calibration?!
Can you try printing one of the pre-sliced G-Code files on the SD card? Prusa logo would be good,
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Z height won't stick after PID calibration?!
My real issue is that after running V2Calibration.gcode or similar and setting my Live Z Adjust to where it needs to be. On the next print, despite what the Live Z Adjust reads, the print head is always several mm in the air. Plastic is being extruded into the air, instead of on the bed, which makes it impossible to print.
What are you trying to print? Is this sliced based on a known working STL like benchy, cat, etc or something 'new'? What material are you using to print? What slicer are you using to slice it?
First thing I would do is print one of the already sliced models on the SD card. If it prints fine, then the issue is with your STL, sliced gcode, slicer settings or something else not related to the printer itself.
I have seen this happen when someone has preheated the bed, while the having the print head close to the bed. The bed heat can cause an issue with the PINDA. I normally make sure mine is raised higher before starting prints, but I usually don't have an issue with PLA (only with ABS/PETG because the bed is at a hotter temperature).
Re: Z height won't stick after PID calibration?!
Since calibrating my hot end, I've adjusted my PINDA probe and rerun the Z calibration. After running a calibration squares print and tuning my live z adjust, I ran the print one more time to verify the z height, and this time my nozzle is not even close to where it was before!
Did you run a script with G87 inside? if not, try to add it at the start of your Z calibration script.
You can also try with G88, but it doesn't seem to do anything.
Re: Z height won't stick after PID calibration?!
Hey guys, sorry, got busy. It turns out that my issue was some difference between the new firmware version and slic3r. I downloaded the latest version of slicer and the issue seems to have resolved itself. *shrug* 😕