Bambu P1S - 840 hours total.
Slicer Settings - NA. Nothing makes a difference to this problem, it seems machine related.
Bambu PLA (Basic) filament.
Hello,
I started to have a problem last night where the printer, when starting a print heats the nozzle up to 250 degrees, primes inside the chute, whilst it’s doing this the bed also seems to come up to the correct temperature but Bambu Studio or Orca both state “Preheating Heatbed” or words to that effect. The print head then moves to the front right (as you look at it from the front) of the printer and it seems like it’s hitting the front harder than it should, it then moves across to the other side (the left) and then goes back to the chute, OR just goes back diagonally from the front right after it hits the front.
It does this in a continual loop, purging each time it returns to the chute and then returns to the front right again, over and over. Bambu Studio still says its on the pre-heating bed part, but the bed is hitting the temperatures which I’ve also checked externally with a laser thermometer.
Obviously I don’t let it go continuously but I do get the impression that it’s not ever going to actually print and I don’t want to physically damage the printer either.
I have removed the AMS from the situation and fed the printhead directly from the external spool as to eliminate everything I can.
I have factory reset the printer
Made a new Bambu account so I had only stock presets.
There are no errors.
No firmware changes.
No hardware has changed.
Nothing that I can think of triggered this.
Nothing else strange before this happened.
I have tried different filament.
I have tried a different nozzle.
The problem exists with or without the AMS in the system.
If anyone could shed some light on this I would appreciate it as it’s driving me nuts.
hey - they both look good, both the same, machine is regularly maintained as it should be. Bed movement up and down is also good, no different to normal. Just a wild print head.
I was thinking the two bearings wouldn’t be slotted evenly, flush on top. This will cause errors, usually bed errors but it could be the head.
I suggest using Handy and reverting to a previous firmware first. I haven’t seen this issue that I can recall. If you haven’t then run calibration again. You didn’t mention it but will not hurt. May not help, maybe it will. I have a hunch, but I’d let support handle it. Ask about the AP board if a revert and calibration don’t cut it.
A failing or full SD card will often do weird things like this. The P1S uses the SD to store and read the print file unlike the X and H series (and perhaps the P2S?).
Suggest trying a different SD card. You can format via the printer or format it to FAT32 via a computer.
A bad filament sensor cable which threw the error I mentioned - it’s just not on the screen all of the time and you HAVE to be on the home/top part of the screen on the P1S to see it, the error didn’t ever appear in Bambu studio for me. It would just get stuck on whatever part of the pre-print process it made it to - usually nozzle cleaning or bed preheating.
ERRATIC BEHAVIOUR / LOOPED PRIMING
TLDR: The erratic behaviour was caused by something else, the quick and dirty fix is to disable “Auto-recover from step loss” which you can find in Bambu Studio → Devices Tab → “Print Options” (top right).
The cause of the priming/homing over and over again seems to be (for me anyway) to do with the PTFE tubing OR the plastic chain that runs from the back of the enclosure to the print head, if either of these hit the side of the enclosure (hard enough… whatever that is) when it’s homing the printer will automatically return to the chute and try and do the homing again and because the tubing or chain always hit the side it triggered this behaviour in a recursive loop which it cannot escape as the very behaviour it attempts to remedy the problem just triggers the same “fix” to run over and over again.
Once I shortened the PTFE tubing and clipped it to the chain at a more aggressive angle it reduces the force that they hit the side of the printer, and it doesn’t trigger the step-loss code.
Hello,
Just to put this to bed incase anyone else comes across this thread in the future.
My issue was either the PCB or the Hall Sensor on the "Extruder Filament Sensor) Even though the cable looked fine and the continuity from the sensor end to connector was also fine on my multimeter (from what I could tell) it seemed like the printer could not detect it at all.
Managed to find somewhere that shipped the item overnight, purchased a new TH cable and extruder interface board (just in case) and made a back up order with Bambu as unfortunately they don’t do next day delivery and I’m impatient.
