Hello, can someone help me find solution to this problem with a1 mini? I started to have some printing. Previously, everything was working normally and correctly. I printed an entire spool of PLA with very good quality. Then, I ordered a new filament Bambu PETG HF. I dried it as instructed on the website(profile in bambu slicer is PETG HF), and I was able to print for a few hours without any problems. Total printing time is less than 80 hours. However, now the printing looks like this. I’m having trouble with the first layers, as the filament keeps detaching in certain spots. Later in the print, it seems like the filament is not being fed properly, and you can hear the printer trying to pull it but struggling, which causes the filament to develop little teeth marks. I’ve tried pretty much every guide available on your website. I cleaned the hotend, the entire extruder following this guide: A1 series extruder cleaning tutorial | Bambu Lab Wiki, unclogged the nozzle, recalibrated the whole printer several times, and even tried a different color filament. I’ve ordered a total of 4 spools, and still no luck. I also cleaned the PEI practically after every print, but nothing has worked. I’m out of ideas on what else could help me 
Welcome to the forum.
Can I ask how you are cleaning your bed?
First off, welcome to the community! Thank you for taking the time to provide a good amount of detail and pictures showing your problem. Helps with troubleshooting.
I have a couple of questions that will possibly help identify the problem.
- How are you washing your build plate? If you are only using isopropyl alcohol, then that won’t be enough to get the oils off of the build plate. Giving it a thorough wash with dish soap is the best way to remove any oil contaminates that would lead to poor first layer adhesion issues.
- Have you swapped your nozzle recently to a different size or made any other modifcations? It can be easy to do nozzle swaps and forget to change it in the slicer, which can lead to all kinds of fun issues.
- Have you tried drying the filament again? Everything I’ve been reading about this new PETG HF is that its super hygroscopic and needs to be dried and kept dry in order to prevent issues. The best way to determine that your filament is completely dry is to weigh it before drying; once it stops losing weight, it’s fully dry.
- Have you tried switching back to PLA to see if it starts printing ok? That’d help identify if it’s the printer or the filament.
Few times tried with IPA alcohole and few times with hot water and soap and then let it dry.
- Few times tried with IPA alcohole and few times with hot water and soap and then let it dry.
- No i didn’t swap nozzle,
- I dried one filament for over 12 hours, and it looks the same as the one dried for 8 hours,
- Yeah I will switch back to PLA but actually I don’t have any because I wanted to print only with PETG, tomorow PLA will arrive and gonna try it and reply results.
I also checked to see if any connectors had come loose, but that didn’t help either. However, I then checked the heater temperatures, and it turns out that the heater isn’t maintaining the temperature it constantly fluctuates between 150-190°C, even though it’s set to 250°C, and the printer also registers that temperature. To ensure that the thermometer is working correctly, I checked the bed temperature, and it was accurate 60°C, 70°C, 80°C, etc.
I also removed the old filament from the nozzle when it was heated to 250°C, and as shown in one of the photos, the filament didn’t melt but instead stretched as if the temperature were half as low. Now, when looking through the nozzle, I can see a hole all the way through, so I don’t think that’s where the problem lies…
So, does this mean that the heater or the Toolhead Board needs to be replaced? Would this issue qualify for a warranty replacement?
Looks like your printer is not working correctly. Open a ticket to BBL and see what they say.
Is it possible to please share the .3mf file of the print that has failed?
Have you changed any settings related to the temperature?
Are you printing directly from the spool, or using the AMS lite?
Have you checked if the filament path is free from any debris, and allows the filament to smoothly reach the extruder?
It also seems like you are using a 0.2 mm nozzle. It is recommended to ensure the profile used is the one for the 0.2 mm nozzle.
If this happens with the nozzle installed, then the problem could be with the heater assembly. But if it happens without a nozzle, this can be normal.
Please also note that measuring the temperature of a shiny surface like the heating assembly might not be accurate, as the measurement device used can be inaccurate in this case.
The temperature displayed on the screen looks to be 250C, the one you set meaning that the thermistor is correctly identifying it.
I don’t think there’s any point in uploading a file since I’ve already tried printing around five different models, including the Benchy in the printer’s memory.
I’m not using the AMS; I’m printing directly from the spool. The nozzle is the standard 0.4 mm, and I’ve had this printer for about two weeks. Everything is original, and I haven’t tried any modifications.
Yes, this issue occurs even with the nozzle installed, and the temperature of the nozzle is actually lower than what I measured directly from the heating element.
I’ve had a few printers before, so I would consider myself an intermediate user 
. I’ve checked everything I could on my own or through the Bambu Wiki.