Hi there,
Since several days I have more and more issues while printing. First it began with PETG (generic) filament, now I have the same issues with original Bambulab PLA. The printing ist not solid. The walls are quite fragile and look like a sponge. Furthermore you can fracture them with a few power.
Does anyone has an idea what the reason for that issue could be?
I used the standard parameters for the filaments (bambu/generic). The problem is the same with each AMS-Slot.
Guido
It looks like some sort of low temp/under extrusion issue. Assuming you haven’t changed any of your printer settings, what’s the ambient temp where your printer is? Years ago, I spent an entire day chasing my tail trying to figure out why the same PLA printed perfectly the previous day, but the next day it failed miserably printing the same part. Turns out it was winter time and I had not turned on the heater, so it was around 60F in my house. I turned the heater on and once the indoor temp came up to over 70F everything was fine.
I just fixed a similar issue on mine with a nozzle change due to a partially clogged nozzle. You might try a “cold pull” first but in my case I had to replace the nozzle.
Your hotend may need replacement or proper maintenance if everything else is in order.
If you have a complete hotend at hand, the replacement is swift. (Replacing the complete hotend assembly / Nozzle Replacement Guide | Bambu Lab Wiki). If not, take a few more steps; nothing difficult (Replacing the hotend/ceramic heater/thermistor/cooling fan | Bambu Lab Wiki).
If you feel that your nozzle is still suitable, you may verify if it is partially clogged or at least try to clean it before stepping into changes. You may start by moving the toolhead to a suitable position and heating it until your filament’s melting temperature. Afterwards, carefully insert the need in the nozzle and verify if there is any obstruction.
Other issues may be related to the temperature sensors. Yet I think that you would receive a warning.
Most of the procedures are detailed in the maintenance section.
BTW, did you print any abrasive filaments recently?
Thank you so far for your answers.
@0x80O0oOverfl0w: the enviroment condition is still the same. I print in the cellar, the temperature did not change
@azCubs76/JayZay: I tried to print Polycabonat several times but I had a clogged extruder than. So I had to clean it. Now I did a cold pull but it seems that the issue is still there. I am in a hurry now, so I will change the nozzle later and give you informations about the result.
By the way: the spring inside the extruder must be as strong as it can be? I tightend the screw as much as I could …
Try drying your filament in the printer and then run your print again.
I dry PLA at 55Âş, PETG at 70Âş, for 8 hours each.
Mine is the same. It was initially tightened to the maximum, and I kept it that way.
PC without additives is not abrasive., at least the ones I use. Are you using the hard steel nozzle?
PS: since you are doing maintenance, also check the PTFE tubes between the AMS and extruder. It is a long shot, but it will not take you a long time to do this check.
It seems that the new print is much better. although I do not understand it because I did not use abrasive Filament. I printed now with generic PETG, because Bambu PLA was empty.
So i will try this way first in the future.
The nozzle should be hardened Steel, it´s the one from the delivery condition. Should I use an other one? PTFE tubes seems to be okay.
I am a bit frustrated because PC does not work, neither TPU from AUX-Slot. With my first printer Anycubic i3 Mega ist was possible and as I read it is also possible with X1C. Probably I will try the one from Bambulab. In the past I used Form Futura Centaur.
TPU is shore 65. The filament stucked in thd extruder. So did TPU 95.
… sorry for changing the topic …
While I am printing the second part of the spool (first one is okay), I see issues in the first layer again 
Although it is still the high temperature plate and I did not have trouble rarely with PETG and the first layer (also using glue stick).
@Ikarus: probably my cellar ist to humid but in the past I did not have problems with old and opened filament. I will also try it.
The last picure is the first part of the spool. The print looks okay but if the first layer ist as bad as in the second part, probably there ist still underextrusion.
You can use hardened Steel or not. For that filament materials, it will not pose an issue.
I didn’t get it; what was the change?
If it was only filament, then I agree with @lkraus comment. You must have a wet filament. My only fails until now were reçlated to the wet filament, which I wasn’t aware of because they work flawlessly in the S1Pro. After drying them, all issues disappeared.
The PC and TPU will work, of that I am sure. But dealing with PLA or PETG makes finding and solving the issue easier. Do you have any filament dryer?
Changing the topic was TPU/PC 
… on a hand it is the same problem probably …
Now I tried serveral prints, they were all a mess. I tried also another complete new original PLA, also the AUX-Slot.
I will try to change the nozzle, but I have to buy it first. The old nozzle ist caked a bit from the outside so I can not pull the clip off. I will send the new printing result wenn I received the stuff.
Any idea what I can do in the meanwhile?
Since you have time, I would do maintenance and check every detail.
If you use the nozzle needle, do you notice any blockage or if you push filament through the nozzle (without an extruder), does it flows smoothly?
There are many tests you can do.
Printing and recording simple(e, g cube) prints: test slightly different temperatures to reduce speed; carry a flow rate test. Maybe it is better to set a plan; depending on the test results, you may change it.
I am also curious about the issue with your printer. To me, it continues to seem is filament or extruder/nozzle.
Didn’t you receive an extra nozzle or compete for hotend with the printer?
it is under extrude for sure your nozzle is bent or partially clogged replace the nozzle if you have spare parts and try again.
I think tomorrow or a day later I will receive the spare parts. I will tell you and hope for better results of course 
That´s good. Nevertheless, if you have time check what is the current issue. It would interesting to know it, and maybe it is still possible to recover your old nozzle.
So here are the results …
I printed with a new stainless steel hotend (complete new). The printing results are better, but the first layer is still a mess, while printing the spool (I printed with 50% speed - standard PETG-settings).
The 5-square testprint (one layer) is okay, I think. Maybe somebody can give me a hint why the first layer of the spool is so bad. I used glue in both cases with the high-temp-plate.
Temp Tower seems to be okay. It looks and feels similar to the old one before the issues.
I did also check the tubes - they are okay.
I did not try drying the filament yet. I dont have a filament dryer but I can do it in the printer.
The new results are with the “old” (not dryed) filament.
The pictures shows the prints after changing the nozzle, with the “old” filament
I agree with @ismart2k 
Looks like you have issues beyond bed adhesion that I’m not sure about. Best guess is you have some carbonized TPU stuck in the nozzle and need to replace it.
That said, I highly recommend the Textured PEI plate for PETG. It sticks great and removes easily after it cools down. No more messing with glue!
I print exclusively in PETG on the textured PEI plate and never have issues. I use Orca Slicer and do full calibrations on all filaments before printing anything. IMO, it’s much better than the Bambu slicer.
I think there can not be TPU in the hotend. I changed it after I tried to print TPU with the old nozzle.
Actually the first layer does not look so bad when I printed the 5 squares. The spool ist always a mess.
I will try it with the PEI plate.
PEI plate + gluestick?
I ordered a drying box … hope this will improve all
I only use the Textured PEI plate and never use glue. I’ve done PETG, Standard PLA, PLA-CF and TPU 95A. No experience with others or with a smooth PEI plate. I’ve found the key is to wipe the plate with IPA between every 4th print or so and never have bed adhesion issues.
So new hotend, and you already did the extruder. I am sorry for you, as this seems hard to solve.
I am no expert in spreading glue on the bed plate, but from the pictures seems too much.
I hate to spread the glue, and I am so bad at it that my first print, the famous fast benchy failed just because I had too much (at least that was my conclusion).
At this point, I assume that you are being careful with the bed cleaning.
So I am getting out of ideas. Or you have a mechanical issue, or the bed mesh is failing. You will need BL support in each case because we cannot read the logs.
One last try is that you record the printing starts, including the startup tuning. I am unsure if this will work, but I hope that by looking at it, we can identify where the issue is or at least discard the mechanical problems.
