Hi all
Need some help. Was getting some missing lines / gaps in my print. Happened halfway through a 12 hour print.
Door was open. It is PLA. I have performed a device test including a manual test of the fans. All appear to be working. I then Used once of those cleaning wires to try and make sure not a block and printed a benchy but no joy, still getting those defects. Cleaned the nozzle again. Did a cold pull and yes I saw “bits” on the pulled filament. Did another nozzle clean with a needle but still having issues.
So I fitted a brand new hotted and it is still happening. Please can anyone provide any guidance.
thanks
Josh
Indeed, that does not look good. Since there are number of things that can cause this, I would recommend this troubleshooting chain:
Of course the filament needs to be dry and the temp should be sufficiently high and stable. For PLA (only), I have found it does not matter much if the door and top are open. I prefer to things closed.
Do a number of hex key cold pulls again. It is common that multiple pulls are needed to clean a partial clog.
While having the hot end in your hand, check the thermal paste. If it flakes, renew. This is also good opp to check that the nozzle is straight.
Before trying a print again, clean the extruder in case of flakes/filament dust travelling back and forth.
While doing that, have a look at the filament cutter in case it is blunted or likes to stick.
Check and if neccessary replace your PTFE’s, in particular to the extruder and from the AMS to the Hub/Buffer (they tend to be my personal pain points).
I hope that one or more of these points are helpful.
Leaving the door open is a misconception. I’m not sure where this idea started, but it’s rarely the cause of these issues. Unfortunately, there’s a lot of bad advice circulating online that perpetuates this myth.
The picture you provided is helpful, but could you upload three more? These shots would provide a clearer understanding:
An oblique angle lower to the plate.
A view of the entire build plate with the whole model.
A “focused” zoomed-in shot of this area. The current image is a bit blurry, and a sharper image would help to confirm some theories.
If you hadn’t mentioned you were printing with PLA, I would’ve guessed you were using a TPU profile. Are you using the default profile or did you calibrate it manually?
There is a clear temperature difference in how the filament was laid down. The filament at the top is at a much cooler temperature compared to the lower layers. The most likely cause is that your fan is turning on when it shouldn’t.
Troubleshooting recommendations (Follow these in order):
Obey Rule #1 of troubleshooting: Change only one variable at a time! This is crucial. Do not make multiple changes all at once—it will only confuse the process. Make no changes to your setup until you can consistently reproduce the issue using a test model. A good practice is to use the same 3MF file and create a second plate to print the diagnostic shape on, ensuring the same settings are used.
Start with a simple primitive, such as a cylinder, at a height similar to your model. The goal is to recreate the conditions on a smaller scale, saving time and filament.
For your case, I recommend making two cylinders and joining them into a single assembly. Scale it to 80mm vertical height, which should be similar to your model.
Once you have this setup, experiment with fan and temperature settings. If the defect doesn’t appear in the test model, you may want to cut a vertical slice from your current model to test a portion of it, creating a reproducible segment for troubleshooting.
Thanks both, I had some time for remediation today. I have changed the hotend as the last one was the original and had 2300+ hours print time. I also cleaned the extruder and there were some bits in there. I washed the plate, twice as you suggested and tested all the fans again to see if they all still come on and they do.
Only had time for 1 test print. The Grey benchy is before and the white is after the above actions. The bench was as 20 layer height and was a 39 min print.
Looks a bit better. I think. Will test again tomorrow.
Thanks for posting a known model. This new information really leads to a filament that is out of calibration. Moisture is a possibility even though it’s PLA. Drying your filament can’t hurt so consider that as a first step in troubleshooting before you go any further. Or you can simply try another filament just to see if you can reproduce the problem.
Based on the line in the middle, it’s clear that you’re experiencing filament shrinkage at the deck line. This is caused by the filament behind the wall having more mass so you’re getting shrinkage which is causing the outer wall to shrink at a different rate than the other walls that are thinner.
Now, you could easily go into your slicer settings and change the wall thickness or switch the wall sequence from the default inner/outer to outer/inner, but that doesn’t address the fundamental issue, which is a filament problem.
You shouldn’t accept anything less than this quality.
Note the smooth hull lines. The model on the left is PLA-CF at 0.28, and the one on the right is PLA at 0.08. I would consider the one on the right an inferior print due to the stringiness I haven’t yet calibrated out, but at least the hull is respectable. Note that there are barely visible hull lines, and there is some ringing in the filament flow on the right side. This may seem picky, but the results on the left are what we’re striving for, and as you can see, yours isn’t even close. I’m not saying this to make you feel bad—it’s just that you need to know what success looks like in order to reproduce it.
I fully agree with @Olias that the benchy is not yet acceptable. Although there’s an important improvement from the lower grey benchy to the white upper one, it is still below X1 capabilities. Give your printer a bit of TLC : Run through the recommended maintenance on the wiki Bambu Lab X1 Maintenance Recommendation | Bambu Lab Wiki. I expect the X1 to reward you with a better benchy.
Thanks for posting the detailed photos and side-by-side comparison. It confirms what I suspected. This shows meaningful progress.
You’re now getting consistent results between the two machines, which is crucial. This means the remaining issues lie with either the filament profile or the filament itself. Have you tried another brand of filament/color?
Here’s what needs to be done next:
Dry your filament: Weigh it before and after drying to verify moisture removal. Even slight moisture can cause these kinds of “layering” effects, and it’s critical to rule out moisture as a culprit no matter how unlikely.
Calibrate your filament manually: Those inconsistent layer lines, especially with PLA, indicate clear flow rate issues. This should be addressed. If you don’t want to initially take the time to perform full calibration, at least drop your print speed by 50% using silent mode. This will help isolate flow rate as the root cause. You could go into the speed menu and make changes there but that’s time consuming and the silent mode is one button click.
Run a temperature tower test: This is critical. You must ensure the filament temperature is optimized for your machine. While moisture can affect print quality, simply changing temperatures won’t solve all the issues.
Don’t waste time on temp towers downloaded from the web—those static STL files don’t include the necessary temperature changes. The G-code must be modified to adjust the temperature at each block, which is something Orca Slicer handles automatically in its calibration menu. If your sliced temp tower doesn’t show clear, distinct temperature blocks, something went wrong.
Use Orca Slicer for testing: If you don’t already have it loaded, there is no downside to having both slicers on your machine. Bambu Studio is too limited for this kind of detailed troubleshooting. Orca Slicer provides the advanced controls you’ll need to effectively run these tests.
Try these steps, and you’ll see immediate improvement. Let us know how it goes.
Thanks for that. Have dried the filament and having the same issues. Printer has 2300 hours on it, filament is the same I have been using for a big project. Got a new extruder on the way and will fit that first and then go back to calibrate.
Given the issue occurred during a very long print after 2 weeks of almost non stop printing I am really thinking a wear and tear issue. Have tested the fans i.e. on and off manually works in case this is to do with heat.
That is a viable theory that I always forget to check. When you get the new extruder, and if it remedies the problem, please post photos of the worn extruder so that he rest of the community can benefit.
BTW: On that line of thinking. You may also want to ensure that your PTFE pathways are unencumbered. Check the wear of the tubing as well as any binding. If you’re using an AMS, one diagnostic step that may help is to do a direct feed bypassing the AMS as a possible culprit.
This theory would also explain the inconsistent layering you’re seeing.
Thank you. I just checked the PTFE pathways and the one that comes into the X1 and goes to the extruder had a ridge in it where it had rubbed.
I replaced that AND bypassed the AMS but unfortunately the result was the same. On the upside I can now rule out the pathways and the AMS. New Extruder has been despatched and will report back in a couple of days when it arrives.
New extruder fitted and so far so good. Big improvement over the cube above.
To anyone who finds this thread after issues then I strongly suggest you follow the great advice I was given above. thanks to @Olias and @EnoTheThracian for their guidance.
The extruder that was replaced does not move smoothly when compared to the new one so clearly it has been worn by the 2300 hours of printing. Going to get another one in to replace the one in the other X1 I have as that has also passed the 2000 hour mark.
Hi,
Here are a few pictures. One is of a first layer of a small print so people can see that issue was fixed with the extruder change. I also took the old extruder apart and took some photos in case people wanted to see what they look like after 2300 hours of printing.
WOW!!! There’s your smoking gun. Look at that wear and tear. The great news here is that you were able to identify and remedy the root cause. That’s got to be cause for celebration. Thanks for sharing.
: Run through the recommended maintenance on the wiki 
Thanks for sharing.