Hi there, i got a commercial order and as always time is little. I have to keep all my printers running at the same time and everything needs to work perfectly to finish printing in time - of course it is the right time for unexpected problems to appear…
Out of nowhere one of my p1s started having these weird weird wavy pattern in layer height. I print this part in batches of 20 and all look the same. I use dried petg but the material doesn’t seem to be the problem since I used it in other printers to print the same parts without any problems. I did recalibrate the printer already but nothing changed. tried grid and gyroid infill without improvement. I am going nuts right now because this is a very important order for me and I am about to fail it. I need all printers to work to make it in time. please anyone got any suggestions?
it is printed in geeetech petg, transparent, 0,20mm layer height, 15% infill, 3 outer lines, different infill patterns used already. the filament and model works great on my older p1s (multiple ones) with even more printing hours on them. however my newest p1s with only about 500h printing time causes these weird waves in height direction.
the last picture shows that there is no adhesion problem. the prints do stick to the sheet pretty well. what is going on here?
I did another test using a primitive with a cut at about 30 degree angle (which comes close to the original part) and can see the defect as well, although it does look a little different
Suggested troubleshooting steps. Not necessarily in any order.
Change the wall order from the default of inner/outer to outer/inner.
Change the infill pattern to “something else”.
Change the infill rotation and note if the wavy lines change locations. If they do, then that implies that he underlying structure and density are influencing the pattern you’re seeing.
Try altering the temperature using one test example with extremely low temps and the other extremely high filament temps.
Last but not least and my personal favorite with transparent PETG, forego infill altogether and increase the wall counts to an extreme value(see photo below of a transparent PETG sample)
This sample was an experiment that used wall thickness of 999 walls. I keep it around as a paperweight. While this may not be practical for production use, it will at least assure you that he filament your using is calibrated and capable of printing smoothly. See this post from 2 years ago on transparent PETG and it will show you that it is indeed possible to achieve near perfect results albeit maybe not one that applies to all use-cases. Transparent PETG Basic - Any tips? - #16 by Olias
Of course, I am assuming you already manually calibrated the filament and did not rely on autocalibration. Clear PETG is a great product from a variety of vendors but in my experience, it still needs TLC and I’ve found that I had to create custom printer and filament profiles depending on just how precise I wanted to dial in results.
Thank you so much for your quick and kind response. I am really stressed out about this. I also noticed that the wavy pattern happens to weirdly fit the exact position where the infill meets the wall - However I want to highlight the following while I will try working along your list:
i do print this job on 4 printers, all p1s, all with the exact same filament and exact same file and settings. only one printer has these problems
I already tried gyroid, nothing changed
since the printing object is tilted I used inner/outer so the most outer line has more to stick to
if you look at the second post you will notice that I printed a different object (primitive with cut for tilted angle) and it is also bad quality
it somehow looks like there may be some sort of slipping in x/y axis. I also thought about some kind of oozing problem or maybe the extended seam. I did two more test objects, reset all settings to default and switch from geeetech transparent petg to Bambu lab petg hf white. they will be ready in about 15 minutes
since this problem is unique to one printer only and happen on other objects as well I would assume that it is hardware related
Yes, it seems to be exclusively on the overhang side but it happens regardless whether the overhang is on the left or right side of the print bed. It appears to be fine at first and start having issues at around 3-4mm or 15-20th layer, regardless color or manufacturer
If you have 3 out of 4 printers working, that at least reduces the troubleshooting dramatically. If you suspect X/Y tolerance issues. The things I would do in the following order.
Ensure that the carbon rods are cleaned only with IPA - See the Bambu Wiki for that. Do not use lube.
Check the movement of the carriage itself. Do this with the power turn off lest you risk damaging the stepper motors. What you want to do is move the toolhead manually and “feel” for any resistance in movement.
Check the chain at the top and make sure that the PTFE tube is not snagging on anything when moving.
If you haven’t already done so, for the purposes of process of elimination, rerun the factory resonance vibration procedure. You may recall, this is the 20 minute test that has increasing harmonic tone. It is available on the P1 panel. I do not expect this to fix the problem you describe but it will rule out harmonics as a cause.
Have you also tried moving the model on the build plate to the far corners and seeing if it influences the outcome? That alone will tell you a lot.
And absolutely last resort. Check the belt tensioning procedure. Note that this is only as a last resort. The procedure is the same for the X1 and P1 so don’t be thrown off by the X1 examples. Belt tensioning procedure | Bambu Lab Wiki
Ok, so after hours and hours of tinkering, I am really exhausted, but I managed to make it work properly again thanks to the help of you both. I really appreciate your help.
However, I am not sure what led to the solution, but in case anyone comes here while seeking help, I will try to explain everything I did in order to solve this:
I blew out the whole printer with pressurised air, especially all fans. They seemed to work fine, had no clogs or dust in it, but you never know for sure.
I cleaned all rods and axis and lubricated where it’s supposed to be. Basically, I did all the maintenance needed. It was my first cleaning ever after 496h of printing (shame on me, I know).
I disassembled the hotend and replugged everything (because I read about loose cable connections for the part cooling fan somewhere else).
I ran the calibration again.
After this, I did another test print and it came out perfect. Whatever solved my problem is included in the steps above.
My best guess is that there was some sort of cooling problem (even when all fans seemed to work as intended!) as @Johnny_Bit suggested above. I could recreate the error before going through the steps, I cannot recreate it afterwards. Maybe i fixed a loose cable connection without noticing it or improved the cooling by cleaning the fans.
