hi, lately I’m getting these weird artifacts.
only of “organic” models. it doesn’t happen on smooth objects (for example I tried printing cilinders, tall boxes,…).
I see it happen to other people, but I haven’t found an answer to what might cause the problem.
Whenever I see artifacts like this my solution is to clean the carbon rods and perform belt tension maintenance. I have found this normally solved the issues for me.
Also check the idler pulleys for buildup of black globs.
I will try that for sure during the weekend, thank you for the suggestion.
I was just hoping to find someone who had that exact kind of artifacts since it seems pretty specific.
thank you, I’ll try that as well
This picture appears to be a ghosting effect. Have you calibrated the filament for pressure advance and flow ratio? It could also be a retraction issue.
this is BL filament, using BL profile, so I guess it should just work?
it also happens with non BL filaments, dual color silk and other matter pla brands.
that’s why I think it’s a problem with the printer, not with the filament itself
I have had to calibrate the last few rolls of Bambu filament. It seems like the last couple spools of grey are very different from black, blue, red, etc.
I have a custom flow ratio profile for Bambu PLA. I have two K-factors for Bambu PLA, one for grey, and one for all other colors.
thank you for your advice, but it’s not the filament.
I used these same filaments before without and they worked perfectly.
this problem happens no matter what filament I use
You could perform a factory reset on the printer. Others have reported it to solve some very strange issues.
I’ll keep that in mind if nothing else works.
what bothers me is that it is such a specifica problem that I’ve seen happen to other people, but there is not a clear answer on how to solve it
in the last month I started to have these weird artifacts appear on every model I print.
before then I used the same filaments and printed some of the same models without any issues.
I’ve just tried to tension the belts and ran a complete calibration.
the filaments are all dry.
I have seen someone else on the internet with the same kind of artifacts but I haven’t seen anyone suggesting for a correct solution.
I think it must be a very specific problem cos it’s different from ringing or ghosting and it creates very specific patterns.
Can you post a few slicer preview’s? Layer height, Flow, Line type (incl. Seams), Fan, Layer time and Line width? Preferrably with the model orientation shown (facing the aux-fan or not).
Guessing from the pic’s, nozzle movement is from left to right? Seams are quite far away from the errors?
aux fan is off.
as I wrote I’ve already used these filaments and printed some of these models one or two months ago without any issues. so it’s not something with the model, or the filaments or the slicer.
no updates, nothing changed.
at some point it started doing that.
my guess it needs some kind of maintenance? (I’ve already followed the guide on how to retension the belts and I greased the screws that guide the plate up and down).
the problem is so specific and it always does those particular artifacts, that I’m sure there is a precise answer to this problem. I’ve seen others report it, but only a few and I haven’t found answers when they ask for help either
Well, what you are seeing is a classical flow dynamics issue. With it probably not located close to the scarf seam there can be a number of very different root causes.
Maintenance related ones are indeed belt tensioning and carbon rod cleaning.
But you may want to run through the package just in case. There is after all the off chance that dust is accumulating in the extruder or (if you have been printing filled filaments) the nozzle having suffered a little.
Do not however discount environmental effects. I have had rolls go bad wirhin hours when particularly nasty weather passed through. So if you had some rain recently wirh the spool open or your AMS shows over 20%, it may be an easy fix.
& 
thank you for all your suggestions.
I’m ruling out filament and estruder only because I keep my filament dried and I’ve already used it successfully. also, the main reason is that I printed a couple of tests: a mix of basic shapes, tall cube and a tall cylinder, and those came out without issues.
the problem seems to only happen with “organic” shapes. the bust of a person, a figurine of character…
I’ll keep trying and any suggestion is welcomed anyway! so thank you again
I re-tensioned the belts, cleaned the carbon rods, lubed the screws, run a full calibration, three times.
nothing changed… I opened a ticket with BL and I hope they will have an answer.
I don’t know if changing the extruder might be the solution?
Not sure if you need to change the extruder. You may want to have a look at the insides of the extruder gear and clean that But I would not put up my hopes. Extruder issues would not be limited to vertical walls in high acceleration areas.
What you could do while waiting for Bambu support to get back to you is to re-dry the filament, re-calibrate it and then do a test print from the rear spool.
Maybe even with accellerations dropped to 25-50% and steady 0.2 or 0.16mm layer height. But check the flow and speed previews. You want to avoid quick changes in accelerations in low flow conditions.
This is just for debugging/root cause elimination purposes. Get a good print first, then add detail before targetting a good, detailed, fast print.
all great suggestions for troubleshooting. thank you
