I am printing with PETG-CF for a while now and I tryed many different settings but my nozzle keeps collecting filament during printing. Anybody with the same issue and a possible solution?
This is a picture after one print with 4 parts on the bed but it also happens with one part in one print.
Is your flow to high and the nozzle dig into the print? Did you calibrate your filament?
Finally, someone who has the same problem. I am not 100% sure, but I would say that I did not have this phenomenon after receiving the printer and before the last firmware update. Unfortunately, I am still too much of a noob in the 3D printing business to be able to carry out a fault analysis.
Yes I calibrated the filament but I thought when I use Bambu filament and their profile it should work. I already tested nozzle temps but just started to go cooler. Flowrate is still default value. Also my overhangs look terrible with that material, but I guess thats another topic. I came from a Prusa where everything worked when using Prusa defaults…
3D printing is not my hobby it just supports my hobbies so I am a bit lazy to try many different things. I thought this printer is the same workhorse like my Prusa just faster. As advertised. But I think thats not true.
Bambu’s PETG-CF is amazing filament if you ask me. It looks great, it is good for functional parts and with a bit of changes, it also prints very nice.
Try following:
Print with closed door and lid. Your chamber temp should be between 40-45 for ideal results. Before print, uncheck “Flow calibration” - it is not needed.
Regarding overhangs - there is a bug in OrcaSlicer in current version, so slow downs for overhangs doesn’t work. If you have a model with many overhangs, consider reducing outer wall print speed.
If you do it like I suggested, then you will get results like this:
I don’t use the Bambu petg-cf but I do use other brands of petg-cf.
Petg as you know can be a dripper and stick to the nozzle one bad thing with petg filament.
They do have nozzle coating you can try. I have never personally used it.
What are your retraction settings ?
You can try putting this in the your petg cf filament overrides but every filament needs to be tested for the best settings.
Length = 1.1
Z hop = zero
Retraction speed = 40
Deretraction speed = 30
Travel distance = 0.6
Use a min 20% infill that don’t overlap - samples gyroid or rectilinear
You might want to check out Orca slicer. It has more settings plus calibration tests.
Get the version 1.6.3 beta
Hope this helps you out 
I just switched back to firmware ver 1.04.01 (for the second time)
I gave it a fair shake but it just won’t work for me and I’ve spent lots of time chasing settings and mechanical issues, which is good because that way you catch other things you may not be looking for and will learn more about it in the process
The nozzle and bed heat sequence on the latest firmware is horrible, the nozzle heats up at the wrong times causing oozing
There is also an extra nozzle wipe sequence in the newest firmware that when matched up with the mis-timed nozzle heating creates messy issues
There are other bugs in the firmware which will get ironed out eventually, until then I suggest you roll back to 1.04.01 so you’re not chasing your tail over a firmware issue
Thank you for your detailed information I will try that in the next days and I also planned to use Orca Slicer for Calibration Tests. Your results are really good! My prints do look good aswell with PETG-CF it is just annoying that the nozzle always builds up that much filament and that it leads sometimes to failed prints when it gets too much and it takes the printed opbject by sticking or crashing from the bed.
So again thanks for the input!
I wasted the sunny day in my basement to fix this problem. And I dont get it. I tried it with the 0.4 and 0.6 Bambu nozzle and also with 0.4 CHT. I calibrated all of them with the orca. But on every print, the nozzle collects so much filament, which fall sooner or later off and ruins the print. I also tried from 0, 20, 30, 40 ,60, 80 and 100% cooling and temps from 240 to 260°C.
This is the only filament where I have such a problem. it looks like the nozzle is a magnet and attracts the filament xD
This is how the nozzle looks like while printing 
I cant even see the nozzle
It looks exactly the same on my side, maybe a little less collecting. I have tried with flow ratio set to 0.95 and with a little bit higher temperature (265) after the first layer and it is since then a little better.
It is really just this filament and I am currently testing PLA-CF and PAHT-CF to check if it is the same and it comes with the carbon…
I have the same issue with the PETG-CF. I loved the first results but when the print is longer (ca.3-4 hours) the results are messy. 1 hour prints are fine as the nozzle can’t collect that much filament.
Maybe the problem is with the material, and Bambu Lab launched it too early?
My other issue is that it sticks to the PEI textured plate too strongly. I tried to lower the first layer temps but not much improvement.
Let it cool down after print. Should be much easier to remove from the plate then.
Blobs on nozzle is something I get too. But if you clean it every couple of hours, it is fine and prints come out OK.
Do you get such huge blob for this small model? Perhaps your infill mode is wrong. Try Gyroid instead of Grid.
When it comes to blobs… what comes to my mind is perhaps playing with retraction settings - maybe larger Z hop could help?
For this example, it was 100% infill. But this should not be a problem. Printed PETG and ASA Parts with 100% infill.
I got my cyclops dryer today and printed parts in ASA for this https://www.printables.com/de/model/336958-eibos-cyclops-drive-mechanism and no problem at all.
For the weekend, i dry it for >12h and try it again. Maybe it was to wet
It’s a longshot, but perhaps the filament is magnetically attracted to your nozzle. The community has been finding various CF filaments are exhibiting magnetic properties.
Side note: Lots of digressing in that thread, no conclusive findings as of yet.
You may try degaussing your nozzle or the filament (somehow, yes that sounds weird.) If this is the issue, no evidence supports any of these claims though.
Let it cool down after print. Should be much easier to remove from the plate then.
Blobs on nozzle is something I get too. But if you clean it every couple of hours, it is fine and prints come out OK.
I tried that, but still soooo much stronger adhesion than my usual Prusa Galaxy black PETG.
My solution for that issue is to use Prusa PETG as the first layer and BBL PETG-CF for the rest. WOrks perfectly.
Same with the blobs. Nothing like this with the Prusa PETG. I tuned the flow and the PA, but nothing has helped yet.
I hope someone figures out the solution because the BBL PETG-CF looks so much nicer than the Prusa PETG.
I forgot to mention - it is also important, that you properly clean nozzle when you are removing the blob. Make sure that nothing is stuck inside the sock - sometimes it gets there. If needed, take the sock down. Or try to put new sock on and see what happens then.
Ive had issues as well with another brand cfpetg. The purged filament would get stuck to the side of the nozzle during the wiping process & then deposit onto the part later. Then there would be buildup forming on the nozzle that would cause blobs on the print.
I tried the retraction calibration & the towers had no stringing at all, so I dont think that is the issue. Ive also done the other standard calibrations (temperature, flow, pa). Filament was dried for 12h at 70 degrees & is stored & used in a drybox with humidity maintained below 10%.
I watched a print & noticed that there are very small pieces of string that form frequently during the print. I mean a couple mm long. I think those are whats depositing on the nozzle & forming the nozzle build up.
After seeing that I suspected that too much of the nozzle is exposed by the silicone sock. I lowered the silicone sock so that only 1mm of the nozzle was protruding from it.
Ive done a few short prints since changing that & have had success. The purged filament gets knocked clean off the nozzle & hits the sock instead of the side of the nozzle, then drops into the purge chute. The strings cant hit the side of the nozzle either so theres no significant buildup on the nozzle.
I have a longer print to do this weekend & will update with results. I also acquired a silicone baking sheet from the wife & am going to try to make a spacer of sorts that sits in the bottom of the sock to further restrict nozzle exposure. Maybe a custom sock mold is in the future.
Definitely look in to printing a mold and then pouring in some silicone to make a sock that fixes your problem. It’s actually a pretty easy and cheap process. The hardest thing will be designing the mold, as mold making is a little bit of a black art until you get the hang of it.
BTW, the ideal of the micro-whisps gathering seems like something I would look into. Have you tried a retraction tower yet to tune it as well as it can be?
Just finished a 7 hour print & there was no issues with blobbing, stringing, or loose pieces of filament.
