A1 - failed print / clogs exclusively on 0.4 nozzle

Bambu Lab A Series Troubleshooting
1

Hi all,

I seem to have a problem with printing on 0.4 nozzle (both stainless and hardened). My nozzles keep clogging after 10-20 hours of print and I can’t even extrude any filament manually.

The fail looks like so - it starts to extrude some miniscule amount and then stops. Skipping resumes and the feeder grind the filament.

It starts like this - new nozzle, all is well, then after some time passes extruder gear starts to click and skip, printer starts to print in the air as there is no filament fed to the nozzle. When I unload the filament there is a clear part where extruder gear ‘ate’ away the filament.

What I tried - replaced extruder gear as I thought the feeder was the problem, then I replaced nozzles (tried two hardened ones and the stock stainless which got replaced shortly after getting the printer so almost brand new anyways - 3 nozzles in total, all with the same problem), but the problem persists. I also tried putting it on 270 Celsius and extruding manually - still fails on a brand new part of the filament (not eaten away).

Now here’s the plot twist, the problem does NOT occur when using 0.2 nozzle. Everything prints as it should and I have no ifs and buts regarding quality. The problem is only when using 0.4 nozzle, which makes me puzzled.

I had the first hardened nozzle for about 900 hours of printing, it stopped extruding as it should so I thought - extruder gear / feeder, replaced, same problem, then checked on 0.2 and since all was well I thought that the nozzle was the problem, replaced 0.4 again and it fixed it for a few hours, but not in the long term.

I don’t think it’s the extruder motor since it’s eating away the filament, but it’s not moving, which makes me think it’s something to do with nozzle - a clog.

New ones (and the one being replaced) was bought from a vendor dealing with original parts so I’m sure it’s not a counterfeit.

I am using SUNLU PLA+ 2.0 always used this one. Even before all those fails. My Ender 3 also uses the same filament without any problems.

Filament temp 220C (tried manual extrusion with 270C)
A1 01.06.00.00
Using Bambu slicer
Nozzle size IS correct
Temp inside the house is constant
All ‘suspect’ screws have been checked and there is no nozzle play whatsoever
Extruder gear / feeder is clean
Total printer time is 950hrs

tl;dr - multiple 0.4 nozzles started to jam, 0.2 prints perfectly from the same filament.

2

sound like there is a lot of resistence pulling the filament? but I wonder why it works with 0.2

3

Same as with 0.2, don’t see any difference

I just finished a print on 0.06 on 0.2 nozzle. Almost-perfect print…

Still can’t comprehend what’s happening with 0.4

4

I had this exact same issue a week ago. My hardened 0.4 nozzle wasn’t feeding, extruder gear was clicking and there were friction marks on the filament when I pulled it out. I tried it with my regular 0.4 nozzle and suffered the same problem!

It turns out that BOTH my nozzles were clogged. I put it down to dust in the environment settling on the open spools in the AMS lite.

Follow this wiki article about performing a cold pull to clear the nozzle.

I also checked the hardened extruder gear was clear. Once I had checked the extruder and confirmed the nozzle was clear, I made a point of running a manual flow calibration. After that I had no more problems.

Good luck!

1 Like
5

Thanks, I managed to ‘revive’ a stainless steel nozzle, and it looks like it helped - filament from the inside had this nozzle shape and I think all got removed with allen key trick, but hardened ones are a no go for some reason, and they keep clogging constantly. I just can’t seem to unclog them any other tricks for unclogging?

6

Apart from the cold pull method, and the steps suggested in that wiki, I don’t have any other suggestions sorry.

All I can say is that did the hot Allen key method followed by a cold pull with filament to make sure there wasn’t anything left in the nozzle.