Chunky filament tip after print

Bambu Lab X1 Series Troubleshooting
1

Hello. After prints very often, when the filament is pulled out by the ams, it goes out. Then when starting a new print, it pushes back through, with a “clank” sound as it goes into the printer. Then it wont push through the extruder. When i then unload it all the way, the end it shaped just large enough to barely fit through the pfte all the way to the extruder. To solve, i pull it all the way out, cut the tip, load. Works fine.
Any ideas what could be causing this?
Thanks

2

Temperatures ? Filament spool having too much friction? PTFE tube clogged/bent too steep?

The worst case scenario is your extruder and hot end clogged. In which case you need to clean it using the wiki procedure.

3

Try manually feeding filament from the input of the buffer see if you can locate something the filament it catching on. I suppose also check the tube is all the way into the buffer.

If you really think the cut end of the filament is bulging check the cutter blade is in good condition.

1 Like
4

Sorry, pla, stock settings for generic pla. Its not bits or clogs anywhere. It is after some prints, various at this point, as hotend cools and filament is pulled back slightly, it seems to cool to a shape/size at the tip that becomes difficult to push through the pfte, but does get through, but wont feed into extruder. I pull pfte tube, cut mis shapen end off, replace pfte tune, load filament, works fine.

The issue is whatever is causing that shape on cool down. Not sure what is causing that part. It so far seems ransom. Even after having just dried the filament.

6

Thanks, ill check the cutter.

1 Like
7

There should not be any cool down. At the end of a print the filament is cut while the nozzle is still hot and then retracted back to the AMS. At the point where it is cut it should not be deformed.

8

It sounds like heat creep in the hot end. Is the fan running properly?

9

Thanks all. I believe it was the cutting bjade. The idea is new to me so i hadnt even thought of it. Luckily i had bought extra.
Now to figure the best way to resharpen them. First one didnt last long.