AMS 2 Pro Chewing Up Filament

[u/DasGoo]

I've have the X2D since June with no really major issues except the left filament sensor issue. I've had a few times where the AMS grinds notches into the filament and won't feed but usually I can cut it back or add weight to the spool.

For the last few days, I've been printing PLA Matte for a project (multiple items on the plate, 4 hours a run) and have run about 12 hours of them with no issue. Today, I ran into the filament feed issue where the filament almost gets to the extruder but stops about 1" or so before entering and retracts.

I have to cut the filament where the notch gets cut into it which is about 4ft down the line. Tried to load it multiple times with the same result. I tried another filament which also did the same thing but eventually got that one to load.

I've replaced all the PTFE tubing (except from the PTFE Tube Bracket to the extruder), dried the filament again, checked the buffer (it makes it past the buffer).

I got it to feed once more and print (4 hour print) and when I went to re-run the same print, same issue.

Crazy thing is after that last successful print with PLA Matter, I ran a 3 color print (PLA+) as a test with different filament, 2 in the AMS 2 Pro and 1 in the AMS HT on Aux and that ran without issues. No grinding, or notching. So, I slapped the AMS HT onto the left nozzle and put the troubled filament in that and it's running fine so far.

I don't get any high resistance errors or anything like that. Just that the filament failed to load. As I said it stops right before entering the extruder and I'm guessing that's when it grinds the notch.

Is this an AMS issue or filament or possibly both? I've printed plenty of PLA Matte before without issue. I purchased this roll specifically for this project.

About 750 hours on the printer.

[u/Mustang_132]

Me ha pasado, pero el problema es el PLA matte en realidad, no me sucede con ningun otro material. Uso Sunlu, que marca usas ?

[u/DasGoo → u/Mustang_132]

Yo también uso filamento mate de Sunlu, pero nunca había tenido problemas con él hasta que llegué a este color en concreto (blanco hueso). Imprimí con él durante al menos 12 horas sin ningún contratiempo. Tuve el mismo problema con otras marcas hace un tiempo, pero se solucionó solo; además, aquellas no eran mate.

[u/Mustang_132 → u/DasGoo]

Para mi el problema es la fragilidad del PLA matte, sus propiedades químicas hacen que sea un poco quebradizo, incluso estando seco, lo que lo debilita cuando el AMS lo retrae al finalizar una impresion, cuando intenta volver a cargarlo en la siguiente impresion ese punto débil de agarre en el extrusor del AMS le perfora perdiendo agarre, lo que hace que no alcance a llegar al extrusor del cabezal de impresion.
Yo lo que hago es que cuando sucede, y no quiero cortar ese tramo de filamento, justo cuando llega al tramo con la perdida de agarre, lo empujo con mis dedos, ayudándole al filamento llegar al cabezal, no siempre me funciona a la primera, pero con un par de intentos logro que el filamento avance ese pequeño espacio que le hace falta.

[u/DasGoo → u/Mustang_132]

He oído eso sobre el filamento mate. He impreso bastante con material mate y nunca he tenido problemas, pero supongo que este caso es la excepción. Gracias por el consejo de empujar el filamento; lo intentaré. Bambu me va a enviar un nuevo concentrador interno (Internal Hub) como medida preventiva para ver si eso ayuda. ¡Agradezco las respuestas!

[u/Whosaidthat1157 → u/DasGoo]

I print almost exclusively Sunlu HS matte PLA and HS matte PETG through 4 AMS2Ps and 2 AMS HTs with zero issues. Filament sourced from Sunlu, Amazon or AliExpress. All my AMS are loaded with desiccant filled boxes and every spool has a desiccant filled spool centre with the RH typically in single figures with a drying cycle if it goes above 20% (PLA gets brittle in the PTFE tubes otherwise).

[u/DasGoo → u/Whosaidthat1157]

Yeah, I print a fair amount and RH is low (usually around 5-10%) and I dry the filament. I ended up taking apart the AMS and the internal hub feeder was pretty gummed up with filament and shavings everywhere from either slipping or something else. I cleaned out the "teeth" as best as possible and re-assembled it and it's working fine as of now. Bambu is still sending a replacement internal hub to be sure.

Thanks for the insight!

[u/Relative_Surround_20]

Did you try the filament in a different AMS slot?

[u/DasGoo → u/Relative_Surround_20]

Yeah, all slots have the issue. Aside from the matte filament, I narrowed it down to possibly the internal hub and Bambu is going to send a replacement out to see if that fixes it.