I have a X1C with AMS combination and I have been printing with them for a few months now. It is a really great machine, but from the moment I first tried it a few months ago it had a problem. It has come to a point were I am starting to avoid multi-color prints and it is even becoming annoying with new prints with the same filament as the previous print.
I am talking about the cutting of the filament. Every time the X1C cuts the filament it makes a small notch in the filament that is retracted. This somehow causes the (after 3 attempts) ‘Failed to load filament into the extruder’-error. I can verify the problem is the notch, because I can cut the filament manually before loading it in the AMS and the loading succeeds.
I tried replacing the blade, since i thought I might got a dull one with the machine, but that did not help. I also checked for any filament debris inside the hot end, but that’s also not the problem since I can cut it manually before loading without an error. The blade handle is also running freely, so it is not bumping into the housing.
I am also currently only using PLA filament from Bambu labs and since it happens to all of them I think the filament is not the issue. I also made sure the filament is dry, which shouldn’t be much of a problem with PLA, but just to rule that out.
I cannot seem to find any topic that has the same problem, but I hope I missed something. Did anyone experience the same or knows of a solution?
Never had this issue and that’s with me being very lazy and never changing my blade! I think I’ve only changed it once in 18 months. I digress…
Are you holding the arm in fully when you re-tighten the holding screw for the cutting mechanism? I’m also thinking maybe something is restricting the mechanism from getting a clean cut (obvious I know!)
Did you make sure the torsion spring was located correctly when you changed the blade? I know you don’t have to take the arm off, but maybe it has come off somehow? Replace the Filament Cutter Lever | Bambu Lab Wiki
From the pic of the filament, I don’t think that should be restricting it going through the AMS. I have had worse looking ends pass through fine. Have you recently taken the PTFE tube out the back of the AMS? Because relocating that properly can sometimes be tricky, you have to make sure it goes all the way in and through into the release mechanism. I would also check the other PTFE connections to make sure they are snug.
Most of this is me thinking out loud sorry, might not be of any help haha
Seeing the photos you’ve posted, I’m noticing the sudden shift upwards.
My recommendation is to inspect the top area of your hotend. The job and design of the filament cutter is that it’ll seat right above the inlet where filament is feed through but overtime the complete mechanism will wear and shift.
I’m saying this because I not to long ago was noticing the filament cutter becoming sticky. When I removed the hotend I had seen the cutting blade was riding along the top and hitting the nozzle portion and also rubbed away some of the black anodizing from the heat sink.
I replaced the cutter and the hotend screws and as an extra layer used machinist files to lap the top surface completely flat.
@ProtoSpyre, I’ve checked the hot end and I can confirm the knife was hitting it, since there are scratch marks on the top. I also filed down a small layer to make sure the top of the hot end was completely flat.
@wizardbynight, I also removed the arm and re-attached it and made sure I hold the lever when tightening the screw.
I also checked if the knife moved freely without the hot-end and it is (unfortunately, I cannot upload any video’s).
But to no avail, the problem remains. Maybe it is the spring that is defunct, hard to debug since it has never worked correctly since i’ve received my printer.
@ford_jake, that is also my go-to at the moment. But when you have 4 or more filament changes you are babysitting the printer and waiting for a notification on my phone to run to the printer and fix it. Not really what I want from a 1500 dollar printer that is supposed to have this feature build in
PERFECTION! This is the way! Honestly not sure when or how it’s happening. By chance is yours a new machine? My 1st gen X1C hasn’t ever had this issue. Now the 2nd gen X1C’s I have all have had the same exact problem of scraping the top and sometimes gets stuck.
I thought due to the blade dulling the cutter was deflecting off the filament then scraping against the heat sink top face. Doesn’t seem like it was entirely that. Inspected some other hotends and noticed the heat breaks were raised above the heat sink fins… so not quite sure 100% but it seems to be a contained issue from a batch of hotends anyways.
