I was printing an object with Bambu-PLA (115 layers in total) as suddenly when reaching layer 94, the AMS started unloading the filament and loaded it again. Then my X1 printed some seconds and then the filament was unloaded and loaded again. This repeated all the time. Sometimes a “the AMS assist motor is overloaded”-message appeared, but the filament was neither tangled nor stuck, I could easily pull it out and reload it.
What might be the problem? The object only contains 1 color/type of filament so loading/unloading wasn’t necessary. The filament is on a self-printed spool (Printables), but till layer 94 everything seemed to be fine.
The same is happening when using one slot on my AMS, the one where I used some abrasive filaments (glow-in-the-dark, fibre-filled etc.), and I also had some genuine jams in it some time ago. In my case I’m hoping it’s a worn out PTFE tube as it seems to be something mechanical that can be solve with some gentle force. Some people reported gears in the AMS slipping (and fixing it by glue). In any case, I would disassemble and inspect it, it really might be just a tube.
I think the AMS goes through the unload load cycle anytime it detects that the filament appears to not be feeding as expected. Check out the filament buffer’s behavior as it prints normally. That’s an easy way to observe what’s going on.
Is your spool rolling smoothly? This is different from being able to pull the filament by hand. Sometimes the spool has some binding as it unwinds
I’ve just had reasonably consistent printing until the AMS started to unload/load repeatedly. I diagnosed my problem (yours may be different) as the Filament Buffer on the back of the X1C. The issue presents itself when you watch the PTFE tube coming out of the buffer—it doesn’t move! The buffer should constantly move in and out as the printer feeds the filament into the extruder from the AMS.
The fix is to remove the two screws holding the Buffer onto the printer. Disconnect all the cables and tubes. Look at the rear of the buffer and push the (black) buffer tube in and out… it should move freely. Mine was sticky, and it had started to bind ever-so-slightly. Hence, the buffer only worked intermittently, and then the AMS started its unload/load, which reset the filament buffer and allowed it to print for a very short while.
My solution to the sticking was to apply lubrication (I had some lithium grease) to the buffer tube’s moving surfaces, just a small amount of lube is required —ONLY the outside surfaces, never where the filament is fed through! I then worked the buffer tube to make sure it moved freely again.