Two scenarios, one of which (scenario 10 was a problem for me, and I wonder what will happen in the other scenario (scenario 2).
Scenario 1:
I have 3 identical spools of filament loaded into the AMS 2 Pro on my H2D. The 3 spools are on rotation, so that when one runs out, the next in the sequence is supposed to load. The print launches successfully and printing continues for a period of time drawing from the filament in slot 1. The two other spools of the same color and type are loaded in slots 2 and 3, waiting to be called upon when the filament in slot 1 runs out. Unfortunately, though, on this occasion when the filament at the end of the spool on slot 1 reaches its end, it doesn’t cleanly detach from the spool, as would normally be the case. I’ve had this occur on more than one occasion. Sometimes it’s because the end of the filament was taped to the spool by the manufacturer (generally with black tape). On this occasion, though, it simply didn’t pull loose from the spool at the end but instead was mechanically stuck to it. In either case, what happens next is the same: probably suspecting a tangle of some kind, the AMS 2 Pro rewinds the filament onto the spool all the way back to where the front-end of the filament nearly pulls out, but doesn’t. It’s in a state similar to if it had been freshly loaded. Then it tries feeding the filament back to the extruder where, no surprise, the end of the filament stays stuck to the spool and no further feeding is possible. So, it rewinds again, feeds again, rewinds again, feeds again, a number of times until it halts with the end of the filament under tension with the spool, and triggers the alarm.
What I wish it had done instead: rewind the remainder of the filament onto the spool and then move on to the next identical spool in the sequence. It was perfectly capable of doing this, and then the print could have continued without waiting for my intervention.
So, what do I find when I arrive? The system is gripping that filament hard. I can’t simply pull it out and replace the now mostly used-up spool with a fresh one.
What should I do? I’m not sure. When I arrived to rescue the unhappy printer, I wasn’t initially aware of what the problem was, so I cancelled the error and told it to continue. That lead it to repeat what happened prior, doing a bunch of feed and retractions, with the same “tangle”, and ultimately alarming again. It seemed to be stuck in a “mode,” and I didn’t see a way out. So, I punted: I cancelled the print and lost the work which had been completed up to that point. However, once the print was cancelled, the filament was no longer being tightly gripped. I pulled it out and tossed it in the trash. Then I loaded up a new fresh spool in slot 1 and restarted the print from the beginning. End of story.
Just a theory on what might have worked if I had tried it: I’m thinking that maybe if I had used cross-cutters and cut the filament loose from the spool after I had attempted to resume the print and it did a few cycles of feed, retract, feed, retract, then all should have gone well from there, since that is what would have happened anyway in the ideal case on its own, without me being there and cutting. Is this what I should have done, or was there some other solution?
Well, that was a lot of typing, so maybe sometime later I’ll describe scenario 2.
