A1 / AMS. Lite / Auto Refill Issues

Bambu Lab AMS AMS lite
1

I thought I would try auto-refill today.

I set two spools (A1 [running out] and A2 [new/full] ) to the exact same filament type/color, and started the print.

I was very pleased to see it use every bit of the A1’s filament and it seemed on its way to a flawless transition until it tried to load A2’s filament. Something was stuck.

I was directed here: HMS_1200-2000-0002-0004: AMS1 Slot1 filament may be broken in the tool head. | Bambu Lab Wiki which directed me to remove power to my Ai, and then to here: Disassembly and cleaning the AMS lite Filament Hub | Bambu Lab Wiki for the details.

A note of puzzlement: the YouTube link https://www.youtube.com/watch?v=b0RSMK8O62M does not show powering off the printer before starting.

The stuck bit of filament was in the filament base. The top end of the bit was bent as if something pushed against it. Still reasonably happy at this point. I put everything back together and powered it back up.

When Bambu Studio reconnected, it offered to resume an unfinished job. Great.

Here comes the problem/issue:

When removing the PTFE tubes from the top of the filament hub, I noticed a bit of downward movement of the whole printer arm. I hoped/expected that it would re-home/re-calibrate when it resumed.

IT DID NOT.

It jammed the nozzle against the left edge of the build plate a few times while trying to move over the it with the nozzle more than a few millimeters BELOW the plate.

I had to cancel the print. I powered down the printer, powered it back up, re-sliced and re-submitted my print job.

It is now printing as it should.

Two concerns here:

First, Why did auto refill jam the printer ? The final end of the outgoing filament was clipped flat before it vanished into the AMS. The initial end of the new filament was the same way.

Anyone see any problems with what I did ?

Second: If I have to unjam the filament hub again, I am going to either cancel the print-in-progress or put blocks under the print arm to keep it from moving down.

Again, anyone see anything I could have done differently on this ?

Even though I may sound like a serious complainer on this, I am still so much happier with my A1 than I was with my Reality Ender 3 Pro that seems to always require tweaking and hacking.

2

I don’t think the auto refill caused the jam, I think it was just bad luck. Maybe a bent piece of filament coming off the old spool that didn’t straighten out well when it fed into the extruder. Depending on the filament manufacture not all spool ends are created equal, some use tape, some bend the filament into the cardboard spool, some don’t have anything holding them in place. If you are around when its going to make the change take a peek at the spool and if the last bit looks funny just snip it off early before it feeds into the PTFE tube.

I have almost 4,000 hours on my A1 and I’ve never had a problem with auto refill. I’ve had some other problems, mostly self-inflicted, as I was learning… :slight_smile:

Not really outside if what you mentioned “put blocks under the print arm to keep it from moving down” I’d likely just cancel the print and start over. I’ve never had much luck recovering from jams or other problems mid print.