Absolutely every time I start a new print with Bambu Lab A1 mini (+ AMS-lite), it retracts the filament breaking it in the tube.
I’m using the same filament spool every time, haven’t changed it between uses and am only using one filament (out of the 4 available slots).
So at the start of every print I have to remove the AMS-lite tube that holds the filament, fish the broken filament out of the tube, connect the tube back to AMS-lite and the printer and feed the filament in again. After that, I can restart (really just start) the printing process.
What’s up with that? That can’t be normal.
I’m using pretty expensive PLA+ filament.
The prints that eventually come out are just fine.
There are no problems during the printing process, only the start of each print.
I know this from Jayo / Sunlu PLA+ 2.0 filament. It soaks moisture and is breaking in the tube just some centimeters before the extruder. My A1 mini is located in the basement with an humidity between 60 and 85%. It seams, that the PLA+ 2.0 is very sensitive to this environment. I don’t have this problem with the normal PLA+ from Jayo / Sunlu.
Humidity shouldn’t be a problem for me - if anything the humidity should be at the lower side since we use heating radiators and in other rooms have had to use humidifiers to raise the humidity to feel comfortable. I can check it of course, gonna place a sensor there.
However if humidity is the problem, should the filament break during the prints as well? The filament only breaks at the starting process of each print - when it retracts the filament for some reason. If that retracting would not take place - the filament would remain unbroken.
There’s a weird thing where the end of the filament is always more brittle. It’s been discussed here before but I don’t think there’s a concrete reason. Maybe where it’s cut absorbs more moisture? You might want to try drying a roll and if that fixes the problem check out those DIY enclosures on MakerWorld for the AMS Lite.
Last year I bought a 10 pack of it when it was on sale on Amazon… it’s the most brittle filament I’ve ever used. Then I googled and found lots of other people saying the same thing. All the other stuff from Sunlu is great but I doubt I’ll ever buy the 2.0 again.
I just bought the filament and the printer. I have currently printed 4-5 things. At the start of each print - straight after the warming up of the printer - the printer cleans the nozzle and ams-lite retracts the filament. Every time it retracts the filament, it breaks it.
In other words - before the printer has even started printing - it does this filament retraction routine (for some reason) and breaks the filament.
Can I not use G-code (or some other config) to stop the printer from doing that?
The filament has not broken during the printing process (even for longer prints) - it only breaks at the start (once for each print) with the retraction process…
The retraction process also seems to be quite violent - retracts it a lot at a time… Maybe thats normal, I dont know - I’m a noob at this.
Yeah, it’s kind of violent on the full size AMS too. My only question is if you take the start retraction out and the next print you do isn’t the same color as the last print that finished how will it handle that? If you do want to dig into it here’s some good info:
I would definitely get a hygrometer though and see where you’re at humidity wise.
Did you ever resolve this? I just got an a1 mini and having a similiar issue using SUNLU PLA+ 2.0, On the rewind sequence at the start of a print job, the rewind snaps the filament leaving a broken off piece in the nozzle.
Have you ever tested another filament? At the moment, there are frequent customer complaints about PLA+ 2.0, saying that it is delivered too moist or / and becomes brittle. Take a good piece in your hand and bend it to the left and right, make a loop, etc. If it breaks, your filament has gone bad. That’s how you can roughly estimate it yourself, as I said, very roughly.
Of course, it could also be something else, but you can quickly test that.
I’ve used many types of filament from MANY companies and this is the worst I’ve ever bought. I have no idea what they did with the formulation but drying doesn’t even fix it. If you search Google you’ll see many similar stories.
I’ve found that filament left in the PTFE tube for long periods tends to get brittle and snap. On my AMS Lite, if something has been in the tube for a while I’ll disconnect the tube at the AMS and pull out a couple of feet of fresh-off-the-spool filament. I haven’t had a break since I started doing that.
Could be a few things going on here. First, for ams lite users, buy an additional ptfe adapter. When printing with one spool, remove the ams adapter and use the spare with the oem spool holder. It’s no frills simpler to use and avoids some of the ams lite problems described above & more. Second, don’t store spools on the ams and avoid loading filament unless using it. This includes ams with printed spool covers. Third, make sure the ams is properly positioned according to the manual. Fourth, consider feeding a single spool from a dryer box when printing petg routed thru a ptfe tube. Fifth, when ams lite is not in use, store the ptfe tube bundle coiled. Otherwise, the tubes will begin sagging which adds not only filament flexing with y axis movement as well as twist. I made these mistakes early, had a pla spool loaded in the ams lite for 2 months. The filament came out in 5 pieces after causing alarm after alarm. I had printed a y tube adapter to be able to load filament from the single spool holder & ams. Just problem after problem, solved with buying a spare $5 adapter to run the single spool and let the ams sit unplugged from printer when not in use. If unplugged, bambu slicer will default to the single spool, eliminating ams color assignment. Ams’ are great tools, but don’t let the tool clutter a workspace when not in use. Just be sure to plug it in before turning on the printer when it’s to be used.
