no it’s normal, at this level of humidity, i have 2 ams 2, and it’s the same.
when i said long print it’s 3/4 days 
Then your filament wasnt really dry in the first place. Maybe the outter layers were. Dry longer. Dry until its stable an hour after it cools from drying. The ams is sealed and with desiccant, holds a super low humidity level
my problem was to store filament outside the dryer, it was only 4 places, now i have bought a lot of watertight ikea box to store them
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I think you might find that the most filaments when dried in general conditions don’t really dry at all. People think they are drying their filaments to 0% but really they are just reducing the moisture content on the outer few layers whilst the centre stays considerably more wet then after it might slowly average out if left for many days. It’s a bit like drying a wet waterproof glove, the actual centre needs to be exposed to air for it to be able to dry, no air or moisture capacity within the air and it stays wet. I have printed from spools with vents and spools without but I think the quality always noticeably degrades over the time of printing the whole spool regardless of time or vents. At first I used to do 12H drying sessions then print to half the spool capacity and then throw it back in for another 12H before I would use the second half of the spool but now I just run the dryer permanently whilst printing as the results are always consistently bulge/zit/string/ooze free. Keeping filament in a sealed PP box with desiccant is just storage solution for me and I would never go back to printing without a drier now. I also print wet filament straight of the spool whilst being dried for 1H prior to starting the print and this also works absolutely perfectly as long as the dryer is left on. I am willing to bet that Bambu Lab will change the firmware to allow for constant drying once someone shows evidence that the filament is still wet even after 12H of sitting on the heated bed, it just takes someone to notice it. I only realised when I printed large items as I would get tiny blobs or really light stringing 700g into the print but it would be flawless at the start. I suspect this is why they added vents to the spool chassis but really what they needed all along was a AMS with a drier AKA AMS 2 Pro, I just hope they allow drying whilst printing. Maybe they don’t because of the tension on the filament whilst it being close to softening temp. In the meantime I will keep using my old AMS with a dryer attached to it.
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The only dryer that can properly dry pa6-cf is the sunlu e2. Lesser temps will work, but it will take days.
There is a tonne of evidence, the key word in the forums is “PETG HF”!
You are totally right about the inside not drying properly and I would also love the dry while printing feature - even if it can’t be turned on with PLA.
Id be interested to see a 1 kilo print where the bottom half looks great but the top half shows signs of wet filament
Pay attention to your own prints and you will probably notice tiny imperfections the further into the spool you go.
That’s all I print now. It’s the least toxic so that’s why I use it but it’s also cheap, the only problem with it is that it can get a bit wet.
Ive actually never seen this before. Ill take your word for it. Im pretty new
#2 is a weird thing to say when there is copious evidence that fresh out the aluminum bag filament is often wet enough to cause problems.
You can print and dry at the same time from AMS HT bypass hole, any filament type. It basically becomes an external spool holder when drying.
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Sunlu build a solution to this for the AMS 1.0 SUNLU AMS Heater, Upgraded your Bambu AMS, Enables Drying while Printing | SUNLU Online Store – Affordable 3D Printing Filaments and Resins
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When you refer to PLA or TPU I can agree with you. but when you run high temp filaments like PA-CF or PPA-CF … heating wile drying is even recommended.
Yes it softened the filament but its also reducing the chances that it will break inside the PTFE tube.
Your insite on this ?
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I wondr if that fits the ams2. I know the ams2 is slightly wider than the ams1, but maybe the lids are the same size. Interesting.
AMS isn’t really designed for those filaments, I kinda agree with bambu’s choice here, you can always just get a proper dry/heating box for those filaments.
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I am not sure if that is the case for PPA-CF. I dried it at 85C and it was just as brittle as at room temperature.
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Same with PAHT- CF IMO
Letters
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If the AMS is truly an airtight unit, could you please clarify the following?
My AMS 2 Pro initially showed a humidity level of 55% while empty. I then loaded it with four brand-new, freshly unsealed Bambu PET-G filaments and dried it for about six hours. The humidity dropped to 10%. I also added 10 new bags of desiccant.
However, just two hours into a six-hour print, the humidity had already risen to 36%.
Wouldn’t it be beneficial if the AMS could maintain a gentle warming function during printing—say around 45°C—to help keep humidity levels stable?
Your filament probably isn’t dry yet. 6 hours isn’t nearly enough time to dry PETG, especially 4 spools at once. 60-65°c for 12-24 hours.
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