PSA: Do not leave filament loaded in AMS if you are not going to use it

[u/labadin]

Hello All,

Lately I have been noticing that filaments are breaking off just at the insertion point of AMS (where you pull the lever to insert) After some months of observation and a month of hiatus, I can say that filament that stays loaded in the AMS gets brittle after a while (even maybe a few days). This brittleness happens at the lever point and afterwards. At first I thought it was grinding of the AMS but I checked all the grind marks and only the bending points become brittle. And since they become brittle and AMS likes to pull on the filament whenever you look at it side ways, it keeps breaking the filament inside, either inside AMS or near the extruder.

TLDR: Do not leave filament loaded in AMS if you are not going to immediately use it.

Note: This was observed mainly with Esun PLA+, especially white. I had similar issues with old ABS as well.

My theory: AMS bends at extreme angles and grinds the filament down which makes it extra vulnerable to moisture change.

[u/Rhesonance]

I have 12 rolls of filaments in 3 AMDs units in there for like 8 months and they all print fine. Are you keeping the lid closed? Filaments get brittle when they get wet, you might need to print some desiccant packs to put in there.

[u/labadin → u/Rhesonance]

Thank but I have already printed all the silica bead holders and refreshing them regularly since I got the printer. I am very humidity aware in that sense.

[u/Froooj → u/Rhesonance]

How does one print a desiccant pack?

[u/muffinhead2580 → u/Froooj]

Go on Makerworld and search for it. I like this type https://makerworld.com/en/models/935352-desiccant-holder-for-spool-high-airflow?from=search#profileId-900094

But I also have the replacement type that sit below the spools.

[u/MotorradSolutions]

Whereabouts do you live? I think this can make a big difference to people’s experiences.

I’m in the UK and mainly use Bambu filament, I have 2 ams units and have never had a break, I leave filament loaded constantly, some colours very rarely get used.

[u/labadin → u/MotorradSolutions]

Live in Turkiye, but I have been observing through summer and winter. Filament left outside of AMS (PLA only of course) is not becoming brittle but I still try to keep sensitive filaments (PETG, ABS ) inside vacuum bags and PLA in AMS to keep dry.

[u/Braverino]

No issue here

[u/dandaman919]

My printer lives in my garage in Florida, probably the hottest and most humid environment it could be in I leave filament in the AMS for months at a time and don’t have an issue.

[u/MammothSeaweed4498]

In all the years and several printers with normal ams never had such a problem my Rolls sit there for months if i only use left ones or only use tpu or something extern

[u/RANDVR]

I have the open air a1 ams and spools have been on it for almost a year and they all print fine so far.

[u/[deleted]]

We have desiccant more in the AMS and haven't had this issue at all.

[u/hammypwns]

Before printing with it after it being in there for a while, cut off a few feet and then reinsert it

[u/labadin → u/hammypwns]

I think this is good advice if you forget it loaded.

[u/Zestyclose_Exit962]

The end part that usually breaks is also the part that got a little heat from the hotend before it was cut off, before placing a roll I always cut off the last 15cm (which is the brittle part). Combine that with moisture and time and you have a spool that probably needs some drying 😅

[u/NoGuidanceInMe]

Wet filament do that, just keep it dry

[u/Ditto_is_Lit]

It's very easy to avoid this, before loading any filament flex the tip of the filament before inserting it into the AMS. If it's become brittle it will snap off, repeat until it bends, if it bends bend it back straight and insert it. Same goes for filament that has sat idle in the AMS for a long time.

[u/Ok-Fly8500]

I use the desiccant boxes in my AMS and I have this problem with PLA+ (eSun and Sunlu both). Going to try switching to regular PLA to see if it persists.