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Storing Filament

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> removing the filament is a pain because trying to reinstall it typically results in disassembling the extruder.


I rebuilt the extruder on my cheap i3-like printer (Geeeetech i3) so I could actually see the filament path in the extruder, things were 100x easier after that.

Dry filament in an oven, then put into moisture barrier bag (same stuff moisture sensitive components come in, like this ) with a large silicagel packet or multiple small. Humidity indicator card can be placed inside too to verify everything is OK. If you reuse old silicagel packets, dry them in the oven too. Can be dried together with filament at higher temperature unless you dry PLA. Then tightly roll open end of the bag with at least a few turns and fix it with 2 or more clothespins or something similar so it stays airtight. In my experience PETG and Nylon must be dried out of the box unless they came in a moisture barrier bag (silvery, non transparent) to begin with, ABS is more forgiving but best to be dried out of the box too. PLA is the least affected by moisture and usually is good enough without drying but it certainly does not hurt to dry it, be vary to not overheat it.

As of vacuum bags sold for filament, they are expensive and a waste of money IMHO. Stuff I've seen are just usual transparent plastic bags which pass humidity. Not to say "vacuum" (very far from real vacuum) barely helps if at all. Sure they are much better than just leaving filament non sealed. But real moisture barrier bags are much cheaper and can keep things dry for years as they have aluminum layer. Such bags are also often called "mylar bag" when sold to general public for food storage but verify what you actually get if you decide to buy such
I store my filaments in lockable Sterilite 03948604 food container
Those are water/air tight with silicone gasket
Quite durable, but not super cheap.
One filament spool nicely fits inside and and I place few bags of desiccant or pill bottle filled with CaCL ( CaCL is much better desiccant them silica-gel ) in center bore of the spool !
As well as cheapo temperature-humidify LR44 battery powered sensor
Big bonus they are transparent so it is easy to see color / filament type

If my filaments get brittle I lock them up with desiccant in such container for a while usually this fixes that problem.
I have some filaments of some odd colors that are about 8 years old and those are still printing fine ! :D
But I use them mostly for draft prints

I run a Prusa clone with a cheap and nasty extruder that doesn't even have a sprung release arm to take the pressure off the filament pinch roller to insert or remove it.  However, as long as you don't break the filament within 50mm of the top of the extruder its trivial to do a filament change using G-code.  You need to know the max. continuous feed rate your extruder + nozzle can sustain, + the distance from the knurled feed drive roller to the inside of the nozzle.

To unload:

* Preheat the extruder to the working temperature for your current filament
* Ram (extrude) for 50mm at double the max. feed rate.  The extruder should start clicking part way through this operation.  The purpose is to purge softened and distorted filament from the throat, and as much as possible from the hotend.
* Fast retract for 10mm less than the feed roller to inside nozzle distance at 100mm/s.  This pulls the filament back out of the hot end with minimal melting and a reasonably clean end.
* Pause for user intervention, so you can grab the filament then slow retract (10mm/s) for 30mm to release it from the extruder.That should leave you with a clean end tapering to a thread.  Clip it off at about 10mm from where it starts to neck down and it will be ready to reload,  Never let go of the end till you've got it secured somewhere - either to the reel or the printer frame.

To load, if the filament end is new, clip it diagonally as obliquely as you can to get a tapered end.  If its been pulled as above it will be ready as-is:

* Preheat the extruder to the hotter of the previous and new filament temperatures
* Creep the extruder (extrude direction) at 1mm/s for 10mm, then pause for user intervention. If you stuff the end of the filament in the feed hole  before doing this, and keep it pressed in while it creeps, it should have a good grip on the filament by the time it reaches the pause.  Give it a moderate tug to check. If not, either use the lever to release the pinch roller and position the filament end manually, or reset the printer and start over.

* Feed at the max extrusion feed for the feed roller to inside nozzle distance.
* Set to the new filament temperature and extrude for 50mm at half the max. extrusion speed to purge the nozzle.It should now be ready to use, but if the last few cm extruded show any traces of the previous colour or filament, manually extrude another 50mm at the same speed to repeat the purge.

Obviously this needs translating into G-code for your printer, and preferably setting up as macros in your G-code sender for ease of use (e.g. as macro buttons in Pronterface), but its well worth taking the time to get it right , as it turns filament changes into a trivial two minute task.

All distances above in terms of filament movement, not length of thread extruded.  N.B. its essential that the throat has a conical entry to guide the filament end into it, and for it to be well aligned with where the feed rollers touch.  If filament curl causes it to miss the throat when attempting to insert it manually, you are S.O.L. and your only hope is to manually load it fiddling the end into the throat using a notched stick or hook or similar, which gets real old real fast, and if you didn't think well ahead when mounting a part cooling fan or BLtouch or similar sensor, you may have blocked access to the top of the throat, which means you cant load the filament without dismantling stuff!  |O

Your degraded filament *may* be salvageable by dehydrating it for a couple of weeks then annealing it, or it may only be fit for recycling.  Don't expect the print quality to be as good even if it responds well to annealing, and don't go too close to, or over the glass transition temperature or try annealing filament on a 3D printed reel!


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