Tips for drying out PVA filament that has been in a humid environment?
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I've recently discovered that a lot of trouble I've been having with my Ultimaker 3E when printing with PVA support that has been due to the PVA absorbing moisture from the air. I live in the Pacific Northwest and in the wintertime the humidity is very high most of the time.  I stored it in an airtight bag, but apparently that wasn't good enough. The PVA has been popping and crackling during printing, presumably due to vaporizing water in the hot extrusion nozzle. Printing results have been very inconsistent, but got immediately better when I swapped in a new roll of PVA. 
 

I tried drying the old PVA roll in a food drier at 125 F for 12 hours and when I tried printing with that roll I obtained much better results, but it still wasn't as good as the fresh PVA. There was still some popping and crackling and the extruded support looked "hairy," i.e. not quite that clean.

 

Has anybody had success with rejuvenating PVA that has been exposed to atmospheric moisture? Can you share any tips you have?

 

Thanks in advance.

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Mike

We use a food dehydrator for ALL of our filament

We simply toss the rolls inside and turn it up to max which is significantly lower than the alteration point of all commercial filaments and then dry them for 12 hours and IMMEDIATELY remove them to a plastic container that has a series of spool rollers inside and outlets for the filament to exit.  The containers have gaskets so no leaking

The filament is never allowed to see the humidity of Florida it goes from dehydrator (or the new box) then into the container which has 2 pounds of rechargeable desiccant as well as a digital hygrometer inside it than thru PTFE tubing to the extruders of the dedicated printer next in line to be used.  The added length of PTFE does add a BIT to the retraction issues of the printers but they do fine once adjusted

The containers hold about 6 rolls of filament

Hope this helps

Dr. Dave

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Dr. Dave, this is very helpful. In Florida humidity must be a big problem. Do you have any recommendations for the plastic container? Did you make it yourself or purchase it? Is it anything like the PolyBox on Amazon?

https://www.amazon.com/Polymaker-PolyBox-Filament-Filaments-Printing/dp/B075DBPY6F/ref=sr_1_3?ie=UTF8&qid=1526198281&sr=8-3&keywords=printdry

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Mike, we use college kids to run our 3d department they are engineering students or biology majors or sometimes graphic arts majors so they all know CAD design and anatomy but the rest is just winging it :)

We have over 50 printers churning out 3d patient models 24/7 

The containers are self-produced they are basically designed for dog food so they have a seal on the lid.  The hygrometers are cheap and crappy on eBay or Amazon.  The fittings to connect the PTFE tubing is on Thingiverse as well as the roller spool holders I think the later is called TUSH or something similar.  You will need standard roller bearings the type used in fidget spinners 4 per spool again Amazon or eBay

Each costs about $25 total and about 3 hours of printing time to print all the parts

The commercial boxes like the one you suggested is a total rip off as are the dedicated filament driers

We bought a REALLY high-end fruit jerky dryer in stainless for like $80 on eBay and it holds several rolls at a time

Sorry I don't have actual links to send you to for the various files and or products but the one is here

https://www.amazon.com/IRIS-Nesting-Airtight-Container-Large/dp/B007RBB6UI/ref=sr_1_5?s=pet-supplies&ie=UTF8&qid=1526232975&sr=1-5&keywords=dog+food+storage

That is the dog food container

Get back to me if you can't find the rest I will get one of the kids to help us out here

Dr. D

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Dr. Dave,
Thanks for the detailed reply. 50 printers!?! I'm shocked because I thought I knew almost everybody that is doing high volume medical 3D printing. I've known the Mayo Clinic radiology people for years, and I don't think even they are doing the kind of volume that you are describing. I'd love to learn more about your operation. Can I message you? Thanks again for your post and being a contributor to the medical 3D printing community. 
Dr. Mike

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If you are a small scale operator (1-2 FDM printers) and you need cheap and reliable solution for your filaments, then you can check CNC Kitchen's Fiament dryer guide.  You can easily use it directly or you can install it on any type of enclosure you're using. All you need is an Ikea plastic box, two bowden connectors,, a PVC tube, a teflon tube and some filament for the 3D printed parts. The cost is under 40 bucks.

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