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Drying filament

Discussion in 'Projects' started by mark tomlinson, Oct 24, 2016.

  1. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    So filament can get wet... that is to say it can absorb moisture from the air.
    Many types can and will do this, PLA and nylon among others. If you live in a place with noticeable humidity this will be the case (I live in the swamps of Florida so this is NEVER in doubt for me).

    For PLA this results in microsteam bubbles in the printed filament and will give it a slightly less than awesome finish look. It will not usually cause the print to fail, but it will make it look less smooth and finished. Eventually the PLA will absorb enough water to become brittle and that is annoying. It can still often be printed, but it is more of a pain.

    Even if you store the filament off the printer and in a sealed container with desiccant you can eventually fall into this problem.

    Given all this I figured I would tackle the idea of drying the PLA out.

    There are a couple of approaches. Taulman suggested use of a lower temperature heat source and blow hot, dry air over the filament. For example an incandescent light bulb and a small fan with a material like silica beads. Ultimately the goal is to get the temperature around the PLA to about 150 Fahrenheit and keep it there for a couple of hours.

    Given that incandescent bulbs are on the wane I thought I would try another route.

    So I looked around and found a cheap (less than $30) convection oven more than large enough to fit my largest spool into. The only downside was that the temperature settings went from off to warm/thaw and then 250 degrees :) So some experimentation was in order with a thermometer probe until I knew where on the dial to set it and get a range of -/+ 5 degrees of 160.

    I then took an old (very old, very wet) partial spool of sacrificial PLA and tossed it in an set the timer for 1 hour (most I could do at a time on the cheap-o oven). I reset it twice so it got about two hours on it. When removed from the over initially the PLA was very flexible, but not at the tG range (it was still quite solid). I then did two more spools.

    When cooled back down the filament seems fine and is no longer brittle. I will do some prints over the evening and tomorrow and let you know if it still works acceptably. It does not appear to have deformed to any extent, but obviously feeding it through the E3D will tell the tale. Assuming this works I may try nylon next.
     
  2. Chuck Erwin

    Chuck Erwin Active Member

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  3. Geof

    Geof Volunteer Moderator
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    1st !

    Super excited to hear how this works out! Thise can be had dirt cheap at yard sales

    2nd!

    If your having problems using uo filament you can always ship ot my way :D


    Share some info on the oven you picked up?
     
  4. danzca6

    danzca6 Well-Known Member

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    That's just a food dehydrator isn't it?

    Mark I see Tom is doing this on Twitter today at about 60 degrees, but that is probably C so about 140F for an hour. I have been looking for a cheap oven as well, but for powder coating :) I've been thinking about just using a toaster oven as well. They make them big enough these days.
     
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  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yea, my biggest roll of filament fit easily and the smaller ones I could get two in there if I wanted.
    60c sounds about right, you want (for PLA of course) to stay under 180 F and (I keep it under 170). With practice and a thermometer you can get it to where it stays pretty much 156-160 all the time.
     
  6. Chuck Erwin

    Chuck Erwin Active Member

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    Yes probably but with fancy gauges and knobs.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I will post a picture when complete, but midway through a print with a 'recovered' spool of PLA and it is going fine.
    Not brittle and no issues with print quality.
     
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  8. danzca6

    danzca6 Well-Known Member

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    That's great Mark. I'll have to give that a try on an old spool I have that wasn't kept in my dry box.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Here are some closer-up pictures. It was fine. Large bore nozzle (0.8 mm) just as a reference.

    20161025_140836.jpg
    20161025_140827.jpg
     
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  10. Geof

    Geof Volunteer Moderator
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    I'd call that a success! Curious to see how it does with nylons or PVA :D those are my problem children
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I will try it with my oldest roll of nylon and let you know.

    Sorry, no PVA on-hand.
     
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  12. Ed Ferguson

    Ed Ferguson Active Member

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    One possibility for a filament dryer is to use one or two ceramic heaters. They screw into a standard light bulb socket. I got mine (use it for curing epoxy) from a local feed store (used to keep chickens warm) along with a 10" diameter aluminum domed reflector / socket. It takes a while to heat an enclosed area, but one or two heaters should reach 160 degrees F and would be safer than a toaster oven which may create localized hot spots. I'd use a heat duct sheet metal tube around the 10" domed reflector. Add a small fan, and control the temp with a cheapo controller. If one heater is not enough, add a second one at the opposite end of the tube.
     
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  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I was a bit concerned about this, but turns out the only thing with a hot-spot is the side of the spool :)
    You want to keep it cool enough not to warp the spool either*. I think Tom's 140-ish is probably the best route.
    The light bulb approach is certainly what Taulman suggests an is both cheaper and (probably) safer.



    *yes, you can do this...I know
     
  14. JoshYourITGuy

    JoshYourITGuy Active Member

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    Could you just crank the temp and run the power cord through a PID controller for a more accurate temp?
     
  15. OutsourcedGuru

    OutsourcedGuru Active Member

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    I'm imagining modding a garage-sale Easy-Bake oven... but then again I might lose some points if it can be seen by my girlfriend using it.
     
  16. OutsourcedGuru

    OutsourcedGuru Active Member

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    The sous vide French method of cooking food in a plastic bag does this, essentially. You use a computer to control the duty cycle of a heating element. https://github.com/maglub/rpi-sous-vide
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    This is why it is far preferable to keep your filament dry as opposed to drying wet filament.
     
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    This lists the drying times/temps:

    http://www.printdry.com/dry

    They sell a commercial version of what I was talking about, but a cheap convection oven works :)

    (granted their dryer is $99 and a cheap convection oven 1/2 that size is like $40 so ... not obscene)
     
  19. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Kinda looks like a repurposed Food Dehydrator
     
  20. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I agree and that is an option to the Convection oven we went with.
    No reason either will not work.

    The concept is simple: get the filament temperature up a bit (but below transition temperature) for a certain amount of time to dry out the water. The small convection oven was a cheap way to test it, but in reality it is a bit finicky since the temperatures you want are usually a bit low for the thermostat they included on the cheaper ones. You can adjust the dial with an actual thermometer used to test the temperatures. <shrug> Nice to see someone has a packaged item, but I think the DIY approach still works. At least the one they sell now is not stupidly priced.
     

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