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In line filament dryer.

Posted: Fri Dec 07, 2018 10:04 pm
by RegB
I have seen the "adapted" Walmart grade dehydrators, meh.

What I would LIKE to create is a small enclosure that I can dry filament in as it passes through in the normal course of printing.
Here are the missing variables, any help in deriving them would be much appreciated;

1) Needed residence time for typically "damp" 1.75 mm filament in a ~100 C heater box
2) Range of feed rates of filament (at its "from the spool" diameter of 1.75) on Artemis.
{I can figure that from print speed and nozzle size, but given travel moves and retraction would not need 100% of it}

3 through n) What I haven't yet thought through.

Right now I am thinking of a fairly large heated "screw" form that the filament would be wrapped around and pulled ONTO as it is pulled OFF OF by the extruder.
Alternatively the heat could be applied external to the screw.

Thoughts ? Criticism ?
i.e. Is this CRAZY because the drying time for a few meters of filament is HOURS ?
or could enough moisture be "driven out" in some reasonably small number of minutes ?
Not ALL of it, I'm not striving for that, but some meaningful reduction that would improve print quality ?

Re: In line filament dryer.

Posted: Sat Dec 08, 2018 7:13 am
by RegB
Looking at a few "typical" prints of mine;
10 or 12 m of filament, 3 hours or so.

If I could "hold" say about 15 m of filament in the in-line dryer that could be enough for my first print of the session.
I am thinking this could be a likely scenario;
1) I turn on the dryer 3 or 4 hours before I want to print, say when I start sketching something up in a CAD program.
Alternatively I could put it on a timer for 4 or 5 a.m. if I want to print at around 8 a.m.
2) I print and in that time the next 10 - 15 m of filament is pulled in and through the dryer ready for the next print.

Simplified arithmetic on a heating spool; A 30 cm drum has a circumference of almost 95 cm., so 15 wraps around that, plus some lead in and lead out would get close enough to 15 m - - may need less than 10 cm along the axis.

I think it would tangle if not guided around in some sort of Archimedes screw groove.

Re: In line filament dryer.

Posted: Mon May 04, 2020 5:35 pm
by RegB
Well, that idea went NOWHERE and took a long time to get there.
I got a new batch of filament last week and the improvement is SIGNIFICANT !
So I started thinking about drying - again.

Looking at the Artemis... a waste paper basket would probably fit quite neatly under the spool with the bottom half of the spool below the rim.
Add about a 50 watt heater under it and each "wrap"of filament would pass through the hot zone several times before heading into the extruder.

Drying/Warming the first 1/2 meter of filament - maybe turn it on 1/2 to 1 hour before loading filament into the extruder ?

An obvious failure opportunity would be getting the filament so hot that the extruder can't drive it, just squashes it - this seems unlikely.

Re: In line filament dryer.

Posted: Tue May 05, 2020 8:30 am
by geneb
What are you printing with where drying is such an immediate concern?


Re: In line filament dryer.

Posted: Sat May 09, 2020 2:46 pm
by PartDaddy
Nylons and even Carbon Fiber PETG benefit. Here's my setup, bucket was curtesy of Atomic Filament.
  • metal bucket with 4mm PTC fitting (SeeMeCNC Part No. 38832)
  • moisture strip from one of my Atomic CF PETG rolls in bottom, these are reusable
  • desiccant dryer, rechargeable type does not need plugged in all the time (like SKU No. 104390999)
  • SeeMeRollin Spool Rollers (SeeMeCNC Part No. 27599)
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