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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.