Heat Deflector/Mixer for Eibos Filament Dryer

POLYCARBONATE REQUIRED

USAGE OF THIS PRINT IS ENTIRELY AT YOUR OWN RISK

This thing is not endorsed by Eibos in any way.

Do not print this thing unless you fully accept all risks associated with modifying a filament dryer.

PETG or PLA will badly warp or melt in this application.  The creator/author of this thing disclaims any and all representations of fitness for a particular purpose, below statements notwithstanding.

Not all brands or types of polycarbonate will necessarily work.  I used Prusament PC Blend.  In my application, in my room, with my room's ventilation and temperature, the thing printed in PC Blend so far seems to hold up to the heat without warping or melting.

In my usage and limited testing so far (over the course of weeks), when I place this thing in the bottom of my Eibos Cyclopes filament dryer (legs down), with the temp set to max 70C, the dryer seems to continue to function without warping itself or warping the thing.  Your experience may be entirely different.

In my usage and limited testing so far, with this thing in place, set to 70C, hotspots are avoided.  Previously, the hotspots were enough to cause PETG filament to slightly stick together if the filament was left in the heater for a long time.

This deflector may also reduce the average temperature in the chamber somewhat, based on power consumption of the overall unit being slightly lower.  This likely means that the PTC heater itself is slightly hotter this way due to somewhat restricted airflow.

In my limited testing so far, I've tried blocking all the holes except 3 of the top vent holes and running for hours, and while the PTC power consumption was further reduced probably indicating an even hotter PTC, the unit didn't obviously melt itself.  I don't recommend running with any holes blocked.  I don't run this way, in the hope that this provides some margin vs. the worst case that I've tried so far, but the margin may be insufficient for my usage or your potential usage.

Running with temp set to max 70C, I measured the average temp in the chamber using a meat thermometer to be somewhat below the recommended 65C for drying PETG, but the dryer still seems to successfully dry PETG from a stringy-printing state to a non-stringy-printing state given enough time, while also avoiding any sticking-together of the filament, and avoiding any obvious degradation of the PETG after drying for many hours (though I didn't test this quantitatively), and also avoiding clicking the relay on and off.

The legs are as tall as I think they can be (without normal spools touching), and the top deflection plate is as thin as seemed workable, to give maximum space for the hot air to flow out from under the plate.  This way the hot air can flow out (to a reduced extent, but still seemingly enough as far as I can tell) and has a chance to mix a little bit more before hitting the spools (I think).  While this just barely avoids the top deflection plate touching the lowest part of a typical spool, smaller diameter spools will undoubtedly touch the top of the plate, which may cause issues with the spool getting out of position.  This might be partly mitigated by having another full spool on the other side.  A touching spool may get too hot (I don't print from smaller spools; I don't know).  Making the legs shorter would likely lead to increased temperature under the deflection plate, which would call for even more careful observation and testing in your specific application.

Eibos may at any time (in the past, present, or future) make design changes to their filament dryer which in combination with this thing may lead to an increased hazard (whether immediate or delayed).  While I have performed limited testing and some extended use of this thing in my own filament dryer without noticing any obvious problems, this limited testing is not a substitute for proper thermal design, evaluation, and testing (which has not been performed by anyone), nor is it a guarantee that there are not any problems (whether immediate or lurking) with this thing in my usage or your potential usage, even with currently-existing dryers.

You are solely responsible for avoiding creating a safety hazard, and if you do create a safety hazard or cause a fire via usage of this thing, it's not my fault, nor is it Eibos's fault, particularly if you had ever put this thing in your dryer at any point while the dryer was on or even still warm.

All the disclaimers aside, I hope folks find that this thing can allow their filament dryer to run set to 70C for drying PETG without hot-spots, like it does for me so far.  But again, it may instead cause your filament dryer to overheat, break, catch fire, etc.  Be careful.  I recommend putting your filament dryer well away from anything flammable so that if your filament dryer goes up in a huge plume of flame, it doesn't take out anything else.  I have not tested the flammability of PC Blend.  If it does catch fire, it may burn aggressively; I don't know.