September 13, 2023
Description
It's short for a redicioulus project: Most Expensive Filament Dryer. And I mean it ;-)
What you need to do is… not hold back. Get everything with the most buck for the bang. As a dry box this would be the smallest prin tsize you can buy, hence an enclosed RatRig 200ish size. Just the best will do. Install two 400 W PTCs in that volume and do high speed AWD printing. Crank every temperature up and get your tech specs to match the requirements. The hotter the more expensive the better. You get the idea. And then try to figure out how to have dry filament available and how to squeeze a spool or two into that printer. Voila.
The only way with such a small enclosure to get a full spool of filament in there is a flat horizontal mount at the bottom beneath the bed. Back wall won't do with a RR200. And if you start looking around for a nice lazy susan style filament holder you will be disappointed. Hence, I needed to design my very own.
There are many pros and cons. I cannot cover them all and opinions might differ. Interesting enough is one trivial reason that works wonderfully for me: the weight. Spool plus holder plus silica gel adds roughly 3 kilos to the printer, further reducing resonances while printing above 1400 mms-1 and over 40k acc. But that is just a side note.
The location is perfect, basically it is unused space if you just use 200 mm of z. At least for a wide Prusament spool it works out perfectly. If you dedicated to a 150 mm z printer you could also use Prusas 2 Kilo spools on the solution here, but that's another topic. The location is perfect for another reason. The PTCs in a RR200 are most probably down there as well as the head room is lower with this printer. So a ceiling install for the PTCs is out of question. Hence, the PTCs are well installed in the lower back corners. In my case thermistors control the heat output by SSRs. They are programmed to run through a temperature program, but in general they will PID at 60 °C. Just that the solution needed to be designed to fit right in there.
The silica gel holders. Although printer enclosures tend to be pretty dry already to the baking conditions silica gel holders are of use. Again, the RatRig design offers many possible locations and it depends on your setup. Within this package you will find side holders that have a stand off to the walls of 19 (20 mm for V02) mm. This is deliberate. Within this RatRig a 20 mm wide isolation was used for isolation purpose. If you don't want to isolate your printer it is still advisable to have a bit of a vibration dampner in between the outer wall and the silica gel boxes. Make it 19 mm wide and all fits again. The holders were designed to hold 1 L of silica gel each. They are detachable and fasten securily to clamps. They should be slightly self regenerating due to the conditions in the chamber, If not sufficient they are to be removed off the printer and regenerated. However you need or like.
The lazy suzan mechanism was designed with 3 circular 625 bearing arms to ensure smooth and accurate rotation with a central hub that features a fourth bearing (608ZZ). The axle is screwed down into the base panel by M4x20-30. The whole base uses two of the base panel fixure screws at the front, mainly an optical feature (also for initial alignment). It is a good advice to also glue it to the base panel. Its main purpose it the reduction of a possible vibration hazard.
The filament spool center tool and holder is based on various ideas the community already had. It's also completely a design by my own, although I am thankful for the work that has been already put into the thought. Several different approaches can be used with various effects, take whatever you need. It screws into the base, so later changes are possible. Use a somewhat flexible material.
All screw holes come with heat inserts from M3 to M5. The center bearing needs to be pressed in. It is also a good advice to use rather sturdy filament for printing. Heat resistance is a must (60 °C plus), so PCCF/ASA/PETG. Most parts print without supports. All fit on a Prusa MK3. A PC4M10 pass through fitting is also needed.
The hygrometer holder was derived from RatRig parts, as well as the 90 degree rotated PTFE holder.
The PTC including the thermistor holder were based on the idea of SvB (and properly mentioned thereof) and were great initially. As I needed to do a bit of redesign and just had a stl available I redesigned it from the scratch (but credits to the idea I still want to give). My decision to use thermistors to PID tune them instead of controlling the chamber temperature lead to a holder for a thermistor. The PTC itself can be bought at AliExpress, but is fairly generic. I swapped the fan for a DC 24 V to attach it to the MCU (separate programming). A separate SSR and a thermal fuse is also required.
License:
Creative Commons — Attribution — Noncommercial — Share Alike
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huskyte
