AIO Filament Dry Box Kit - Universal Expandable Adjustable

AIO Filament Dry Box Kit - Universal Expandable Adjustable
Description:
Tired of zip-lock bags and needed a filament dry box, one where I didn't have to mess around too much when changing a spool or changing filament.

There's A LOT of great filament dry-box designs out there, but after looking at probably hundreds of them I wanted one that met my ever-growing list of requirements. First off, the parts had to be cheap, or ideally printed and prints had to be reasonably sized.
I needed to fit any box and be easily changed or moved to a bigger box if I ever needed to in the future. I also wanted something I could use with a multi-filament feeder and hopper in the future, so rollers and bowden setup had to have reasonably low resistance.

So I decided to take the best ideas and put together a kit.
Many of the included parts in this kit are designed by others, some are modified/remixed, and some I designed myself.

This dry-box kit is expandable and will fit any box and most filament spools.
The rollers themselves are ajustable with 10mm travel. They come in two parts A and B, there's also two sizes, 65mm and 75mm. They're friction fit (0.1mm offset) and can be glued in to a fixed length if you want to.

With this setup you can pull out the filament and the spool, slap a fresh spool in, push the filament down the bowden into the hotend, and start your print.
No tools needed. No messing with PTFE connectors. No rods or nuts to unscrew or pulling off rollers just to change a spool.
Unloaded filaments can rest in their own separate tube above the Y splitter/adapter.
The idea was to not leave any open holes letting air get in.

NB! When changing filament you might have to cut the tip/blob off the filament before pulling it up into the splitter/adapter or you might jam filament in there.
It's possible to alleviate the blob problem by reducing the size of the blob with a decent filament change macro, however such a macro will be specific to your printer. The gist of it looks like this:
set filament temp->short fast extrude->short fast retract->slow retract until unloaded.
(see "Teaching Tech"s explanation here:

Hardware:
Box with a lid that fits your desired amount of spools - I recommend using a transparent polypropylene (PP) box with a gasket making it airtight.
M3 socket head screws (M3 SHSC) - my box had 1.5mm thick walls and I used 8mm long ones, you might need longer or shorter ones depending on the walls of your box.
M3 hex nuts - because they're the cheap and readily available.
8MM rods - any 8mm rod will work.
I used M8 threaded rods because they're cheap (~4$ per meter for zink plated stuff).
Alternatively you can use steel, carbon, wood, plastic. Anything rigid enough as longs as you can cut them to the length of your box and the 608 bearings fit snugly.
608 bearings - you don't need expensive bearings, you can either 3D print some (files included) or use some cheap 608/608RS/608ZZ bearings.
8mm shims or 8 mm spacers
PB4-M10 PTFE tube connectors - Get some that allow the tube to pass all the way through (I had to drill mine).
~2m ~4mm PTFE tube for 1.75mm filaments
mine was ~4.1mm outer diameter
ideally, you could use capricorn tubing.
Silica Gel Balls - 3 mm balls is ideal.
Do not use silica gel kitty litter (it doesn't absorb moisture from air well enough).
Do NOT use silica gel with small particles, as this will unnecessarily leave silica gel dust on your filament.
Do use silica gel balls with indicator, this tells you when they're saturated. Then you can heat them at 100degC for an hour or so to renew them, ur use a microwave (carefully).
Sponge - for the dust filter
I used a typical kitchen sponge
(Optional) Sealing foam tape(PVA) or rubber/silicone sealing strip - If using a box without a gasket
I used a 5mm wide window sealing strip rated for 1-3mm compression.
Print settings for rollers and rod mounts:
Supports: No supports
Nozzle: 0.4mm
Layer height: 0.2mm - 0.25mm layer height, higher probably works fine too.
Material: PLA (or any other rigid filament)
Bed Adhesion: No (unless you need it)
Walls: 3 or more
Infill: 30-100% (make sure they're reasonably durable).

Print instructions for remixed parts can be found in originals:
PTFE Tube Cutting Guide_4.2_0.75:
PTFE Tube Chamfer tool:
Y-Splitter / Adapter:
608 Bearings:
Valve:
PTFE_Cap:
Dust Filter:
Assembly:
1 - Rod Holder
Measure your rod holder placement using the rod holders (rod groove should face directly upwards)
You want to leave 5-10cm at the bottom for your silica gel beads.
Drill the first m3 hole using a 3mm wood drill bit (a bit with a pointy end) (Do not use force it as you might shatter the PP box, go easy and let the drill do the work.)
insert an m3 screw and align it
drill the rest of the holes
insert hex nuts into the holders, use some pliers to press them into the slot.
screw in rest of the m3 screws, make sure they're making good contact with the hex nut threads.
2 - Measure and cut rods to length
3 - Install the rollers onto the rods
press-fit the 608 bearings into the rollers
slide the rollers on the rod
add one or two spacers between each roller
adjust your roller length
(optional) glue rollers (CA or CyanoAcrylate glue is fine)
add some spacers to each end of the rods, this is to compensate for the wall angle so your roller does not rub on the walls of your box.
4 - Install valves (mounts for PTFE/bowden tube)
Measure the placement and mark the center hole (use the valve itself as a guide)
to get the least rolling resistance you want the center hole aligned with the center of your rollers at the center of the coil of filament.
Drill the PTFE tube hole using a ~4-5mm wood drill bit (go easy on it as to not shatter the box)
put a piece of PTFE tube through the holder and through the hole to help keep it aligned.
drill the remaining 4 m3 holes using a 3mm wood drill bit (go easy on it)
5 - Cut and chamfer PTFE tubes
Filament box to splitter
2x ~40cm - one end cut straight , chamfer the outside edges one the other end (use the included cutting and chamfer tools).
2x ~45cm -
from splitter to hotend
Length depends on your setup, this should be long enough to reach your hotend.
make it a little longer than you think you need, this helps you move it around. Allowing it to coils with the filament reduces resistance.
Chamfer the inside edge of the end that goes into the output of the splitter with a 4mm metal drill bit, small knife, scalpel or v bit.
this is required to let the filament pass through the y splitter smoothly
6 - Install the PTFE tubes in the Y splitter (4to1 / 2to1)
Test and make sure you're able to pass the filament all the way through the Y-splitter easily. There should not be much resistance, just a small bump at the intersection between the ptfe tube and the output of the Y splitter.
7 - Assemble and install the dust filter
cut the sponge into pieces that fit the dust filter
clamp it onto the filament before the input ptfe tube inside the dry-box
Possible future upgrades and additions:
Drilling jig/stensil/guide
3d-printable spacers
rod holder locking mechanism
Humidity sensor - will probably add or build an IoT sensor to integrate with Home Assistant
Heater - will wait and see if there's a need for one
8mm rod holder locking mechanism - the rod is very easy to remove, maybe too easy
Built-in filament hopper - looking into it, but might opt for an external hopper due to space restrictions
large low profile Silica gel container
2 part Y-splitter (easier to clear out in case you get something stuck in there)
Enjoy
Hope you find some good use of use this.
Do let me know if you want wider or shorter versions of the rollers, or if you have any ideas for changes or additions.