Introduction: 3D Filament Storage Box (in an IKEA SAMLA Box)
3D printing is amazing - it gives you so many possibilities to play with. And if you're like me, you've got multiple rolls of filament to try out different colors and materials.
However, 3D filament is hygroscopic - meaning it will absorb moisture from the air over time. That means that in a few years, your precious filament may be too brutal to print with and the print quality will be worse due to the water molecules that turn into steam when heated in the nozzle.
Some filaments like nylon and ABS are more prone to degradation over time, while others like PLA take longer.
Luckily, there is a cheap and simple solution to that problem: dry boxes - and in this Instructable, I will show you how to make one for pretty cheap and out of commonly available materials.
Most of the pieces will b 3D printed, but we'll still need to buy some stuff:
_some Silica Gel (I used around 500 grams)
_a Storage Container (mine's a 22L SAMLA box from IKEA, but I suggest you buy a storage box from a hardware store that already has clips on the side and a built-in sealing ring to make your life easier)
_Bowden tubes and connectors
_a Humidity Sensor
_M4 nuts and bolts
_a Sheet of Rigid Plastic or Aluminium (optional)
Step 1: Watch the Video
I made this one minute video on the building process to give you a quick overview of what to do:
Step 2: 3D Print the Parts
For most parts, I found perfectly designed models from Thingiverse. Here they are:
SAMLA box lid Clips: https://www.thingiverse.com/thing:2110134
Bowden connectors: https://www.thingiverse.com/thing:2953325
However, in all the dry box designs that I have seen the silica gel is at the bottom of the box. It's certainly the easiest solution, but I wanted to try something different: attach the silica gel under the lid to make it easier to get it out for drying. For that, I had to design these custom brackets: https://www.thingiverse.com/thing:4692850
They require more work and tinkering, but in the long term, they'll save you time when maintaining the box.
I also created a mount for the Xiaomi humidity sensor (more on that later): https://www.thingiverse.com/thing:4692828
Step 3: Mount the PVC Tube and the Bowden Connectors
The assembly is fairly simple: just drill the holes and attach the 3D printed parts with m4 bolts and nuts.
I didn't use any templates and it turned out fine, but to be extra sure, you can also print some guides from here.
NB: if you plan to mount the silica gel on top of the spools like I did, you'll have to mount the spool holder lower to make room for the silica bag.
For the PVC tube, I cut it at around 31 cm but if you mount the spool holder to the original height, the tube has to be cut 31.5 cm.
I also didn't add Bowden tubes for all the spools, as I won't probably need to access all of the spools at the same time.
Step 4: Mounting the Silica Gel
Silica gel is the same stuff you find in these little bags that come usually with shoes or 3D filament to keep them dry. It absorbs moisture and when heated, becomes dry again - so you can use the same beads again and again.
There is also gel on the market that changes color when going from dry to humid, but I decided to buy it in a closed fabric bag to prevent spilling the gel beads everywhere when I have to take them out of the box to purge them from humidity.
To make the purging process even easier, I decided to mount the silica gel under the lid of the box. The key to make this system work is to use a sheet of material that's as rigid as possible. If you use something flexible like plexiglass, it will bow under the weight of the silica gel and touch the filament spools - thus blocking them on the PVC pipe. That's why it's best to use something like aluminum to prevent any excessive bending.
You can use long-nose pliers to keep the nuts in place while screwing in the bolts, as it takes some fiddling to get everything in place.
The lid of a SAMLA box isn't flat, that's why some parts have the word 'Mid' in their name. The mid parts have to be mounted in the middle of the lid, to keep everything level.
Step 5: Mounting the Sensor
I decided to use this smart Xiaomi sensor, as it can be connected to a home network through a gateway to send notifications when the humidity level in the box gets too high - or you could set up your speakers to give you a musical reminder when the humidity level gets critical.
For that to work, you'll also need to buy a Xiaomi gateway, that will connect the Bluetooth equipped sensor to your home WiFi - without the gateway, you'll just have an overpriced minimal looking humidity sensor.
To mount it, you'll need 4 m4 12mm bolts and 4 m4 nuts. Just press the nuts in the 4 slots on the bottom piece and screw the bolts in from the top.
Step 6: Done!
Now that you have finished the box, you can finally set up the filaments inside. If they had already absorbed some humidity, you can dry them in an oven for a few hours (40°C for PLA and 80°C for ABS = 104°F for PLA and 176°F for ABS).
Then, set them on the PVC tube rack, close the box with the 3D printed clips and enjoy your new dry box!
Depending on how often you open your box and how airtight it is, you'll have to dry out the silica gel in an oven or on a radiator every few months - if you used a box with a rubber seal, you don't have to worry as much about the silica bag.
After a month of use, I have to confess that I actually don't use the PVC tube rack to hold the spools - I usually just take a spool out and place it on top of my 3D printer when I need it. But I still use the box to store the filament when I'm not using them, and the weight of the silica gel bag pushes the lid down, helping to make a better seal. If I had a printer with dual extrusion or the MMU from Prusa, I'd probably use the box to its full potential with the included Bowden tubes.
I hope you liked my Instructable. Stay creative, and have a beautiful day!
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