Update 04/03/2024 - License changed from “Standard Digital File License” to “CC-BY-NC-SA”. Multi-body STP file uploaded.

Oh yeah, I over-engineered the hell out of this one! I went through more than 12 iterations and I think this is going to be my final version. The main challenge was designing outer walls that print without a million retractions so I didn’t want to just put regular holes and slots around the perimeter. These cheese grater looking holes are opened up both towards the inside and outside in alternating patterns creating quite large vent areas. Each section has a single line of extrusion per layer so it prints fast and isn’t too torturous for all 4 motors.

I printed mine in clear polycarbonate and it was super easy because there aren’t any long straight walls that cause warping. ASA would also be a good choice but I chose polycarbonate so I can see the colour of the indicating desiccant without opening the canister.

Design Objectives:

• Large vented surface area, even when installed into a spool, for quick drying of enclosed airspaces
• Multiple cross-flow air paths for quick drying of desiccant without removal of the desiccant beads from the container
• Design primarily for the Bambu reusable spools and sits flush with the sides of the spools. (However, as different manufacturers are converging on a more "standard" spool size thanks to the AMS, these should fit some other spool brands)
• Work as a Bambu reusable spool's "spool shim" to prevent the spool pieces separating
• Fast print, minimise filament retractions when printing vents on vertical walls
• Strong and sturdy to last a long time - no vase mode
• Desiccant cannot fall out when moving the holder between spools

Print material:

• OK to use PLA if you don't plan on drying the desiccant inside the canisters
• PETG recommended as a minimum if you want to dry the desiccant gently without removing them from the canisters
• ASA/ABS/PC recommended

Print settings:

• For Bambu users: print from the app.
  • Feel free to add print profiles here if you changed something and think it may be useful to others.
• For those who are getting the STLs and slicing it yourself:
  • Import the “cap” and “cap mesh" together and put them in an assembly to keep them aligned
  • Likewise, import the “body" and “body mesh" together and put them in an assembly to keep them aligned
  • The mesh parts should have no walls, no top, no bottom and 50-60% triangular infill (or as you see fit)
  • Use 3 walls for all parts, 3 layers for the bottom, 4 layers for the top
  • Layer height as you see fit (I use 0.20m)
  • Even if you have a fast printer, slow down the outer wall speed for part durability and consistency in gloss level (I use 50mm/s)
  • ARACHNE WALL GENERATOR MUST BE ON!
  • The preview should look something like below:
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Spool Compatibility

• These work well with Bambu spools and eSun cardboard spools.
• For eSun plastic spools, you will need to turn the retainer around for a tighter fit (these spools are getting phased out anyways).
• Please check out the comments and makes as they come through - on this page and on Printables - as users post these with their spools - I've seen one already fitted on a Polymaker cardboard spool.
• Sorry these are not compatible with Prusament spools but this one works with them.

Fitment

• Overall, it's important to have your pressure advance (k value) tuned so that the seams don't bulge out and make it harder to thread parts together.
• The cap is designed to fit very tightly. If you print from PLA, you might find that it threads in really easy but if you print from PETG (which has higher friction and generally doesn't print as cleanly), it is a bit hard on your fingernails to thread in. This is to ensure the cap doesn't come off and spill all the beans during use. I have included a cap installer/remover to make it a bit easier on your fingers.
  • Unfortunately, even with all the settings and printer dialed in properly, variations in filament batch may create fitment issues. It's not necessarily your fault - don't be disheartened by seeing 99% of users say it's perfect but yours isn't! Measure your filament diameter. Sometimes it can be 1.72mm, sometimes 1.78mm - the latter will make the fit tighter. Either reprint just the cap in a different filament, a different section of the same roll, or scale it down slightly. (Another user has already created print profiles for easier fitting parts!)
• The retainer has been designed with a larger clearance than the cap so it should thread in nicely. However, the thread pitch is quite fine because it's designed to fit tightly to the spool so it stays on in the AMS with the constant winding and unwinding. This can, with some spools, make it difficult to remove. User @urzhiataer has made a tool to help remove the retainer, check it out!

That's all, enjoy!

Wait two more things: print this canister holder to dry 7 of them at once in your filament dryer:

And if you have lots of little fragments of desiccant because you microwaved them on high, perhaps try out this filter scoop: