Bambu Dry Spool - Dries Filament While Printing!

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(Scroll down for assembly instructions)

 

Update 3/5/26: Modified AMS Lite adapter so it has a tunnel inside and will serve as a spacer tube for filament and permit tighter systems from tensioning the filament in a chicane too tightly and restricting smooth filament flow. Also added QR code to cap piece, allowing easy access to the model page for assembly instructions and model files to print just off of the spool itself.

 

Anyone with an external spool or an A1 series printer has eventually come to this problem: Filament getting wet. This results in brittle strands that snap like spaghetti, failed prints, stringing, and a host of other inconveniences. Nobody wants a print failure on large prints or even in batches of miniatures, where precision and consistency is key, and one mistake can ruin the rest of the group with zero margin for error. Having the spool exposed to the open air, subject to wind and air conditioning, is simply a death wish for any important print, especially considering that Murphy's Law applies to 3D printing more than anything. 

 

Most people turn to pre-drying or even massive enclosures for their spools to ensure low filament humidity when it matters most, but drying the filament before each print is a pain, and enclosures limit easy access to the filament, which is also an issue because we all know wet filament isn't even close to the only issue you can have with a 3D printer. Additionally, some enclosures are extremely expensive and only work with certain tools and configurations, leaving behind those who use other tools or can't afford an automatic feeding system.

 

With these issues in mind, I set out to create a tool that was cost-effective and universally compatible while keeping filament dry all the time and permitting easy access to the filament in the event of an error. This resulted in the invention of my first model in 2024: the Enclosed Spool. This was convenient and useful, but it had several flaws. Firstly, it had a complete Rolling Bridge to keep wet air out of the spool, which jammed in the AMS, broke when retracting in several cases, and rendered it AMS-incompatible. Secondly, while it did work for external spool use, it lacked a system to adapt and adjust its feeding angle for different systems. This caused it to jam and “snap” back when feeding to the external spool and the AMS Lite. The angle was also sometimes too shallow for the Lite to feed, but when it was adjusted, there was too much friction because the feeder kept pulling the spool in and creating an impossible feeding angle, and since the spool lacked a system to counteract this, it also jammed in some cases. 

 

This host of problems caused me to spend about a year tinkering with the different designs, among other projects. While other accommodations and upgrades will be released in the future, I have created a functional and adaptable spool that is compatible with every Bambu feeding system (released before the H2D and its accompanying products; AMS 2/HT are still in beta since I do not have either) by having a small notch taken out of its place in the AMS feeder and a stabilization apparatus to hold position in the AMS, can maintain a consistent and smooth feeding angle for the AMS Lite without jamming, and can adjust its angle ~60° to accommodate any feeding system that requires a dry spool, whether shallow or near-vertical. This system is truly a huge improvement over its predecessor and I truly hope it helps those of you out there who need an efficient and compact way to keep your external spools dry while you print them.

 

Assembly Instructions:

1. Gather all the parts from the print (Plate 1 has the base, plate 2 has the cap, and plate 3 has the Rolling Bridge and all its accessories: the two halves of the Gimbal Wheel and the AMS Lite adapter.)

   
    

2. Determine if you are using a spool with ~850g or more. If you are, then do not assemble the full Gimbal Wheel and use only the main piece. This will sit flush with the interior of the Rolling Bridge and will not interfere with the additional filament volume. 

   
    

3. Assemble the Gimbal Wheel (if applicable) and install the AMS Lite adapter into its storage position. A full assembly plus proper installation of the two AMS Lite adapter configurations (for immediate use with the AMS Lite) is shown: 

   https://drive.google.com/file/d/11Cg2467Nn2z4WdLNUedt-UzjG9QAOTdV/view?usp=sharing

   
    

4. Take the spool from which you are planning to transfer the filament and place it so its “cap” piece faces down (the locking mechanism will be visible from above in this position). Unscrew the “base” piece and replace it with the Dry Spool base piece, then screw it back in. 

   
    

5. Now that the spool is complete and secure again, flip it upside down and unscrew the “cap” piece. Take care to ensure filament does not spill out and fly back, as its integrity is crucial to the respooling process, especially on fuller spools. (If it did, then respool the filament and make the top of the filament flush with the RFID tag for best results. This spool is designed slightly wider to accommodate small errors in the process.) Additionally, take the Rolling Bridge and feed the filament through the Gimbal Wheel along the direction of the bridge so that it flows smoothly. (This example uses a half-complete Gimbal Wheel flush with the Rolling Bridge's walls, as the spool shown contains 950 grams of filament and cannot accommodate a full Gimbal Wheel. An example of the full Gimbal Wheel being used will be shown later in the instructions.) If a spool contains more than 950 grams of filament, it may have trouble fitting and may need to be used a bit before spooling into the Dry Spool, else friction may impede functionality. Refills can be opened and may have similar issues.

   
    

6. Install the Rolling Bridge into the spool. As described above, the volume and quality of the filament may affect how snugly the bridge fits onto the spool. If there is excess space, desiccant can also be added to keep the filament drier, while the spool preserves humidity.

   
    

7. Install the cap and complete the lock. It may be slightly loose, but friction will ensure it is secure in such cases. The spool is now complete.

   
    

8. If the spool has less than 850g of filament, then a complete Gimbal Wheel may be useful to accommodate a wider variety of systems and to reduce the risk of it falling out during installation and printing. A very small amount of filament is shown in this example.

 

Installation

External Spool

Install the spool how it fits best on the printer with the filament having a straight line to the PTFE tube. If it does not fit or jams too easily (when the spool has less than ~950g) then please contact me for troubleshooting and model improvements.

 

AMS Lite

Install the AMS Lite adapter according to the side on which you want to install the spool. Shown are two images and their according compatible spool slots on the Lite depending on which direction the extension is facing. 

Install the spool as shown with the filament spread out and the adapter acting as a spacer to ensure smooth and shallow filament flow:

AMS

Place the spool in its corresponding spot with the AMS Lite adapter stored properly. Feed the filament in like so:

 

If the spool does not correct itself during the feeding process to the position shown below or does not feed into the AMS properly:

1. Shake/rattle the spool a little bit and try to slide it into position if it looks similar to the image above.
2. Pick the spool out of the slot and adjust it to fit in as shown above. 
3. Increase the weight of the spool by using publicly available models or by placing heavy items into the core. Ensure that the weight does not fall out.
4. Remove the AMS Lite Adapter and check for improved performance.

Further troubleshooting:

Please contact me directly so I can add further advice to this description and help out future creators and improve the model for everyone!