Sunlu Spool Converter for Bambu Lab Refills

This adapter is to convert empty Sunlu spools by widening the walls of spools for Bambu Lab filament refills.

I like the idea of Bambu Lab's filament refills. It saves the environment by putting less empty spools in the land fills or into recycle process and saves cost on 3D printing.

Typical problems I encountered from using other converters in the market:

1. Breaking retention tabs.
2. Spool halves are separated or getting loose during printing or during unloading from AMS.
3. Adapter is so hard to be assembled on an empty Sunlu spools.
4. No retention “tab” to grab the notch on refill's cardboard tube. This prevents the function of AMS lite which has auto spool/filament retraction when changing filaments. The filament must rotate with the spool.

I modelled this adapter to solve the above problems.

Key features of this Sunlu Spool Converter:

1. Thank you for the comments from users. I learned that there are different SUNLU Spool sizes out in the market.  It looks SUNLU has been changing their spools over time. Two converter sizes are included in the print profiles. Please use the correct print profile for your empty Sunlu spools. Do not scale the size yourself or the cardboard tube of Bambu Lab filament refills may not work.  Let me know your spool center OD size. I'll make a print profile specifically for you. 😉 
   • 70.7mm center OD size and 51.5mm center tower tall.

   • 71.5mm center OD size and 51.5mm center tower tall. 

     

     

2. Both converter versions are designed to be pressed fit onto the Sunlu spool.
3. Sunlu spool have 3 locking bumps. This model ensure all 3 locking bumps are fully engaged with the retentions on the converter. You will hear a satisfying full engagement “click” sound with the solid engagement feel when assemble the spool together. Other designs have the retention bumps set at 120° apart, but the actual locking retention feature on Sunlu spools are NOT. There are various angle among them. Many of the models in the market thus has a weak single retention and lead to the risk of falling apart during operation.
4. The slot on the adapter has matched 3 keys ways to ensure the shorter half of spool has only one correct way to assemble together to ensure good locking together.
5. Adapter length match the refills cardboard tube length. This to keep the spool side wall tight with the filament to maintain packed winding and prevent tangling problem.

Printing Material:

PETG or higher temperature resistance material should be used if your filament will be put in dryer. I found that the material use on Sunlu spool can only withstand about 75°C. I learned it in a hard way. 😅

Assembling:

1. Before push the printed converter onto an empty Sunlu spool. Please designed if you will put your filament in dryer in the future or not. If yes, I highly recommend you to use glue (I use E6000 craft adhesive) between the converter and the long shaft of Sunlu spool. I found that PETG printed converter changed from press fit to transition fit after 3 hours in the dry box at 65°C. I experienced this only on the Blue Sunlu Spool only. On the clear translucent spool, the converts remained tightly bonded on the spool. Use glue which has heat resistance higher than your drying temperature just prevent loose spool in the future.

2. Align the “tab” on the converter's outer wall to the location you desired. I prefer to align it just next to one of the “triangle” shaped window/cut out, so that I can better align the “notch” on the refill carboard tube later, and yet ensure the RFID tag is held between the filaments and the spool wall. Do not align the tab to the “middle” of the triangle window, or the RFID tag can flip outward which could get damaged in future operations.

   

3. Press the converter about 10mm down onto the long tube of the spool halve. If glue is needed, it's good time to apply it on the outer surface of the long tube. Don't apply too much glue. Excessive glue will be wipe down by the converter.

   

4. Press the converter all the way down to touch.

   

5. Load the filament refill onto the converter. Lower the refill roll slowly down. And finally, align the “tab” aligner on the converter with the “notch” on the refill's cardboard tube.

   

   

    

6. After pressed all the way down, the converter top is flush or just a bit (< 1mm) above the cardboard tube.

   

7. In the above picture, the length “Key slot” #1 is the shortest. This is to for the shortest “Key” on the shorter half of the spool.

   

8. Align the shortest key to the shortest key slot, the short half of the spool can simply “drops” into the right position even by a single hand. Just like in the video.

   

9. Finally, turn the shorter spool half in clockwise direction until you hear the satisfactory “click” sound. This design ensure all 3 locking bumps are well engaged to yield the full retention strength as the original spool halves.

   

Hope you'll enjoy converting your empty Sunlu spools for Bamblu Lab filament refills. 😊