The (almost) Perfect Master Spool

This project is still in development so any feedback is welcome! 😊

Everybody knows there are a lot of master spool designs available for the Bambulab refill filaments (and other brands). But while I was searching for one, all of the designs were missing a feature that others did have and vice versa. None of the designs had ALL of the features you wish to see in a master spool. I was charmed by the MasterSpool that FormFutura has designed, but that one wasn't compatible with BambuLab refills, just their own. So I went out and design my own, of course. (relevant XKCD: https://xkcd.com/927/ ).

My master spool needs to have the following features:

• Compatible with Bambu Refill filaments and coincidentally in my case Azurefilm refill filaments,
• Compatible with all the AMS systems that exist.
• Lightweight (±100gr total)
• To be able to strap your refill filament again for storage and be able to switch between refills. So you don't need to have a masterspool for every refill you have in use. (this is the case with Bambu's own masterspools for example).
• Have plenty of slots to attach the end of filament to when storing a spool with the refill still on it. These slots are not holey like you see on branded spools, but more kind of slots you press the filament into. This ensures that the filament wont stick out from the side of the spool. Handy!
• There is the option to use velcro straps (recommended) or tie-wraps. Velcro strap max width is 10mm. You can buy a 25meter roll of 10mm velcro at Amazon for about 10€. Cut 3 strips of 25cm of it for each refill spool. So 25 meter will have enough velcro for over 30 refill spools.
• Have an option for securing the spool without velcro with a separate locking thread cylinder to prevent the spool breaking apart in an AMS for example.
• An indication of approx how much filament is left. I made it in meters and not grams, as not all filaments have the same density but do have the same length.
• Have an open design for when you want to use a filament dryer to actually be able to dry the filament.

As I think a design like this can always be improved upon I'm open for ideas or suggestions for features you're missing.

You can print the spool in PLA of course, but printing in PETG or better even ASA/ABS is recommended. This is for the temperature resistance when using the spool in a filament dryer or inside a printer.

If you like this design, consider buying me a beer ❤