Bộ chuyển đổi lõi cuộn Prusament - Tiết kiệm nhựa, chỉ cần 30g và 4 sợi dây rút!

An easy way to reuse Prusament spools!

I have a few Prusament spools laying around, and don't need their full size for remnants of spools I want to offload. This solution let you shrink down the hub and make better use of them!

This also uses way less filament than other solutions - 30g for the 40mm hub, and even less for the other. And who doesn't have 4 zipties laying around? :D

Printing:

For the hub, I suggest anything but PLA since it has the likelihood to release over time. PETG has worked great for me! Any layer height and nozzle will do. 

You can use PLA no problem for the jig with standard print settings.

You may note that the hubs are 1mm wider than the given width, this is because there's a small inset where the hub sits so I figured I'd compensate to make it a true even width.

Assembly:

The inner hub flanges are 20mm each, so without any work you can join them as a 40mm wide spool, or 2/3 of a normal spool.

I really wanted half spools, so in order to get that width I had to use my dremel to cut the flanges down to 15mm. I made an attachment just for that (included in the files), and use a thin metal saw bit to cut the whole thing to size. I kept the jig flat against the inside of the spool, made sure the dremel was perpendicular and just rotated the hub on the table as I held the dremel in place.

The dremel jig has a line inside the guard where you can line up your blade for 15mm.

Feel free to drill a hole for the filament to start in, but I've just used a small piece of tape just to get it going. 

The Magic of Zipties!

While the hub is generally tight enough to hold the two sides, I also use zipties to keep them together. So far they haven't loosened at all for me! I found this better than screw-in hubs that end up making the spool wider. 

There are a set of half-hex holes around the inner hub, and they fit those little black zipties you get from Prusa printer builds perfectly! 

Push a ziptie through the hole and out the other hub, and click another ziptie to the end.

Snip off the excess of that second ziptie and push it all the way into the spool's hex as an anchor. Use a pair of pliers to make sure it's tensioned.

Repeat on the opposite hole. You can add more but I've found 2 to be enough.

Due to the geometry it's not as straightforward as stretching out a hub for a larger size. Just ask for a different size if you need it!