August 4, 2025
Description
This is the all new Retracting Spool Holder Pro and it fits just about any spool up to 1kg.
While this model keeps the user friendly retraction function of the original version,
it is not just an upgrade, but a complete new system.
Of course, your external filament can still be retracted from the toolhead without having
to open the box and let humid air in. Which is especially usefull when the spool holder is connected to the toolhead via a PTFE tube.
But this version also comes with a lot of new features.
When i planned and designed this model, i always thought of it as the perfect enclosure to print my TPU from, both in „top feed“ and „through the tube“ situations.
My upload also contains my bambu X/P- and H-series holder „SPiNE“
The Bottom Holder part is designed to stay on your printer at all times. The Top section is installed via a chunky dovel connection that just slides in and is secured by the weight of the assembly.
The Top glass of your printer does not need to be removed for the installation of SPiNE, even if the retracting spool holder is attached.
The whole system is setup in seconds.
Of course there is also a holder that allows you to setup the spool holder next to your printer. This is the recommended setup for non flexible materials. I print my nylons and PET this way for example.
Let me know if you want to see some more mounting mechanisms! Maybe a wall holder? Skadis? Just make your suggestions in the comments :)
My original model „retracting spool holder“ has gotten tons of great feedback, i never would have thought that it will we so popular after only a few months of being online. Thanks guys ❤️
I received many suggestions for additional features for a future version, such as:
-Compatibility with more spool brands
-a window to be able to check how mich filament is left
-more room for desicant
-a better closing mechanism (some folks seemed to have issues closing the first version)
The body of the model is chambered and can be filled with desiccant from outside. I recommend using 2-4mm diameter reusable silica beads.
When the desiccant needs go be changed, the spool does not need to be removed from the container. Everything is done through the two ports on the outside.
I added two sections, a big one with only a window, and a smaller window with an outlet. These parts are interchangable and can be mounted in different orientations, to fit your personal needs.
How you assemble it determines what kind of setup it suits the best!
Thanks to the center bearing installation, the universal retracting spool holder ensures minimal resistance, which is technically optimal for consistent extrusion, especially for flexible filaments.
In test phase however, i experienced that too little resistance can also be an issue:
When the toolhead moves quickly, pulling the filament out of the box, you don‘t want to have the spool keep spinning inside the container after the movement is finished.
That would lead to entanglement inside the container pretty quickly.
Of course, I could have added a part that engages with the spool and prevents the filament from slipping over its edge.
That was no option, as it would have ruined the „fits all spools“ feature of this model.
I added an adjustable brake, that puts pressure on the internal axle via a „print it place“ part that translates a rotation to a linear movement. and it works very well to keep the filament on the spool! With no restrictions regarding spool sizes.
Adjust it so that the filament can be pulled out without too much resistance, but also so that the spool does not keep spinning in an uncontrolled way.
the spool is secured via this jig:
the part that says „55mm diameter“ is a centering helper for bambu lab spools, it is included with the internal parts profile by default. The model also works without this part. I will upload this object as a remixable model soon.
this pressure ring allows you to install spools with a core diameter from 45 to 59mm.
I will extend the range via various size rings very soon, ut this should work for most spool designs!
The lid for the container now just screws on with a big thread! It does not need much force to close. For opening, i added a tool to help you. It can be a bit hard to open when it was overtightened!
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#####PRINTING#####
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To complete the spool holder itself, you have to print the profile „Exterior Parts“, „Internal Parts“ and „TPU Parts and gaskets“. There is multiple choices for materials for each profile.
Check the details in the profile descriptions for further details!
SPiNE and accessories are also found as their own profiles!
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####HARDWARE####
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Retracting spool holder:
2 Pcs - Bearings - 27mm OD, 20mm ID, 4mm thickness (bambu store EA005)
16 Pcs - M3 short heat set inserts
(max mm tall)
10 Pcs - M3x8mm countersunk screws
8 Pcs - 4x2mm round magnets
1 Pcs - rectangular thermo/hygrometer
1 Pcs - transparent plastic sheet, max 0,5mm thick, i used 0,3mm
SPiNE for H2D:
6 Pcs - M3x8mm countersunk screws
1 Pcs - M3x10mm buttonhead screw
2Pcs - BT3x12mm self tapping screw
SPiNE for P1/X1:
6 Pcs M3x8mm countersunk screws
3 Pcs M3x10mm buttonhead
screws
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####ASSEMBLY####
###############
Retracting Spool Holder Pro
Install 16 Pcs of M3 heat set inserts (max 4mm tall)
use these two TPU gaskets as templates for cutting the pvc sheet windows, normal scissors do the job well. Cut inside of the line, make sure the windows are not too large
you don‘t need to be extremly precise, all cutted egdes will be hidden when the model is fully assembled. Instead of cutting the small holes round, i just cut a small cross through their center. The screws will find their way in the next step
Assemble the small window/outlet section like this
the two „non-TPU“ parts just snap together via a pressure fit
Assemble the resistance adjustment mechanism
Now you must decide how you want to assemble the box. Install the two panels according to your needs
The TPU gasket is inserted first for both window panels.
the two rectangular gaskets have different thicknesses, the thinner one is for the large window
Secure everything with 8 M3x8mm countersunk screws
Assemble the universal spool fixture. The TPU friction pads just sit in their pockets with zero tolerance and hold very well (they will be under pressure anyway, so dont worry about them coming loose)
The part that says „55mm diameter“ is a centering helper for bambu lab spools. You can skip this if you don‘t print bambu filament. The threaded nut with TPU friction ring also centers every spool from 45 to 60mm core diameter to a certain degree. Some manual adjustment might be needed, but not a big deal!
Tighten your spool down in the spool fixture. Make sure that it‘s tightened well.
Put the assembly inside the eclosure and click in the x brace. The first few installations of this part can take a little force. Once the parts are worn just a little, it gets much easier
Lay the big TPU gasket around the thread for the lid, install the TPU shaft seal in the lid and push the rotary wheel through
flip the lid over to the other side and insert the t-shaped hex key. Secure the holding plate with two M3x8mm countersunk screws
screw on the now fully assembled lid - it should not take much force, make sure to not apply much downward pressure! If you get stuck, rotate it counterclockwise and start over
Install the hygrometer (it is a tight fit!)
Fill the desiccant chambers with rechargeable silica beads (2-4mm size).
Each of the chambers can hold up to about 100grams of it.
I added a helping tool to make the filling processa more user friendly:
the filling nozzle is made from TPU and screws onto the container. I will also add a funnel as a second option instead of the container soon.
Install 8 pieces of 4x2mm round magnets for attaching the two labels.
If you print multiple of these boxes, make sure that the polarity is the same throughout all of them, so you can use each label on every one of your boxes!
You can now secure your PTFE tube with the small printed nut. Make sure that the tube reaches all the way inside the box. The hole diameter is big enough to feed it through
If you are planning to use the rtracting spool holder next to your printer, you are done with the assembly!
If you also printed one of the SPiNE variants, continue like this:
Both P/X and H version of SPiNE share this same part. It is attached to the retracting spool holder with 6 M3x8mm countersunk screws
The bottom part of the P/X version is attached to the printer with 3 M3x10mm buttonhead screws. The rest of the parts just slide together with dovetails/dovels
The bottom part of the H2D version is mounted in a very similar way, but uses two BT3x12mm self tapping screws in the top and one M3x10mm buttonhead screw in the bottom
The only thing left to do now is to slide in that big dovel and you‘re done with the assembly!!
The P/X Version is designed to be compatibe with top glass risers of up to 25mm height whilst the H2D version is not compatible with risers.
The TPU part profiles contain this little PTFE tube end cap that also holds the end of the filament:
I recommend also printing this handy tool for opening the container (found as a separate profile), if you ever struggle to unscrew the lid, it will serve you well!
Congratulations is you‘ve made it here! I hope your soft TPU prints come out as flawless as mine now! These spool holders can be used for any other kind of non AMS materials too, it is not exclusively for TPU!
I really hope you lile it! See you for the next one!
Kind regards,
M.I.M
License:
Standard Digital File License
Made.In.Meidling
