Phil's Auto-Rewind Drybox

TLDR: Everything you need to build a filament Drybox for 3D printing and/or storage - with a built-in Auto-Rewinder!

This Phil's Auto-Rewind Drybox Collection project combines my new designs as well as my remixes of the other referenced designs to provide a complete automatic filament spool rewinding drybox - to eliminate problems with tangled filament due to MMU (https://www.prusa3d.com/category/original-prusa-mmu3/) ejection of filament with each filament change - without requiring an MMU buffer! It can also be used with a BMCU (https://www.reddit.com/answers/f827651b-eacb-459b-85a3-993cb9bb8e29/?q=Overview+of+BMCU+product+and+features&source=PDP) or even without any filament changing system to help ensure tangle free spools whenever you unload filament from your 3D printer. If you add desiccant beads to the container, it also helps keep your filament dry.

Shortly after I first started using @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) design, I made a small change to the Base to accommodate larger diameter filament spools, and I published that as a remix. Fast-forward a year or so, and I've redesigned most of Mark's parts to make them better suit my needs and created brand new parts and tools for my own dryboxes (24 of them now), and I've published each of those designs for others to use. Having multiple separate projects is not ideal for anyone who just wants the ability to download and print a complete cereal container drybox, so this is a collection where I've combined all of these projects into one!

In the text and images that follow, I've separated the required and optional printed and purchased parts. I've also called out different versions of each part when appropriate.

These designs support 1kg filament spools that are up to 68mm (~2.68") wide with a diameter up to about 204mm (~8.03") and a center hole diameter of at least 50mm (~1.97"). Most 1kg filament spools should work as long as they are within these size constraints. The size of the cereal container is the main reason some spools will not fit; if the spool touches the sides, the top, or the bottom of the cereal container, then the Auto-Rewinder will have trouble operating as intended.

1kg spools of Prusament PETG and PLA, Bambu PETG and PLA, Sunlu PETG, FilaCube PLA, Yxpolyer Nylon (PA), and several other filament brands/types are known to work well.

Prusament PC Blend spools are a bit too wide for free rotation in the cereal containers. I have not yet tested Prusa's new reusable spool design (from late 2025), so I don't know if those spools will play nicer with the cereal container and the larger versions of my Auto-Rewinder TPU Drum Sleeves.

You probably shouldn't use this or any other Auto-Rewinder with TPU (Flex) filament, since it usually won't push back onto the spool in the drybox - just be sure to omit the PTFE tube from the drybox if using an MMU with TPU; the pushed-back TPU filament should curl up outside the drybox. Using an MMU and a stock Auto-Rewinder with TPU will probably end with the filament pulling right out of the MMU and completely winding back onto the spool when the filament is unloaded from the hotend! If you do want to use an Auto-Rewinder with TPU spools for uniformity, then I recommend that you disable the rewind feature by leaving out the piece of the spring that has the gears - which will allow smooth rotation without rewinding the spool!

Except for the optional TPU (Flex) Drum Sleeves and the TPU Filament-Holding Drybox Cap (aka Coupler Cap Gen 3), all of these parts are intended to be printed in PETG, though PLA should work as well. Note that you shouldn't print the parts that go inside the drybox in PLA if you plan on attaching your drybox to an active dryer such as the Polymaker PolyDryer!

The following photo shows all the 3D-printed parts used in my dryboxes that I designed or remixed (except TPU Drum Sleeves and TPU Filament-Holding Drybox Cap) - represented by the "philsRewinderDryboxALL" 3MF file:

The following screenshot shows the 4 build plates included in the "philsRewinderDryboxALL" 3MF file:

The following photo shows all the purchased and printed parts used in my dryboxes to make a single Auto-Rewind Drybox:

The following photo shows one of my Auto-Rewinder Dryboxes assembled - ready for a spool of filament:

The following photo shows one of my Auto-Rewinder Dryboxes in use:

REQUIRED PURCHASED PARTS:

---------------------------------------------

Note that the images below are not to scale!

1 - Cereal Storage Containers (4 liter, 6 units) - https://www.amazon.com/gp/product/B07NP98YKY

2 - 608 RS Bearings - two required - https://www.amazon.com/dp/B09PKD8QZZ - pressed into each end of the Drum Assembly

3 - PC4-M10 (PTFE tube) coupler - https://www.amazon.com/dp/B01IB81IHG

You can use the parts linked above or any equivalent parts.

OPTIONAL PURCHASED PARTS:

---------------------------------------------

1 - Desiccant Zipper Bags - optional - https://www.amazon.com/dp/B0DBVDD2MV - filled with desiccant beads and placed in Base on bottom of drybox

2 - Desiccant Beads - optional but recommended - https://www.amazon.com/dp/B01I5Y2DG6 - placed in Desiccant Bags or other suitable container

You can use the parts linked above or any equivalent parts.

3 - Hygrometer (rectangular humidity and temperature indicator) - https://www.amazon.com/dp/B08P3NRH95 - inserted into Hygrometer Holder

REQUIRED 3D PRINTED PARTS:

---------------------------------------------

DRUM - 2 VERSIONS...

1a - Standard Drum Assembly - consists of a Drum and a Drum Cap - remix of Vincent Groenhuis's (https://www.thingiverse.com/vincentgroenhuis/designs) Integrated Auto-Rewind Spool Holder (https://www.thingiverse.com/thing:3781815) where the entire Drum Assembly has been stretched by 23.33% in the z axis only and a grid pattern of ridges has been cut out of the outside of the cylinder to provide more grip on the filament spool. Note that if you want the arrows on the Drum and the Drum Cap to be a different color than the rest of these parts (cosmetic only - to make the arrows stand out), then you should add a filament color change in your slicer at a height of 1.4mm (layer 7 with 0.2mm layer height).

1b - Solid Drum Assembly - consists of a Solid Drum and a Drum Cap - remix of Vincent Groenhuis's (https://www.thingiverse.com/vincentgroenhuis/designs) Integrated Auto-Rewind Spool Holder (https://www.thingiverse.com/thing:3781815) where the entire Drum Assembly has been stretched by 23.33% in the z axis only, a grid pattern of ridges has been cut out of the outside of the cylinder to provide more grip on the filament spool, and the diamond-shaped cutouts on the side of the Drum have been removed. This version is useful if your printer has trouble making clean cutout edges. Note that if you want the arrows on the Drum and the Drum Cap to be a different color than the rest of these parts (cosmetic only - to make the arrows stand out), then you should add a filament color change in your slicer at a height of 1.4mm (layer 7 with 0.2mm layer height).

2 - Spring Assembly - consists of a 7-part 3D-printed Spring - remix of Vincent Groenhuis's (https://www.thingiverse.com/vincentgroenhuis/designs) Integrated Auto-Rewind Spool Holder (https://www.thingiverse.com/thing:3781815) where the entire Spring Assembly has been stretched by 23.33% in the z axis only and the drum and drum cap have been moved into a separate file.

.

.

SADDLE - 2 VERSIONS...

3a - Saddle - two (identical and interchangeable) saddles - remix of @DanVystrcil_1418479's (https://www.printables.com/@DanVystrcil_1418479) Center Roller for the Ultimate Cereal Container Filament Drybox For Rewinder (https://www.printables.com/model/1274921-center-roller-for-the-ultimate-cereal-container-fi) where a cutout has been added to the Saddle's cradle to guide the Axle Assembly. Use the Saddle version (this one or the Short one) that works best for any given filament brand to keep the spool from touching the top and bottom of the drybox. I almost always use this version.

3b - Short Saddle - two (identical and interchangeable) short saddles (~7mm shorter than standard Saddle) - remix of @DanVystrcil_1418479's (https://www.printables.com/@DanVystrcil_1418479) Center Roller for the Ultimate Cereal Container Filament Drybox For Rewinder (https://www.printables.com/model/1274921-center-roller-for-the-ultimate-cereal-container-fi) where a cutout has been added to the Short Saddle's cradle to guide the Axle Assembly. Use the Saddle version (this one or the standard one) that works best for any given filament brand to keep the spool from touching the top and bottom of the drybox.

4 - Axle Assembly - consists of an Axle and two (identical and interchangeable) Axle Flanges - remix of @ManelTo's (https://www.printables.com/@ManelTo) Spool Auto-Rewinder For PolyDryer (https://www.printables.com/model/1192508-spool-auto-rewinder-for-polydryer) Axis (eje) and Wheel (rueda) where both parts have been redesigned from scratch - preserving only the general dimensions - to provide a robust click-to-connect axle assembly.

.

BASE - 2 VERSIONS...

One of the following Bases is required.

5a - Standard Base - remix of @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) Base where the center crossbar has been lowered to accommodate larger diameter filament spools. Note that the Base Covers from Mark's design are not supported with this Base. I recommend placing two zipper pouches filled with desiccant beads on the bottom of the container to manage humidity in the container (one zipper pouch option is listed in the links above).

5b - Split Base - consists of two (identical and interchangeable) Base parts - remix of @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) Base where the center crossbar has been lowered to accommodate larger diameter filament spools, and the Base has been split into two parts that slide together - to allow printing on small bed (180mm by 180mm) printers such as the Prusa MINI or Bambu Lab A1 mini. Note that the Base Covers from Mark's design are not supported with this Base. I recommend placing two zipper pouches filled with desiccant beads on the bottom of the container to manage humidity in the container (one zipper pouch option is listed in the links above).

OPTIONAL 3D PRINTED PARTS:

---------------------------------------------

1 - Hygrometer Holder - redesigned version of @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) hygrometer holder that attaches to the Base to ensure that the hygrometer display is always perfectly level (horizontal) without having to fiddle with the position of the Coupler Nut inside the Drybox - as was required in the original design!

.

2 - Tag Holder - redesigned version of @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) tag holder that remains on the drybox at all times - the filament tag only needs to be swapped out when a different brand or color of filament is loaded into the drybox. In the original design, the Tag Holder snapped onto the Coupler Cap - requiring you to keep track of which Coupler Cap and which filament tag belonged on each drybox every time you unloaded filament from your printer.

3 - Coupler Nut - redesigned version of @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) coupler nut that now includes PC4-M10 Threads and a Flange for a perfect, secure fit with the PC4-M10 PTFE tube coupler. I used the PC4-M10 Threads from @jurassic73's (https://www.printables.com/@jurassic73) PC4M10 - Tapered threaded opening STEP/STL for design (https://www.printables.com/model/889353-pc4m10-tapered-threaded-opening-stepstl-for-design) to get the correct pitch and taper for the PC4-M10 coupler threads - increasing the X and Y dimensions of the thread by 2% each to allow hand-tightening of the Coupler Nut to the PC4-M10 coupler.

.

4 - Filament-Holding Drybox Cap (aka Coupler Cap Gen 3) - completely redesigned replacement of @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) coupler cap that improves the grip on the loose end of the filament and eliminates the bending of the end of the filament as seen with Mark's original design. Consists of two parts: a Base and a Knob printed with Bambu Lab "TPU for AMS" (or a Base printed with TPU 95A Base and a Knob printed with PLA or PETG Knob) that you twist to grasp the filament with a built-in clutch before pressing onto the PC4-M10 coupler to seal the drybox opening where the filament is fed into your printer.

.

TPU DRUM SLEEVE - 3 VERSIONS...

Note that a TPU Drum Sleeve helps increase the grip of the filament spool on the Auto-Rewinder Drum. It isn't needed for many filament spools, but can help improve rewinding for nearly empty spools or spools that have a very slippery center hole.

Also note that spools with a cardboard center hole typically don't need a TPU Drum Sleeve due to their already high grip on the Drum!

6a - 51 Plus TPU Drum Sleeve - may be used to provide more grip on plastic filament spools. This "rewinderUltimateDryboxDrumSleeve51plusTPU-7c" version is a general purpose sleeve that remains on the Drum at all times. It allows some movement of the spool from side to side - which is ok, since the Saddle keeps the spool from shifting too far to either side. It works with almost any filament spool with a center hole diameter of 51mm (~2.01") or more and a maximum spool thickness of 68mm (~2.68"). A spool with this sleeve should be able to wind the Spring on the Drum but still allow slippage when the Spring has been wound more than 5 to 9 full turns. Please refer to the following photos for proper usage of this sleeve.

.

.

6b - 58 to 66 TPU Drum Sleeve - may be used to provide more grip on plastic filament spools. A spool with this "rewinderUltimateDryboxDrumSleeve58to66TPU-7c" version will be able to wind the Spring on the Drum but still allow slippage when the Spring has been wound more than 5 to 9 full turns. Ribs on the inside of this sleeve act like a clutch to hold onto the Drum but also slip as the Spring tension increases. This version is designed for spools (such as Sunlu and FilaCube) with a center hole diameter between 58mm (~2.28") and 66mm (~2.60") and a maximum spool thickness of 65mm (~2.56"). This sleeve is pushed into a filament spool's center hole before being snapped onto the Drum. Please refer to the following photos for proper usage of this sleeve.

.

.

6c - Standalone (54 Plus) TPU Drum Sleeve - may be used to provide more grip on plastic filament spools. This "rewinderStandAloneDrumSleeveTPU-1c" version is an alternative general purpose sleeve that remains on the Drum at all times. It has a lip on each edge of the sleeve to limit side-to-side movement of the spool to within the sleeve. Note that this sleeve does NOT support Prusament filament spools! It works with any filament spool with a center hole diameter of 54mm (~2.13") or more and a maximum spool thickness of 64mm (~2.52"). A spool with this sleeve should be able to wind the Spring on the Drum but still allow slippage when the Spring has been wound more than 5 to 9 full turns. Please refer to the above photos for the "51 Plus TPU Drum Sleeve" for proper usage of this sleeve.

OPTIONAL 3D PRINTED PARTS THAT ARE NOT INCLUDED WITH THIS PROJECT:

---------------------------------------------

1 - Filament Identification Tags from @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox) that slip into the Tag Holder to identify what filament is in each drybox.

2 - Lid Seal from @GunplaMark's (https://www.printables.com/@GunplaMark) The Ultimate Cereal Container Filament Drybox (https://www.printables.com/model/1249376-the-ultimate-cereal-container-filament-drybox). I prefer to use Mark's Lid Seal, since I sometimes use a Polymaker PolyDryer with Mark's Adaptor to dry my filament in my dryboxes, but you can alternatively (carefully) snip off the tab that protrudes from the existing cereal container closure seal.

OPTIONAL 3D PRINTED TOOLS:

---------------------------------------------

1 - Coupler Hole Jig - a tool that I recommend printing and using is my Ultimate Filament Drybox Coupler Hole Jig (https://www.printables.com/model/1292539-ultimate-filament-drybox-coupler-hole-jig) remix; this tool makes it much easier to position the coupler hole in the drybox than the original version. Note that this tool is used when building your drybox!

.

2 - Coupler Nut (Inside) Wrench - a tool that I recommend printing and using is my Coupler Nut (inside) Wrench from my Improved Coupler Nut and Wrenches for Ultimate Filament Drybox (https://www.printables.com/model/1566890-improved-coupler-nut-and-wrenches-for-ultimate-fil); this tool makes it easy to install (or remove) my redesigned Coupler Nut that is inside the drybox. Note that this tool is used when building your drybox!

3 - Coupler (Outside) Wrench - a tool that I recommend printing and using is my Coupler (Outside) Wrench from my Improved Coupler Nut and Wrenches for Ultimate Filament Drybox (https://www.printables.com/model/1566890-improved-coupler-nut-and-wrenches-for-ultimate-fil); this tool makes it easy to install (or remove) the PC4-M10 coupler that is outside the drybox. Note that this tool is used when building your drybox!

The following photo shows all the 3D-printed tools that I use to build my dryboxes - represented by the "philsRewinderDryboxTOOLS" 3MF file:

The following screenshot shows the build plate included in the "philsRewinderDryboxTOOLS" 3MF file:

The following video shows the Auto-Rewinder for Ultimate Filament Drybox rewinding filament as it's unloaded from the MMU:

link for above video

The following video shows the Auto-Rewinder in operation. The important thing is that the spool must slip when the spring is wound the full 5 to 9 turns - since there is no internal clutch. The video begins with the spring already fully wound (due to printing) and the spool slipping (as intended) on the drum. At the end, the spool rewinds as the filament is retracted from the MMU:

link for above video

MY RELATED ORIGINAL DESIGNS AND REMIXES:

---------------------------------------------

The following section lists my own previously published original designs and remixes that are collected in this project. Refer to them if you need more information about a particular part - including more detailed assembly and usage instructions.

1 - Auto-Rewinder for Ultimate Filament Drybox - https://www.printables.com/model/1327488-auto-rewinder-for-ultimate-filament-drybox

2 - Auto-Rewinder Remix - https://www.printables.com/model/1327579-auto-rewinder-remix

3 - Ultimate Filament Drybox Coupler Hole Jig - https://www.printables.com/model/1292539-ultimate-filament-drybox-coupler-hole-jig

4 - Filament-Holding Drybox Cap (aka Coupler Cap Gen 3) with TPU Filament Clutch - https://www.printables.com/model/1674135-filament-holding-drybox-cap

5 - Tag Holder for Ultimate Filament Drybox (remains on drybox!) - https://www.printables.com/model/1369428-tag-holder-for-ultimate-filament-drybox-remains-on

6 - Stand-Alone Auto-Rewinder - https://www.printables.com/model/1503754-stand-alone-auto-rewinder (only Standalone TPU Drum Sleeve included)

7 - Split Base for Auto-Rewinder for Ultimate Filament Drybox - https://www.printables.com/model/1545254-split-base-for-auto-rewinder-for-ultimate-filament

8 - Improved Hygrometer Holder for Ultimate Filament Drybox - https://www.printables.com/model/1563279-improved-hygrometer-holder-for-ultimate-filament-d

9 - Improved Coupler Nut and Wrenches for Ultimate Filament Drybox - https://www.printables.com/model/1566890-improved-coupler-nut-and-wrenches-for-ultimate-fil

ADDITIONAL INFORMATION:

---------------------------------------------

To allow modifications, I have provided STEP (.stp) files for most parts; in a few cases where the STEP file is huge, I have provided an STL (.stl) file instead.

3MF files have been provided for all parts in my typical drybox as well as for the individual parts and assemblies. The provided 3MF files with "-Bambu" in the filename are intended for use with the Bambu Studio slicer; the 3MF files without that suffix or with "-Prusa" in the filename are designed for Prusa Slicer. If you use a different slicer, you should probably use the 3MF files intended for the Bambu Studio slicer - though I haven't tested any other slicers with this project.

If you download the "MODEL" files from this project, then you'll find the Prusa Slicer 3MF files in the "prusa" folder and the Bambu Studio 3MF files in the "bambu" folder.  STEP and STL design files are in the "stp_stl" folder.  If you use the 3MF files that I have provided, then all of the settings discussed below will already be applied!

If you download the "OTHER" files from this project, then you'll find a ZIP file with an "all_images" folder that contains all the photos, screenshots, and renders seen in this project as well as the same content from the multiple projects from which this collection was derived!

Except as noted below, all of the parts seen in the photos were printed in PETG (and/or PLA) with a 0.4mm nozzle at 0.2mm layer height with a 10% or 15% gyroid infill. The specific infill type and density aren't critical, so you can generally use whatever infill options you prefer. Default values for most other slicer settings are fine, though you can experiment if you wish!

Supports and brims are not needed for any of these parts and should only be used if your printer can't print the parts otherwise.

The optional TPU Drum Sleeves seen in the photos must be printed in TPU (Flex) filament; I used Giantarm (95A) TPU for all of mine.

I used 3 perimeters (instead of the default 2) for the two Wrenches, but they will still be plenty strong for their intended purpose with the default value.

If you are printing the optional 58 to 66 TPU Drum Sleeve using Bambu Slicer, then you must either use the provided "rewinderUltimateDryboxDrumSleeve58to66TPU-7c-Bambu" 3MF file or you must change the following Line widths in Bambu Studio from the default 0.42 values to 0.4 or the outer edges will not print: Default, Outer wall, Inner wall, and Top surface! This is not an issue with Prusa Slicer.

Be sure to check out my other designs - including universal key covers and a diverse collection of household accessories and 3D printing tools - on Printables at https://www.printables.com/@PhilCaruso/models AND on MakerWorld at https://makerworld.com/en/@PhilCaruso