ASR Spool Holder Retractor

ASR Filament Spool Retractor

The Problem

When it comes to filament spool rewind on the Bambu AMS Lite, half a revolution is all you get. For the External Spool on the Bambu A Series printer, you get zero revolutions — unless you equip the External Spool Holder with an Adapter and a Bambu AMS Lite Rotary Spool Holder (Yellow). But even then, you still only get half a revolution.

The Solution

Introducing the ASR Filament Spool Retractor Insert. By repurposing the constant force spring from a retractable ID badge holder, we have upgraded the AMS Lite Rotary Spool Holder to deliver up to 15 full revolutions of retract when needed. The ASR Insert simply replaces the orange (or green) spring-loaded insert in the Bambu spool holder with an easily printable two-piece, spring-loaded device that works much like a retractable ID badge holder or a carpenter's tape measure.

What You Need

• One retractable ID badge holder (the spring is the only part you need — the rest goes in the trash)
• A printed ASR Retractor Insert (two pieces — hub and insert)
• The Bambu AMS Lite Rotary Spool Holder (Yellow or Green) or a printed replacement

Installation

You can install this on an existing Bambu Spool Holder, or print your own spool holder. Thanks to the generous licenses of BIQU/BIGTREETECH and Redsnapper, this model includes both a single printable Spool Holder and an External Spool Holder Adapter for the Bambu A1 Mini in their unmodified original versions, with links to the source models above.

Simply remove the spring from the badge holder and install it in the printed hub. See the cover photo for correct spring placement — there are two windows in the hub that allow you to install the spring from either direction:

• Yellow Spool Holder: Wind the spring Counter-Clockwise
• Green Spool Holder: Wind the spring Clockwise
• Seat spring inside hub
• Apply white grease to the top of the insert where the hub and insert will touch each other
• Apply white grease to tapered part of the underside of the insert
• Install the hub on the insert and engage the spring through the slot on the center post
• Insert the completed assembly into the Bambu or printed spool holder in place of the original orange or green insert

Compatibility

This retractor was designed as part of the ASR 5th Wheel complete 5th filament automation system for the Bambu A Series. The ASR 5th Wheel's automated Unload feature retracts filament from the PTFE tube when swapping External spools. The Spool Retractor ensures all that filament winds back onto the spool automatically, keeping your workspace clean and your filament tangle-free. It works equally well as a standalone upgrade for any Bambu A Series External spool setup, with or without the ASR 5th Wheel. It also can help keep the spools on your AMS Lite tightly wound when the AMS retracts filament.

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