Overview

Easily connect/disconnect different filament sources. Original design introduces a locking feature to prevent separation when loading filament with the Bambu Lab AMS.

I have my AMS on a shelf above the printer and wanted to be able to easily disconnect and move the printer (such as for printing ABS in a different space).

As a bonus, this allows easy switching between the AMS and an external filament spool without using one of the many popular Y-splitter mods for Bambu Lab printers. Since these connectors press two segments of PTFE together perfectly (assuming a perfectly square cut), there is less friction introduced in the filament path than with a splitter.

These connectors can also be used on the back of the AMS. Or anywhere else you want to be able to quickly and securely attach and detach a run of PTFE tube.

What to Print

If you have a Bambu Lab printer and Bambu Lab Basic PLA, grab one of the “Bambu” 3MF files and it will have everything you need to get started in under an hour of print time.

Otherwise, start by printing one of the Test Fit models. Confirm the hardware is a tight press fit (no glue needed). Adjust hole sizing with XY-hole compensation in your slicer or by modifying the STEP files as needed. The test fit parts are designed to be easily destroyed with flush cutters to recover the hardware.

Once the test fit looks good, print a couple of the Wing Connectors (or Standard connectors but the wing design provides better grip for nominal extra print complexity) and a Lock Connector. If you will be mounting this with the optional Mounting Bracket, either split to objects and delete the M3 screw hole plugs in your slicer before printing, or download the “Lock Connector for Bambu Mount” with those plugs pre-removed.

If using with the AMS, a Lock Cap is also a good idea to block off the end of the tube coming from the AMS hub/filament buffer when switching to using an external spool, just in case you accidentally send a print with the “use AMS” box checked when that tube isn't hooked up to the printer.

The Mounting Bracket is an added convenience for Bambu Lab printers, allowing one handed quick-connect operation. Note that this does require slightly longer runs of PTFE tubing between both the filament buffer and magnetic connector and the magnetic connector and the toolhead. If you don't have extra PTFE you can still use this system, just without the mounting bracket (in that case it just takes the exact place of the pass-through push fitting included with the printer).

An Alternate version of the Mounting Bracket has been added as of 2024.01.13 that is optimized for printing in a horizontal orientation. Both versions are functionally identical, but when printed alongside other connector pieces on a single plate the horizontal version is preferred because there is no tall section rising above the rest, so layer time/cooling is more consistent throughout.

Variations

There is an option to use ECAS fittings that are pressed into place, PC4-M10 fittings that thread into the plastic, or a friction fit version.

Choose the files corresponding to your fitting (or no fitting) of choice. Photos are of the ECAS variation.

Print Settings

• 3 outer perimeters
• 4 solid top & bottom layers
• 15% infill (doesn't really matter)

Material

Tested with Bambu Lab Basic PLA. Almost any other filament should work too, but tolerances may be different so print one of the Test Fit models first.

Hardware BOM

Item	Quantity	Details
6x3 mm round magnets	3 per connector	Cheaper magnets such as N35 grade are fine because they are used for lateral alignment, not high pull strength.
4mm-OD PTFE tube	Variable	The 2.5mm-ID Bambu Lab PTFE tube is recommended. 3mm-ID might work, but is more subject to deformation.
ECAS or PC4-M10 fitting	1 per connector	Recommended, but not required (I added a friction fit variant that doesn't use these fittings, but it's untested). PTFE must pass all the way through. ECAS (inserted diameter 8.4mm, inserted depth 7.2mm) PC4-M10 (threaded diameter 9.2-9.7mm, threaded depth 6.3mm) Friction Fit (should be very difficult to insert PTFE)
M3x6 screw	2 per mounting bracket	For attaching lock connector to Bambu frame mount (optional). Designed for socket head cap screws.
M3x8 screw	2 per mounting bracket	For attaching Bambu frame mount to the printer (optional). Designed for socket head cap screws.

Assembly

Before installing any of the hardware, make sure the Standard/Wing and Lock connectors fit together smoothly but not loosely. All files are published as STEP for easier modification if needed.

Magnet orientation in the first fitting you assemble doesn't matter, although I recommend facing all three magnets in the same direction.

For subsequent connectors, align the magnets based on the first connector.

Standard/Wing Connectors

Use parallel pliers to press the magnets and ECAS fitting into place. Or thread in the PC4-M10 fitting if using that version.

Press PTFE tube in until it is flush with the side with the magnets.

Lock Connectors

Use flathead screwdriver to press magnets into place. Use parallel pliers to install ECAS fitting or thread in the PC4-M10.

Bambu Lab Frame Mount

*Requires slightly longer PTFE tube than the one that is attached to the toolhead by default.*

Insert PTFE tube into lock connector and screw on mounting bracket (the M3x6 bolts thread directly into the plastic if you print the version of the lock connector that has the two holes on the bottom).

Then feed the PTFE tube into the printer and mount the bracket to the frame using M3x8 screws.

Optional: snap on a magnetic PTFE clamp to reinforce the correct tube path.

Inside the printer, trim the PTFE to length and insert into the toolhead. You can reinstall the stop-fitting on the tube, but it's not necessary since the tube is now fixed by the mount on the back of the printer.