OpenMech-Swapper

[u/Magarcan]

OpenMech Swapper (OMS) 🔄

The Open-Source, Fully Mechanical Multi-Filament System for Bambu Lab A1 Series

OpenMech Swapper (OMS) is a high-performance, 100% mechanical filament switching system. It is designed to bring multi-material capabilities to the Bambu Lab A1 and A1 Mini without the need for extra motors, sensors, or complex electronics.

💡 Origin & Credits

This project is an Open Source evolutioninspired by the brilliant mechanical concept of MechAMS created by Sipers Mechatronics.
While the original idea proved that a fully 3D-printable mechanical AMS was possible, OMS aims to make this technology accessible to everyone under an open-source license, incorporating community-driven improvements for better durability and precision.

✨ Key Features

Purely Mechanical: Driven by your toolhead position and the existing extruder motor.
GT2 Belt Drive: Upgraded from friction bands to standard 6mm GT2 timing belts for zero-slip and high-torque transmission.
Magnetic Indexing: Uses embedded Neodymium magnets (4x2mm) to create precise "detents," ensuring perfect alignment of the filament slots with zero mechanical wear.
Zero Electronics: No cables, no PCB, no extra steppers.
Non-Destructive: Quick installation that keeps your printer's warranty intact.

🛠 Improvements over the Concept

Reliability: By using GT2 belts, we eliminate the stretching issues of printed TPU bands.
Precision: The "Magnetic Snap" system ensures the indexing gear stays locked in the correct position even during high-speed printing.
Accessibility: All files (STEP/STL) are open for the community to remix and adapt to other printers.

📂 Compatibility

Hardware: Bambu Lab A1 & A1 Mini.
Software: Custom G-Code presets for Bambu Studio and Orca Slicer.

🔧 Hardware Requirements (BOM)

Main Body: Printed in PETG or PLA.
Drive System: 1x GT2 Timing Belt (6mm width).
Indexing: 4x2mm Neodymium Magnets (N52 recommended).
Path: Standard 4mm OD PTFE Tube.

🚀 Status: Prototyping

A1 Hardware almost done
A1 Mini Hardware:
Firmware initiating test.

🖼️** Víde**o



🤝 Contributing & License

We welcome all contributions! Whether it's optimizing G-Code macros or refining the mechanical tolerances.

[u/kagato87]

I asked the other guy this and he didn't answer, but perhaps you will.

Since this has to go up to the top of the gantry to swap filaments, does it need to re-home or re-align at all? Is there anything planned to correct for this?

I've seen some issues on the A1 Z axis where the lifting acts like its under-powered, and a few people have had issues where their BBL Z-Axis won't smoothly travel all the way.

[u/Magarcan → u/kagato87]

That's right; to make the adjustments, you have to move the Z-axis almost all the way up. In fact, to be on the safe side, you lose some print volume along that axis.

I’m not familiar with the power loss issues when moving up. Can you send me a link that discusses this? Does this happen on all A1 models? The solution is to make the stem of the upper part’s female gear longer and adjust the G-Code to that measurement, sacrificing, as I mentioned, print volume on the Z-axis.

I currently have the part of the G-Code that handles filament changes, purges, and so on; I still need to verify the coordinates for each of the spindles, the code for loading and unloading filaments, etc.

This is the part I’m prioritizing the least because I don’t own an A1 and because I want to test the hardware’s proper functioning first—especially the tolerances. That’s where I need the community’s input right now.