AHS-A1

Welcome to the official repository of AHS-A1 (Automated Hotend Swapper for Bambu Lab A1 Series)!

AHS-A1 (Automatic Hotend System for Bambu Lab A1 Series) is an Open Source project that aims to reduce or eliminate filament purges during multi-material printing on the Bambu Lab A1 by automatically swapping hotends.. To achieve this, the system uses the BMCU as the primary communication interface with the printer, coordinating the swapping process alongside a dedicated controller responsible for the mechanical system.

Status: 🚧 Under development.

Why this project?

Multi-material printing has evolved rapidly in recent years, yet most available systems still rely on purging processes to switch materials or colors. These purges result in significant filament generate unnecessary waste.

Commercial solutions have recently emerged that aim to minimize this issue through hotend swapping mechanisms or independent feeding systems. However, these solutions are often limited to specific printer models, come at a high cost, and offer little room for community modification.

The AHS-A1 was created as an open, modular alternative that leverages the BMCU to integrate with the Bambu Lab A1 and coordinate an external system capable of automatically swapping hotends.

Changelog

July 26, 2026 : Repository created.

System architecture

The project consists of several modules that work in a coordinated manner:

flowchart LR

A[Bambu Lab A1] 
B[BMCU] 
C[AHS Controller] 
D[Robotic Arm] 
E[Sensors] 
F[Hotend Dock System] 
G[Active Hotend] 

A <-->|Communication| B 
B <-->|UART| C

    C --> D
    C --> E

    D --> F
    D --> G

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Main Components

Component	Function
Bambu Lab A1	Main printer.
BMCU	Main interface with the printer. It coordinates the filament change and communicates with the external controller that performs the print head (hotend) swap.
AHS Controller	Controls the robotic arm, sensors, and swapping logic.
Robotic Arm	Extracts, transports, and positions the hotends.
Sensors	Verify the correct execution of each stage of the swap.
Hotend Dock System	Keeps available hotends organized and protected.

Objectives

• Reduce filament waste.
• Automate hotend swapping.
• Integrate the system with the BMCU.
• Develop an open-source hotend swapping solution for the Bambu Lab A1 Series.

Roadmap

v0.1 — Project Foundation

• Create repository.
• Define project architecture.
• Organize repository structure.
• Initial documentation.
• First architecture diagrams.

v0.2 — Hardware Design

• Hotend dock design.
• Robotic arm design.
• Gripper design.
• Mechanical validation.
• First printable prototype.

v0.3 — Electronics

• Electronic architecture.
• Controller integration.
• Sensor integration.
• Wiring documentation.

v0.4 — Firmware

• BMCU integration.
• Communication with external controller.
• Hotend swap sequence.
• Error handling.
• Safety checks.

v0.5 — Functional Prototype

• Assemble first prototype.
• Validate automatic hotend swapping.
• Reliability testing.
• Performance optimization.

v1.0 — First Public Release

• Complete documentation.
• Assembly guide.
• Release firmware.
• Release hardware files.
• Stable release.

Contributions

Contributions will be welcome !