Bambu Lab has filed three Chinese patent applications covering new nozzle-monitoring and automatic printhead-changing technologies. The designs include illumination integrated into cooling ducts and a storage rack capable of exchanging multiple replaceable printheads.
Filed by Shenzhen Tuozhu Technology Co., Ltd., the company behind Bambu Lab, the applications target camera-based extrusion monitoring and multi-color or multi-material printing. Two closely related patents address different parts of an automatic printhead exchange system intended to reduce flushing waste and maintain positioning during changes.
Toolhead lighting integrated into cooling ducts
One patent application, CN 122560409 A, describes a 3D printer toolhead that integrates illumination components into its part-cooling air ducts. Filed on June 30, 2026, the application is titled Tool heads, 3D printers and 3D printing systems and lists Liu Weitong and Chen Dangdang as inventors.
The proposed toolhead combines a hot end, air supply assembly and illumination system on a common mounting base. The light-emitting components are positioned inside the cooling air ducts, and light exits through the same openings used to direct airflow towards the nozzle. This arrangement is intended to reduce the overall size of the toolhead and limit the amount of build volume occupied by its components.
The air ducts also form part of the optical system. Internal guide surfaces direct cooling airflow and reflected light towards the extrusion region. One embodiment combines a lower-reflectivity matte black surface with a higher-reflectivity matte white surface to control illumination around the nozzle and reduce overexposure in captured images.
The illumination system is intended to support camera-based monitoring of extrusion. The application describes cameras capturing the nozzle area to identify abnormal extrusion and adjust printing parameters in response. One configuration uses two cameras whose combined fields of view cover opposite sides of the nozzle, with the illumination system lighting the regions being monitored.
Rack-based automatic printhead changing
Patent CN 122560413 A describes a 3D printer architecture that automatically exchanges complete printheads using a storage rack inside the machine. Filed on June 30, 2026, the application lists Chen Tianyi, Chen Peng, Xiong Xianwu and Liu Xin as inventors.
The proposed system uses a single toolhead capable of picking up and depositing replaceable printheads stored on a rack. Each replaceable unit can incorporate a filament path, throat, heating element and nozzle, while the moving toolhead provides components including the extrusion mechanism used to feed material. The patent says different printheads could be selected according to filament type, color, maintenance requirements or other printing needs.
A central part of the design concerns how these printheads are exchanged. After moving a printhead into alignment with the rack, the printer transitions it from its attached or “mating” position to an unlocked position while simultaneously placing it into its storage position. The patent therefore combines unlocking and deposition into the same movement rather than treating them as separate operations.
According to the application, this reduces the number of movements required during a change and allows the same drive and transmission components to perform multiple functions.
Positioning elements on the rack secure the printhead during the exchange, with embodiments using hooks, pins, magnets or spring-loaded mechanisms. The rack is designed to accommodate multiple printheads in a relatively small area. Because the toolhead does not need to move sideways between adjacent printheads during the placement operation, the patent states that the center-to-center spacing between storage positions can be smaller than the width of the moving toolhead itself.
The patent specifically links this arrangement to multi-material and multi-color printing. Using separate replaceable printheads can reduce flushing waste and filament-change time by allowing different materials or colors to remain associated with individual printheads rather than repeatedly purging a shared hot end.
The toolhead can also release the filament before detaching a printhead by increasing the gap between its extrusion wheels. During installation, the sequence is reversed, with the printhead attached before the wheels close around the filament.This avoids pulling material from the heating chamber or obstructing the exchange.
Stabilizing replaceable printheads during automatic exchanges
A third application, CN 122560412 A, from the same four inventors focuses on stabilizing replaceable printheads as they are aligned with and deposited into a storage rack. It defines an alignment direction as the toolhead approaches the rack, an assembly direction used to attach or detach the printhead, and a third direction perpendicular to both.
Positioning features constrain the printhead along this third axis when it would otherwise be relatively free to move. Two sets of guides can surround the printhead at different heights as it approaches its storage position, reducing sideways movement and rotation that could lead to inaccurate placement or collisions with adjacent printheads.
Other positioning elements can subsequently constrain the remaining directions. One can retain the printhead along the alignment axis, while another secures it along the assembly direction once it has been placed. Proposed interfaces include hooks and slots, pins, magnetic connections and spring-loaded locking mechanisms. In some embodiments, the toolhead itself temporarily pushes a locking element aside as it approaches the rack; once it withdraws, a spring returns the mechanism to secure the stored printhead.
The application also describes angled magnetic interfaces intended to limit unwanted forces during alignment. Opposing magnetic surfaces can be inclined so attraction is less disruptive while the printhead approaches its final position, before increasing as the surfaces become properly aligned.
Finally, it introduces a blocking assembly beneath stored printheads that can cover the nozzle outlet during placement. Because the assembly extends below the printhead, the patent describes lowering the heated bed during early-layer printhead changes to avoid interference with the bed or areas used for nozzle wiping, flushing and marking.
Bambu Lab targets purge waste and extrusion reliability
Bambu Lab has previously identified purge waste and nozzle contamination as constraints in multi-material 3D printing. When it revealed its Vortek automatic hotend changing system in 2025, the company said engineers had evaluated exchanging the gantry, complete toolhead, hotend assembly or nozzle. Bambu selected the hotend assembly as a compromise between reliability, machine footprint and cost, while identifying repeatable nozzle alignment as a key requirement.
Camera-based nozzle monitoring is also already present in Bambu Lab’s hardware. The H2D 3D printer introduced a macro-lens nozzle camera designed to identify material build-up, clumping, air printing and other extrusion failures, alongside a dual-nozzle architecture intended to reduce purging during material changes. The new illumination patent addresses a narrower part of that monitoring system: providing controlled light around the extrusion point while using the existing cooling-duct volume.
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Feature image shows cross-sectional view of the proposed toolhead showing illumination elements integrated into cooling ducts on either side of the nozzle. Image via Shenzhen Tuozhu Technology CN 122560413 A patent application.
