Anycubic Kobra 3

Anycubic's 2024 mid-range flagship: a 600 mm/s Cartesian bed-slinger with Klipper running inside, multi-colour capability via the ACE Pro unit, and an optional AI camera — all behind a locked interface that the community has worked hard to reopen.

What it is

The Kobra 3, launched mid-2024 at around $349, is Anycubic's current mid-range workhorse and the direct successor to the Kobra 2 line. It is a Cartesian bed-slinger with a direct-drive extruder: bed moves on Y, toolhead on X and Z — a familiar layout, now running at up to 600 mm/s rated speed (300 mm/s is Anycubic's practical recommendation) with a 20,000 mm/s² acceleration ceiling enabled by resonance compensation and an accelerometer-based input shaping calibration routine.

Build volume is 250 × 250 × 260 mm — a meaningful step up from the 220 × 220 × 250 mm of the Kobra 2 Neo. The hotend reaches 300 °C; the bed reaches 110 °C on a PEI spring-steel plate. Levelling is handled by LeviQ 3.0 — an inductive auto-levelling system with automatic Z-offset setting. A 4.3-inch capacitive touchscreen (30–60° adjustable tilt) runs the stock Kobra OS interface.

The Kobra 3's signature feature is its multi-colour architecture. It uses an ACE Pro unit (sold separately as the Kobra 3 Combo, ~$500+) that manages up to four filament spools with a built-in dryer, feeding a multi-input hot end for up to 8-colour prints via colour mixing. On its own the Kobra 3 is a single-colour machine; the multi-colour system is optional hardware.

Connectivity is dual-band WiFi (2.4 GHz and 5 GHz), USB, and the Anycubic App. An optional 720p HD camera enables AI-based print monitoring from the app. The camera is not included in the base printer price.

Openness

The Kobra 3 sits in a specific — and genuinely interesting — tier of openness: Anycubic used real open-source components under the hood, published partial source under GPL-3.0, and then locked the user-facing interface. The community has unpicked most of that lock. Here is the full picture.

• Firmware — Klipper inside, user kept out. The Kobra 3 runs GoKlipper (Anycubic's Go-language port of Klipper, GPL-3.0) as the host-side firmware on a Linux-based Kobra OS. The MCU-side C code is published separately at ANYCUBIC-3D/K3-klipper-mcu under GPL-3.0. Both releases satisfy the GPL obligation from using Klipper's GPL-3.0 code. What they do not provide is user access: there are no editable config files, no Moonraker API, and no SSH connection by default. You know Klipper is in there; you simply cannot touch it. Anycubic explicitly notes that "certain proprietary features are not open source and have been encapsulated" in the MCU release — automatic flow calibration is one documented example.
• Mainboard — RV1106G3 SoC, no official docs. The control board (TriGorilla_Spe_B_V1.1.5) is built around a Rockchip RV1106G3 (ARM Cortex-A7) SoC with eMMC storage for the Kobra OS Linux image. The same SoC is used in the LuckFox Pico Ultra W, which makes community tooling (Rockchip's maskrom recovery, SDK cross-compilation) applicable. All hardware documentation available publicly — pinouts, eMMC recovery procedures, maskrom access — is community-sourced from teardowns and the Anycubic-Kobra-3-rooted project. Anycubic has released no schematics.
• Klipper — locked by default, unlockable via Rinkhals. Because GoKlipper is GPL-3.0 and the hardware runs Linux, the community can — and has — installed the full stock Klipper stack on the machine. The Rinkhals project (now also at rinkhals-community/Rinkhals) installs as a standard firmware update, keeping all stock Anycubic UI features (print screen, calibration, multi-colour tools) while adding Mainsail, Fluidd, Moonraker, SSH access, USB camera support in web clients, and OTA updates. Rinkhals currently supports the Kobra 3, Kobra 2 Pro, Kobra 3 V2, Kobra S1, Kobra 3 Max, and Kobra S1 Max. This is a genuine, well-maintained community unlock — not a fragile exploit.
• Slicer — open options available, multi-colour favours vendor slicer. Anycubic ships Anycubic Slicer Next, an OrcaSlicer fork under AGPL-3.0. OrcaSlicer and Cura work directly for single-colour prints; Anycubic's own slicer is strongly recommended for multi-colour work because the ACE Pro integration, colour sequencing, and purge tower logic are tuned there. Single-colour prints have no forced dependency on the vendor slicer. No vendor account is required to slice or to print locally.
• Ecosystem — cloud-connected by default, local mode exists. The Kobra 3 is online by default: dual-band WiFi, Anycubic App binding, and cloud account required to use the AI camera and remote monitoring features. A local LAN mode exists — you can control the printer via Anycubic Slicer on the local network without cloud dependency — but the default posture is cloud-first. Anycubic's cloud has a documented incident (see below). Buyers who want to stay local-only can do so, but they give up the AI camera functionality.

AI tooling

The Kobra 3's AI story is the most capable Anycubic has shipped — and the most cloud-entangled. The optional 720p HD camera connects to the printer and enables AI spaghetti detection: the system watches the print via the camera feed, detects failure patterns (stringing, layer delamination, "fried noodle" masses), and can automatically pause or stop the print. Sensitivity is adjustable (Low / Medium / High) and the response on detection is configurable. Early firmware versions were over-sensitive; recent updates improved the tuning.

Using these AI features requires: (1) an Anycubic account, (2) binding the printer to the account via app QR scan, (3) cloud connectivity. The detection itself runs cloud-side — frames are sent to Anycubic's servers for inference. There is no local inference option and no way to connect the camera to a self-hosted system like Obico (formerly The Spaghetti Detective) in the stock configuration.

If you install Rinkhals, the USB camera is exposed to Mainsail/Fluidd as a standard V4L2 device — at which point you can connect it to Obico or any MJPEG-capable monitoring tool independently of Anycubic's cloud. That is a meaningful unlock: the AI detection becomes self-hostable, severing the cloud dependency entirely. But it is community work, not a vendor feature.

The resonance compensation (input shaping) and flow calibration routines in Kobra OS are accelerometer-driven automation — sophisticated sensor integration, but not AI or machine learning in the technical sense.

A note on the 2024 MQTT security incident

In February 2024, an unknown actor exploited a vulnerability in Anycubic's MQTT cloud API and pushed a warning file to approximately 2,000 cloud-connected Anycubic printers worldwide. Anycubic had ignored three responsible-disclosure emails before the public exploit. A patch followed in March 2024. The Kobra 2 Neo was not affected (no WiFi), but the Kobra 3 is WiFi-connected by default and therefore sits inside this attack surface. Anycubic's cloud account is required for the AI camera features. Buyers should treat that as a real, documented risk — not a hypothetical one. Sources: BleepingComputer (Feb 2024), BleepingComputer (Mar 2024).

Where it wins

• Klipper already running inside. The underlying firmware is GoKlipper on GPL-3.0 Linux. The architecture is genuinely open; only the interface is locked. Rinkhals makes the full stack accessible without losing stock features — a much better starting point than a machine that doesn't run Klipper at all.
• Fast, capable hardware at mid-range pricing. 600 mm/s rated speed, 20,000 mm/s² acceleration, 300 °C hotend, 110 °C bed, LeviQ 3.0 auto-levelling, and a 250 × 250 × 260 mm build volume at ~$349 is genuinely strong value.
• Multi-colour architecture without proprietary filament. The ACE Pro system uses standard 1.75 mm filament from any brand. There is no proprietary cartridge or NFC chip. Multi-colour printing requires the Anycubic slicer for full ACE integration, but the filament itself is unrestricted.
• Open slicer for single-colour work. OrcaSlicer and Cura work directly for single-material printing. No account needed to slice or print locally.
• Local LAN mode. Anycubic Slicer can reach the printer on the local network without the cloud, making offline single-colour printing genuinely cloud-free if the camera is not connected.
• Rinkhals is mature and actively maintained. The community unlock exists, is well-documented at jbatonnet.github.io/Rinkhals, and supports over-the-air updates. This is not a fragile hack.

Where it's locked down

• No user Klipper config access out of the box. Despite running Klipper, stock Kobra OS gives you no printer.cfg, no Moonraker, no terminal access. Everything is mediated through the vendor UI. For anyone accustomed to Klipper on a Prusa or a Voron, this is a jarring experience.
• AI camera requires cloud account. The spaghetti detection feature — the most visible AI selling point — mandates cloud binding and sends frames to Anycubic's servers. It cannot run locally in the stock configuration.
• Firmware source is partial. The MCU C code is published under GPL-3.0, but Anycubic explicitly notes that proprietary features (including automatic flow calibration) are "encapsulated" and withheld. The GoKlipper repository is GPL-3.0 but the interface layer and Kobra OS are not fully documented.
• No published hardware schematics. Board documentation is entirely community-derived from teardowns and maskrom investigations. Repairability depends on that community knowledge rather than official support.
• 2024 MQTT incident on the vendor's cloud record. This is a documented incident, not a hypothetical. Any machine that connects to Anycubic's cloud is in scope.
• Camera is an add-on, not included. The AI features require purchasing the optional camera separately. It is not part of the base $349 machine.

Who it's for

The Kobra 3 is the right machine for a maker who wants capable, fast, multi-colour-ready hardware and is comfortable doing the Rinkhals unlock to get a genuinely open Klipper stack. It is an excellent printer that asks something of you before it fully opens up. If you want open out of the box — editable Klipper config, SSH, no mandatory vendor account — the Prusa Core One or a Voron are the right answers. If you want the fastest, cheapest path to multi-colour printing and are prepared to run Rinkhals and treat the cloud as an optional feature rather than a requirement, the Kobra 3 Combo earns its position.

Specs & links

• Type: Cartesian bed-slinger (bed moves Y; toolhead moves X and Z), direct drive.
• Build volume: 250 × 250 × 260 mm.
• Speed: rated 600 mm/s; Anycubic recommends 300 mm/s; 20,000 mm/s² max acceleration.
• Hotend: max 300 °C, 0.4 mm nozzle standard (0.6 / 0.8 mm optional).
• Bed: PEI spring-steel plate, max 110 °C.
• Levelling: LeviQ 3.0 inductive auto-levelling with automatic Z-offset.
• Display: 4.3-inch capacitive touchscreen, 30–60° adjustable tilt.
• SoC (host): Rockchip RV1106G3 (ARM Cortex-A7), eMMC storage, running Kobra OS (Linux).
• Mainboard: TriGorilla_Spe_B_V1.1.5 — no official schematics; community teardown docs at Bushmills/Anycubic-Kobra-3-rooted.
• Firmware: Kobra OS; GoKlipper (Go port of Klipper) as host, ANYCUBIC-3D/Klipper-go (GPL-3.0); MCU C code at ANYCUBIC-3D/K3-klipper-mcu (GPL-3.0, partial — proprietary features encapsulated).
• Klipper unlock: Rinkhals (also at rinkhals-community/Rinkhals) — adds Mainsail, Fluidd, Moonraker, SSH; preserves stock UI. Docs: jbatonnet.github.io/Rinkhals.
• Slicer: Anycubic Slicer Next (OrcaSlicer AGPL-3.0 fork, recommended for multi-colour); OrcaSlicer and Cura work for single-colour.
• Connectivity: dual-band WiFi (2.4 GHz + 5 GHz), USB, Anycubic App; local LAN mode available.
• AI camera: optional 720p HD, sold separately; cloud spaghetti detection requires Anycubic account.
• Multi-colour: ACE Pro unit (sold separately, Kobra 3 Combo ~$500+); standard 1.75 mm filament, no proprietary cartridges.
• Price: ~$349 printer only; ~$500+ as Kobra 3 Combo with ACE Pro unit (as of mid-2024 launch; check current pricing).
• Official product page: store.anycubic.com — Kobra 3.
• Firmware (GoKlipper): github.com/ANYCUBIC-3D/Klipper-go.
• MCU firmware: github.com/ANYCUBIC-3D/K3-klipper-mcu.
• Community unlock (Rinkhals): github.com/jbatonnet/Rinkhals.
• Community hardware docs: github.com/Bushmills/Anycubic-Kobra-3-rooted.

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