Multi-material & Filament-changer Tooling

The "more than one filament" problem. The 2026 landscape: Bambu's AMS dominates the closed/turnkey side; ERCF and its forks (notably Box Turtle and Tradrack) are the FOSS-community answer; Prusa's MMU3 sits in the middle as the best-supported, conservative option. Pellet extrusion is a niche but growing alternative for cost-per-kg.

Bambu / closed turnkey

• ★ Bambu AMS / AMS 2 Pro / AMS HT — closed source, paid; deep integration with Bambu Studio and OrcaSlicer, RFID-tagged spools, in-AMS humidity tracking. The "it just works" tier for multi-color FDM in 2026. Bambu-printer-only.
• Bambu AMS Lite — for the A1 / A1 mini; cheaper, fewer features.

Prusa MMU3

• ★ Prusa MMU3 — open source (firmware + hardware design files); 5-color, single-extruder. The most-tested, best-documented FOSS-ish multi-material unit in 2026. Compatible with Prusa MK3.5 / MK3.9 / MK4 / MK4S. Fine but slow vs. Bambu AMS.
• Prusa XL toolchanger heads — five toolheads on the XL; not a unit but worth mentioning as the "real" multi-material answer.

ERCF & friends (Voron / Klipper community)

• ★ ERCF V2 / Enraged Rabbit Carrot Feeder V2 — open source (CC); Klipper community's flagship MMU. Belt-driven, modular, the standard for self-built multi-material on Klipper printers. Pair with Happy Hare plugin for Klipper.
• Tradrack — open source (Annex Engineering); alternative belt-fed multi-material unit; simpler than ERCF for some.
• Box Turtle (Annex Engineering) — open source; newer (2024+), DIN-rail-based, scaled for higher color counts; heir-apparent to ERCF for many. Pair with Happy Hare.
• Pico-MMU / Pico-3MMU — open source community designs; smaller / cheaper.
• 3MS / NightOwl / Astrid — niche FOSS designs; varying maturity.

Klipper-side multi-material plugins

• ★ Happy Hare — open source; Klipper plugin that abstracts ERCF / Tradrack / Box Turtle / others into one config. The de-facto standard 2026 driver.
• MMU2S Klipper module — older, ERCF-pre-Happy-Hare era.
• Klipper tool / tool_probe — built-in support for toolchangers (E3D Toolchanger, Voron Stealthchanger).

Toolchangers (multi-extruder, not multi-spool)

• ★ E3D Toolchanger / Motion System — closed-source kit, paid; the original parking-tool multi-head FDM. Strong community.
• ★ Voron Stealthchanger / TapChanger — open source CC; Voron community's FOSS toolchanger answer.
• RatRig V-Core 4 + StealthChanger — popular RatRig + Voron toolchanger combo.
• Jubilee (E3D Jubilee fork) — open source toolchanger platform.
• Prusa XL (already mentioned) — closed-source, paid, 5-tool turnkey.

Pellet extruders

• ★ Mahor.xyz / Dyze Pulsar / Erlanger / LDO Pulsar / Direct Drive Pellet — open or semi-open pellet extruders; cheaper material per kg than spooled filament; common for large-format printers.
• Yagi (open hardware) — DIY pellet community designs.
• Direct3D / Massive Dimension — paid; industrial.

Mixing extruders / Diamond / Palette

• Mosaic Palette 3 / Palette 3 Pro — closed source, paid; splices filaments before they enter the extruder. Vendor-agnostic but increasingly out of fashion since AMS / ERCF.
• Diamond hotend (E3D, retired) — multi-in/single-out hotend; technologically interesting but largely obsolete.

Slicer-side multi-material

• ★ OrcaSlicer multi-tool / multi-color workflow — supports Bambu AMS, ERCF, MMU3, manual M600. The most flexible.
• ★ Bambu Studio — Bambu AMS-first; works with non-Bambu printers too in 2026.
• PrusaSlicer multi-material — best for MMU3 + Prusa XL; supports manual M600 elsewhere.
• Cura multi-extruder — works with toolchangers and dual-nozzle printers.

Filament-change scripting (no MMU)

• ★ OrcaSlicer / PrusaSlicer "filament change at layer" — manual M600 swaps; the cheapest multi-color (just stand there and feed filament).
• HueForge — paid; generates layered filament-change G-code for full-color art (lithophanes, flat art). See G-code Tools.

Drying / handling

• PolyDryer / Sovol SH01 / SUNLU FilaDryer — keep multi-material spools dry while loaded.
• AMS HT (Bambu) — heated AMS for engineering filaments.
• DIY enclosed AMS-style boxes — Klipper community designs.

Pick this if…

• Bambu printer, want easy multi-color: AMS / AMS 2 Pro.
• Prusa printer, want multi-color: MMU3.
• Voron / RatRig / DIY Klipper, want FOSS multi-color: ERCF V2 (mature) or Box Turtle (modern); both via Happy Hare.
• Want a real toolchanger, not a single-head MMU: E3D Toolchanger (paid kit) or Voron Stealthchanger (DIY).
• Cost-per-kg matters more than convenience: pellet extruder.
• Cheap occasional multi-color: OrcaSlicer "filament change at layer" + a bench timer.