Bambu Lab AMS: What It Does and Which One You Need

The Bambu Lab AMS (Automatic Material System) is a spool holder that feeds filament into a Bambu Lab printer automatically, so one print can use several colors or materials without you swapping spools. Bambu sells four versions: the original AMS, the AMS lite, the AMS 2 Pro and the AMS HT.

What does the Bambu Lab AMS do?

An AMS stores spools next to the printer, reads each spool's RFID tag, and loads and unloads filament on demand. That lets a slicer assign different colors or materials to different parts of a model, and lets the printer switch to a backup spool of the same filament when one runs out. Bambu describes the AMS lite as supporting automatic filament backup, RFID sync and snap-away or dissolvable support material, and the same ideas carry across the family. For how multicolor printing works in general, including the waste it produces, read multicolor 3D printing explained.

Bambu's wiki says the AMS, AMS 2 Pro and AMS HT all use a two-stage feeding system. A feeder unit inside the AMS pushes filament to an assist motor, which continues feeding it to the toolhead. Because the toolhead extruder and the assist motor rarely run at exactly the same speed, a filament buffer must sit between the printer and every one of these units. The AMS lite is different: it uses one stage, feeds the toolhead directly and needs no buffer.

Which Bambu Lab AMS models exist?

Bambu's connection guide lists four: the AMS (first generation), the AMS 2 Pro (second generation), the AMS HT, and the AMS lite designed for the A1 series. The table below uses figures from Bambu's store pages and wiki; prices are left out because Bambu's store redirects by country and they change often.

Spool size matters too. Bambu lists AMS lite spools at 40 to 68 mm wide with a 53 to 58 mm inner diameter, and AMS 2 Pro and AMS HT spools at 50 to 68 mm wide, all for 1.75 mm filament.

What is the difference between AMS lite and AMS 2 Pro?

The AMS lite is the cheaper, simpler unit built for the A1 series, with no assist motor, no buffer and no drying. The AMS 2 Pro is the second-generation unit with an assist motor, sealed storage and a heated, rotating drying mode up to 65 °C. Bambu's A1 guide also says the A1 series came with AMS lite originally and only needs an AMS Hub to run the newer units.

Filament support differs as well. Bambu's AMS lite page lists TPE and TPU among unsupported filaments, along with wet PVA and BVOH and anything containing carbon or glass fiber except Bambu PLA-CF. The AMS 2 Pro page lists PLA, PETG, ABS, ASA, PET, PA, PC, PP, POM, HIPS and several Bambu composites, and says TPE, generic TPU and carbon or glass fiber filaments are not supported, with Bambu's own TPU for AMS as the exception.

What is the AMS HT for?

The AMS HT is a single-spool unit built to dry and feed high-temperature or high-performance filaments, with drying up to 85 °C. Bambu's page says each AMS HT needs an external 220 V power supply for drying, supplied in the box, because the printer cannot power it. It also has a bypass outlet, an independent path for soft or brittle materials, and Bambu notes the AMS HT cannot run filament drying while feeding a print through that bypass port.

Bambu's AMS 2 Pro page states that filaments marked as needing a higher drying temperature, including ABS, ASA, PA and PC, cannot be dried completely in an AMS 2 Pro, and recommends an AMS HT for them. For drying in general, see how to dry filament and how to choose a filament dryer.

How many AMS units can each printer take?

Limits come from Bambu's multi-AMS compatibility guide:

• A1 series: one AMS lite, or up to four units of AMS, AMS 2 Pro and AMS HT in any mix. The newer units need Bambu's A1 AMS Hub and firmware 01.07.00.00 or later, and AMS lite cannot be combined with them.
• X1 and P1 series: up to four AMS units in total. One unit needs a filament buffer; two or more need an AMS Hub.
• P2S: up to four AMS 2 Pro and four AMS HT at once, eight units with 20 slots. The P2S Combo includes the buffer.
• H2 series: up to four AMS 2 Pro and eight AMS HT. The H2S is single nozzle, so it reaches 24 colors; the dual-nozzle H2D and H2C reach 25 with an external spool. The buffer is built in.

Printer pages on this site cover each model: Bambu Lab A1, P2S and H2D. The A1 versus P1S comparison shows how AMS support differs between them.

Which AMS do you need?

Pick by printer and by filament. On an A1 or A1 mini, the AMS lite is the unit the printer was designed around, and you move to an AMS 2 Pro or AMS HT only by adding the AMS Hub. On a P1, X1, P2S or H2 printer, the AMS 2 Pro suits PLA and PETG with built-in drying, and the AMS HT suits materials that need hotter drying. Mixing is allowed on those printers within the unit limits above.

Powering the dryer is a separate cost. Bambu says an H2, P2 or X2D printer can power one AMS 2 Pro for drying, while A1, P1 and X1 printers need a Switching Adapter for each AMS 2 Pro. Bambu also says the AMS 2 Pro cannot dry on its own without a 6-pin cable to a powered-on printer. Using Bambu filament helps, since RFID tags set the profile automatically; third-party spools must be set by hand, as covered in the Bambu Lab filament guide. If filament snaps or stops feeding, see how to fix an AMS filament jam. To plan a first purchase, the beginner printer guide is a good start.