Does the Bambu Lab AMS 2 Pro Still Need Desiccant?

Yes. The Bambu Lab AMS 2 Pro still uses desiccant alongside its active drying system. Drying removes moisture from filament; effective desiccant helps maintain a dry environment around it during storage.

If your AMS 2 Pro can already dry filament, adding desiccant may seem unnecessary. But a drying cycle and the days between print jobs create different moisture-control needs. Understanding both helps you protect your spools and decide whether a refillable desiccant container would make maintenance easier.

Bambu Lab still lists desiccant as an AMS 2 Pro component and describes its purpose as keeping the internal chamber dry. Its replacement desiccant is also specifically listed for the AMS 2 Pro. Bambu Lab H2D user manual, section 1.3, Bambu Lab desiccant overview.

What does the AMS 2 Pro drying function do?

The AMS 2 Pro combines heated drying with active moisture discharge. Bambu Lab specifies a maximum drying temperature of 65°C, alongside sealed storage and temperature and humidity monitoring. Use the drying settings recommended for your exact filament and spool; the maximum temperature is not the correct setting for every material. Bambu Lab AMS 2 Pro specifications.

During drying, heat helps moisture leave the filament, and the system provides a route for that moisture to leave the chamber. This addresses moisture that a spool has already taken up.

Once a drying cycle ends, the next task is preserving that condition. A spool waiting for your next print still needs a suitable storage environment.

Why does filament need protection after drying?

Drying does not make filament permanently resistant to moisture. Its storage conditions continue to matter.

Bambu Lab makes this distinction in its guidance for Support for PLA: dry the material before printing, then keep it sealed in the AMS with desiccant throughout printing. That is a material-specific recommendation, but it clearly shows drying and protected storage working together. Bambu Lab Support for PLA printing tips.

Consider a typical spool change. You open the lid, remove one spool, load another and close the machine. That opening exchanges some chamber air with room air. Dry storage guidance from Prusa likewise identifies frequent opening and poor sealing as causes of increased internal humidity. Prusa: managing drybox humidity.

This is the practical reason to keep effective desiccant available between drying cycles: the storage environment changes as you use the system.

Drying, sealed storage and desiccant have different jobs

Part of the setup	Main job
Active drying	Remove absorbed moisture using a suitable temperature and duration
Closed, sealed chamber	Reduce exchange with the surrounding room air
Effective desiccant	Take up water vapor inside the storage space
Humidity monitoring	Help you track the condition of the chamber air

These functions complement one another. A useful routine addresses the spool's starting condition, the enclosure and ongoing desiccant maintenance.

Where does a desiccant container help?

The AMS 2 Pro already provides a way to use the supplied desiccant. An additional container is an optional maintenance accessory; the presence of a heater alone does not make it necessary to buy one.

A refillable container becomes useful when you choose loose desiccant beads and want a convenient way to handle them. Its value comes from practical details:

• Bead retention: openings should allow contact with chamber air while keeping the intended bead size contained.
• Refilling and removal: you should be able to replace or remove the contents without spilling beads into the machine.
• Visibility: a design that exposes the indicator beads can make condition checks easier.
• Fit: the installed container must leave the lid, spools, rollers and filament path free to operate.
• Temperature compatibility: if it remains inside during drying, check the stated limits of the complete container assembly against the intended cycle.

These are selection criteria, rather than a guarantee that any particular container will lower humidity by a fixed amount. A well-fitted holder organizes the desiccant; the desiccant itself provides the moisture uptake.

Choose a design explicitly made for the Bambu Lab AMS 2 Pro, and check its installation instructions rather than assuming an original AMS accessory will fit.

A practical drying and storage routine

1. Check the filament first. If it needs drying, use the manufacturer's procedure with suitable equipment. Confirm both drying and feeding compatibility for the exact material.
2. Check the desiccant. Follow the indicator guide for the product you actually use. Bambu Lab describes its listed replacement desiccant as changing from yellow to purple when it needs replacement or drying for reuse. Other products may use different colors. Bambu Lab desiccant overview.
3. Close the chamber properly. Check that the lid and seal are clear of anything that could prevent normal closure.
4. Review humidity under comparable conditions. Record a baseline after the closed chamber has settled. If readings rise persistently under similar conditions, inspect the seal, desiccant and recent spool changes.
5. Protect spools outside the AMS too. Use appropriate sealed storage with effective desiccant when moving a dried spool out of the machine.

Treat this as a maintenance routine you can repeat, rather than a fixed calendar promise. Your usage pattern and room conditions will influence how often the desiccant needs attention.

Frequently asked questions

Can desiccant replace filament drying?

For a spool that needs drying, use the prescribed drying process. Prusa explicitly distinguishes its silica-gel storage drybox from equipment for drying already-moist filament. Desiccant-based storage helps preserve a prepared spool; do not assume it will restore a wet one within your printing schedule. Prusa USS Drybox guidance.

Does every AMS 2 Pro owner need extra desiccant containers?

No. Start with the supplied arrangement and monitor how it works for your materials and environment. Consider a refillable container when easier bead handling, inspection or replacement would improve your routine.

Will an AMS 2 Pro filament cycle fully regenerate my desiccant?

Do not assume so. Follow the regeneration instructions for the exact desiccant, including its required temperature, time and permitted equipment. A filament drying preset is not evidence that the desiccant has completed its own regeneration process. Check the holder's instructions separately if heating it with the contents.

Does a low humidity reading prove the filament is dry?

The reading describes the surrounding air, rather than directly measuring water inside the filament. Use it to monitor storage conditions alongside the material's drying guidance. A low reading alone cannot confirm that a previously wet spool has finished drying.

For more on maintaining the desiccant itself, read our guide to when to replace desiccant in your Bambu Lab AMS. When choosing a refill, see our orange silica gel and 4A molecular sieve comparison.

Make dry storage easier to maintain. For your next AMS 2 Pro accessory, prioritize secure bead containment, straightforward refilling and clearly specified fit and temperature limits.