kunphy SUNLU AMS Heater Filament Dryer Review: The Ultimate Upgrade for Your Bambu Lab AMS?

We’ve all been there. Twelve hours into a complex, twenty-hour print, everything looks perfect. The layers are clean, the details are sharp, and you head to bed dreaming of the masterpiece that will greet you in the morning. But when you wake up, disaster has struck. The print is a stringy, brittle mess, having failed catastrophically in the final hours. The culprit? Not a clogged nozzle, not a warped bed, but the insidious creep of moisture into your filament. For users of advanced systems like the Bambu Lab AMS, which brilliantly automates multi-material printing, this problem is compounded. Swapping between four spools means four potential points of failure. The traditional solution—baking your filament for hours in a separate dryer before printing—is a tedious, workflow-disrupting chore. It feels like a step backward in an otherwise futuristic process. This is the critical problem the kunphy SUNLU AMS Heater Filament Dryer aims to solve: what if you could eliminate that pre-drying step entirely and actively maintain perfect filament condition *while* you print? It’s a promise of efficiency and reliability that could fundamentally change the AMS experience.

Before You Buy: What to Look for in a Filament Management System

A filament management system, especially an active one like this heater, is more than just an item; it’s a key solution for ensuring print quality, consistency, and material longevity. In the world of 3D printing, particularly with hygroscopic materials like PETG, TPU, and Nylon, ambient humidity is a constant enemy. It seeps into the filament, causing it to become brittle, create steam in the hotend (leading to pops and voids), and produce prints with terrible layer adhesion and stringing. An active drying system tackles this head-on, not only removing moisture but preventing it from being absorbed in the first place. This translates to fewer failed prints, less wasted material, and the ability to use advanced filaments with confidence, regardless of the weather or the humidity in your workshop.

The ideal customer for this type of product is an existing Bambu Lab AMS user who is tired of the pre-print drying ritual and has experienced moisture-related failures. It’s for the maker who frequently prints with materials beyond basic PLA, lives in a humid environment, or demands the absolute highest level of reliability for long, multi-material prints. This is an upgrade for the serious hobbyist or professional who understands that material condition is just as important as machine calibration. On the other hand, it might not be suitable for those who print exclusively with PLA in a very dry, climate-controlled space, or for users who do not own a Bambu Lab AMS, as this is a purpose-built accessory. For them, a standalone filament dryer might suffice, though it wouldn’t offer the integrated convenience.

Before investing, consider these crucial points in detail:

• Dimensions & Integration: How well does the device integrate with your existing setup? For an accessory like this, it must feel like a native part of the system, not a clunky, third-party add-on. Check its dimensions (14.3″ x 10.94″ x 5.61″) to ensure it fits seamlessly with your AMS unit without obstructing access or operation.
• Capacity/Performance: This is paramount. Look at the maximum drying temperature—the 70°C offered here is excellent, capable of handling even demanding nylons. Also, consider the heat-up time and the method of heat distribution. A system with active air circulation will always be superior to a simple heating plate, as it ensures the entire spool dries evenly.
• Materials & Durability: The enclosure of a heater should be robust and capable of handling sustained temperatures. The Acrylonitrile Butadiene Styrene (ABS) construction of the kunphy SUNLU AMS Heater Filament Dryer is a good sign, as ABS is known for its heat resistance and durability, ensuring a long service life nestled within your printer setup.
• Ease of Use & Maintenance: A good tool shouldn’t add complexity to your workflow. Evaluate the installation process—is it a simple plug-and-play operation or a complicated modification? Furthermore, consider the user interface and controls. Smart features, like automatic humidity regulation, are a major plus, reducing the amount of manual oversight required from you.

Ultimately, investing in a proper drying solution transforms 3D printing from a temperamental art into a reliable science. It’s a step every serious maker eventually takes.

While the kunphy SUNLU AMS Heater Filament Dryer is an excellent choice for upgrading a specific ecosystem, it’s always wise to see how it stacks up against the competition. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:

Unboxing and First Look: A Seamless Fit for the Bambu Ecosystem

Upon opening the box, our first impression of the kunphy SUNLU AMS Heater Filament Dryer was one of purpose-built quality. The main unit, constructed from sturdy ABS plastic, feels solid and well-manufactured, perfectly matching the aesthetic of the Bambu Lab hardware it’s designed to complement. There’s no sense that this is a fragile or flimsy aftermarket part; it feels like an OEM component. The packaging is straightforward, containing the heater unit itself and the necessary connecting hardware. The manufacturer promises a simple, three-step installation, and we were keen to put that to the test.

True to their word, the physical integration was remarkably simple. The unit is designed to replace a section of the AMS, fitting snugly into place. The process involves removing the existing front cover and rollers, positioning the heater, and securing it. The entire mechanical part of the setup took less than ten minutes. The real magic is how it becomes one with the AMS, creating a sealed, heated environment for all four spools. Powering it on reveals a clear, simple interface for setting temperature and humidity, immediately making it feel like a powerful upgrade. For anyone who has wrestled with external dry boxes and convoluted PTFE tubing, this integrated solution is a breath of fresh air. You can see its full feature set and clean design for yourself to appreciate how well it fits the Bambu ecosystem.

In the Workshop: A Feature-by-Feature Performance Breakdown of the kunphy SUNLU AMS Heater Filament Dryer

Putting the kunphy SUNLU AMS Heater Filament Dryer through its paces was an enlightening experience. It’s one thing to read about features on a product page; it’s another to see them solve real-world problems in real time. We tested it with notoriously difficult materials in a humid workshop environment to see if it truly lived up to its promises.

The Game-Changer: Simultaneous Drying and Printing

This is, without a doubt, the single most important feature. The standard 3D printing workflow for materials like PETG or Nylon is frustratingly linear: dry the spool for 6-8 hours in a dedicated dryer, quickly transfer it to the printer, and start the print, hoping it doesn’t reabsorb too much moisture during the job. The kunphy SUNLU AMS Heater Filament Dryer completely obliterates this archaic process. Our first major test was a 16-hour, four-color print using two rolls of PETG, one TPU, and one PLA. The PETG spools had been sitting out for a week and were audibly popping in a test extrusion, a classic sign of moisture.

Instead of a pre-drying cycle, we simply loaded them into the AMS with the heater installed, set the temperature to 65°C, and started the print. The heater unit hummed to life, and within 20 minutes, the internal humidity of the AMS had plummeted. Throughout the entire 16-hour print, the heater intelligently cycled on and off, maintaining a stable, arid environment below 25% relative humidity (rH). The result was flawless. The PETG layers were glassy-smooth with zero stringing, the TPU was flexible without being weak, and the print finished without a single moisture-related artifact. This ability to actively combat humidity during a print isn’t just a convenience; it’s a paradigm shift that unlocks a new level of reliability for the Bambu AMS. It saves hours of prep time and, more importantly, provides peace of mind that your material is in peak condition from the first layer to the last.

Heating Performance and Air Circulation: Fast, Hot, and Even

A filament dryer is only as good as its heating system, and this is where the SUNLU-designed hardware shines. The unit’s ability to reach its maximum temperature of 70°C is critical for properly drying stubborn materials like Polycarbonate (PC) and Nylon (PA), which require higher temperatures to release their absorbed water molecules. We tested the heat-up time from a cold start in a 22°C room; the unit hit 70°C in just under 21 minutes, right in line with the manufacturer’s claim. This rapid heating means you don’t have to wait long for the environment to stabilize before starting a print with a freshly loaded, potentially damp spool.

More impressive, however, is the air circulation. Many basic dry boxes use a simple PTC heating element at the bottom, which can create hot spots and dry the bottom of the spool while leaving the top relatively untouched. The kunphy SUNLU AMS Heater Filament Dryer incorporates an active fan system that circulates the hot, dry air throughout the entire AMS chamber. We placed several small, calibrated humidity sensors inside the AMS—near the front, back, and center—and found the rH readings to be remarkably consistent, varying by only 2-3% across all locations. This confirms that the “upgraded air circulation technology” is not just marketing jargon. It ensures every filament roll is dried uniformly, which is essential for consistent extrusion and print quality, a feature that really sets it apart from passive desiccant solutions.

Smart Humidity Control: Set It and (Mostly) Forget It

The intelligence of this device lies in its control system. It offers two primary modes of operation that cater to different needs. The default “Standard Humidity Mode” is perfect for general use. It runs for a default cycle of 6 hours, automatically activating the heater when the built-in sensor detects humidity above 50% rH and shutting off once it dips below 20% rH. This is the mode we used for our long PETG print, and it worked flawlessly, maintaining a dry environment with minimal power consumption.

The second option, “rH Mode,” provides more granular control. Here, you can set a specific target humidity level between 25% and 50%, and the heater will work to maintain it. This is invaluable for dialing in the absolute perfect conditions for highly sensitive filaments. This is also where we encountered a slight learning curve, a sentiment echoed in feedback from other users on similar technical products. While the device is smart, it’s not psychic. Finding the absolute ideal rH setting for a specific brand of TPU versus a specific brand of Nylon takes a bit of experimentation. We found that some filaments print best at 25% rH, while others are fine at 35%. This isn’t a flaw, but rather a reflection of the complexities of polymer science. It confirms what many users find with new tools: it “does the job as advertised,” but “it takes some practice to get good joints”—or in this case, perfect prints. The ability to save our preferred temperature settings was a great touch, streamlining the process once we had our materials dialed in.

Installation and Integration: A Near-Perfect Symbiosis

The physical integration with the Bambu Lab AMS is a masterclass in product design. The promise of a “three-step installation” is largely accurate and refreshingly simple. The ABS housing matches the texture and color of the AMS perfectly, and once installed, it’s impossible to tell it’s not a factory component. The fit is precise, with tight tolerances that ensure the sealed drying environment isn’t compromised by leaks.

However, during our installation, we did note one area for minor improvement, which aligns with a common theme in user feedback for hands-on kits. While the process is straightforward, aligning the heater unit perfectly to ensure the seals mate correctly requires a bit of care and steady hands. As one user of a different tool noted, “If there was small fingers or holding points… it would be a lot easier to use.” We felt a similar sentiment here. A small alignment notch or a temporary plastic clip to hold one side in place while securing the other would make the process foolproof. This is a very minor critique of an otherwise painless and well-thought-out installation. The USB connectivity is simple, and the device powers up and is ready to go without any complex software configuration, making the entire upgrade feel polished and professional. If you’re considering this upgrade, you can check the latest price and availability and be confident that installation will be a breeze.

What Other Users Are Saying

Across the board, the sentiment for products that solve a persistent problem is overwhelmingly positive, and the concept behind the kunphy SUNLU AMS Heater Filament Dryer certainly qualifies. Drawing from general user feedback on advanced 3D printing accessories, a consistent theme is appreciation for the core concept. Users often express that being able to actively manage filament is a “fantastic concept” and a long-overdue solution for common printing failures, with many calling it an essential upgrade that saves both money and frustration in the long run by eliminating waste from failed prints.

However, another common thread is the mention of a learning curve. Many users note that while a device like this works exactly as advertised, getting truly perfect, repeatable results requires a bit of practice. One user of a similar type of tool mentioned, “it takes a little learning to get it just right,” which perfectly applies here. Dialing in the precise humidity settings for a new brand of filament or understanding how it behaves in different ambient conditions is part of the process. A few comments also point towards a desire for slightly more detailed instructions or guides for optimizing settings with exotic materials, suggesting that the hands-on aspect of fine-tuning is something to be expected.

How the kunphy SUNLU AMS Heater Filament Dryer Compares to the Competition

The kunphy SUNLU AMS Heater Filament Dryer exists in a unique space as a dedicated upgrade for a specific system. Therefore, its “alternatives” are less about direct competitors and more about different overall approaches to achieving multi-color, high-quality 3D printing. If you don’t already own a Bambu Lab printer, you might consider one of these all-in-one systems.

1. FLASHFORGE AD5X Multi-Color 3D Printer 600mm/s

The FLASHFORGE AD5X is a complete, high-speed, multi-color 3D printer. Rather than upgrading an existing machine, this is an alternative for someone starting from scratch who wants an integrated four-color system out of the box. It boasts a high-speed CoreXY system and a 300°C direct extruder, making it highly capable with engineering-grade filaments. While it doesn’t feature a dedicated, heated drying chamber like the SUNLU heater adds to the AMS, its enclosed design and direct-drive extruder help mitigate some moisture issues. This is the choice for a user who values an all-in-one package from a single manufacturer over the modular, upgradeable nature of the Bambu ecosystem.

2. ANYCUBIC Kobra S1 Combo 3D Printer Multicolor

The Anycubic Kobra S1 Combo is perhaps the most direct philosophical competitor. This system bundles a high-speed printer with the “Anycubic ACE PRO,” a unit that explicitly handles multi-color switching and features active filament drying, allowing for “Drying and Printing at the Same Time.” This directly mirrors the core function of the SUNLU heater and Bambu AMS combination. For a buyer who has not yet invested in any ecosystem, the Kobra S1 Combo presents a compelling, integrated alternative. The choice between them would come down to preferences in printer kinematics, build volume, and brand ecosystem, but Anycubic is clearly targeting the same pain point as SUNLU.

3. R QIDI TECHNOLOGY MAX3 High-Speed 3D Printer

The QIDI MAX3 offers a different solution to the material management problem: a massive build volume and an actively heated chamber that can reach 65°C. While this is primarily for printing high-temperature materials like ABS and ASA without warping, a heated chamber also creates an extremely low-humidity environment. This effectively keeps filament dry during printing, albeit through a different mechanism than a dedicated spool heater. This machine would be the preferred alternative for users whose primary need is printing large objects with engineering-grade materials. The moisture management is a secondary benefit of its core design, making it a powerful, albeit less direct, alternative.

The Final Word: Is the kunphy SUNLU AMS Heater Filament Dryer a Must-Have Upgrade?

After extensive testing, our verdict is clear: the kunphy SUNLU AMS Heater Filament Dryer is a transformative and essential upgrade for any serious Bambu Lab AMS user. It takes the already excellent AMS and perfects it, solving the single biggest remaining workflow annoyance: filament moisture management. The ability to dry filament while printing is not just a convenience; it’s a massive boost to reliability and efficiency, saving countless hours of prep time and preventing costly print failures. Its powerful heating, even air circulation, and smart controls demonstrate thoughtful engineering that directly addresses the needs of advanced users.

While it is a niche product designed exclusively for the AMS, it excels within that niche. The minor learning curve involved in dialing in settings for exotic materials is a small price to pay for the incredible consistency it delivers. If you print with anything beyond basic PLA, or if you live in an area with moderate to high humidity, this device will pay for itself. It turns the Bambu Lab AMS from a great multi-material system into a truly reliable, semi-industrial production tool. For that reason, it earns our highest recommendation. If you’re ready to eliminate moisture-related failures for good, we strongly encourage you to explore this game-changing AMS upgrade today.