Welcome to the deep dive into AMS mechanics! If you're here, you’re probably wondering how OpenAMS turns a proprietary system into a Klipper-compatible marvel. Hold onto your spools; it’s about to get nerdy.
The AMS (Automatic Material System) from Bambu Lab is a sleek, proprietary filament management solution with a few tricks up its sleeve:
Cool, right? Except it doesn’t work with Klipper out of the box. Why? Because Bambu Lab’s engineers built it to play exclusively in their sandbox.
To make the AMS Klipper-compatible, we had to rewire its brain and sensory organs. Here’s what we did:
Mainboard Replacement:
Filament Buffer Replacement:
The AMS and Klipper speak entirely different languages. RS485 is great for the AMS’s closed ecosystem, but Klipper prefers CANBus for its modularity and efficiency. Instead of forcing Klipper to learn RS485, we bridged the gap with hardware that speaks Klipper’s native tongue.
The AMS relies on real-time adjustments, like syncing its BLDC motor with the printer’s extruder using a pressure sensor. Klipper, on the other hand, plans everything ahead like a chess grandmaster. By offloading real-time functions to the FPS board and OpenAMS mainboard, we bridged this fundamental difference.
So, how does it work? Magic. Well, engineering magic. We took the AMS’s core mechanics, replaced its proprietary brain and buffer, and made it play nice with Klipper. Now you can enjoy all the speed and reliability of the AMS in your Klipper-based setup.
Cue the applause, or maybe just start printing. Either way, you’re welcome.
Let’s get one thing straight right out of the gate: the Bambu Lab wiki mentions "tension" in the filament buffer, but plot twist—it’s not tension at all. The filament in the AMS is actually under compression and constant pressure, thanks to some clever engineering. Let’s unpack this.
The filament buffer isn’t just a fancy spring-loaded doohickey—it’s a precision-engineered preload system. The spring in the buffer applies continuous pressure to the filament, not tension. Here’s why that’s important:
Pre-Loading the Extruder Gears:
The pressure ensures the filament is always pushing against the gears in the direct extruder at the toolhead. This eliminates backlash in dual-gear extruder setups, leading to more consistent filament flow.
Better Layer Stacking:
By keeping the extruder preloaded, you achieve better layer alignment and fewer artifacts in your prints, especially with materials that are finicky about flow rates.
So, next time someone tells you the AMS relies on "tension," give them a knowing smile and politely explain that it’s all about compression. After all, the difference is like night and day—or a flawless print versus spaghetti.