Graylag-PD / Goose-Belt-Purger

Goose Belt Purger (GBP) A simple, lightweight, and low-cost belt purger for 3D printers.\ An alternative to blob-producing purging routines and devices, or traditional purging into towers.\ Officially supported printers are Voron Trident and 2.4, but it is small and light enough to be adapted for other printers. See also our promo video on YouTube, or slightly older video with more detailed depiction of purger in action. Currently in Beta testing — proven as a functional design, but can have unexpected issues and design might change any time. If you have any questions, you can visit my Discord server. If you find this useful, a like or a make on Printables helps others discover and trust the design. About Like many makers, I've been fascinated by single-nozzle multicolor/multimaterial printing. But like many, I hate purge towers. They can be large, ugly, and take up valuable print bed space. This is why I was intrigued by the Blobifier — but there are several issues. First, I use a Voron Trident, which isn't compatible. While there are adaptations of the Blobifier concept for the Trident, none have gained significant traction. Second, both the original Blobifier and its Trident adaptations generally share the drawback that each purge requires toolhead parking near the bed edge, blocking part of the bed and potentially risking collisions. Third, the produced blobs are volumetrically inefficient. Even though the blobs are relatively compact, their shape means they can't utilize the waste bin space effectively. This is even worse with the loose coil "poops" produced by some printers. There had to be a better way. And then it struck me — use a belt to produce compact "line" purges. To be fair, this isn't an entirely new idea. There have been mods involving purging on stationary aluminum platforms or kinematic belts, but none of those options felt right. I wanted something simple, affordable, and buildable from stuff you already have lying around your workshop.\ This is why the Goose Belt Purger was created. What does it have to do with geese? Nothing. I just like geese. Design The core of the GBP is a silicone wristband — the kind you can get anywhere, often for free. The most common size, which GBP is designed around, is 12 mm wide and 20 cm in circumference. You can use any similar band, even ones with embossing or printing, since we'll use the smooth inner surface. Changing the belt is easy, so use whatever you have and swap it later if needed. Silicone rubber is ideal for this use. When filament is extruded onto the smooth side, it sticks but releases easily at the end of the straight belt section. Silicone is heat-resistant enough to endure the nozzle heat, provided it keeps moving. However, if the nozzle stays in one place too long, the band will discolor (brown or black) or even burn. The belt moves along two printed pulleys. How does it stay in place without flanges? Dark magic. Don't ask. One pulley is driven by a cheap miniature DC motor with a gearbox. A 50rpm or slower version is recommended, up to 15rpm if you want really thick extrusions.   > [!WARNING]\ > Motor is an inductive component. Skipping the recommended protection (e.g. flyback diode) can cause voltage spikes and permanent damage to your controller. > >Read the “Electrical connection” section and install all safety components. >Use at your own risk. The other pulley spins freely on a tilting arm. The arm pivots on a bearing around the motor shaft and is pushed upward by a pair of magnets acting as springs. The arm's purpose is to press against the nozzle but move away to avoid collisions with the nozzle or printhead. GBP is mounted using an Armored Turtle brush mount or universal Klicky style mount. But you can also design your own mount and connect it with AT mount styled dovetails. Bill of Materials (BOM) Purger • 1x Silicone wristband (12 mm wide, 200 mm circumference) • 1x DC motor, 12 mm diameter, 6V/12V, 15rpm — commonly sold as GA12 N20 or N30. See note below. • 3x 623 bearings • 2x 6x3 mm magnets (Voron standard size) • 3x heat-set insert M3x5x4 (Voron standard size) If your board supports 5V on fan outputs, you may use a 6V motor. If only 24V is available, use a 12V motor with [!IMPORTANT]\ > The DC motor is a strong inductive load and will generate large voltage spikes, which can destroy your board's MOSFET or even the MCU if untreated. At minimum, use a properly sized Schottky flyback diode across the board output. I also recommend an RC snubber on the motor terminals. > > Some boards (e.g., BTT Octopus) already include protection diodes. Others rely only on the MOSFET's internal diode, which is usually insufficient. You can check comprehensive table here, or consult your board's schematic. When unsure, ask someone. > > For the RC snubber, I used a 47 Ω resistor and a 10 nF, 50V ceramic capacitor. Solder one leg of each component together, then solder the free legs to the motor terminals. This configuration dampens voltage spikes while preserving PWM response. You may use a larger capacitor for extra safety, but note that increased capacitance degrades PWM response. Avoid using a capacitor alone (without resistor), as this can cause resonance and make things worse. I confirmed the effectiveness of these measures with an oscilloscope, but I can't guarantee that no fast transients were missed (e.g., during PWM changes). Data is still limited, so proceed with care and understand what you're doing. If you want some better alternative to manually soldering components to motor, see amazing MicroFlip project by Ntrondle. You can make it yourself, or check our Discord if anyone has any boards for sale. Keep in mind, that MicroFlip is **not** developed as part of this project. If you like it and would like to support its creator, do so on his GitHub page. Software and Slicer Configuration For more information about provided configuration file, slicer configuration and integration into AFC o…