A rotating nozzle helps reduce filament waste in full-color FDM 3D printing

Posted on August 23, 2024 by Elliot S.

The rotating nozzle in action

Multi-color FDM 3D printing has gained popularity thanks to innovative systems like Bambu Lab’s AMS, which has paved the way for a new generation of machines capable of handling multiple filaments simultaneously. This system, which quickly inspired other manufacturers such as Anycubic and Creality, allows for the creation of multi-color objects with increased precision and ease. However, the filament changeover process remains time-consuming and generates a considerable amount of material waste, especially during the purging required to avoid unwanted color mixing.

It is in this context that Heinz Löpmeier developed an innovative solution: a rotating nozzle capable of changing color without purging the filament, thus reducing waste and speeding up the printing process.

The design of the rotating nozzle and a prototype On his Twitter account, Heinz Löpmeier shares the creation of his coaxial nozzle.

An innovative concept: the rotating nozzle

Heinz Löpmeier, known as “sophier” on Reddit, shared his invention: a “rotating mixing nozzle.” This nozzle, unlike the systems mentioned above, does not require purging colors between changes, eliminating filament waste. The nozzle works by using a Python script in Blender, also created by Heinz Löpmeier and published as open-source on github, that associates specific colors with nozzle angles, allowing for smooth color transitions and even “halftone” effects (for gradient effects).

The concept emerged after years of experimenting with standard mixing nozzles, which tend to create a “toothpaste” effect by not fully mixing filaments of different colors. Heinz Löpmeier first tried to control this effect by using a printer whose bed could rotate to change colors, but this approach proved too slow given the mass of the bed and the 3D print that had to be set in motion.

Operation and applications

The operation of this rotating nozzle is relatively simple, but very effective. When in action, the nozzle rotates to change the color of the extruded filament without changing the mixing ratios of the three filaments used. The script in Blender also allows for subtle effects to be created by positioning the nozzle at a specific angle between two colors, thus producing prints with complex shades and gradients without the need for additional structures like purge towers.

Heinz Löpmeier uses Marlin firmware, configured with an additional axis for nozzle rotation. One of the key innovations of this design is the ability of the Bowden tubes to twist and untwist during print head movements, ensuring smooth operation and avoiding kinks or blockages.

Multi-color orbital printer The previous prototype used the same process, but with a rotating plate.

A powerful tool for creators

One of the major strengths of this system is its integration with Blender, a widely used software for 3D modeling. Using Blender's Python API, Heinz Löpmeier developed an add-on called "nozzleboss", which allows G-code paths to be manipulated directly inside Blender. This opens up vast creative possibilities, allowing users to sculpt or paint modifications directly onto the tool path.

Additionally, this approach removes the need for traditional slicing software, giving creators increased flexibility to customize their prints.

Perspectives and implications

Heinz Löpmeier’s rotating nozzle could well mark a turning point in the field of FDM 3D printing, especially for those looking to minimize waste while exploiting the benefits of multi-material. Its innovative design, while potentially worthy of a patent, has not yet been protected, opening the door for ambitious companies or individuals to turn it into a commercial product.

Rotary nozzle and non-planar printing In addition to his rotating nozzle, Heinz Löpmeier uses non-planar 3D printing in his designs.

However, Heinz Löpmeier himself seems unconcerned by this prospect, preferring to focus on innovation rather than protecting intellectual property. This attitude contrasts sharply with recent patent disputes in the industry, notably between Stratasys and Bambu Lab.

With this rotating nozzle, Heinz Löpmeier not only offers a technical solution, but also a more sustainable and efficient vision of multi-material 3D printing. It remains to be seen how this technology will evolve and whether it will be adopted by the broader community of makers and 3D printing professionals. For more information on the project, check out Heinz Löpmeier’s Reddit post HERE.

source: https://www.3dnatives.com/ All photos credit: Heinz Löpmeier