Josef Prusa has long been a champion of Open Source, but defending its use has been an uphill battle. Last July, he surprised no one at all when he announced that “open hardware desktop 3D printing is dead.” He pointed to his company’s 2016 MMU1 multiplexer as an example of an open source design copied and used by competitors.
The Prusa Research multiplexer allows four filaments to enter a single hotend via a hub mounted on top of the tool head. Bambu Lab’s A1, Anycubic’s Kobra, and…