[Proper Printing] Obviously enjoys pushing the boundaries of 3D printed content, and sometimes this requires creating custom 3D printers or at least ending their business. Flexible filaments can be a bit of a pain to deal with, as most extruders are designed to push the filament to the hot end with a simple hood bolt (or pinch roller setup) and only work reliably due to the plastic’s own rigidity. Once you become flexible, the rigidity decreases and the filament often moves to the side and the extruder becomes jammed. The longer the filament path leading to the hottend, the harder it will be. The dual belt drive extruder (they call it the ‘proper extruder’) grasps the filament on both sides with a pair of supported belts, allowing it to deviate to the side, leading it to the hottend. The extruder body and gears were resin printed (but, we tested – the design is also suitable for FDM printing).
The extruder design seems a bit tweaking, since the belts themselves were deviated, but after a few repetitions to add some guide rails, it seems to be working pretty well. Of course we don’t usually see all the failures along the way! Tolerate this, they quickly begin testing the flexible filament in a logical manner, with a minimally flexible filament with a minimum rigidity on the edge of 93A, before moving to the NinjaFlex (85A hardness) and even successfully printing a gear on an unknown 60A hardness filament.
The test printer was a Creality CR-10, with a WhamBam mutant tool-changer installed, so it needed an adapter plate to allow the ‘proper extruder’ to be mounted. The belt-driven design has proven to be a bit more for ordinary NEMA17 stepper motors used for direct drive extruders with additional friction from changes, so they need to use a beaver unit. Due to the heat from this larger motor, it needed to be printed on polycarbonate (we think the video is obscure) to prevent warp during operation, but this should not be a major obstacle for the ruthless manufacturer who wants to duplicate this work. , We count.
We are not unfamiliar with 3D printing with flexible materials, and related hacks to control them, such as this modified Bowden driver for TPU. There are numerous and important applications for printing with Flex, such as custom gasket printing, as the name implies, so anything that reduces the difficulty of printing with floppy stuff is a great step in the right direction in our eyes.
Thanks [BaldPower] For the tip!