There are times when a photo, or better yet a video, really says more than a thousand words, and [heinz]’S polar dual disc 3D printer is one of those projects. Perhaps the best way to describe it is as an inverse SCARA system that moves the print bed around the hot end, creating strange and mesmerizing paths of motion.
The Z axis runs on a column through the center of the printer, while the print bed is a gear disk that can rotate independently around its own center as well as around the central column. This gives the printer an easy way to use multiple extruders: simply mount the extruders at different angles around the central pillar, then rotate the bed around to the extruder currently in use. (See the video demo below.) Since the extruder only moves in the Z direction, there is no need to make it as light as possible. In one test it worked perfectly with a five-filament, two-kilogram direct drive extruder, although it proved a bit fiddly.
[heinz] The rotating disks and a few other parts of the printer were 3D printed and two GT2 timing pulleys and the bearings from a Lazy Susan were used to drive and rotate the disks. The surface of the print bed is made of fiberglass and because it is unheated, a pattern of small holes are drilled into it to allow molten plastic to seep in and adhere. A nice side effect of the rotating print bed is that it is a turntable effect on time-lapse videos.
We covered this project once when it was a little earlier in development, and somehow we missed when it was upgraded to its current state. Let’s just say we’re impressed!
Polar 3D printers may make it a bit more difficult to visualize paths, but they can do unique things like printing with four heads at a time or printing in non-planar paths.
#toolchanging #Inverse #SCARA #printer