There have been a few posts on Hackaday over the years involving knitting, either by modifying an old Brother knitting machine to incorporate modern hardware, or by building a 3D printed knitting machine. All of these hacks are examples of flat knitting, and are incapable of making a seamless tube. Circular Knitic bucks that trend by using 3D printing and laser cutters to create an open source circular knitting machine.
Circular Knitic is an expansion on an earlier build that gave a new brain to old Brother knitting machines from the 70s. This build goes well beyond simple manipulation of electrons and presents an entire knitting machine specifically designed for circular knitting. It’s completely automated, so once the machine is set up, a giant tube of knit yarn is automagically created without any human intervention.
This isn’t the first completely open source knitting machine; OpenKnit can be made with aluminum extrusion, some electronics, and a few 3D printed parts. Circular Knitic is, however, the first circular knitting machine we’ve seen, and according to the Github is completely open source.
The creators of Circular Knitic, [Varvara] and [Mar] have been showing off their machine at an exhibition in Zaragoza, Spain called DOERS, where they’ll be knitting for the better part of six months. You can see some video of that below.
[John] modeled several 3D sculptures in Rhino containing similar geometric properties to those found in pinecones and palm tree fronds. As the segments grow from those objects in nature, they do so in approximately 137.5 degree intervals. This spacing produces a particular spiral appearance which [John] was aiming to recreate. To do so, he used a Python script which calculated a web of quads stretched over the surface of a sphere. From each of the divisions, stalk-like protrusions extend from the top center outward. Once these figures were 3D printed, they were mounted one at a time to the center of a spinning base and set to rotate at 550 RPM. A camera then films the shape as it’s in motion at a 1/2000 sec frame rate which captures stills of the object in just the right set of positions to produce the illusion that the tendrils are blooming from the top and pouring down the sides. The same effect could also be achieved with a strobe light instead of a camera.
Many years before he was 
There is a business lesson here too. Once upon a time the Choctopus was a 3D printer but economic constraints have led to him downgrading to 2D. Any 3D requirements are served from an alternate RepRap. The purpose of an 8-armed printer is to mass produce, but for the price, most clients were only interested in a one-off. The products that pay the bills are the much more affordable 2d extrusions in bulk.
