Solid knitting: 3D printing with yarn

Researchers at Carnegie Mellon University developed a way to create solid objects made of yarn through the power of knitting.

The technique was first envisioned by Yuichi Hirose, a PhD student at Carnegie Mellon University. Called solid knitting, the process is similar to 3D printing. Like a 3D printer shapes objects by adding layer by layer of material, solid knitting builds objects by adding knitted layers.

The main advantage of using knitting, however, is that the layers are only tied together, not fused. Like any knitwear, the thread can be unravelled if the design isn’t wanted anymore, and can be reused for a new one.

It is possible to produce solid knitting by hand (you can find an instructional video here). However, Hirose developed a knitting machine capable of solid knitting, which was recently unveiled at SIGGRAPH 2024, an annual conference of computer graphics and interactive techniques.

The prototype is still limited in the sizes and shapes it can produce. It can make triangular and rectangular prisms of varying lengths. The machine stretches the yarn loops quite a bit, so the researchers have used elastic cord as their yarn. Yet the resulting solid knits are surprisingly firm. Eventually, it is the goal to create a machine that can produce solid objects automatically, both large scale, like furniture, and on a smaller scale.

Photos: Carnegie Mellon University