Printing teddy bears: a technique for 3D printing of soft interactive objects

This paper considers the design, construction, and example use of a new type of 3D printer which fabricates three-dimensional objects from soft fibers (wool and wool blend yarn). This printer allows the substantial advantages of additive manufacturing techniques (including rapid turn-around prototyping of physical objects and support for high levels of customization and configuration) to be employed with a new class of material. This material is a form of loose felt formed when fibers from an incoming feed of yarn are entangled with the fibers in layers below it. The resulting objects recreate the geometric forms specified in the solid models which specify them, but are soft and flexible -- somewhat reminiscent in character to hand knitted materials. This extends 3D printing from typically hard and precise forms into a new set of forms which embody a different aesthetic of soft and imprecise objects, and provides a new capability for researchers to explore the use of this class of materials in interactive devices.