3D printing teddy bears and other soft things

A new device combines a 3D printer with a sewing machine to make cuddly things. Instead of lines of melted plastic, it extrudes yarn.

With the exception of body parts and maybe pizza , most 3D printed items are made of metal or plastic. A new device combines a 3D printer with a sewing machine to make soft, cuddly things. 

In a collaboration with Disney Research, Scott Hudson of Carnegie Mellon developed the felting printer that turns wool and wool blend yarns into fabric objects reminiscent of hand-knitted items. 

Like other 3D printers, the machine makes objects by working directly from designs on a computer, making it useful for rapidly prototyping and customizing products. The machine operates on the same principle as Fused Deposition Modeling (FDM), the most common process used in low-end 3D printers. In an FDM printer, melted plastic is extruded in a thin line into a layer. To get the desired shape, multiple layers are added successively, adhering to each other as the plastic cools. 

With this felting printer, the extrusion head feeds out yarn instead of lines of melted plastic. Then a barbed triangular felting needle attached to the printer head pierces the yarn repeatedly, dragging individual fibers down into the layers of yarn below -- this entangles the fibers, bonding the layers together. 

Because yarn is thick, the machine can’t achieve the same dimensional accuracy as other 3D printers. To reinforce the object, stiffeners like nylon mesh fabric, as well as hardware and electronics, can be embedded. For example, yarn can be overlaid on a little articulated teddy bear arm that can bend to, say, wave or give a hug (watch the video below). According to Hudson, it should be possible soon to design a “mixed materials” printer that produces both fabric and plastic elements in a single fabrication.

 The new printer could be useful for making clothes, accessories like scarves and hats, and of course, plush toys. It also might be used to produce parts for “soft robots” that are designed to touch and interact with people. 

The work [pdf] was presented at the CHI Conference on Human Factors in Computing Systems in Toronto last week. 

Images: Carnegie Mellon / Disney Research Pittsburgh 
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