A research team from Cornell University and Carnegie Mellon University has developed a prototype knitting machine that can build arbitrarily rigid three-dimensional structures by layering stitches horizontally on top of each other. Different stiffnesses can also be implemented at various points within a 3D structure.

The knitting machine developed by the two scientists builds upon a private knitting machine project by François Guimbretière, Professor of Information Science, and Victor Guimbretière, a student at Cornell Engineering. This project was largely realized with 3D-printed components in a home basement during the Covid-19 pandemic. The idea was to be able to create 3D objects with variable stiffness using simple yarns.

The scientists improved the knitting machine in collaboration with two other researchers and described it in the study “Using an Array of Needles to Create Solid Knitted Shapes”, which was published in the Proceedings of the 38th Annual ACM Symposium on User Interface Software and Technology.

Knitting Solid Structures

At its core, the apparatus consists of a “6 x 6” block of knitting needles. The needles have a special design in the form of a symmetrical double hook, where the front and back parts can move independently. The researchers created the needles using a 3D printer. They are each connected to a brass support tube. The double hook allows stitches to be added to the left or right, depending on which of the two independent hooks picks up the stitch first. This allows stitches to be added forwards, backwards, and diagonally.

The knitting head, located directly above the needle block and feeding the yarn, can move to any desired position. This enables the machine to create complex knitted structures. Depending on how a stitch is attached, the stability can also be influenced. This allows 3D structures to be manufactured that have different stiffnesses at different points.

The researchers developed not only the machine but also a matching control software with a code library for each different stitch type. This allows a special program to be generated for each individual object.

However, the prototype still has its quirks, as François and Victor Guimbretière admit. Sometimes stitches fall off or the yarn gets caught in the needles. The researchers now plan to work on making the knitting machine more robust for practical use. They also want to enlarge the needle block to be able to knit with more needles.

The scientists see potential applications primarily in the medical field. One of these is knitting structures for artificial ligaments or veins.

(olb)

Don’t miss any news – follow us on Facebook, LinkedIn or Mastodon.

This article was originally published in German. It was translated with technical assistance and editorially reviewed before publication.