LiTexTextile & Technology

How Conductive Metal Yarn is built

A metal layer coiled helically around a core polymer yarn. How many times it is wound, and in which direction, is the whole specification — it sets resistance, diameter and toughness together.

Reading a grade name

A grade like 010/N(K)30'*3/2S2Z ends in its covering pattern. The digits count coverings in each direction and the letters give the helical direction: S and Z are opposite hands, named after the middle stroke of each letter. So 1S is a single covering, 1S1Z is two wound against each other, and 4S4Z is eight.

One covering, wound in the S direction. The finest commercial grade at 0.27 mm uncoated.
1S1 coveringOne covering, wound in the S direction. The finest commercial grade at 0.27 mm uncoated.
Two coverings wound in opposing directions, which balances the torque the first layer introduces.
1S1Z2 coveringsTwo coverings wound in opposing directions, which balances the torque the first layer introduces.
Four coverings. Roughly a third of the resistance of 1S, and materially tougher.
2S2Z4 coveringsFour coverings. Roughly a third of the resistance of 1S, and materially tougher.

What more coverings buy

Across the published range — 1S through 4S4Z, one covering to eight — resistance falls from about 4.4 Ω/M to about 0.8 Ω/M while toughness rises from the weakest grade to the strongest. Diameter rises with it, from 0.27 mm uncoated to 0.65 mm. Choosing a grade is choosing where on that curve an application sits.

Coverings are tinned copper. Coating options are PU and FEP (Teflon). A copper-nickel version was listed as coming soon in the 2018 catalog; its current status is unconfirmed.

See the full grade table with diameters and resistances →

Why coiled rather than bundled

The coiled construction is what lets the yarn bend without the filament fracture that affects brittle heating elements, and it is made ready to use on LiTex's own looms rather than assembled by hand — which is what makes it mass manufacturable. Compared against carbon fibre, heating film and steel fibre →

Source: 2018-non-carbon-electrical-heating-textile.pdf p.3, and images/cmy-structure1.jpg. Figures are from the 2018 catalog and have not been re-confirmed with LiTex.