1. Engineering of the electronically functional yarn
M-N. Nashed, T. Dias
Advanced Textile Research Group
School of Art and Design
Nottingham Trent University
Abstract
Aims & Objectives
Smart textiles integrated with electronics have been developed over the last two decades. Based on the manner in which electronics have been integrated with textiles, we can classify electronic textiles into three generations. In the first generation of electronic textiles, electronic components were simply attached to the fabric permanently or temporarily, while in the second generation, incorporating conducting yarns into the structure of the textile added the electronic functionality to these fabrics. Finally, in the third generation of electronic textiles, integrated circuits are fully incorporated into yarns prior to garment production.
In this research we will focus on embedding electronic Circuits in the yarn to get a functional yarn can be used in the daily used garments. Fig(1) shows supposed structure of the Electronically functional yarn (EFY) which we will work on in this project.
A detailed study regarding the parameters of the circular warp knitting machine has not done in previous work on the manufacture of the EFY. The aim of the proposed research project is to find the best way to fabricate warp-knitted yarns that contain micro pods with semiconductor devices and interconnects of fine copper wires. This involves:
Preventing fine copper wires from protruding through the surface of the resultant electronic yarn;
Preventing failure of interconnects due to excessive twisting, strain or fatigue;
Enhancing the characteristics of the resultant yarns to improve flexibility and texture;
Study of knittability and weavability of electronic yarns.
Research Methods
RUIS small diameter circular warp knitting machine will be enhanced with electronic yarn delivery systems from BTSR to achieve the project objectives. While The input tensions of the yarns used to form the outer circular warp knitted sheath of the EFY will be measured during the knitting process, and the yarn input tension data will be analysed to study the relationships between yarn input tension, the stitch length and the stiffness of EFY. Fig (4c) shows a tension variation on the core fibre during stitches formation.
The following parameters will be studied in relation to the properties of the EFY.
The Tension of the input yarn during the knitting for the covering process.
The nature of the covering tarns.
Fig 1. Fully integrated Circuit in the Yarn
Introduction
In order to protect the chips in the EFY from the negative effects, Dias proposed that chips are encapsulated in polymer micro pods which protect the chips hermitically. At the same time it should supported by other filaments and covered by a shell structure fig(2) which protects the conductive interconnects and the encapsulated chips from the mechanical stresses and at the same time gives it the form of a yarn, that can be used in textile and garments manufacture process.
This technology will enable the resultant yarn to be processed on available textile manufacturing platforms without or with minor modifications, thus minimizing production cost of electronically functional smart textile products.
ATRG uses a small diameter warp knitting machines to cover the carrier yarn with chips to produce the final EFY Fig (4a). This process enabled the group to produce a fine yarn contain the micro pods with a diameter less than 2 mm Fig (3).
Knitting machines are in need for control of the input yarn tension continuously. this control improves the quality and the productivity of the knitting machine. where Increasing the yarn tension to a certain value will negatively affect the knitting process, resulting in yarn break during the feeding process and/or deform the stitch shape causing a change in the characteristics of the final product, while low tension cause loose stitch which deform the structure. On the other hand fluctuations in the tension will lead to variation in the stitch length. Therefore, it is important to control the yarn delivery during the covering process of the manufacture of EFY. a b c
Fig 4. (a) RIUS circular warp knitting machine, (b) Knitting Zone, (c) Tension Graph from the BTSR ultra feeder tension controller.
Bibliography
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Gligorijevié, V. et al., Yarn tension and oscillation in the process of warp knitting. Fibres and Textiles in Eastern Europe, 11(1), pp.25–27.
Langenhove, L. Van, Smart Textiles for Medical and Healthcare.
Pohlen, V. et al., Optimisation of the warp yarn tension on a warp knitting machine. Autex Research Journal, 12(2), pp.29–33.
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Zhou, N. & Ghosh, T.K., On-Line Measurement of Fabric Bending Behaviour: Part 1: Theoretical Study of Static Fabric Loops. Textile Research Journal, 67, pp.712–719.
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K.P.Weber ,An Introduction to the Stich Formation in Warp Knitting , Published by Karl Mayer, Germany
Fig 2. Encapsulated Chip surrounded by a group of filament to protect the chip (proposed by T.Dias 2010).
Fig 3. A conductive filament inside a warp knitted tube with a diameter less than 2mm.
For More information you can contact:
M-Nour Nashed
PhD Student