Production engineering research for the manufacture of novel electronically functional yarns for multifunctional smart textiles

This proposal is concerned with the research and development of new manufacturing methods that add electronic functionality to the heart of textiles by incorporating semiconductor devices into yarns. Textiles are one of the most common materials with which humans come into contact, but, at present, their functionality is limited to their appearance and physical properties. There is considerable and growing interest in multifunctional textiles with added electronic functionality: These will offer a far greater range of functionality that can include sensing, data processing and interaction with the user and, as a result, can be applied in a vast range of applications. Electronic textiles (E-textiles) need to not only perform well but also be robust, comfortable to wear and be readily used, worn, washed, and maintained.
Currently, electronics have been integrated with textiles by either attaching or printing the electronics onto the surface of a textile (first generation), or the electronic functionality is added at the textile manufacturing stage (second generation). The first generation E-textiles will always interfere with the textile properties of a garment; even thin film devices or circuits printed on textiles. As a textile conforms to a shape some regions bend and some go into shear deformation: Both factors are important for drape and conformability. Knitted and woven textiles are able to conform to a shape as they bend and shear however, a thin polymer film can bend but, as it cannot shear, it will buckle and crumple rather than conform to a shape. The second generation textiles may retain a textile feel but are limited in their applications, such as the creation of electrical pathways, and electrode-based sensing. Therefore, Professor Dias (the PI) pioneered the development of a platform technology for embedding semiconductor packaged dice within the core of yarns, in order to integrate electronics into the heart of textile structures. The production process starts with re-flow soldering of package dice onto fine copper wire. A carrier yarn is placed in parallel to provide improved tensile strength to the copper wire populated with packaged dice. The package dice and carrier yarn are then encapsulated within polymer micro-pods to provide protection from moisture ingress. The micro-pod and copper interconnects are finally surrounded with additional fibres held tightly together within a knitted fibre sheath to create an electronic yarn (E-yarn).
The aim of this project is to create the underlying knowledge to produce E-yarns in an automated fashion reliably, and to demonstrate an automated pilot manufacturing line (TRL4). The ability to produce E-yarns in a semi-automated fashion using two-terminal packaged dice has already been demonstrated by the investigators. The programme of research will extend this expertise to the reliable creation of E-yarns based on semiconductor devices with more than two terminals, massively extending the scope for the types of E-yarn that can be created. To achieve this ambitious goal the following research areas must be addressed: thermal energy management for soldering semiconductor dice; encapsulation of soldered dice; optimisation of the techniques of covering copper wires populated with dice to prevent their migration to the surface of the E-yarn; development of testing methods for the E-yarns.
This proposal concerns a platform manufacturing technology that can address a range of E-textiles applications. The research will ensure that the technology can deliver the required functionality, meet the requirements of practical use, and provide the platform for commercialising the E-yarn technology. Project results will increase industry capability in the UK to lead the E-textile sector, which is expected to grow to a $5 billion market by 2028; hence the proposed research is timely.
[1] www.idtechex.com/research/reports/e-textiles-2018-2028-technologies-markets-and-players-000613.asp

This proposal will radically alter the way electronic textiles are produced through the large-scale manufacture of electronic yarns (E-yarns), where semiconductors are integrated into the yarn. These E-yarns can then be incorporated into existing industrial processes to manufacture textiles, composite structures or cables; placing electronic functionality within the fibres of the final product. The advantage of this approach is that E-yarns are both inherently light-weight and flexible. The E-yarns can also incorporate and position functionality in a way that reduces the impact on aesthetics or mechanical characteristics of the product. Any product that contains yarns or fibres has the potential to have electronic functionality built in.
This project originates from a public-private partnership of yarn/textile supply chain partners, and yarn technology and production engineering researchers. The consortium is focused on the translation of an experimental E-yarn production process developed by the investigators into a pilot production setting, so novel multifunctional textile products can be developed and demonstrated. The research will be transformative, providing an enabling technology that can be applied in healthcare, defence, performance sports, automotive, aerospace, fashion, wearable technology and PPE applications; e.g. the project will seek to demonstrate with Polyco Healthline the impact of a vibration sensing and monitoring glove. H&S specialists understand that the effect of vibration is not uniform across workers, with operator physiology being a major consideration. The impact will be to progress the R&D of a bespoke vibration-reducing glove that can be personalised to both the wearer and the equipment they operate. The glove will incorporate E-yarn with MEMS accelerometers and the optimum placement of the sensors will be established as part of this project.
The research proposal includes seven project partners, three involved in the manufacturing supply chain and four end users. The end user beneficiaries (Camira Fabrics, Polyco Healthline, Dstl and QinetiQ) will benefit from the research by having the technology to develop new products and capabilities. TechniTex Faraday will benefit by partnering with end user companies to take the technology to market. Plessey Semiconductors will benefit from a new range of applications, for example incorporating EPIC sensing dies into yarns and remote heart-rate monitoring into textiles. Stretchline International will benefit by manufacturing E-yarns and developing a wide range of intimate products with sensing and monitoring capability. In addition to these project partners, new collaborators will be sought through actions identified in the Impact Pathways.
Wider economic benefits include the growth in business and competitive advantages from new opportunities enabled by the technology. The technology will provide opportunities for enhanced functionality in existing products as well as radically new products. Creative industries will benefit from the capability of the technology to develop garments that interacts with, responds to, and creates stunning visual effects for the wearer. For example, effects demonstrated by bespoke illuminated stage costumes used in the music industry will become available on the high street. Medical applications of the technology will benefit patient care through improved patient monitoring, enabling rapid warning of problems (e.g. through wound monitoring). These wider benefits are likely to occur within two years of the end of the project. It is a key objective of the project to bring end users together with members of the supply chain to facilitate further development and create demand pull as well as technology push.
The project is interdisciplinary and research staff working on the project will benefit from the opportunity to develop expertise in new sectors, working with industrial partners in the development of demonstrators.