Modeling embroidered contacts for electronics in textiles

For over a decade, textile circuits have been realized by embroidering conductive yarns onto fabric. Even machine embroidery has been applied. The standard method for connecting these circuits with electronic components has been hand sewing. However, volume production requires the integration of the connection process into the machine embroidery process. For end-user satisfaction and market acceptance, reliability of the contacts is vital. This publication, for the first time, develops a complete theoretical model of the contact mechanism underlying embroidered contacts. Based on this model, potential failure mechanisms are identified. An experimental implementation of the model is developed. To validate the model, test samples of the model and such of the machine-embroidered contacts are exposed to temperature cycles, chosen as an exemplary reliability test. In addition, reliability test results of four encapsulation technologies are presented.