EVALUATION OF THERMOFORMABILITY OF ADDITIVELY PRINTED CIRCUITS PRINTED USING GRAVURE OFFSET PRINTING TECHNIQUE AND INVESTIGATION OF IN-MOLD ELECTRONIC CIRCUITS

Throughout the past decade, the field of printed electronics has gained increased research impetus and has started to make entryways into the consumer electronics product market. The applications of additive printed electronics are numerous and range from healthcare devices and smart packaging to energy harvesting systems and intelligent textiles. Another novel application area for printed electronics is in-mold electronics (IME) which is a process that involves the integration of printed electronic circuits into injection-molded parts. In this process, electronic circuits are printed onto a thin, flexible substrate, such as polyethylene terephthalate glycol (PETG) or polycarbonate (PC), which is then thermoformed using a mold. The thermoformed sample is then overmolded with another thermoplastic which results is a single, integrated part that combines the functionality of the electronic circuit with the mechanical properties of the plastic part. Using IMEs offers several benefits such as weight and bulk minimization along with maintaining ergonomic design, which are important concerns in automotive design. In this study, additively printed lines have been printed using gravure offset printing technique on different substrates such as PETG and PC have been subjected to vacuum thermoforming wherein the substrates are heated to their heat deflection temperature and vacuum formed on an aluminum mold. The change in resistance of the lines pre- and postthermoforming, as well as the effect of degree of material stretching of the substrate with different thermoforming parameters such as thermoforming temperature and thermoforming time has been studied. Finally, a component attachment study has been conducted for thermoformed circuits with a functional thermoformed full wave rectifier circuit demonstrator