Sensors and Process-Performance Interactions for Additive In-Mold Electronics
The study explored printed electronics' suitability for in-mold electronic circuits. The study explored the effects of print parameter variations of direct ink write systems on the final thermoformed traces on PETG, PC, and HIPS samples.
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Authored By:
Pradeep Lall, Ved Soni, Fatahi Musa, Md Golam Sarwar
Auburn University
Electronics Packaging Research Institute
AL, USA
Scott Miller
NextFlex National Manufacturing Institute
CA, USA
Summary
The development of additively manufactured electronics processes has made it possible to integrate safety features into automotive touch surfaces for assessing driver alertness and stress levels. While current touch surfaces in vehicles are primarily for aesthetic purposes, the potential advancement through the integration of the human-machine interfaces using additively printed in-mold electronics presents interesting possibilities. However, the processes for printing sensors and integrating surface mount electronics for signal processing in additively printed conformal electronics are still not well understood.
In-mold electronics offer opportunities for eliminating wire harnesses and reducing the vehicle's weight to meet stricter CO2 emission standards and minimize the carbon footprint. This study investigates direct ink write and gravure offset print processes for thermo-formed in-mold electronics on various substrates. It also explores surface mount component attachment using conductive adhesive and the creation of signal processing and electrodermal sensors for measuring galvanic skin response, which is useful for assessing driver emotions and health.
The objective of this study is to establish fabrication guidelines for in-mold electronic circuits, including ink print parameters, curing times for ink and adhesive, and thermoforming parameters to achieve optimal electrical performance and mold conformity.
Conclusions
The study explored printed electronics' suitability for in-mold electronic circuits. The study explored the effects of print parameter variations of direct ink write systems on the final thermoformed traces on PETG, PC, and HIPS samples. Gravure offset printing made conductive traces on PC and PETG substrates. PC had a narrow thermoforming range, needing precise temperature and time for acceptable results. PETG, more formable due to material and thickness, showed lower post-thermoforming resistance than PC, affected by under-sintering owing to PETG's low heat deflection temperature. A component attachment study using ECA on PETG shaped the ink and ECA curing profile for thermoformed full wave rectifier demonstrator circuits. DIW based thermoformed biosensor with PETG substrate was able to measure precisely EDA signal.
Initially Published in the SMTA Proceedings
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