Sensor-based filament fabrication with embedded RFID microchips for 3D printing

Composite filament materials with embedded sensors are increasing in demand to create 3D printed hierarchical sensor structures in a cost-effective and scalable way for the development of wearable and geometry-conforming sensing devices. Traditional methods of encapsulating sensors with polymers are implemented through techniques such as adhesive bonding and potting. For microelectronic device encapsulation, the plastic moulding technologies are employed. However, final products from these methods have geometry constraints and are not easily customizable. This paper presents a methodology of fabrication of polymer filaments embedded with 550-µm radio-frequency identification (RFID) chip using extrusion process for 3D Printing applications. The fabricated filament (3 mm diameter) is manufactured with a 1.5 mm extrusion nozzle specifically designed for this process and controlled by an RFID reader. The RFID sensor filaments produced by this extrusion encapsulation technique were successfully used to produce objects on an existing Fused Deposition Modelling (FDM) 3D printing machine. Such filaments and printed devices are wireless, battery-less, flexible, customizable, and repairable, and hence are advantageous in new sensor applications including the internet of things (IoT). The 3D printed objects produced via this process will have the ability to sense the environment and communicate with reader devices due to their unique embedded RFID codes. This development will subsequently open new avenues for meeting the growth in IoT demands forecast as a pillar of industry 4.0.