Fabrication of smart parts using powder bed fusion additive manufacturing technology

Energy system components with embedded sensors, or smart parts, can be a pathway in obtaining real-time system performance feedback and in situ monitoring during operation. Traditional surface contact or cavity placed sensors increase the possibility of disturbing the normal operation of energy systems due to changes in part design required for sensor placement. The fabrication of smart parts using additive manufacturing (AM) technology can allow the flexibility of embedding a sensor within a structure without compromising the structure and/or functionality. The embedding of a sensor within a desired location allows an end user the ability to monitor specific critical regions that are of interest such as high temperature and pressure (e.g., combustor inlet conditions that can reach up to 810 K and 2760 kPa). In addition, the non-intrusive placement of the sensor within a part's body can increase the sensor's life span by isolating the sensor from the aforementioned harsh operating environments. This paper focuses on the fabrication of smart parts using electron beam melting (EBM) AM technology as well as the characterization of the sensor's functionality. The development of a “stop and go” process was explored that comprised of pausing a part's fabrication process to allow the placement of piezoelectric ceramic material into pre-designed cavities within a part's body, and resuming the process to complete the final product. A compression test was performed on the smart parts fabricated using EBM to demonstrate the sensor's capability of sensing external forces. A maximum sensing voltage response of approximately 3 V was detected with a maximum pressure not exceeding 40 MPa. The sensor responses showed good agreement with the applied force in four different frequency conditions (i.e., 10 Hz, 15 Hz, 20 Hz, and 25 Hz). This research work demonstrates the feasibility of fabricating smart parts with embedded sensors without the need of post-processing (e.g., CNC machining and polishing). In addition, the sensing capability of monitoring a component's performance has been validated, leading to the possibility of fabricating other smart parts that could impact industries such as energy, aerospace, automotive, and biomedical industries for applications like air/fuel pre-mixing, pressure tubes, and turbine blades.