Evaluation of novel piezoelectric actuators for metal-based micro diaphragm pumps

The development of micro metal diaphragm pumps (MMDP) represents a significant area of research in medical technology, particularly with regard to implantable drug delivery systems. Conventional piezoelectric actuators used to date, such as those based on lead zirconate titanate (PZT), contain lead and are therefore potentially harmful to both humans and the environment.
To promote a more sustainable alternative, lead-free piezoelectric actuators based on potas sium sodium niobate (KNN) are to be integrated into the further development in this Thesis. To investigate the functionality of these lead-free actuators, electromechanical tests, including static and dynamic measurements as well as performance evaluation in both air and water media, are being conducted. A central part of this work also involves analyzing the actuators load capacity and their impact on the pump’s performance. For this purpose, robustness tests followed by functional tests are carried out. The results demonstrate the feasibility of employing KNN-based actuators in MMDPs, offering promising alternative to conventional PZT ceramics.
Another challenge in the further development of piezoelectric MMDPs is their optimization for medical applications, such as precise control and monitoring of the flow rate. However, the fluidic system may be subject to various failure modes, such as blockages or air bubbles, which cannot be detected without external sensing. To address this issue, a piezoelectric actuator with an integrated sensing layer is being investigated. The aim is to evaluate the potential of this actuator design to detect fluidic disturbances in the pumping system. The experimental results confirm that piezoelectric actuators with integrated sensing capabilities can successfully detect such disruptions. The findings of this work contribute to a deeper understanding of the functionality and potential of various piezoelectric actuators and aim to identify new approaches for optimizing and expanding the functionalities of MMDPs.