Piezoceramic Mounting Process and Adapted Pretension for Improved Microvalve Functionality and Reliability

Active microvalves enable opening and closing of a microfluidic path at any desired time, therefore, piezoelectric actuation is very well suited to ensure fast response times, energy efficient operation, and high forces for valve closing. In order to develop piezoelectric microvalves exhibiting high fluidic performance as well as long-term reliability, it is important to understand the influences of its key design features on microvalve leakage rates and piezoceramic stability and to use the gained insight for device optimization. Following our recent studies on our novel piezoelectric titanium microvalves with integrated O-ring soft sealing, we present an elaborated piezoceramic mounting process with an adaptation of the electro-mechanical pretension for optimized microvalve leakage performance. We verify the adaptability of the presented process by fabrication and comparative tests of three groups of microvalves with a variation of valve seat height and sealing material. Our optimized titanium microvalves show both material and sealing performance stability in a 1*10^6 actuation cycles fatigue test.