Conference paper

Assembly of microvalves actuated by PZT bender

At small sizes, piezoelectric bending actuators are more practical and have more favorable downscaling properties than traditional electromagnets in the field of microfluidics. However, their application is limited by the difficulty of ensuring proper clamping during assembly. Emerging PZT thick-film technologies are promising as they solve the clamping problem, but their performance is still unsatisfactory for most applications. Therefore, the use of bulk PZT benders assembled onto LTCC or alumina by gluing/soldering often still represents the most practical solution. The present work will address the issues involved when assembling a commercial PZT bender onto an alumina substrate, simulating an electrovalve. This study will focus on the loss of bending capability (amplitude and force) resulting from the mechanical strength and stiffness of the joint suffering from thermal cyclic fatigue effects, and the degree of the PZT depoling as a function of the assembly method and conditions. We will show that glues performed better than solders, at the expense of the processing time.

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