Prefabrication and Automated Micro Assembly of Piezoceramic Fiber Array Transducers in Microstructured Surfaces of Sheet Metals

Abstract : In order to realize resource-efficient products and manufacturing processes, lightweight construction solutions have become enormously significant in many areas. Generally, material savings are always done at the expense of rigidity. However, additional weight can be saved through functional integration. One possibility is given by the functional material piezoceramic. This material can be used as sensor or actuator. A new approach for the structural integration of piezoceramic in sheet metals is with the technique joining by forming. Therefore, PZT fibers are assembled in a local microstructure of a sheet metal, which is followed by the joining operation. The article is a contribution to transfer this approach into a high-volume production process, which is necessary for the industrial area to take root. Manufacturing processes for PZT fiber arrays with minimal manufacturing tolerances are presented. The process of stacking PZT plates with distance elements and subsequent dicing into slices is shown as a suitable variant. Furthermore, an automated assembly system is tested with regard to the measuring technology. A machine vision and a chromatic confocal sensor are compared in the assembly system. The results show that the machine vision system is better suited for pose measurement of the PZT fiber arrays and the chromatic confocal sensor achieves better results for the microstructured sheet metals.