Requirements for a process chain for manufacturing of piezoceramic-aluminum sandwiches

Lightweight solutions and functional integration become more and more important in different fields of industry. In order to achieve a sensor and actuator functionality of shaped sheet metal parts, today a generally manual application step of the piezomodule is necessary. This subsequent process is time consuming and leads to high costs. In earlier studies a method was presented allowing the fabrication of a formable compound with an integrated sensor and actuator functionality [1, 2]. The formability of the compound is achieved using a viscous adhesive, surrounding the piezomodule during the forming operation. The low viscosity of the adhesive allows a relative movement between the piezomodule and the sheet metals and drastically reduces the transfer of critical strains to the piezomodule. Curing of adhesive takes place after the forming operation. To improve the efficiency of the process chain an advanced adhesive system with robust application properties has to be used. Furthermore, the productivity of several fabrication steps and their sequence in the process chain have to be verified and improved. The paper presents the process chain designed for automated production of formable sandwich sheets with integrated piezomodules, including the production steps for the fabrication of the semi-finished part as well as the forming operation. Aiming on a good formability during the shaping operation and on a stiff connection between the piezomodule and the sheet metal in the finished sandwich part, one focus is set on the adhesive properties required during the different process steps.