Weight reduction in structural design can be achieved using lightweight materials and functional integration. A new approach consists in the direct integration of piezo ceramic elements into micro structured aluminum sheets in order to act as sensors or actuators. Typical applications are structure health monitoring or active noise canceling. Thereby piezo ceramic rods are inserted into micro embossed channels. However, the necessary embossing process involves high compression stresses in the sample leading to increased friction, adhesive tool wear and failure. The goal of the research is a decrease of the forming force in the generation of micro channels. For that purpose, the tool and the samples are heated. In addition, the achievable precision and reproducibility should be similar to cold forming. Process parameters like stamp velocity, holding time and lubrication are varied and their influence on the formed channels is investigated. At a forming force of 80 kN, the deepest channels were obtained at the highest temperature applied, which amounts to 200 °C. Because of the thermal contraction of the aluminum samples during the cooling down process, structure dimensions are only significantly smaller compared to cold formed samples. The reproducibility of the forming process was demonstrated within an additional test series.
Müller, B., & Schubert, A. (2017). Micro structuring of AlMg4.5Mn0.7 sheets by a warm forming process. In Procedia Engineering (Vol. 207, pp. 1045–1050). Elsevier Ltd. https://doi.org/10.1016/j.proeng.2017.10.1128