Technology development and control concept for vibration assisted forming of micro-channels in aluminium sheets
Presentation held at Wissenschaftliches Symposium "Leichtbau durch Funktionsintegration", 27./28.03.2018, Chemnitz
Technologieentwicklung und Steuerungskonzept für das vibrationsunterstützte Umformen von Mikrokanälen in Aluminiumblechen
The subproject A02 develops automated manufacturing technologies for the direct integration of lead-zirconate-titanate (PZT) fiber arrays into micro structured aluminum sheets. The permanent clamping between the micro structured metallic carrier material and the piezoceramic is produced in a joining by forming process without additional adhesives. The aim is to quantify process capability and to derive measures for increasing the end product quality and throughput of the production process. In the first, step micro-channels are formed into an aluminum sheet using a micro extrusion process with vibration assistance. The next step involves the micro assembly of prefabricated PZT fiber array transducers into the micro-channels. In the third step the PZT fibers are joined with the aluminum sheet through joining by forming. This work focuses on the improvement of the forming of the micro-channels. An approach for the reduction of the necessary forming force to obtain lower loads on the tool consists in a vibration-assisted micro forming process. As vibration source, a piezo power module is placed directly in the force axis of the forming press and coupled with the control system of the press. The test geometry, micro channels with a depth of 300 mm and a width of 300 mm are formed into 1.5 mm thick AlMg4.5Mn0.7 aluminum alloy sheets. The focus of the research is the investigation of the influence of process parameters like frequency and applied oscillation amplitude onto the material flow and the achieved channel depths. To investigate a possible influencing of the friction conditions due to the vibration assistance, different lubrication conditions are applied. The vibration assistance in combination with the low viscosity forming lubricant shows a significant improvement regarding deeper channels compared to reference samples. A slight trend that higher amplitude can lead to deeper channels was found. In summary, it can be stated that with the vibration assistance a larger deformation or material flow could be achieved. Measured by the geometric parameter channel depth, the improvement is slightly more than 12 %.