Experimental Characterization of Coated Aluminum Sheets for Deep Drawing Applications

Sheet metal forming is widely used in many industries, especially in manufacturing automotive body parts and white goods. For many years, coated kitchen utensils are being used because of their properties such as non-stick property. The most used coating is polytetrafluoroethylene (PTFE), known as Teflon. Kitchen utensils are mainly manufactured by deep drawing processes, which require a good knowledge of the behaviour and the formability of the material. To characterize the formability of the sheets, it is necessary to determine the forming limit diagram (FLD). The FLD can be obtained throughout different essays such as Marciniack test and Nakazima test. With the FLD it is possible to compare the formability of different materials. Also, knowing the FLD can reduce the process’ development time. In this work, aluminium sheets coated with Teflon are studied experimentally. Firstly, dilatometer and tensile tests were carried out to investigate the thermal and the mechanical properties of the coated sheets. Furthermore, Nakazima test was conducted to obtain the forming limit diagram (FLD) of the studied material. Also, a numerical approach based on the Finite Element Method (FEM) is being developed to determine the limit of the considered deep drawing process.