Formability Evaluation of Aluminum Alloy Sheets in Incremental Sheet Forming Process using Various Forming Parameters

Single point incremental forming (SPIF) is a sheet metal forming technique in which a sheet experiences a small local deformation at each predefined step using the forming tool. The process is a die-less method, whereas the symmetric and asymmetric products can be manufactured just by the punch tool alone. Due to this advantage, this process is extensively adopted in automobile, aeronautical, and medical industries for manufacturing complex parts. In this paper, the main objective is to investigate the formability of AA5052 aluminum alloy material with various wall angles and working parameters using the modified computer numerical control (CNC) vertical milling machine. Here, the shape accuracy and the surface roughness are focused in terms of computing the forming depth, wall angle, and spring-back for obtaining better parts with a proper material surface finish. For confirming the real-time experiments and evaluating the presence of stress, strain, and thickness variations, the SPIF process was modeled in the LS-DYNA tool by incorporating the true stress-strain curves into the material card for describing the material plastic behavior during the forming process. Consequently, the finite element (FE) model results were tested against the experimental data to confirm the usefulness of the proposed FE model. Thereafter, the thinning behavior, including its location, area, and size, strain distribution, and geometric changes, are discussed in detail. From the numerical results, it was observed that the thinning happened in tested samples was found to be uniform in the wall region and small oscillation identified close to the forming tool retraction region. Besides, the thinning phenomenon was estimated higher for the wall angle of 60o than that of the wall angle of 45o ; also, the machining time was comparatively larger for the same forming condition.