Optimization of two-point incremental forming process of AA1050 through response surface methodology

Abstract

Two point incremental forming (TPIF) process is used in the industry to enhance the dimensional accuracy of formed parts. However, the process limits the formability of metal sheets due to tension between two points i.e. tool and mandrel. Hence, selection of optimum TPIF process to enhance formability is a key issue in manufacturing of complex parts. In the present work, an experimental study based on response surface methodology was made to analyze formability of aluminum 1050 in two-point incremental forming process. Here, Box-Bhenken experimental design was utilized taking into account mandrel angle, tool nose diameter, sheet initial thickness and step down as input parameters as well as thinning ratio and maximum resultant force as output responses. Analysis of variances was also performed to find contribution of factors on the responses. From the results, it was found that the wall angle is the most influential factor for thinning ratio; while, initial thickness followed by step down have great impact on forming force. By performing multi-objective optimization, it is found that for simultaneous minimization of thinning ratio and forming force, setting of 45° wall angle, 15 mm tool nose diameter, 1 mm initial thickness and 0.5 mm step down should be selected. The obtained optimal solution was further verified by confirmatory experiment and results showed accuracy and predictability of proposed approach.