Multi-criteria quality assessment of parts produced by single point incremental forming process: application of the ELECTRE method

The Single Point Incremental Forming (SPIF) process is being considered an ideal candidate in several industrial sectors thanks to its flexibility, versatility and capability to target the paradigm of the product customization. Moreover, shorter development cycle and lower cost, considering that the die is not essential, make the process attractive even from the environmental point of view. Nonetheless, the product customization is still an open question; therefore, several indicators, sometimes even conflicting, are generally defined to quantitatively evaluate the quality of the final part. Moreover, the SPIF process is influenced by a large set of parameters, which combined with the multiple indicators, excludes the possibility of identifying unique optimal conditions and opens the way to a less straightforward multi-objective optimization. In such complex scenario, the Elimination and Choice Expressing Reality (ELECTRE) technique has been selected to identify different combinations of the process parameters to simultaneously satisfy the main output indicators of the process (i.e., the maximization of final depth, and minimization of the maximum load and the surface roughness of the formed part). Thanks to the ELECTRE capability of building outranking-based relations and by giving different combinations of weights to the output indicators, a multi-criteria evaluation and prioritization approach was effectively applied to the SPIF process allowing the identifications of different optimal manufacturing conditions.