Analysis of the thickness distribution varying tool trajectory in single-point incremental forming

Single-point incremental forming (SPIF) presents a great competitive advantage with respect to the conventional stamping processes, in particular when small batches have to be produced. The competitiveness of such a process cannot be evaluated only by comparison with other traditional manufacturing processes. It is clear that the process allows metal forming in the critical 'necking-to-tearing' zone and this results in a strong thinning before failure if the process is well designed. What is more, the process is complex because of the number of variables involved. Thus, it is not possible to consider that the process has been well assessed; several aspects remain that must be clarified. In this paper a wide-ranging investigation of tool trajectory selection versus material formability is presented. In particular, although the same shape has to be manufactured, it is possible to select a particular trajectory among the many possible ones; this choice will affect the final thickness distribution and formability, accordingly. In conclusion, it is possible to state that tool trajectory can be regarded as an optimization variable in the process design.