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Multi Stage approach is used in Single Point Incremental Forming (SPIF) to overcome one of the main forming limitations, namely the maximum wall angle, characterizing the single stage process. In this paper, different multi-path strategies for the production of parts with flat edges are considered in order to evaluate the best solution in terms of feasibility and geometrical accuracy of the final part: A) mono-directional incremental draw angle; B) mono-directional incremental draw angle with increasing part side; C) Multi-directional approach with non-horizontal path planes. Strain evaluation by means of CGA (Circular Grid Analysis) and defect analysis have been carried out in order to identify the main limitations of each approach. A defect-free part has been obtained with Strategy C. The developed numerical analysis, showing good agreement with experimental thickness distribution, highlighted the peculiar material redistribution from the thicker zones to the thinner ones occurring using Strategy C.

Solid state recycling (SSR) is a new approach for making metals recycling more efficient with respect to remelting-based approaches. Friction stir consolidation (FSC) is a new solid-state process that is employed to recycle metallic scraps. Until now, a single-step FSC process was applied to recycled metal chips. During the single-step approach, critical processes parameters, especially processing time and rotational speed, are considered vital to control the quality and mechanical properties of the billet. However, the effectiveness of process parameters is highly restricted by challenging masses of recycling chips and machine competency. The present study first highlights the issues of the single-step FSC process, such as unconsolidated billet and poor mechanical properties at the bottom of the part, i.e., far away from the stirring action. Then, for the first time, three different two-step FSC methods were introduced as new approaches to overcome the existing challenges of the single-step method. The effectiveness of these methods was evaluated through the Vickers hardness measurements, and microstructure analysis. The results showed that two-step FSC methods successfully led to a fully consolidated billet and considerably improved mechanical properties.

This paper describes the forming characteristics and mechanics of magnetic field–assisted single point incremental forming (M-SPIF) in which an Nd-Fe-B magnet ball tool is placed on top of a piece of sheet metal and is driven by an Nd-Fe-B magnet placed below the workpiece. To gain an understanding of the force mechanics that power M-SPIF, the tool motion and forming force were experimentally analyzed. In M-SPIF, the forming force is applied multi-directionally, and the resultant force direction is nearly colinear with the polarity of the permanent magnet ball tool. This suggests that the forming characteristics in M-SPIF may be controllable by controlling the magnetic polarity of the tool.

This paper describes magnetic field-assisted single-point incremental forming (M-SPIF) with a Nd-Fe-B magnet ball tool. In M-SPIF, the tool driven by magnetic force plastically deforms a sheet. The polarity of the magnet tool helps to make the magnetic force (i.e., forming force) more controllable. In creating a truncated cone, the direction of the magnetic force gradually points more outward as the process progresses, and material is forced outwards from the cone center, increasing thinning in M-SPIF, while the cone center remains undeformed in traditional SPIF. Moreover, M-SPIF creates less localized plastic strain than traditional SPIF while forming the desired geometry.