Improving formability of sheet metals in incremental forming by equal diameter spiral tool path

Abstract

In order to improve formability of sheet metal in incremental forming, a new tool path strategy is proposed. When using the tool path strategy, the tool feeds at each layer while making an equal diameter spiral movement around the forward direction. A detailed procedure for generating the tool path is described. The procedure includes the use of commercial CAD/CAM software to generate a common tool path, outputting the common tool path in the form of tool path points, interpolating the output tool path points, and transforming the interpolated tool path points in space. A series of experiments for forming varying wall angle conical frustums were carried out by the spiral tool paths with different spiral directions, spiral diameters, and spiral leads, respectively. The experimental results show that the method of generating equal diameter spiral tool path proposed in this paper is feasible. Within the experimental range, the spiral tool path in both directions can improve the sheet formability, compared with the common tool path in incremental sheet forming. And, the formability with the anti-right-hand spiral direction is better than that with the right-hand spiral direction when the tool moves counter clockwise; the formability increases with the decrease of the spiral lead and the increase of the spiral diameter. In addition, the influence of spiral parameters on the surface quality of the sheet metal was also experimentally studied. The results show that the surface quality of parts decreases with the increase of spiral lead, while the effect of spiral diameter is not significant.