Formability of AA7075 Sheet in Single Point Incremental Forming

Abstract

This article presents formability analysis of aluminium alloy 7075 thin sheets in single point incremental forming (SPIF) through prediction of forming limit curve (FLC) and maximum formable wall angle. Deformation instability method based on tool-sheet contact and non-contact zones in incremental forming was used for the prediction of limit strains for plane strain and equi-biaxial stretching strain path. FLC of the material was also determined experimentally, after measuring limit strains for deformed sheet through groove test for the process. Further, maximum forming wall angle of the material was determined for deformed sheet in a square pyramid shape. The theoretical limit strains predicted by deformation instability approach were compared to the experimental values. Theoretically, calculated limit strains were observed to be higher for plane strain path but approximately close for equi-biaxial strain path compared to experimental limit strains. The maximum formable wall was found to be 55˚ for the material in the process.

Investigations on formability of tailor laminated sheets in single point incremental forming

“…Parametric study and multi-objective optimization of formability of aluminum alloy sheet in SPIF were investigated by Maji and Kumar. 13 Theoretically predicted forming limit curves for different aluminum alloy sheets (AA6061, AA5083, AA7075) using deformation instability method [14][15][16] were observed to be higher compared to the experimental values predicted by incremental sheet forming tests as reported by Do et al 17 Maji et al 18 also studied the effect of friction stir welding on formability in SPIF process for AA5083 sheet and lower formability of the welded sheet was observed compared to the base sheet material. Asghar et al 19 developed a mathematical model based on mechanics to improve the dimensional accuracy in SPIF process for sheet metal deformed parts.…”

“…The detail methods for calculation of forming and supporting forces in SPIF of monolithic sheets have been reported by authors. 15,16 The friction and shear effect along the circumferential direction, elastic deformation in the NZ due to tool movement, and material anisotropy are neglected in this method.…”

"A Review for the Formability of Single-Point Incremental Forming (SPIF) Process "

“…Yoganjaneyulu et al [25] presented that the forming limit of the topmost sheet was maximum in the case of multi-sheet incremental forming of a titanium sheet, and it decreased towards the bottom sheets. Kumar and Maji [26] presented the estimations of the forming limit of aluminium alloy sheets during SPIF via the deformation instability method (Figure 3). Fig.…”

Emerging Trends in Single Point Incremental Sheet Forming of Lightweight Metals

“…Yoganjaneyulu et al [145] showed that the forming limit of the uppermost sheet was highest in the case of multi-sheet incremental forming of a titanium sheet, and it decreased towards the bottom sheets. Kumar and Maji [146] showed predictions of the forming limit of aluminium alloy sheets in SPIF by the deformation instability approach (Figure 11a-c). Su et al [78] determined suitable process parameters to maximise the forming limit in SPIF of aluminium alloy sheets using numerical simulations and experiments.…”

“…These materials are prone to adhesive wear and galling. Currently, assurance of the correct friction conditions is mainly done through novel lubrication, the optimisation of the forming strategy, and modification of the tool surface (Table 2) [146][147][148][149][150][151].…”