Influence of Tool Size and Step Depth on the Formability Behavior of AA1050, AA6061-T6, and AA7075-T6 by Single-Point Incremental Forming Process

Single-Point Incremental Forming (SPIF) is suitable for a small-batch specialized process that is versatile and flexible. Metal alloys with a high strength-to-weight ratio are generally tough to form because of their partial formability at room temperature. This current study highlights a comparative investigation on the formability of commercially available aluminum alloy sheets, i.e., AA1050, AA6061-T6, and AA7075-T6. The formability is reported in terms of maximum wall angle (θ_max) fabricated to varying wall angle conical frustum (VWACF) with hyperbolic generatrix with SPIF. The statistical analysis is used to check the effect of process parameters on the formability. To identify the significant parameters and their interactions, the RSM's D-optimal design and ANOVA were utilized. The effect of tool size and step depth and their mutual interaction is studied, whereas feed rate, spindle speed, and lubricant type were kept constant. The individual impact of tool diameter and step depth has been discussed in detail. ANOVA study reveals that tool radius ‘R’ is the most important factor affecting formability of the part for AA1050 and AA7075-T6, whereas step depth ‘Z’ is the most significant factor for AA6061-T6. The microstructure, micro-hardness and geometrical accuracy study of the formed part was investigated at optimal forming condition. Furthermore, a guideline of step-depth and tool size selection to enhance the formability were also presented.