Abstract In the current study, robot assisted incremental sheet forming (RAISF) was performed on sheets of aluminum alloy 6061, which was supported from underneath by fluid; this process is named robot assisted incremental sheet hydro- forming (RAISHF). A variable wall angle conical frustum was fabricated both with and without the fluid support. The cone formed by RAISHF was 6.67% steeper and 28.47% deeper than with RAISF alone. Spring back was also reduced by 77.14%, suggesting better accuracy of the formed part. The role of fluid in enhancing the performance of RAISHF was explained by considering a through thickness element and considering the equilibrium equations. For cones of identical wall angle formed with RAISF and RAISHF, the thickness distribution, tensile properties, microhardness, major and minor strains in the plane of the sheet, microstructures, and residual stresses are characterized, with RAISHF showing greater and more even thickness distribution, more even strain distribution, and less hardening. X-Ray diffraction analysis revealed the residual stress in both processes to be tensile, with RAISHF showing lower residual stress. Microstructures of the samples taken from formed cones revealed that, due to dynamic recrystallization, more strain can be obtained by RAISHF.
Singh et al. (Mon,) studied this question.