A rotary flange forming process on the lathe using a ball-shaped tool

Flanging of tube ends is carried out using casting or assembly joining, which have drawbacks due to improper strength, defect generation or low efficiency. In this work, flange forming of Al tubes was performed on the lathe utilizing a ball-shaped tool attached to the lathe carriage, and fed outwards radially while the specimen clamped to the lathe chuck and rotated. Tubular specimens, were rotated at 500 rpm, and the tool feed was 0.314 mm/rev. Ball diameter (Dball) of 12.8 mm was fixed, while the tool advance distance (Ta) at the start of flanging was 0.125, 0.25, 0.5, 0.625Dball. Oil was used as a lubricant. Results showed that the radial flanging force was increased as t0 and Ta increased. An approximate contact area calculation was presented and the calculated loads were in agreement with the experimentally obtained ones. Relatively large flanging ratios (FR) were obtained and those were found to increase as t0 decreases and Ta increases. Maximum thinning was observed at the flange edge followed by an increase in thickness towards the area between the tube and flange. Surface hardness increased as t0 increased.