Suitable tool path conditions for incremental tube burring with a bar tool are determined to obtain a uniform wall thickness distribution at the edge of a branched tube by an explicit finite element simulation. In the determination, an aluminum alloy tube, A5083-O, of 400 mm diameter and 6.0 mm wall thickness and a bar tool of 65 mm diameter are modeled. In this study, the second stage of incremental tube burring process is focused on, which is the crucial burring stage predominating the feasibility of burring process and product quality. As to the rocking condition of a bar tool at this stage, it is found that decreasing rocking angle by 5 degrees per cycle is suitable for preventing fracture and achieving high product accuracy. In addition, the simulation results show that an initial rocking angle of 45 degrees is effective in decreasing burring torque and wall thickness reduction ratio at the edge part of branched tube. This reveals that simulation is valid as a design tool for the process optimization of this multistage incremental forming.
