42nd International Deep Drawing Research Group Conference - IDDRG 2023

Robot-assisted flexible flanging (RAFF), a cost-effective and promising forming technology for producing large-size open-edge flanging parts in multi-variety and small batches, is expected to be widely used in aerospace, automotive and other technological industries. Depending on whether the flanging angle of the forming roller is adjusted, the RAFF process of every pass can be summarized as two stages: The first stage in which an industrial robot drives the forming roller to rotate to the target flanging angle is defined as the pre-flanging stage, and then in the next stage called flanging stage, the forming roller moves to complete the flanging process of the whole blank sheet along the predetermined toolpath while the flanging angle of the forming roller remains constant. The toolpath of a certain pass is determined by the rotation velocity (to adjust the flanging angle), the revolution velocity (to complete the flanging process of the whole blank sheet) and the matching relationship between two velocities in the pre-flanging stage (synchronously or asynchronously). In this paper, the process principle of RAFF technology is illustrated by the example of shrink flanging firstly, then four different toolpaths are proposed to investigate the effect of the toolpath on the quality of the target 5A06 aluminum alloy flanging part with the forming angle of 60°. The revolution velocity of the forming roller is set to 1°/s by default as invariant in all conditions and the rotation velocity is set as 1°/s, 1.33°/s, 2°/s and 4°/s, respectively. Moreover, the matching relationship between the rotation velocity and the revolution velocity in the pre-flanging stage is also considered. Compared with the asynchronous motion of rotation and revolution of the forming roller, the maximum height of edge waves is decreased from 2.1 mm to 0.19 mm when the forming roller is set to rotate and revolve synchronously. Meanwhile, the maximum stress gradually increases from 575.4 MPa to 621.6 MPa when the rotation velocity decreases from 4°/s to 1°/s.