Research on the influence of die head arrangement on the precision of discontinuous deformation in multi-points stretch-bending of profiles.

This paper proposes and develops a novel flexible 3D multi-point stretch-bending and twisting (3D MPSBT) forming equipment with six degrees of freedom to manufacture profiles with different bending radii and twisting angles at a lower tooling cost. Due to the discretization of the machine, the deformation characteristics and forming accuracy of the profiles differ from those of continuous molds. The size of the forming error for rectangular profiles is investigated by employing two different arrangements and numbers of dies. The results show that the forming errors occur in the free deformation zone due to stress effects. When the number of dies is the same, arranging the dies uniformly along the formed arc length yields higher accuracy in the shape of the formed profile. For a rectangular hollow aluminum profile with half the length of 1500 mm, the forming error in the free deformation zone of the profile can be reduced to less than 0.6 mm by using 12 die units arranged along the arc length. However, when the dies are uniformly arranged along the pre-deformation length of the profile, the minimum forming error exceeds 0.6 mm when the number of dies increases to 15. The minimum number of dies required for forming different bending radii is determined. Finally, the accuracy of the numerical simulation and the feasibility of forming complex-shaped aluminum profiles using the 3D MPSBT machine is validated through experiments. [ABSTRACT FROM AUTHOR]