Analysis and control of edge effects in laser bending

Laser forming is a spring back free and non-contact forming technique. The process requires no hard tooling or external forces. Bending is achieved by plastic deformation induced by thermal stresses resulting from rapid nonlinear thermal cycles. Laser bending has the potential to deal with materials which are either extremely difficult or impossible to bend mechanically. Numerical and experimental investigations are presented to advance the understanding of the edge effects in the straight line laser bending process under TGM. More insights into the causes of the edge effects are obtained from the numerical results of temperature, bending angle and plastic strain. A total of six varying velocity scanning schemes of numerical and experimental investigation are carried out. It is evident that scanning schemes significantly influence the bending angle distribution along the scan line. In an attempt to reduce the edge effects, the influence of varying velocity scanning schemes has been investigated. The results show that the combination of acceleration and deceleration scanning schemes can minimize the edge effects. By comparing these varying velocity scanning schemes, the staircase varying velocity scanning scheme reduces the edge effects greatly.