This work describes a method of applying residual stress within micro fin model to understand the deformation of the fin machined by wire electrical discharge machining (WEDM). Firstly, transient temperature distribution on a workpiece caused by WEDM discharges was calculated using finite element method (FEM). Then, the result was used to calculate the residual stress. It was found that the residual stress in the radial direction, σr (z) along the centre axis of each discharge crater was distributed non-linearly in thickness direction from the crater top surface. Then, based on structural analysis, the σr (z) was imposed within the micro fin model. Here, thermal stress field caused by series of sequential discharges was considered. The summation of calculated deflections after three sequential discharges was approximately equal to the measurement result. As a result, the non-linear distribution of σr (z) was found to be the main reason that causes the non-uniform bending of the micro fin.
