Bending process is the one important process in the sheet metal forming in many industries, there are many parameters having a large effect on it. Spring- back is considered one of the most important indications to specify the quality of product parts. The objective of the present study is to find the optimum bending parameters to get lowest spring back on aluminum- silicon (Al- Si) alloy by applying the Taguchi method. The basic parameters which were taken into consideration in this work are: punch speed, hold time and the orientation of material in order. Experiments have been conducted by using L9 orthogonal array with three levels for each parameter. The bending process were done on Instron device ,the optimum combination of process parameters has been found through analysis of main effect of spring back value (αs) and Signal-to-Noise S/N ratio, and the significant parameter was identified depending on ANOVA analyses. In the present work to determine the level of importance of spring back parameters, the results show that the significant factor is the orientation of metal followed punch speed and hold time, and the obtained results from the experiments are acceptable for the ranges of forming conditions that have been selected in this case study.