Hybrid machining - forming technology is a combination of two emerging manufacturing technologies: thin structural machining and incremental forming. Complex geometry products like blades can be manufactured by means of this technology without the need for 5-axis CNC machines. Parts that are fabricated by this technology require less raw material compared to the ones created by means of CNC machining. The main purpose of this research was to study the effects of machining residual stresses on springback and reduce it through the machining parameters in the deformation machining bending mode. To do this, a simple geometry was used, where a wall was machined from a block and then was bent 45 degrees. The material was aluminum alloy AA7075- T651 which is a widely used in aerospace industry due to its high strength to weight ratio. In this study, the effect of different machining parameters on springback was first studied. It was found that the parameters of cutting speed, axial depth of cut, mode of milling and milling path had a slight effect on springback. However, machining feed had a considerable effect on the fracture failure of the part during the forming stage. As the feed increased, the material forming limit increased, and therefore the forming tool was allowed to get closer to the workpiece root without breaking the workpiece . As a result, the springback considerably decreased. The tool safe distance from the workpiece root was experimentally obtained for three different feeds. The results showed that, by increasing the feed from 0.01 mm/tooth to 0.3 mm/tooth, the springback decreased by about 13%. Finite element simulation was also used to understand the cause of these events. From the simulations, it was found that the residual stress of machining did not directly affect the springback after forming. This is due to the fact that the distribution of residual stress in the longitudinal direction in the straight wall is symmetric. A series of tests were also designed to validate this comment. Therefore, a few samples were first machined and then stress relieved by heat treatment. In order to preserve the material properties, the T651 heat treatment process was applied on all samples and were finally formed by incremental forming. The results confirmed that the machining residual stresses had a slight effect on springback. The simulation results showed that the longitudinal residual stress were negative on the outermost layer of the workpiece at the end of the machining stage and it raised with increase in machining feed. The negative stresses prevent the crack growth and allow the forming tool to get closer to the workpiece root, This helps the springback to reduce. Keywords: Deformation machining, Thin structural machining, Incremental forming, Residual stress, Springback.