Flow-forming is an incremental forming process. In this process the work peace is formed by local yielding the material on a helix path using form rollers. The process is important because it eliminates material removal and chipping and it produces accurate work-peace. In this project the process and main affecting parameters in flow-forming are studied. The process is modeled and the required forces are calculated. For this purpose, principles of pre-form design are discussed and suggested. The main design principles of flow-forming machine are also described. Then detailed designs of a machine which can withstand the calculated forces are presented. On the other hand the effect of rollers radial position on work-peace accuracy and the applied forces are studied. A new method for adjustment of rollers radial position is suggested. In addition, the effect of pre-form eccentricity on work-peace accuracy is investigated.