Incremental Sheet Forming is a prosperous process to manufacture sheet metal parts that is well adapted for prototypes or small batch production. Compared to traditional sheet forming technologies this relatively slow process is only profitable for the above mentioned production types but it can be used in different applications in automotive and aircraft industries, in architecture engineering and in medical aids manufacturing. In this paper indirectly obtained axial forming force on Single Point Incremental Forming (SPIF) of variable wall angle geometry were studied under different process parameters. The estimation of the forces on AlMn1Mg1 sheets with 0.22 mm initial thickness is performed by continuous monitoring of servo motor currents. The deformation states of the formed parts were analysed using the ARGUS optical strain measurement system of GOM. Interaction plot of forming speed, incremental depth, tool diameter and lubrication were also reported.