Finite Element Analysis and Experimental Study of the Ultrasonic Vibration-assisted Single Point Incremental Forming (UVaSPIF) Process

The mechanism of Single Point Incremental Forming (SPIF) process is based on localized plastic deformation of a sheet metal using a hemispherical-head tool that follows the path programmed into the controller of a CNC milling machine. In this process, no die is used under the sheet metal for support. The researchers' findings show that by applying ultrasonic vibration in forming processes, metallic samples are subjected to plasticization transiently and considerably. The beneficial results of applying ultrasonic vibration in the forming processes are due to volume and surface effects that are related to the change in the properties of material and change of frictional conditions, respectively. In this article, the Ultrasonic Vibration-assisted Single Point Incremental Forming (UVaSPIF) process was simulated in finite element software. The results of numerical analysis showed that ultrasonic excitation of the forming tool and increasing of the vibration amplitude reduced the friction force and the vertical component of forming force. In the following, the results of the simulation process were compared with the experimental results at a frequency of 20 kHz and 7.5 μm vibration amplitude. The study of the results showed that there was a very good agreement between the values of the vertical component of the forming force resulting from the numerical analysis and the experimental test.