Influences of Process Parameters on Forming Performance of Sheet Metal Incremental Forming Based on Numerical Simulation

In order to investigate the process of ISF through numerical and experimental approaches, finite element method (FEM) models for two truncated pyramids were developed to simulate the process and the simulated thickness distributions were compared with experimental results. The influences of process parameters on equivalent plastic strain, the maximum equivalent plastic stress and forming force were also discussed. The results show that ISF process is basically to be a plane strain deformation. Wall angle is a more significant influence factor of forming performance than tool diameter and depth increment. With increasing tool diameter, decreasing wall angle and step increment, uniform thickness distribution will be achieved. However, more wall angel, less tool diameter and depth increment contributes to decrease forming force. Additionally, process parameters have no connection with work hardening for a certain material during ISF.

Study on Mechanism of NC Sheet Metal Incremental Forming

The principle of NC incremental sheet metal forming process as well as the experiment of cone forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to stretch deformation, the deformed region of sheet metal thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. The experiment results show that in the case of the parallel line type tool path, a uniform thickness of the deformed region is maintained and in good accordance with that obtained by the sine law. It is found that success in the forming depends on the forming half-apex angleθof the truncated cone. It can be obtained that NC incremental sheet metal forming process is a plane deform process and conforms to the sine law, i.e.t=t0 sinQ.

Study of Sphere NC Sheet Metal Incremental Forming

The principle of NC incremental sheet metal forming as well as the process planning, experiment of sphere forming are presented. Because the deformation of sheet metal only occurs around the tool head and the deformed region is subjected to shear deformation and thins, and surface area increases. Sheet metal forming stepwise is to lead to the whole sheet metal deformation. According to sine law, a sphere can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. Thus, the two time path process method is presented to form the sphere, and the experiment is made to verify it. A sphere can be formed from a sheet metal in NC incremental forming process by choosing appropriate tool-path planning. The fracture in the forming component can be avoided by these methods. A sphere of uniform wall-thickness can be formed from the truncated cone by NC incremental forming process.