Investigation of Fracture Depth of Metal-Polymer Three‑Layer Sheet in Single-Point Incremental Forming Process

Incremental forming is one of the new forming methods. Single-point incremental forming (SPIF) has shown significant potential for forming complex metal parts. In the single-point incremental forming, a spherical tool head moves along a pre-defined path to form the desired geometry. The aim of this study is to optimize the fracture depth and forming forces of the three-layer metal-polymer sheet by using the single-point incremental forming process. By using response surface methodology (RSM), a series of experiments were designed in which tool diameter, step down and spindle speed were considered as process input parameters. The influencing parameters in fracture depth and forming forces have been identified by using statistical tools (response table, main effect diagram and ANOVA). Analysis of variance was used to show potential differences between the means of variables by testing the population value in each sample, which enables it to show the effects of input variables on output variables. The results show that the forming forces increased and the formability decreased by increasing the step down and the tool diameter. The highest forming force is 1476 N and the lowest value is 1045 N. Similarly, the highest fracture depth is 8.8 mm and the lowest is 7.1 mm. The best conditions are achieved when spindle speed is 2340.9 rpm, tool diameter is 7.51978 mm, and vertical step is 0.329552 mm. In this condition, the fracture depth is 8.50552 mm and the forming force is 776.03 N.