Influence of Geometric Parameters on Strain and Thickness Reduction in Incremental Forming Process

The aim of this study was to investigate the influence of geometrical parameters by experimental optical methods on strain and thickness reduction in single point incremental forming process. Specifically, we aimed to study the influence of the punch diameter and the step in vertical direction and in the sheet plane. Measurements were made on parts produced from two different types of materials with different thicknesses. Measurements focused on determining the major and minor strain and thickness reduction. Three different types of trajectory were chosen and 8 parts were produced for each version of trajectory. In the first version, the punch was placed asymmetrically and initially it had a perpendicular movement on the sheet's initial plane, until it reached the final depth. In the second phase, the punch followed a rectangular trajectory along the die sides. In the second version, initially the punch had a vertical motion with a step of 8 mm. In the second phase, it followed the trajectory along one die side, and then a trajectory in steps (an increment of 2 or 4 mm) along other die side, until the entire surface of the part was made as a wrap of the punch trajectory. In the third version, the punch had a step motion (the value of the increment was 1 or 2 mm) in the vertical direction. After each step, the punch again followed a rectangular trajectory, as in the first version. The conclusions on the influence of geometrical factors on strain and thickness reduction in the three versions are presented.