Experimental Investigation of Incremental Forming Process of Bilayer Hybrid Brass/St13 Sheets

In this study, the incremental forming of two layers’ brass/St13 sheets through the single-point process was experimentally examined. To investigate the formability of sheet in this process, the desired shape was designed through solid works software, and then surf cam application was used to observe tool motion and extraction of CNC program. G-codes were transferred to the CNC machine and the incremental bilayer sheets forming process was carried out in two different modes, that is, in one case, the brass sheet was placed on top and the steel sheet below, and in the other case they exchanged places. Afterwards, the effects of parameters such as forming tool diameter, vertical step size, and feed rate at three levels on fracture height, fracture angle, and strain were studied. In order to minimize the experiments, the experiment design based on response surface method (RSM) was employed. The results indicated that by increasing the tool diameter, vertical step, feed rate, the fracture angle, and fracture height decreased. The maximum fracture height and angle were estimated 46.5 mm and 71.44 degree, respectively, with tool diameter of 10 mm, speed of 1800 mm/min, and vertical step size of 0.25 mm. According to strain measurement results, steel sheets could bear higher strain rate than brass sheets, and in the case that the steel sheet was on top, the fracture height of bilayer sheet increased. The maximum strain of 0.72 was obtained in SB mode with tool diameter of 10 mm, feed rate of 1000 mm/min and vertical step of 0. 5.