Parametric investigation on laser forming of 3mm and 5mm FE-410 sheets for brake pedal and clutch pedal applications

Laser forming is a flexible manufacturing process which has potential use in the manufacturing and automotive industry. In this process, a high power laser scans the metal sheet across its length. The metal sheet absorbs the laser and a steep temperature gradient is generated across the sheet thickness. The induced uneven thermal stresses, and the resulting bending moments, during the process deform the sheet metal without the use of any external forces. In this paper, steel sheets of FE-410 are bent using high power CO2 laser. Experiments were performed on 5 mm and 3 mm FE-410 steel sheets using CO2 Laser with maximum energy of 3000 W. Various parameters were varied namely power (1.5 KW to 3 KW), number of passes (0 to 130), scan speed (10 to 30 mm/s), laser spot diameter (4 mm to 13 mm) and frequency (500 Hz to 20000 Hz) to get maximum bend angle. The variation in the bend angle with respect to the power, scan speed, spot diameter, number of passes and thickness is studied. A data set of 320 samples is obtained from the experiment. This data set in the form of multi-input and single output is used to develop an optimum artificial neural network model to predict the bend angle. Here the output variable is bend angle and input variables are laser power, scan speed, spot diameter, sheet thickness and number of passes or scans. Micro-structure analysis of the deformed region and the heat affected zone in comparison with the base material is done. And a comparative study of the variation in micro-hardness of all these regions is done.