Laser Percussion Drilling of Hastelloy X Superalloy: The Effect of Process Parameters on Hole Geometrical Characteristics and Subsequent Optimization
A. Khorram, M. Paidar and M. O. Shabani
Nd:YAG laser percussion drilling of Hastelloy X superalloy was carried out. The effects of process parameters including pulse frequency, pulse width and focal plane position on the hole geometrical characteristics (hole entrance and exit diameter, circularity and hole taper) was studied using response surface methodology (RSM). Then optimization of the laser percussion drilling process was performed by multi-response optimizer within the Minitab 18 statistical software. The results show that the higher pulse frequency leads to greater hole entrance and exit diameter, less hole entrance and exit circularity and lower hole taper. By increasing the pulse width, the hole entrance and exit diameter increases while the hole entrance and exit circularity decreases. Also, the hole taper reduces by increasing the pulse width. Increasing the focal plane position leads to increase the hole entrance and exit diameter, decrease the hole entrance and exit circularity and reduce the hole taper. The experimental values obtained from optimization reveal that the error percentage for the hole entrance diameter, the hole exit diameter, the hole entrance circularity, the hole exit circularity and the hole taper are 0.4, 3.1, 8.0, 8.7 and 17.0%, respectively.
Keywords: Nd:YAG laser, hastelloy X, superalloy, laser percussion drilling, hole geometry, response surface methodology (RSM), optimization