Parametric study for laser hole drilling of Inconel 617 alloy

In order to improve the practical laser hole drilling application, the assessment of the end product quality is essential. One of the methods of assessing the hole quality is to analyze the features of hole geometric sections by statistical methods. In the present study, laser hole drilling in Inconel 617 alloy is considered and the factorial analysis based on the statistical technique is introduced when identifying the significance levels of the operational parameters. The parameters selected are drilling ambient pressure, laser output energy, focus settings of focusing lens, and workpiece thickness. In order to complete the factorial analysis, four levels of each parameter are taken into account. The laser drilled holes were cross-sectioned and examined under the microscope. A marking scheme is introduced to evaluate the geometric features of the hole cross-section. It is found that the workpiece thickness and focus setting are the most significant parameters for the formation of hole cross-section. The effects of ambient pressure on the resultant hole geometry are also found to be significant.