Performance analysis of process variables on laser beam machining of inconel-718 alloy

Abstract

Carbon-dioxide laser beam machining (LBM) is used for machining intricate shapes and hard materials which are inconceivable with conventional machining methods. Inconel 718 finds its prime applications in manufacturing high pressure turbine components and structural components of aerospace industry. Inconel 718 alloy exhibits superior physical and mechanical properties at elevated temperature, Strength-to-density ratio and higher corrosion resistance. The objective of the current work is to determine the optimal setting of the process parameters like laser power, cutting speed, gas pressure while machining Inconel-718 material using oxygen gas. The experiment was conducted using Taguchi L9 orthogonal array. A square washer with four holes of diameter 8 mm and one hole of diameter 64 mm was machined using laser beam machining and the best combination of process parameters to acquire better response parameters is computed. The optimized value of surface roughness was found to be 3.5µm and similarly material removal rate to be 45.56 m3/min when operated at 2.1m/min cutting speed, cut of type rough, 1mm of focal point and 4000bar gas pressure, The effect of input variables on various response parameters namely surface roughness (Ra), Heat affected zone thickness (HAZ), material removal rate (MRR), Taper, Circularity, hardness were studied. Morphology of the machined surface was investigated using SEM analysis.