Investigation on Hybrid Jet Assisted Machining of Inconel 718 Superalloy and Multi Objective Optimization of Process Parameters

Conventional machining of Inconel 718 superalloy due to specifications such as high hardness and low thermal conductivity, results in low surface quality and high cutting forces. In this research hybrid high pressure jet assisted machining process was employed to improve machining conditions of this superalloy. To obtain suitable conditions of process applying optimal range of jet pressure proportional to other process parameters is essential. Experiments were conducted in five jet pressures, 1, 50, 100, 150, 200 bar, three cutting speeds, 50, 75 and 100 m/min, two feed rates, 0.05 and 0.14 mm/rev, and 1 mm of depth of cut with full factorial designed to reach possibility of process parameters investigation. By executing the experiments, cutting forces and surface roughness were measured. In order to multi-objective optimization, NSGA-II was employed to artificial neural network models which were trained by genetic algorithm, and optimized jet pressure ranges proportional to other process parameters were obtained. The multi objective optimization results demonstrate that for feed rate of 0.05 mm/rev and cutting speed range of 50-100 m/min, optimal range of jet pressure is 80-109 bar.