Wearing Evaluation in nickel super-alloys turning for the development of a predictive model for CAM Optimization

Nickel super-alloys are characterized by: high temperatures resistance, high hardness and low thermal conductivity. For this reason they are widely used in critical operating conditions. However, due to their excellent mechanical properties, nickel super-alloys are hard to machine. Tool wear is a major problem in nickel super-alloys machining; the high temperature at the tool rake face is a principal wear factor. Flank wear is the most common type of tool wear; it offers predictable and stable tool life evaluation. In this work, the authors present a flank wear evaluation in Inconel 718 turning, in order to develop a predictive model for CAM optimization. An appropriate database has been developed thanks to an experimental activity (V-B as a function of: the cutting time T, cutting speed S and feed rate F). The objective of the optimization procedure is to maximize the Material Removal Rate (MRR) under the constraint represented by the flank wear limit. The developed procedure operates directly on the part program code, using the original one as starting point for the application of the knowledge about the wear behaviour. After the optimization phase the given output is represented by a new part program code obtained in accordance with: the maximum MRR within the respect of the wear limit