Modeling and analysis of coated tool temperature variation in dry milling of Inconel 718 turbine blade considering flank wear effect

This work is motivated by a fact that an excessively worn tool will continue to be used in practical machining of difficult-to-cut materials, such as nickel-based superalloys. Quantitative comparison of worn tool temperature variations with a sharp tool shows great practical significance. A thermal model is presented to describe the coated tool temperature variation in dry milling of nickel-based superalloys for a turbine blade. The influence of flank wear is considered according to the rapid tool wear. In the proposed model, both heat fluxes into the tool from the rake face and due to flank wear are calculated to estimate the tool temperature distribution at different tool states. Feed rate optimization at the convex and concave surfaces of blade based on the force constraints is employed to investigate its influence on heat generation and tool temperature rise. A comparative experiment for dry milling of an Inconel 718 turbine blade is carried out to validate the model. Considering a set of experimental data and the output of the numerical simulations in the present work, a key global heat transfer coefficient (HTC), working as a partitioning coefficient which determines the heat amounts flowing into the chip and the tool, respectively, is assessed through an inverse procedure. This comparison indicates a good agreement in both trends and values. With the alternative method, an accurate simulation of the tool temperature variation can be achieved by the assessed global HTC which is used as an input in the FE model. As the influence of tool wear should be considered, this work can be further employed into the feed rate scheduling guidance in machining complex parts.