Definition of Thermal Conductivity of Cemented Carbide Cutting Tools with Multilayer Wear-Resistant Coatings

Introduction. The output parameters of cutting process, particularly the quality of machined surface, are largely determined by the character of chip-forming processes and contact interaction of parts and tool materials. Adaptive cutting process control for modern automated CNC machinery allows ensuring the reliability of the output processing parameters. The development of mathematical models, which take into account the thermal conductivity of tool materials, is the necessary condition for realizing the possibilities of adaptive control of modern equipment in digital production systems (DPS) for machining operation. Cemented carbides are the main tool materials for edge cutting of carbon, alloyed and stainless steels. At the same time, there is currently no complex of information on the thermal conductivity of instruments with multilayer coatings for machining operation of various materials, for various processing conditions and methods for applying coatings. This problem is a limiting factor for the development of reliable mathematical models for technological preparation of production and control of the output parameters of the cutting process. Therefore, the analysis of thermal and physical properties of modern cemented carbide tools with wear-resistant coatings and offering of practical recommendations are the up–to–date scientific and practical task. The purpose of the work is to define a value of thermal conductivity of modern cemented carbide tools with wear-resistant coatings for subsequent use in development of mathematical models linking the modes and processing conditions with the current cutting forces and the output processing parameter – the surface roughness. The research methods are: the analysis and systematization of information on the chemical composition and designs of multilayer coatings based on the method of coating, modes and conditions of machining and materials to be machinined, as well as determining the thermal conductivity coefficients of hard-alloy tools with coatings by the calculation method. The results and discussion. Based on the analysis and calculations, the most widely used in manufacturing practice values of thermal conductivity coefficients for cutting tools with multilayer coatings are obtained. These values are intended for use in the development of mathematical models that link the modes and processing conditions with the output processing parameters and are based on the consideration of thermal and physical processes during cutting. The models developed on the basis of these data are planned to be used for the technological preparation of production and the adaptive control of modern equipment in the DSP for machining.

Cemented carbide tools, Multilayer coatings, Thermal conductivity,Mathematical models, Digital production systems