Special Issue on Difficult-to-Cut Materials
Nickel-based super alloys, Ti alloys, CFRP, hardened steels, etc., are widely used in aerospace, automobile, chemical, and other industries because of such superior properties as high operating temperature, superior specific strength, outstanding hardness and/or great toughness. These properties, however, also present difficulties in machining, cutting temperature, cutting, adhesiveness, chip controllability and wear. Other distinguishing properties include instable tool life, surface finishing and chip control in machining. This means that the stabilization of cutting is very important, especially when machining NC machine tools. Metal machining involves many parameters, such as cutting tools, cutting oil, cutting speed, feed rate, depth of cut, and machine use. A metal machining engineer therefore must decide all of these parameters to ensure their most suitable values under boundary conditions such as machining time, accuracy and the surface roughness of machined parts. Machining, especially of difficult-to-cut materials, is an optimization problem occurring under specified boundary conditions. Choosing machining parameters, including tool geometry and the most favorable features of work materials, must thus be figured out and optimum cutting conditions selected based both on metal machining theory and on practice. This special issue covers recent development in the machining of difficult-to-cut materials, including hardened steel, stainless steel, titanium alloys, Inconel 718, hard brittle materials and CFRP. All of the papers in this special issue are of great interest and value in machining these materials. We thank the authors for their invaluable submissions and the reviewers for their earnest efforts, without which this special issue would not have been possible.