Integration of heat treatment into the process chain of a mill turn center by enabling external cylindrical grind-hardening

The modern mill turn center enables the manufacturing of complex cylindrical parts on a single machine tool. In many cases, complete machining is inhibited by using conventional heat treatment processes, e.g. induction hardening, which cannot be included in the metal-cutting process chain. An innovative approach for surface hardening is the grind-hardening process, which uses the heat generated during material removal with geometrically undefined cutting edges to realize a martensitic phase transformation within the surface layer. This paper presents a methodology for applying the grind-hardening process to a conventional mill turn center. The process layout is supported using numerical methods, e.g. the finite element method. The recommended process strategy eliminates the process-specific hardness slip beneath the plunge zone area and allows for a repeatable process behavior. Thus, the methods presented within this paper support a sustainable industrialization of the grind-hardening process.