Effect of cutting fluid supply conditions on tool loads during continuous and interrupted orthogonal cutting

Abstract In metalworking, cutting fluids play an important role by reducing heat and friction during machining, extending tool life, and improving surface finish. Although the positive effects of cutting fluid have been confirmed in many studies, the relevant cutting fluid parameters such as nozzle cross-section area and supply pressure, as well as their influence on the thermo-mechanical loads of the cutting tool, have been insufficiently investigated. This study investigates the effects of cutting fluid supply conditions on tool loads during continuous and interrupted orthogonal cutting processes. The research specifically addresses the impact of nozzle geometry and fluid jet orientation on the thermo-mechanical loads on the cutting tool, which have been underexplored in previous studies. A prototype tool holder, designed and additively manufactured for this purpose, allows for variations in nozzle geometry and jet orientation. Experiments were conducted under varying cutting parameters, nozzle geometries, and fluid pressures, with tool temperature being monitored through an embedded thermocouple. The results show that nozzle geometry significantly affects chip shape, which directly affects cooling efficiency and, consequently, tool temperature. The study also uses an inversely calibrated analytical model to analyze the tool temperature distribution, which shows that the highest temperatures occur in the tool-chip contact area, while temperatures outside this area decrease rapidly. In addition, the percentage of heat conducted into the tool decreases with increasing Péclet number, which is consistent in both continuous and interrupted cutting scenarios. These findings provide a deeper understanding of how cutting fluid nozzle design affects tool performance and establish a foundation for model-based temperature analysis in machining processes.