Experimental and Finite Element Analysis of adapted cutting fluid supply on tool temperature and wear progression in Inconel 718 turning

Cutting fluids are crucial when machining difficult-to-cut materials such as nickel-based alloys, as they facilitate heat removal from the tool-workpiece contact area and minimize heat generation through lubrication. In addition to conventional flood cooling, the application of high-pressure cutting fluids is proving to be an advanced method for increasing tool life and promoting efficient chip removal. Although the benefits of high-pressure cooling are well recognized, a comprehensive investigation of cutting fluid parameters, such as nozzle opening area and supply pressure, and their effects on machining performance have not yet been sufficiently investigated. This research presents an innovative prototype toolholder with adjustable nozzle designs and temperature measurement capability. This toolholder allows the nozzle opening cross-section to be modified without changing the cooling channels or nozzle angles. Integrated thermocouples within the toolholder provide real-time temperature monitoring during machining. Experimental findings reveal that nozzle geometry had no influence on the tool temperature for the investigated process parameters, provided that an effective chip break is achieved. At 80 bar, increased cutting fluid flow enhanced chip fragmentation for inserts with chip breakers and improved tool wear, leading to longer tool life. Additionally, greater cutting fluid coverage along the cutting edge significantly reduced tool wear, with data showing up to a 20% reduction in tool wear for optimal nozzle configurations. Simulation studies support the link between enhanced chip breaking and increased cutting fluid flow through the cutting zone. This study offers quantitative evidence that optimized nozzle design and fluid parameters can improve tool life and machining efficiency.