Optimizing machining efficiency: a comprehensive study on PVD cathodic arc evaporation coated turning tool inserts with TiAlN/AlCrN multilayer coatings

The effectiveness of turning processes in manufacturing depends on the efficiency of cutting tool inserts. Coating these inserts is one common method that has been used to prolong their life span, reduce friction and increase wear resistance. The main purpose of the present study was to enhance the efficiency of turning tool inserts by exploring different combinations of coating substances such as TiAlN, AlCrN, and TiAlN/AlCrN. Cutting speed, feed rate, cutting depth and type of coating material were important input parameters for optimization. It was observed that tools with coatings like TiAIN and AlCrN had higher performance than those with single-layered ones. The use of multilayer coated inserts comprising TiAlN/AlCrN increased the hardness but reduced the wear thereby enhancing machining effectiveness. For Taguchi Grey Relation Analysis (GRA) optimization technique with L27 array for hardness and flank wear output parameters aimed at enhancement of input process parameters in turning operations. The coatings crystalline structure, phase composition and other crucial details for their performance were analyzed using Energy Dispersive (EDS) Spectroscopy and Scanning Electron (SEM) Microscopy techniques. The TiAlN/AlCrN coatings showed greater machinability than those with only TiAlN or AlCrN, even at high spindle speeds. The best processes were identified using the Taguchi and Grey relational optimization techniques. Some of these parameters include a speed of 600 m min-1, a feed rate of 0.10 mm rev-1, a depth of 1.5 mm, and a TiAlN/AlCrN coating. This meant that the hardness was at 3772 HV while flank wear is 6.45 mm for optimum parameters among others obtained from experiments. The Grey relation analysis results demonstrated significant improvement in grade indicating the good performance of selected parameters. Various relationships can be displayed using contour plots which are usually visual representation between several factors in an experiment such as hardness and wear resistance which is shown by multilayer coating compared to single-layer coatings.