An investigation of multilayer coated (TiCN/Al2O3-TiN) tungsten carbide tools in high speed cutting using a hybrid finite element and experimental technique

Temperature and heat distribution in metal cutting are key factors that influence dry and/or high speed machining processes. In particular, during dry high speed machining these factors can lead to premature tool failure resulting in higher process cost. In this work, a hybrid methodology was employed in which finite element modelling (FEM) and experimental tests were used to evaluate the performance of multilayer functionally graded coated tools on the basis of heat partition into the tool and growth of flank wear. Cutting tests were conducted on AISI/SAE 4140 low carbon steel using multilayer coated tungsten carbide tools with TiCN/Al2O3 coatings on the rake face and TiCN/Al2O3/TiN coatings on the flank face. The tools were restricted contact length with a grooved profile. Cutting tests were conducted over a wide range of cutting speeds ranging from 200 to 879 m/min. The prediction of heat partition was carried out by matching finite element simulated temperatures to experimentally measured temperatures at 12 separate points on the tool. The study reveals that by using the functionally graded coating layouts, a significant reduction in heat distribution into the cutting tool can be achieved. Furthermore, the results suggest that in addition to the coating system, the tool rake face profile is also important in controlling heat flux and reducing flank wear.