Tool performance and chip control when machining Ti6Al4V and Inconel 901 using high pressure coolant supply

Single point continuous turning tests were carried out on Ti6Al4V and Incon el 901 using various geometries of straight grade (K20) cemented carbide in serts using a high pressure coolant jet directed at the tip of the tool whe re the chip is formed. Trials were also carried out using a conventional co olant supply for comparison. The test results show that improved tool life can be achieved when machining the titanium-base alloy under the high press ure coolant jet while shorter tool life was obtained when machining the nic kel-base alloy. The use of high pressure coolant supply during machining ge nerally maintains constant cutting forces and reduces the chip-tool contact length, thus increasing stresses at the tool edge. This behavior tends to accelerate notching that is predominant when machining the Inconel 901 allo y, resulting in shorter tool life. This effect is not obvious when machinin g Ti6Al4V where the tools failed mainly due to excessive flank wear. Effect ive chip control was achieved when machining both materials because of the cyclic fragmentation mechanism of the newly generated chip.