Investigations on surface milling of hardened AISI4340 steel with minimal fluid application using a high velocity pulsed jet of cutting fluid

Abstract

Growing environmental concern has led to stringent legislation on the use and newlinedisposal of cutting fluids. The cutting fluid application should not harm the personnel and newlinethe environment prevailing on the shop floor. In this context pure dry machining may appear as logical alternative, which is totally free from the problems associated with storage and disposal of cutting fluid. But it is very difficult to practice on the shop floor, as it needs ultra hard cutting tools and extremely rigid machine tools. It is not possible to introduce pure dry machining on the existing shop floor simply by introducing an ultra hard cutting tool. The machine tool also need replacement as it may not be rigid enough to support pure dry machining using an newlineultra hard cutting tool. The best alternative is to introduce pseudo dry machining or machining with minimal cutting fluid application. In this method extremely small quantities of cutting fluids are used and for all practical purposes resembles dry machining and at the same time free from the problems associated with conventional wet machining. In this research work surface milling of hardened AISI4340 steel with minimal pulsed jet fluid application has been investigated in depth and its performance is evaluated on the basis of surface finish, flank wear and cutting force. An effort is made to investigate the effect of cutting parameters (cutting velocity, feed and depth of cut) and the fluid application parameters (pressure at the fluid injector, frequency of pulsing, rate of fluid application, composition of cutting fluid and direction of cutting fluid application) on cutting performance. An investigative comparison with dry and conventional wet milling under same newlineconditions has been done to evaluate the relative performance of hard milling with newlineminimal fluid application. Effect of semisolid lubricant as performance enhancer during hard milling with minimal fluid application was also investigated.