Effect of Process Parameters on Hole Diameter Accuracy in High Pressure Through Coolant Peck Drilling Using Taguchi Technique

Machining with pressurized coolant is nowadays widely accepted technique in the manufacturing industry, especially in high performance machining conditions. The data on the effects of variation of high coolant pressure in drilling operation is limited. This paper presents the effect of high coolant pressures along with spindle speed, feed rate and peck depth on hole diameter accuracy. Experiments were performed on EN9 steel with TiAIN coated through coolant drill on CNC vertical machining center. Taguchi technique was employed for design of experiments and analysis of results. Results showed that the higher values of optimal coolant pressure and spindle speed were demanded for drilling at bottom of hole as compared to that for drilling at top of hole. The optimal values of feed rate and peck depth were same for both the cases of drilling at top and bottom of hole. Use of high coolant pressure in drilling permits higher peck depth for better hole diameter control which results in reduced cycle time and hence production cost.