Experimental Investigation and Analysis of Relationship between Surface Roughness and Cutting Force during MQL Turning of AISI 4340 with Nano Fluid

The objective of this research work is focused on to establish the relationship between surface and cutting force under Minimum Quantity Lubrication using nano fluid in turning of AISI 4340. A study of effect of cutting parameters in turning of AISI 4340 under MQL condition with nano fluid on the cutting force generated and machined surface roughness is carried out. In the experiment conducted, five values of feed rate, three values of depth of cut, two values of cutting speed and tool nose radius respectively, are used. The test pieces were turned on a CNC lathe machine under MQL mode using nano fluid with different levels of cutting parameters by using full factorial design of experiment orthogonal array. From result analysis, it was found that, feed rate played a major role in producing lower surface roughness followed by depth of cut whereas cutting speed has least significance in producing lower surface roughness under MQL using nano coolant. It was observed that at constant depth of cut and cutting speed for tool nose radius 0.8 mm and 0.4 mm as feed increases, surface roughness and cutting force values increases. From Least square technique the curve fitting equation (power equation) between surface roughness and cutting force is obtained. Also it is found that, agreements between surface roughness and calculated cutting force is excellent (99%) and confidence interval for co-relation coefficient r₁, r₂, r₃, r₄ is significant. So from the analysis of result the relationship between surface roughness and cutting force is established.