Experimental Analysis and Optimization of Machining Parameters of AISI 4140 Steel

Metal cutting is viewed as a process consisting of dependent and independent variables to produce a desirable output performance characteristics. The independent input variables are work piece material, geometry of the work piece, type of machining processes, tool material and cutting parameters. The dependent variables of the turning process are power, cutting force, tool wear, material removal rate, surface finish etc. The fundamental and most common operation in almost all mechanical engineering industry is “Turning”. To survive in this combat competition the industries are required to be more cost conscious. Therefore, they are in need to use the resources very effectively, producing high quality end products with minimum possible or zero defects. Turning is one of the fundamental operations in mechanical industry. The process parameters involved with the turning process are generally spindle speed, feed rate, depth-of-cut, tool nose radius and tool rake angle. Cutting speed and feed rate affect surface roughness. Cutting tool inserts are helpful in obtaining better finishing cuts, which results in a very fine surface finish. Alternatively, when the inserts are used for roughing cuts, tool tends to fracture uncertainly. An experimental study found that Depth of-Cut (DOC) does not have an effect on surface microstructure, whereas, the feed, nose radius, work material, speed and tool point angle have a direct impact on surface roughness. The surface quality plays an important role. The fatigue strength, corrosion resistance are improved by machined surface. Hence, surface roughness also affects the functional attributes of parts, such as contact causing surface friction, wearing, light reflection, heat transmission, ability of distributing and holding a lubricant, coating, or resistance fatigue. The surface roughness is mainly a result of various processes parameters.