Abstract: The literature study on optimization of surface roughness states that there are many parameters that affect optimum surface roughness to be reached after machining. It is primarily seen that many researchers carried out their studies on various cutting parameters (viz. speed , feed , depth of cut) as their input parameters and concluded that Feed is important parameter[5][6][8][9][12][14] for optimizing surface roughness and also some researches made clear that depth of cut[2][3][8][10] affects the response of surface roughness.Researches were also carried out by studying the effect of input parameters like changing the tool inserts and also by changing nose radius of various inserts [6][13]. Experiments were also carried out by varying the quantity of lubrication[15] The optimum value of surface roughness was reached by using taguchi[1][3][5][8][9][12] method and response surface methodology[6][8][13] The research carried out on EN 19 / AISI 4140 for optimum surface roughness was studied by taking cutting parameters like speed, feed and depth of cut ,states that the depth of cut is most significant parameter[2][3][8][10] . No research states appropriate tool insert with appropriate nose radius at the optimized depth of cut for EN 19 / AISI 4140 at hardness of 35 HRC.

Keywords: Taguchi, surface roughness, turning, optimization.