Evaluation of desirability function approach and grey relation analysis for modeling circularity, perpendicularity and cylindricity in drilling magnesium AZ31

Development in the field of materials brings numerous newer grades, but the machinability studies over those materials have to be done. Drilling is the major manufacturing process which covers around 25% of machining processes. Magnesium AZ31 is considered for the present investigation to perform the drilling operation. Control over the responses like circularity, perpendicularity and cylindricity will improve the life of fastening element due the reduction of compressive and shear stress. The deviation of above responses will increase compressive and shear stress leads to fatigue and also increases the assembling time. This work concentrates on the reduction of such distinctive properties. Empirical model was developed to find the responses for the usage of process planning engineer, later optimization carried out through Desirability Function Approach (DFA). The multi objective optimization suggesting the spindle speed of 1100.02 rpm, the feed rate of 0.038 mm/rev. and the drill diameter of 6 mm for minimizing all the responses considered. Similarly Grey Relational Analysis (GRA) applied to reduce the responses. Evaluation made between DFA and GRA which highlights the superiority of GRA for circularity and cylindricity. The DFA be the superior technique for minimizing the perpendicularity.