Experimental Investigation and Multi-Response Optimization of End Milling Process Parameters for Surface Integrity on Al7075-B4C-BN Nanocomposites

Abstract

This research investigation reports the multi-response optimization of end milling process parameters for the improvement of surface integrity on Al7075-B4C-BN nanohybrid composites. The composites are prepared using a conventional stir casting process. The composites are fabricated with varying the wt.% of the secondary particles BN as 3, 6 and 9 wt.% and B4C as kept constant at 3 wt.%. The fabricated composites were characterized using Scanning Electron Microscope (SEM)and Energy Dispersive X-ray Spectroscopy (EDAX. HSS end mill cutter is preferred for machining operation for the fabricated samples by varying the spindle speed, feed rate, axial depth of cut, radial depth of cut and radial rake angle on temperature rise. During end milling operation, an increase in temperature can seriously affect the structural integrity of milled components. Thirty-two sets of experimentation are performed through Central Composite Design. The statistical influence of parameters with respect to responses is studied using Analysis of Variance (ANOVA) and Response Surface Methodology (RSM) is used to explore the direct interactions of parameters for machining and responses. The multi-objective optimization problems are solved with Multi-Objective Genetic Algorithm (MOGA) using MATLAB solver. The results revealed the statistical values of R2 (90%) for temperature rise, R2 (98%) for micro-hardness. While analyzing the temperature rise (relation between interaction and direct surface plot), it is established that the temperature can be accomplished minimum between spindle speed (1400 and 2000 rpm), feed rate (0.04 and 0.05 mm/rev), axial depth of cut (0.4 and 0.6 mm), radial depth of cut (0.4 and 0.6 mm) and radial rake angle (12° and 15°).