Innovative optimization of feed and spindle speed levels for surface roughness and cylindricity tolerance of the drilled holes in liquid stir casted Al6061 hybrid composite reinforced with 15% weight fraction of SiC+Fly ash and comparing the above results

Abstract

Aim: The motive of this research is to optimize the feed and spindle speed levels based on surface roughness and cylindricity tolerance values of the drilled holes in liquid stir casted aluminium hybrid metal matrix composite reinforced with a 15% weight fraction composed of 7.5% silicon carbide and 7.5% fly ash and compare the results with pure as-cast Aluminium 6061. Materials and Methods: For g power calculations (threshold level: 0.20, confidence interval: 80%) gives a sample size of 39. Samples of dimensions 150mm x 150mm and thickness 10mm are fabricated using the stir casting method under controlled process parameters adhering to standards. On each sample, 13 holes with 13 different combinations of feed and spindle speed derived using the RSM method are drilled using an uncoated HSS drill bit of 10mm diameter. Cylindricity tolerance and Surface Roughness values were taken on the cylindrical inner surface of the holes on samples from both the experimental group (AHMMC) and control group (As-cast AL6061). Results: With the help of Design-Expert, the effect of feed and spindle speed on surface roughness and cylindricity tolerance is examined and the optimum value for feed rate and spindle speed to reduce the surface roughness [6.8%] and cylindricity tolerance [7.2%] of the drilled holes is found with an insignificance level of 0.4485 (p>0.05). Conclusion: Within the limitations of this study, It is revealed that AHMMC with a 15% weight fraction of SiC+Fly ash exhibits optimum surface roughness and cylindricity tolerance for the speed of 945 rpm and feed rate of 0.09 mm/rev.