Eco friendly coolant assisted flow drilling of hybrid aluminium matrix composites using decision tree approach

Abstract

In the recent days, aluminium-matrix composites are extensively usedin aerospace industries, automobile fields, military, mining and otherengineering applications. Its high specific stiffness, light weight and highstrength makes it possible for applications such as robots, high-speed rotatingshafts, high speed machinery, automotive engine and brake parts. In the entiremanufacturing scenario, drilling operation is the most predominant processvamong all these applications. Reinforcements in aluminium-matrix compositesvmakes drilling more complicated in conventional drilling, because of theirabrasive nature. Due to heat generation, the conventional drill tool losses itseffectiveness quickly and the work piece gets hardened resulting in difficulty inpost drilling operations. A non-traditional hole making process, known as flowdrillingovercomes these difficulties. Using frictional heat between a flow-drilland work material, hole is formed along with a bushing and there is no chipformation. The work piece material softens as there is a rise in temperatureduring the process. The bushing thus formed has a thickness almost 3 timeshigher than the work piece thickness. The main contribution of flow-drilling is toincrease the effectiveness of the thread length, as well as screw coupling, whichis used for load clamping in joining applications. Flow-drilling also known asthermal drilling, is an excellent alternativefor hole stamping, nut welding andjoining of dissimilar materials. Moreover, flow-drilling holds several technicaladvantages such as absence of material wastage, swift operation cycle, excellenttool life, etc.In the present work, flow-drilling is employed as an effective newlinealternative for conventional drilling process. Hybrid aluminium-matrixcompositesare developed with distinct reinforcements such as silicon carbide,graphite and boron carbide at different weight percentage and combinationsusing stir-casting furnace newline newline