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Drilling is a very important hole making process. It is very much useful for assembly of parts. Incorporation of hard ceramic particles into the matrix of metallic composites made them difficult to machine. So, it becomes inevitable to optimize the drilling parameters. The foremost objective of this research work is to fabricate Hybrid Aluminium Matrix Composites(AMCs) of LM6/B4C/Fly Ash with 3%, 6% & 9% by weight percentages of both reinforcements, equally using stir casting technique. The next objective is drilling of composites with feed, speed, drill and percentage of reinforcement as input process parameters at three levels each by Taguchi’s Design of Experiments approach. The final objective is to optimize the drilling process parameters for achieving low thrust force, low surface roughness and minimum burr height using the multi-objective Grey Relational Analysis. Results reveal that drill material plays a major role, being closely followed by feed and speed.

The objective of this investigational analysis was to study the influence of process variables on the response during the drilling of LM6/B4C composite materials. Stir casting was employed to produce the LM6/B4C composites. A Vertical Machining Center (VMC) with a dynamometer was used to drill the holes and to record the thrust force. An L27 orthogonal array was used to carry out the experimental work. A grey relational analysis (GRA) was employed to perform optimization in order to attain the lowest Thrust Force (TF), Surface Roughness (SR) and Burr Height (BH). For minimal responses, the optimum levels of the process variables viz. the feed rate (F), spindle speed (S), drill material (D) and reinforcing percentage (R) were determined. The process variables in the drilling of the LM6/B4C composites were indeed optimized, according to confirmational investigations. The predicted Grey Relational Grade was 0.846, whereas the experimental GRG was 0.865, with a 2.2% error—indicating that the optimization process was valid.

Due to their abrasive behaviour, metal matrix composites (MMCs) are difficult to machine, so it is necessary to develop a suitable technology for their efficient machining. The ultimate goal of the research is to study the impact of process variables such as reinforcement, drill type, speed and feed rate on the thrust force and burr height during AMCs drilling. Aluminium Matrix Composites were manufactured with LM6 aluminium alloy as matrix and B4C as reinforcement through the low cost stir casting process. Experiments were performed using L27 orthogonal array in a CNC Vertical Machining Centre equipped with cutting tool dynamometer to measure the thrust force and burr-height was measured using vision measuring system. Experimental results demonstrated that this strategy enhances the performance characteristics expected in the drilling phase.

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