Optimization of drilling of AA7075 metal matrix composites using response surface method

Cast aluminum matrix composites reinforced with ceramic particles are widely used in aircraft and automotive parts due to their excellent properties such as light weight, high strength, and increased stiffness. In this research work, metal matrix composites reinforced with AA7075/BN have been used. Boron nitride ceramic powder is added with different weight percentages such as (0, 4 and 8). Drilling tests on the fabricated composites are performed through a CNC vertical drilling machine using a full carbide drill and by varying the process parameters such as spindle speed, feed, and drill tip angle. After that, by changing the angle of the cutting tool (118°, 108° and 98°), the drilling test is performed. Milling tool dynamometer is used to detect the axial force during drilling. The response surface method is used to optimize the axial force output responses and surface roughness effects of perforated metal matrix composites. The adjustment of experimental parameters is done with L27 Box–Behnken design factors and with four three-level factors. This study has shown that the advance and angle of the apex are the main influencing factors on the axial force and surface roughness. Because the reason for this is that by increasing the advance, more chips are removed in each round, and therefore more force is needed to break and remove these chips. Increasing the advance also increases the surface roughness, as well as the angle of the tip and increasing the angle of the tip of the drill on the quality. The final level has an effect.