Ultrasonic Vibratory Drilling Carbon Fiber/Graphene Nanoparticle Reinforced Polymers to Produce Desired Hole Quality: Experimental Analysis and Optimization

Carbon fiber-reinforced polymers are widely used in advanced applications due to their superb specifications. One of the principal problems in drilling such polymers is delamination which deteriorates the composite strength and can lead to part rejection during assembly. Ultrasonic vibration-assisted drilling is a newly developed machining method that induces higher workpiece quality. In this study, a comprehensive experimental examination was conducted with both mechanical and materialistic views. The materialistic parameters include graphene nanoparticles and lay-up arrangement. Furthermore, the mechanical parameters include drilling feed rate, tool type, and ultrasonic vibration. To follow this aim, different carbon fiber-reinforced polymer specimens were fabricated with various lay-up arrangements and graphene nanoparticle amounts. Besides, an analysis of variance was utilized to indicate the significant parameters. The results showed that the feed rate has the most effect on thrust force and delamination damage. Besides, graphene nanoparticles% and tool type were the significant parameters of delamination. To find the optimal settings, grey relational analysis was used. That was suggested to produce carbon fiber-reinforced polymer segments with symmetrical lay-up arrangements to reduce delamination damage. Furthermore, a lower feed rate value with 5% cobalt high-speed steel tool was suggested. Exerting ultrasonic vibration on the tool was also beneficial to improve the hole quality.