Investigation of the effect of symmetrical hybrid stacking on drilling machinability of unidirectional CFRP, GFRP and hybrid composites: Drilling tests and damage analysis

Fiber-reinforced plastics are undoubtedly superior to metals in many sectors due to their advantageous properties. Especially carbon fiber reinforced plastics (CFRP) and glass fiber reinforced plastics (GFRP) are widely used in industry. Although CFRP offers higher strength, its use is limited due to its high cost. However, with hybridisation, it is possible to produce composites that will provide sufficient strength at lower cost. The mechanical behaviour of hybrid composites may be different compared to glass or carbon composites, as well as the damage behaviour during machining. In this study, the influence of hybrid stacking in drilling hybrid composites was investigated. The results showed the hybrid stacking, especially the position of the carbon plate, has a significant impact on the force generation and damage formation in the drilling. Although stacking the carbon layer at bottom caused an increase in thrust forces, it reduced the damage formation at the hole exit.