An Experimental Investigation of Inclined Hole Drilling for CFRP Under Various Lubrication Techniques

Carbon Fiber Reinforced Polymer (CFRP) is favoured in the aerospace, automotive, structural and sports-based industries due to its high strength-to-weight ratio, rigidity and comparatively higher stiffness. CFRP is termed as a difficult-to-machine material due to the problems associated with its machined quality, surface integrity and tooling cost. As per the industrial applications and requirements, drilling operation is mainly conducted on the CFRP material. Due to the layered structure of CFRP material, drilling operation produces defects such as delamination, burr formation, uncut fiber, fiber breakout and fiber pullout etc. These defects are mainly observed at the entrance and exit of the drilled hole. This poor surface finish and associated defects can play a very critical role towards the load carry capacity, reliability and service life of the final product, especially if the component is more prone to experience fatigue type of loading. There are several applications where the requirement is to have a hole at some inclination angle. To facilitate and develop the understanding of CFRP machining performance under inclined drilling, the presented study is focused on the drilling of inclined hole. The study will also incorporate different lubrication strategies such as dry cutting, conventional flood and minimum quantity lubrication (MQL) during the drilling of CFRP material.