Drilling of basalt fiber reinforced nanocomposite materialsinvestigation of the effect of tool nose geometry on operations

Composite materials are highly valuable materials widely used in many industries due to their combination of strength, lightweight, and special properties. Since these materials are formed by combining different components, they may require different processing methods than traditional metals or single materials. At this point, drilling processes in composite materials are of great importance. Drilling processes in composite materials are filled with various challenges and factors to be considered. The primary goal is to create a hole with the desired dimensions and properties in a precise and effective manner. However, the structure and properties of composite materials are different from traditional metals, and there are certain special considerations to be taken into account during the drilling process. Due to the fibrous nature and the inclusion of different reinforcement materials, problems such as crack formation or damage to the reinforcement material may occur during the drilling process. Therefore, the selection of appropriate methods, tools, and parameters is of great importance for drilling operations. On the other hand, the introduction of nanotechnology into our lives has opened new doors for composite materials as well. In various studies, nano particle reinforcement can enhance many properties of composite materials, making them stronger, more durable, thermally manageable, and customizable. These advantages can contribute significantly to various application areas in different industries. Furthermore, it is known that reducing crack formation, increasing wear resistance, and enhancing thermal conductivity are important effects in the drilling processes of composite materials. In this thesis study, hand lay-up and vacuum infusion methods were employed to produce basalt fiber-reinforced epoxy polymer matrix composite (BFTK) plates for the investigation of drilling parameters. To minimize or eliminate potential undesired conditions arising from drilling parameters, the matrix material was modified with halloysite nanotubes (HNT) to produce basalt fiber-reinforced nanocomposite (BFTnK) material. Standard and specially designed carbide drill bits were used for hole drilling in composite materials. Additionally, cutting parameters of 0,005, 0,05, and 0,1 mm/rev feed rates, and 50, 75, 100 m/min cutting speeds were applied in hole drilling processes. The study examined the effect of both the special tool tip and nano-modification on thrust force, delamination factor, and hole surface roughness in the drilling of basalt fiber-reinforced epoxy polymer matrix composite plates. Furthermore, post-drilling damage development on hole surfaces was analyzed using optical and scanning electron microscopy (SEM).