Investigation of the effect of cooling conditions on machining quality in milling of fiber reinforced composites

Lightweight and high strength composites such as fiber reinforced plastics are widely used in the aerospace, aviation and automotive industries. Various machining is required in the assembly of these materials. One of them is milling. When these materials are machined in dry conditions, they cause low surface quality such as deformation and high surface roughness. However, when it is machined using cutting fluid, health and environmental problems are encountered this time. In recent years, minimum quantity lubrication (MQL), which performs cooling and lubrication functions, has been preferred instead of using cutting fluid. Sometimes nano-level additives are added to increase the performance of MQL. In this thesis study, end milling of glass fiber reinforced plastic (GFRP) composites in different spindle speed, feed rate and cutting environment was investigated. The aim is to investigate the effects of cutting parameters such as spindle speed, feed rate and cutting environment on cutting force, delamination and surface roughness. End milling experiments were performed at 1000, 2000 and 3000 rpm spindle speed, 0.05, 0.10 and 0.15 mm / rev feed rate and dry, MQL-CF (Minimum Quantity Lubrication-Cutting Fluid) and MQL-CF-Gr (Minimum Quantity Lubrication-Cutting Fluid-Grafen) cutting environment. In the experiments, 8 mm diameter TiN coated hard carbide (WC) cutting tools were used. It was determined that the cutting forces decreased with the increase of the spindle speed and the cutting forces increased with the increase of the feed rate. It was observed that the delamination increased with the increase of spindle speed and feed rate. Surface roughness increased with increasing feed rate while decreasing with increasing spindle speed. The best results were obtained from experiments with MQL-CF-Gr, while the worst results were obtained from experiments in dry environment. Keywords: Fiber Reinforced Composites, Delamination, Milling, Cutting Force, Minimum Quantity Lubrication, Surface Roughness