Investigation of drilling performance of curved surface glass fiber reinforced polymer composites

Today, composite materials are widely used in industrial areas such as construction, maritime, space and aviation etc. due to their high corrosion resistance, lightness, high strength, high chemical resistance, and ability to absorb vibrations. In this case, it causes interest to concentrate on composite materials. In order to use composite materials, second manufacturing is required after production. Especially in this second manufacturing method, the most used is drilling the composites for assembly. However, during drilling in the material, depending on the machining parameters, delamination occurs around the hole and reduces the lifespan of the composite. In order to prevent this situation, it is necessary to drill quality holes and ensure that the material is subject to minimal deformation. In this thesis study, glass fiber reinforced polymer composite materials with free-form surface different feed (0.1, 0.2, 0.3 mm/rev), spindle speed (1000, 1250, 1500 rev/min), tool diameter (Ø5, Ø7.5, Ø10 mm) and fiber orientation angle (0°-90°, 45°-45°). In addition, unlike literature studies, drilling was performed on surfaces with hole inclination angles of 15°, 30° and 45°. In the results obtained, it was observed that delamination at hole entry and exits increased with the increase in feed and tool diameter, and delamination at hole entry and exit was decreased with the increase of spindle rotation. It was determined that the delamination occurring in samples with a hole inclination angle of 45 ° was higher than in samples with a hole inclination angle of 15°. In addition, it has been observed that the hole surface roughness increases with the increase of feed, spindle rotation and hole inclination angle and decreases with the increase of the tool diameter. Finally, the SEM images of the drills used in critical machining parameters were taken and the abrasions occurred were examined. As a result, it has been observed that hole inclination angles have a significant effect on drilling and surface roughness as well as machining parameters.