2Çankırı Karatekin University, Engineering Faculty, ÇANKIRI
The use of commercially available molybdenum materials, which exhibit good mechanical and thermal properties, has been increasing day by day, and therefore their machinability has become important. Due to their good mechanical properties, shaping of these materials through machining methods causes some problems such as rapid tool wear, low surface quality and tool breakage. Besides, the determination of the machining conditions and methods of these materials which are quite expensive compared to other metals and alloys is very important in terms of improving the machined part quality and reduced costs. In this study, it is aimed to determine optimum cutting conditions in drilling of molybdenum of commercial purity using high speed steel (HSS) drill bits. For this purpose, experimental studies were carried out to reveal the effect of cutting parameters on surface roughness, drill bit wear, deviation on hole diameter, cylindricity error and drill bit temperature. It is seen from the experimental results that the drill bit failed quickly when drilling over 40 m/min. Significantly high surface roughness values are obtained nearly at all the conditions. As the cutting speed and feed rate increase, the drill bit temperature increases.