Design and Development of Friction Stir Drilling and Tapping

Friction stir drilling and tapping is a process in which drilling the hole and tapping is performed with the help of combination tool. The mechanism of hole formation in friction drilling is due to thermal softening followed by the penetration of tool into work. Drilling is traditionally a hole making process. Friction drilling work is performed by a sharp cone of circular shanked high speed steel. The tool is rotated at high speed to develop sufficient temperature and thrust is applied to form a hole without chips, hence some investigators prefer to call this method as form drilling, thermal drilling, flow drilling, or friction stir drilling. The sequence in friction drilling process, a rotating conical tool contacts the workpiece and heat is generated due to friction between mating surfaces, owing to this the work softening occurs and on further advancement of tool into the workpiece, the softened material is pushed side ward and forms the bushing. The shoulder of tool contacts the workpiece and does the trimming. The present work is to design the combination tool, modelling and experimentation validation is carried out using this combination tool and results are obtained