Bending vibrational tool for friction stir welding process
Beside beneficial aspects of friction stir welding such as solid state joining process, no melting, no recasting, etc. there are some disadvantages like considerable axial forging force especially for high strength materials. Researchers have developed several innovative ideas to diminish the process problems. In the present study, to investigate the effect of bending vibrations, an ultrasonic vibratory tool of friction stir welding, in bending mode, has been designed and manufactured. Firstly, the vibratory tool was designed for the operating resonance frequency of 20 KHz in ABAQUS software. This tool consists of transducer, horn, and welding tool. Using the optimal dimensions achieved from the modal analysis, the FSW tool has been manufactured. Then, experimental investigations verify the validity of the tool design process, such as clamping flange position, resonance frequency, and so on. The friction stir welding of aluminum Al6061 and Teflon plates has been done with lathe machine. FSW assisted ultrasonic vibrations in bending mode show some advantages in comparing with linear mode, such as decreased tool length and increased efficiency of vibrational energy transferring to the tool tip. Finally, with respect to the indicated improvements, reduction and rise of welding forces and temperature have been observed, respectively.