Externally induced low frequency tool chatter for optimizing the FSW weld of Al–SiC matrix

Linguistically synonymous, but from an engineer’s perspective vibration is a quantifiable value whereas chatter is a resultant reaction individual to the setup assembly, and is generated mostly during material removal processes in the form of audible noise. In ultrasound assisted friction stir welding (UaFSW) of Al–SiC metal matrix composites, the presence of ceramic carbides embedded into softer metal matrix and the addition of externally induced ultrasonic vibrations indirectly through the tool not only increases efficiency but also operational and maintenance costs. Further the observed acoustics are very minimal or inaudible. The induced oscillations are observed to contribute to higher tool wear along with SiC particulates and a spike in pre-existing tool motions as a majority of studies use refurbished milling and lathe machines. Identifying the need for more economical approaches, an experimental study using frequencies lower than 150 Hz and by observing the resulting chatter generated across the work piece which is recorded using a diaphragm-based microphone setup is presented. When coupled with dynamic control of rotational rate (RPM) of operation using a FPGA for data collection, an SBC with ARM processor for analysis and a microcontroller to implement the tweaks, an improved tool life with minimal compromise in quality is observed.