Hybrid-hybrid turning of micro-SiCp/AA2124 composites: A comparative study of laser-and-ultrasonic vibration-assisted machining

Machining of micro SiCp/AA2124 composites remains a challenge with conventional machining yielding poor surface quality with high tool wear. In this paper, we study two distinct and unique hybrid machining processes with the aim of improving the machining outcome of three types of micro-SiC/AA2124 composites with different particulate volume fractions and sizes. The class of composites studied is available commercially and is being used in industrial applications, thus assessing the machining outcomes becomes even more pertinent. Vibratory machining where the tool is made to vibrate at ultrasonic frequencies, known as ultrasonically assisted turning (UAT), is shown to yield some clear improvements in machining. Next, we incorporate laser assistance with the goal of inducing thermal softening in the process zone. This hybrid-hybrid machining process which is referred to as laser-ultrasonic-assisted turning (LUAT) has the potential for improved machining outcomes with significantly reduced machining forces and surface topology improvement. Our studies indicate that an optimum laser power exists for each type of metal matrix composite considering the particle size and volume fraction of the particulate reinforcements yielding benefits in terms of machining force reduction, surface topology improvement and potentially tool life enhancement. In addition, a computational machining model was developed which can be used to predict the machining outcomes with variable machining parameters.