Tool wear evaluation in micro-milling of Al6061/GNPs nanocomposite

In the present study, micro-milling experiments were conducted on Al6061/GNPs nanocomposite fabricated through ultrasonic-assisted stir casting (USSC) to analyze the machinability of the fabricated nanocomposite. Microchannels with varying machining lengths (30 mm–510 mm) were fabricated using TiSiN-coated tungsten carbide tools under dry conditions. The cutting force, surface roughness, and burr width were investigated with reference to the different machining lengths. Tool wear on the micro end mill was observed, and the change in the cutting-edge radius and diameter was assessed based on the geometry of the machined microchannel. The results showed that the cutting-edge radius increased from ∼2.5 μm to ∼8 μm, while the tool diameter decreased by ∼5.1 % due to the gradual wear of the tool. The resultant force increased by six fold due to the progressive rounding of the cutting edge with the machined length. The built-up edge (BUE) formation and higher tool wear led to an increase in up-milling and down-milling side burr width by ten folds and six folds, respectively. The surface roughness of the fabricated microchannels increased by 20 % with increasing machined length, primarily due to progressive tool wear marks and detached BUE particle depositions. Adhesion, abrasion, flank wear, and BUE formation were identified as the dominant tool wear mechanisms during the micro-milling of the USSC-manufactured Al6061/GNPs nanocomposite.