Online monitoring of end milling for Al/SiC/RHA hybrid composites using temperature and vibration analysis

This paper investigates the machinability of Aluminium (Al7075) / 12% Silicon Carbide (SiC) / 8% Rice Husk Ash (RHA) hybrid metal matrix composites in end milling operation. The machining conditions and geometry of end mill tool was complex during machining of composite materials; hence, research pertaining to their machinability characteristics is yet to be explored. The experiments were carried out using a vertical machining center equipped with a High Speed Steel (HSS) end mill cutter. The acceleration amplitude was measured using twin-channel Fast Fourier transform (FFT) analyzer at two different points on the machine tool. Temperature rise was monitored using a K-type thermocouple positioned 2 mm below the cutting surface. The considered input parameters encompass machining conditions, including spindle speed, feed rate and depth of cut, as well as tool geometries such as helix angle, nose radius and rake angle. Experiments were conducted using various combinations of these process parameters to systematically analyze their effects on the outcome. The study found that cutting speed significantly influenced acceleration amplitude 1, nose radius impacted acceleration amplitude 2, and feed rate affected temperature rise. Optimal parameter levels for each response were identified using the Taguchi method. Multi-objective optimization using the desirability function approach resulted in an optimal parameter combination of alpha (level 4), r (level 5), gamma (level 3), v (level 1), f (level 4), z (level 2) to minimize acceleration amplitude and temperature rise, achieving a desirability function of 0.9064.