Analysis of the machining characteristics in reaming AlSi12 alloy with PCD reamer

Machining characteristics were studied for the reaming AlSi12 alloy using six flutes polycrystalline diamond reamer on DMG DMU 50 linear five-axis CNC machine. The output measures for this experiment comprise of cutting torque, cutting thrust, hole diameter, hole cylindricity, and workpiece surface finishing. Cutting forces were in real time monitored by Kistler Dynamometer during the experiments. Hole diameter, hole cylindricity, and surface finishing (surface roughness and surface integrity) of the machined surfaces were measured after machining. It is indicated that the cutting force of thrust and torque decreased with increase of cutting speed and decrease of cutting feed. High accuracy of hole was achieved because the hole measurements satisfied the standard deviation. Hole diameters were within tighter tolerance value of 3300.025, and cylindricalities varied in the range from 0.002 to 0.014 um (less than 0.02 um). As to surface finishing, high surface performance could be obtained by eliminating surface defects on initial hole such as cavities and voids after subsequent finishing operating of reaming. However, the reamed surface damages of AlSi112 alloy under inapposite cutting conditions were involved with re-deposited work material (chip), surface grooves and notch, feed marks, surface shrinkage cavities and porosities, metal debris, and micro-pits. Moreover, surface roughness improved with an increase in the cutting speed from 2,000 to 6,000 rpm, but it deteriorated evidently when the cutting speed increased from 6,000 to 10,000 rpm. Cutting speed of 6,000 rpm and cutting feed of 3,000 mm/min were the recommendable cutting parameters to ream AlSi12 alloy because best hole quality could be produced in comparison of other cutting parameters.