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Fig. 3 Surface roughness profiles of the a before finished straight bevel gear; and b fine finished
straight bevel gears
bevel gear for evolution of surface roughness, bearing area curve (BAC) and surface
morphology. Figure 3 depicts 3D surface roughness profiles of the before finishing
(Fig. 3a) and fine-finished straight bevel gear (Fig. 3b). It can be noticed from Fig. 3
that AFF decreased values of max. and avg. surface roughness values from 7.93 to
7.71 µm and from 0.82 to 0.68 µm for the fine finished straight bevel gear.
Figure 4 depicts bearing area of the before finished and AFF finished straight
bevel gear at 30 min of finishing time. Improvement in surface finish makes bearing
area of fine finished straight bevel gear (Fig. 4a) more uniform as compared to
their before finishing state (Fig. 4b). These reductions in surface roughness and
consequent improvement in bearing area of straight bevel gears will improve their
wear characteristics which will result in their better tribological performance during
their service life.
Figure 5 presents optical micrograph depicting surface morphology of the flank
surface of the before finished and fine finished straight bevel gear. Roughness peaks,
cutter marks caused by gear manufacturing process, pits and burrs were present on
flank surface of before finished straight bevel gear (Fig. 5a) which were completely
removed after their finishing by AFF as shown in Fig. 5b. The presence of microchips and abrasive flow marks indicate micro-cutting and ploughing mode material
removal.
Fig. 4 Bearing area curve for a before finished straight bevel gear; and b fine finished straight
bevel gear