Influence of MQL and hobbing parameters on microgeometry deviations and flank roughness of spur gears manufactured by MQL assisted hobbing

Conventional cutting fluids used in gear hobbing have negative impacts on the environment and health of the machine operators thereby adversely affecting the sustainability of the gear hobbing process. This paper reports on MQL assisted hobbing (MQLAH) using environment friendly fatty alcohol-based lubricant to manufacture superior quality spur gears. Experimental investigation was conducted to study of influence of six parameters of MQLAH namely hob cutter speed, axial feed, depth of cut, lube flow rate, air pressure, and nozzle angle on microgeometry deviations, avg. and max. values of flank surface roughness, and material removal rate to identify their optimum ranges to manufacture better quality spur gears with maximum productivity. Deviations in total profile, lead, cumulative pitch and radial runout were used to evaluate microgeometry of the spur gears. It revealed that depth of cut has no considerable effect on the spur gear quality. It identified that higher value of hob cutter speed, lower value of axial feed, optimum values of lube flow rate as 100 ml/h, nozzle angle as 30^◦, and air pressure in a range from 3 to 5 bar yield superior quality of spur gears by MQLAH.