Finishing of Bevel Gears using Abrasive Flow Machining

Abstract

Abrasive flow machining (AFM) is a precision finishing process with a deforming tool. In this process, a semi viscous carrier material that holds the abrasive particles acts as a multi-point flexible tool with tiny cutting edges. In the present study, effects of few important parameters such as extrusion pressure, abrasive mesh size, processing time and media flow rate on finishing EN-8 steel bevel gears have been investigated. A new tooling for fixing bevel gears has been designed and developed in such a way that the abrasive media passage is thoroughly restricted to abrade the gear tooth surface only. The initial surface roughness of the as received bevel gears was 1.4 to 1.8 micrometers. Taguchi orthogonal array was used to investigate the signal to noise ratio, main effect and parametric optimization. Finished gears were monitored using an optical profiler to assess the surface roughness. Finished gear surfaces were subjected to roughness measurements at five different locations (for each sample) and average of those values was considered. The results indicated that the improvement in surface finish was more than 50%, however, the enhancement in material removal was marginal. It was observed that the extrusion pressure has the highest contribution of about 73% on the process output; the other significant parameters being abrasive mesh size and processing time.