Performance study of a natural polymer based media for abrasive flow machining

Abstract

Abrasive flow machining (AFM) is a non traditional finishing process used for finishing parts with predominantly irregular geometry. In AFM, material removal and surface finish takes place by flowing viscoelastic abrasive carrier across the surface to be machined. The media (carrier + abrasive) is the key element in the process because of its ability to precisely abrade the selected areas along its flow path. In this study, an attempt is made to develop a new carrier as an alternative to the existing commercially available media. The newly developed carrier is characterized through Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). Performance evaluation of the carrier is carried out by considering extrusion pressure, abrasive concentration, viscosity of media, and media flow rate as a process parameters and surface finish improvement and material removal as process responses. The ester based newly developed media is capable of withstanding a temperature to work up to 71°C without changing its characteristics. It is found that the developed carrier is flexible enough to be used in AFM process and performance study reveals that the new polymer based medium yields a good improvement in surface finish as well as material removal. Material removal does not get influenced significantly by the varying media flow rate, but surface finish increases with media flow rate above 796 Pa-s. An operational pressure of 20 bar and abrasive concentration of 50:50 (abrasives: carrier) is observed to be better parameter levels for the conditions attempted in the present study.