CHARACTERIZATION AND PERFORMANCE STUDY OF A NEW POLYMER MEDIA FOR AFM

Abstract

Abrasive Flow Machining (AFM) is a precision finishing process being extensively used since last five decades especially for finishing internal primitives. The semi-viscous abrasive carrier (media), which carry abrasive particle through the passage to be finished, plays a major role in this process. Worldwide research is on to develop an efficient, low cost media that can be used to finish advanced materials. This will significantly contribute to improving the process performance apart from being cost effect. The commercially available abrasive carriers, on the other hand, are costly and consume relatively longer time for preparation. In the present work, a natural polymer based media has been developed that can be successfully used as an alternative abrasive carrier for AFM process, while developing a media for AFM, it is important that the rheological properties remain largely similar to the existing media so that working nature of the basic process do not get affected while the performance of the carrier becomes better. The newly developed media was characterized and compared with the most widely used commercially available media. Both the media, the new media and the commercially available media, were prepared in the laboratory following standard practices. Fourier Transformation Infrared spectroscopy (FTIR) analysis was carried out, to understand the functional group existing in the carriers. Thermo Gravimetric Analysis (TGA) was carried out to understand the thermal behaviour and weight loss against ageing with the temperature. Field Emission Scanning Electron Microscope • (FE-SEM) analysis was carried out to understand the elements present in the media after machining. The performance analysis of the newly developed media and the existing media was carried out using a hydraulically operated, double acting horizontal AFM experimental setup. During experimentation, brass was taken as the work piece material and extrusion pressure, abrasive mesh size, processing time, viscosity, media flow rate and abrasive concentration were taken as process parameters. Surface finish improvement and material removal were considered as process responses. The experimentation was planned using L9 Orthogonal Array (OA) and Response Surface Methodology (RSM). Further experiments were carried out with optimized process parameters and the results were compared for both the media. It was found that the newly developed media has been repeatedly showing excellent characteristics and enhanced performance while compared with . existing media. The Newly devolved media is cost effective carrier to prepare,. Also its environment friendly and can be reused.