Abrasive Flow Finishing of Stainless Steel 304 Biomedical Devices

Abstract

In this experimental study, magnetorheological abrasive flow finishing (MRAFF) process is utilized to observe the effect of different finishing parameters on final surface finish quality. Ability to control over rheological properties of magnetic abrasive medium in MRAFF with exerting an external magnetic field let us reach internal surface finishing process due to its special rheological behavior. A new finishing set designed and manufactured to meet needs for these experiments that consists of a hydraulic-mechanical power unit, abrasive fluid containers, permanent Fe-Nd magnets, workpiece fixtures and a base frame. Finishing fluid in this study contains iron particles as magnetic bonders and SiC particles in different mesh size as abrasive part. In addition, a specific volume percentage of liquid paraffin and glycerin constitute base medium. Experiments were conducted on austenite stainless steel pipes in different magnetic field strength, abrasive particle size and finishing cycle time and were designed in full factorial mode. With increase in magnetic field strength and abrasive particle size, an increase in surface roughness is obviously observed but with increase in finishing cycle time, a different behavior is seen.