Modeling Of Polishing Mechanism In Magnetic Abrasive Polishing

The 12th International Conference of International Association for Computer Methods and Advances in Geomechanics (IACMAG) 1-6 October, 2008 Goa, India Modeling of Polishing Mechanism in Magnetic Abrasive Polishing M. G. V. S. Raghuram, Suhas S. Joshi∗ Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai – 400 076, India Keywords: super finishing, magnetic abrasive polishing, surface roughness, material removal rate, Taguchi methods ABSTRACT: Magnetic Abrasive Polishing (MAP) is a super-finishing process primarily used for polishing of nonmagnetic and hard materials like, ceramics and stainless steel. This paper deals with the detailed parametric study in polishing of stainless steel work surface. Statistically designed experiments based on Taguchi methods show that size-ratio, tool-work surface clearance, polishing speed, magnetic abrasive diameter and polishing time have significant effect on the surface roughness obtained. A minimum surface roughness of 20 nmRa was achieved by this process. The surface roughness predicted by the proposed analytical model was found to agree reasonably well with the experimental results . 1 Introduction Magnetic abrasive polishing (MAP) is a relatively new super-finishing technique used primarily to obtain nanometric level of surface finish especially on the non-ferrous and hard material like stainless steel and ceramics . It uses a controlled magnetic force of extremely small magnitude on ferromagnetic abrasive particles which are a conglomerate of abrasives and iron particles for the material removal. Thus , the tool in this process becomes virtually resilient. The process therefore is free from most of the ill-effects of conventional superfinishing processes , which use hard grinding wheels that inflict micro-cracks, geometrical errors and distortions on the work surfaces. The process is widely used for ultra-fine polishing of very hard and brittle non-magnetic materials. Two most commonly polished materials are stainless steel and ceramics. A number of researchers have developed experimental set-ups mainly for MAP of cylindrical surfaces since 80’s mainly to demonstrate the feasibility of the process. It is observed that the material removal phenomenon in MAP is complex, being influenced by a large number of parameters related to abrasives, workpiece and metal removal process. In spite of the large number of experimentation (Fox et al., 1994; Shinmura et al., 1992; Shinmura et al., 1993; Shinmura et al., 1994; Kremen, 2000), limited information is available on this process in the open literature. Also, there are very few attempts to model the mechanism of material removal in MAP process mathem atically. Kremen et al. 1994; Kremen et al. 1996) have developed a mathematical model based on the