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ABSTRACT
Study of new and cost effective finishing processes has alwaysbeen an area of keen interest to overcome the difficulties ofexisting finishing process. Magnetic Abrasive Finishing(MAF) is a process in which a mixture of non-ferromagneticabrasives and ferromagnetic iron particles is used to dofinishing operation with the aid of magnetic force. The ironparticles in the mixture are magnetically energized using amagnetic field. The iron particles form a lightly rigid matrixin which the abrasives are trapped. This is called FlexibleMagnetic Abrasive Brush (FMAB), which when given relativemotion against a metal surface, polishes that surface.The major studies concerning MAF have been done regardingthe behaviors of the process under the effect of variousparameters like working gap, mesh number of abrasive, speedof relative motion on cylindrical and flat work-pieces takingone type of material, non-ferromagnetic or ferromagneticonly. But limited comparative study by taking stainless steelwith ferromagnetic behavior has been done to analyze thesurface roughness that is generated during the process.This paper has aim of development of Magnetic AbrasiveFinishing Process & studying the effect of the processparameters (percent composition of iron powder, meshnumber of abrasive and current) on the surface roughnessduring MAF of ferromagnetic S.S. work-piece material forflat work-pieces. The results of the experiments arestatistically analyzed using design expert v.7 software for theresponses generated during the process.In case of ferromagnetic work-piece, percent composition ofiron powder has more effect than the other parameters. Withincrease in mesh size of abrasive, percent improvement insurface roughness increases. With increase in current thepercent improvement in surface roughness value increasesmuch more than the other parameters, therefore effect ofapplied current is seen to the most significant amongst all theparameters.Keywords: Magnetic abrasive finishing, Surface Roughness,Mesh number, Stainless steel, current
I. INTRODUCTION
A magnetic abrasive finishing process is defined as a process bywhich material is removed, in such a way that the surfacefinishing and deburring is performed with the presence of amagnetic field in the machining zone. Magnetic abrasive finishing(MAF) has a magnetic field which assisted finishing process. Thework piece is kept between the two poles of a magnet.. Themethod was originally introduced in the Soviet Union, withfurther fundamental research in various countries including Japan.Nowadays, the study of the magnetic field assisting finishingprocesses is being conducted at industrial levels around the worldA. Working PrincipleThe working gap between the work piece and the magnet is filledwith magnetic Abrasive particles (MAP), composed offerromagnetic particles and abrasive powder. MAP is preparedby sintering of ferromagnetic particles and abrasive particles.Themagnetic abrasive particles join each other along the lines ofmagnetic force and form a flexible magnetic abrasive brush(FMAB) between the work piece and the magnetic pole .Thisbrush behaves like a multi-point cutting tool for finishingoperation. When the magnetic N-pole is rotating, the MagneticAbrasive Finishing Brush (MAFB) also rotates like a flexiblegrinding wheel and finishing is done according to the forcesacting on the abrasive particles. .In external finishing of cylindrical surface, the cylindrical workpiece rotates between the magnetic poles, with the MAP filled inboth the gaps on either side (Fig 1). Whereas in internal finishingof cylindrical surface, the work piece rotates between themagnetic poles and the MAP .as shown in Figure 2. The magneticfield generator can be either electromagnetic coils or permanentmagnets. The relative motion between the induced abrasiveparticles of the FMAB and work piece generates the necessaryshearing action at the abrasive–work-piece interface to removematerial from the work-piece in the form of miniature chips.