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Effect of the process parameters on the surface roughness during magnetic
1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME310EFFECT OF THE PROCESS PARAMETERS ON THE SURFACEROUGHNESS DURING MAGNETIC ABRASIVE FINISHINGPROCESS ON FERROMAGNETIC STAINLESS STEEL WORK-PIECESShrikant Thote1, Diwesh Meshram2, Kapil Pakhare3, Swapnil Gawande41(Mechanical Department, G.H.Raisoni Academy of Engineering & Technology, NagpurMaharashtra, India)2(Mechanical Department, G.H.Raisoni Academy of Engineering & Technology, NagpurMaharashtra, India)3(Mechanical Department, G.H.Raisoni Academy of Engineering & Technology, NagpurMaharashtra, India)4(Mechanical Department, G.H.Raisoni Academy of Engineering & Technology, NagpurMaharashtra, India)ABSTRACTStudy of new and cost effective finishing processes has always been an area of keeninterest to overcome the difficulties of existing finishing process. Magnetic AbrasiveFinishing (MAF) is a process in which a mixture of non-ferromagnetic abrasives andferromagnetic iron particles is used to do finishing operation with the aid of magnetic force.The iron particles in the mixture are magnetically energized using a magnetic field. The ironparticles form a lightly rigid matrix in which the abrasives are trapped. This is called FlexibleMagnetic Abrasive Brush (FMAB), which when given relative motion against a metalsurface, polishes that surface. The major studies concerning MAF have been done regardingthe behaviors of the process under the effect of various parameters like working gap, meshnumber of abrasive, speed of relative motion on cylindrical and flat work-pieces taking onetype of material, non-ferromagnetic or ferromagnetic only. But limited comparative study bytaking stainless steel with ferromagnetic behavior has been done to analyze the surfaceroughness that is generated during the process. This paper has aim of development ofMagnetic Abrasive Finishing Process & studying the effect of the process parameters(percent composition of iron powder, mesh number of abrasive and current) on the surfaceroughness during MAF of ferromagnetic S.S. work-piece material for flat work-pieces. TheINTERNATIONAL JOURNAL OF MECHANICAL ENGINEERINGAND TECHNOLOGY (IJMET)ISSN 0976 – 6340 (Print)ISSN 0976 – 6359 (Online)Volume 4, Issue 2, March - April (2013), pp. 310-319© IAEME: www.iaeme.com/ijmet.aspJournal Impact Factor (2013): 5.7731 (Calculated by GISI)www.jifactor.comIJMET© I A E M E
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME311results of the experiments are statistically analyzed using design expert v.7 software for theresponses generated during the process. In case of ferromagnetic work-piece, percentcomposition of iron powder has more effect than the other parameters. With increase in meshsize of abrasive, percent improvement in surface roughness increases. With increase incurrent the percent improvement in surface roughness value increases much more than theother parameters, therefore effect of applied current is seen to the most significant amongstall the parameters.Keywords: Magnetic abrasive finishing, Surface Roughness, Mesh number, Stainless steel.1. INTRODUCTIONA magnetic abrasive finishing process is defined as a process by whichmaterial is removed, in such a way that the surface finishing and deburring isperformed with the presence of a magnetic field in the machining zone. Magneticabrasive finishing (MAF) has a magnetic field which assisted finishing process. The workpiece is kept between the two poles of a magnet. The method was originally introduced in theSoviet Union, with further fundamental research in various countries including Japan.Nowadays, the study of the magnetic field assisting finishing processes is being conducted atindustrial levels around the world.1.1 Working PrincipleThe working gap between the work piece and the magnet is filled with magneticAbrasive particles (MAP), composed of ferromagnetic particles and abrasive powder. MAP isprepared by sintering of ferromagnetic particles and abrasive particles. The magnetic abrasiveparticles join each other along the lines of magnetic force and form a flexible magneticabrasive brush (FMAB) between the work piece and the magnetic pole .This brush behaveslike a multi-point cutting tool for finishing operation. When the magnetic N-pole is rotating,the Magnetic Abrasive Finishing Brush (MAFB) also rotates like a flexible grinding wheeland finishing is done according to the forces acting on the abrasive particles. In externalfinishing of cylindrical surface, the cylindrical work piece rotates between the magneticpoles, with the MAP filled in both the gaps on either side, whereas in internal finishing ofcylindrical surface, the work piece rotates between the magnetic poles and the MAP as shownin (Fig 1). The magnetic field generator can be either electromagnetic coils or permanentmagnets. The relative motion between the induced abrasive particles of the FMAB and workpiece generates the necessary shearing action at the abrasive–work-piece interface to removematerial from the work-piece in the form of miniature chips.Fig. 1 External cylindrical finishing & Internal cylindrical finishing.
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME3122. LITERATURE REVIEWChange in the strength of magnetic field in the direction of the line of magnetic forcenear the work-piece surface will actuate the magnetic abrasive particle. The effective way ofchanging the force/finishing pressure and rigidity of MAFB is through the change in diameter“D” of magnetic abrasive particle. Hence, ferromagnetic particles of several times thediameter of diamond abrasive “d” are mixed to form the magnetic abrasive brush. MAF isaffected by the material, shape and size of the work-piece, and shape and size of the magneticpole. Pressure increases with increase in flux density and decreases as the clearance gapbetween tool & work-piece increases. Larger the particle size, poorer the finishing (except for50µm particles) but higher is the stock removal which increases linearly with finishing time.The surface roughness is predicted as a function of finishing time by a model that hasbeen derived from the removed volume of material. Thus, it is possible, from the surface-roughness model, to predict the time when existing scratches are completely removed .The magnetic force acting on the magnetic abrasive, controlled by the field at the finishingarea, is considered the primary influence on the abrasive behavior against the inner surface ofthe work-piece. .With increase in working gap, the percentage improvement in surface roughnessincreases initially, reaches a maximum value and then it starts decreasing . Removal ofburrs in large surfaces with drilled holes using MAF shown that this method can be appliedboth for ferromagnetic and non-magnetic parts. This method can be improved as applied tonew tasks of deburring .The finishing characteristics of unbonded magnetic abrasive within cylindricalmagnetic abrasive finishing. The unbonded magnetic abrasive is a mechanical mixture of Sic-abrasive and ferromagnetic particles with a SAE30 lubricant. Iron grit and steel grit, threeparticle sizes were prepared for both and were used as ferromagnetic particles, each of thembeing mixed with 1.2 and 5.5 µm Sic abrasive, respectively. Results indicate that steel grit ismore suitable for magnetic abrasive finishing because of its superior hardness and thepolyhedron shape. However its corrosion resistibility decreased on a surface that was finishedvia steel grit mixed with SiC abrasive .Important parameters influencing the surfacequality generated during the MAF were identified as: (i) voltage (DC) applied to theelectromagnet, (ii) working gap, (iii) rotational speed of the magnet, and (iv) abrasive size(mesh number). .Efficient finishing of magnesium alloy is possible by the process. The volumeremoved per unit time of magnesium alloy is larger than that of other materials such as brassand stainless, that is, high-efficiency finishing could be achieved. Micro-burr of magnesiumalloy could be removed easily in a short time by the use of MAF .MAF process creates micro scratches having width less than 0.5 µm on the finished surface.Moreover, the surfaces have finished by the shearing of the peaks resulting in circular laysformed by the rotation of the FMAB. It shows that the finished surface has finescratches/micro-cuts which are farther distant apart resulting in smoothened surface. Butthese fine scratches would also disappear by using higher mesh number (finer abrasiveparticles) .A new technique was developed to compare the performance of the magneticabrasive powders and to find the powder that is appropriate for finishing and deburring ofdrilled holes placed on a plane steel surface 
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME313Proper deburring conditions are suggested to satisfy the productivity and theaccuracy. In addition to deburring, efficiency influence to surface roughness is analyzed. Toimprove the surface roughness and purity, volume of powder, height of gap, inductorrotational frequency, feed velocity and the method of coolant supply are analyzed and provedthat the continuous flow of coolant and the Fe powder without abrasive is effective fordeburring and surface quality. 3 EXPERIMENTAL SET-UPFundamental requirements of the experimental set-up are:3.1 Magnetization UnitBasic purpose of magnetization unit is to generate the required magnetic field to assistthe finishing process. Main parts of magnetization unit are –• D.C. Power supply• ElectromagnetTo energize the electromagnet a constant voltage/current D.C. regulated power supply ofoutput voltage from 0 to 30 V and output current from 0 to 5 A was used. By controlling theinduced current from D.C. power supply the generated magnetic field can be controlled.3.2 ElectromagnetA round flat faced electromagnet with diameter of 100 mm and height 57 mm wasused for experimentation. Electromagnet has a centered N-Pole (diameter 42 mm), surroundedwith a coil (thickness = 24 mm), further surrounded by an outer S-Pole (Thickness=6mm).Other dimensions of Electromagnet are given in Table 1.Table 1 Dimensions of ElectromagnetDimensionsExternal Diameter of magnet 110 mmHeight of magnet pole 55 mmPermissible current value 0– 6 ampWire used for winding CopperPermissible required voltage 0– 25 VMagnetic field intensity 0– 1.2 TDiameter of north – pole 42 mmThickness of south – pole 5 mmThickness covered by the coil 24 mmMaterial used for outer body shell EN – 8Carbon Bush dimension 31.5 × 20 × 7.5 mm33.3 Magnet Rotary Motion UnitTo get the finished surface, it was necessary to get relative motion between FMAB andwork piece. This unit was used to rotate the magnet and consequently to get the relativemotion between work piece and FMAB. This facility already exists in vertical millingmachine available in our machine tool lab.
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME3143.4 Motion Control UnitThe machine is equipped with a precise motion control unit (MCU). The work piececan be easily and accurately positioned to get the finished surface. There are three differentlead screw attachments to accurately position the work piece with respect to the electromagnetin three mutually perpendicular directions viz. X, Y, and Z, respectively. The work piece canbe controlled in X, Y and Z direction. The X and Y directions are automatic controlled and Zdirection is manually controlled.3.5 Fixture and Work PieceMagnetic stainless steel was chosen as work piece material. The work piece was madeof rectangular shaped. The length of the work piece was 100.6 mm which is slightly greaterthan the diameter of the electromagnet which was 100 mm. It was taken slightly moredeliberately because, in this case there was not chance of breaking of flexible brushphenomenon during finishing. During experiments the work pieces were mounted on the tablewith a base plate without the fixture.4 EXPERIMENTAL PROCEDUREThe experiments were conducted according to following steps-4.1 Work pieces were initially ground by surface grinder to give most same initial surfaceroughness value.4.2 After the grinding process, the work pieces were manually cleaned by acetone to removethe foreign particles. Initial surface roughness values were measured by using Telesurfanalyzer’ with least count of 0.001µm.4.3 To conduct the surface finish experiments, the work piece was mounted on the table ofMAF machine with a base plate. The work piece was made parallel to the electromagnetusing a dial indicator (least count-0.01mm) to maintain proper gap between them. The workpiece was made parallel in both X and Y direction. The position of work piece in XY planewas kept in such a way that the center of the electromagnet coincide with the center of thework piece.4.4 Working gap between electromagnet and work piece was maintained by a filler gauge andthis gap was filled with the MAP. The amount of MAP depends on the working gap. Percentby weight method was used to calculate the amount of MAP in the working gap.4.5 The current to the electromagnet was supplied and got it energized and abrasive powderfill between the electromagnet and work piece making FMAB. By giving rotation to themagnet, this FMAB performs the actual finishing operation.4.6 After completing the finishing operation, work piece was again cleaned manually usingacetone and final surface roughness value was measured.
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME3154.7 Selection of parameters for experimentationAs per the data given by various researchers, various parameters such as Type and sizeof abrasive particles, Percentage composition of iron particles and abrasive particles, Size ofiron particles , RPM of magnet, Finishing time etc. effect the surface roughness produced, butall of the above cannot be taken for experimentation due to various practical difficulties .Therefore only three parameters were chosen for present study are-4.7.1 Mesh size of the abrasive particles,4.7.2 Current suppliedTable 2 Variable parameters and their rangesParameter ValuesMesh size of the abrasive particle 30 # - 200 #Current(Amp) 0.2 - 1.0Percent composition of iron in MAPs 60 % - 90 %Table 3 Fixed parameters and their valuesParameter ValueGap 2.5 mmSize of iron particles 80#Abrasives used in MAP Al2O3Percent of oil in MAP 2 %Finishing time 12 minWork-pieces Flat stainless steel4.8 Response CharacteristicsThe effect of selected process parameters was studied on the response characteristic ofMAF process.The surface roughness was measured at near centre of work-piece using Digital Surf AnalyzerCY510 having least count 0.001µm. The average of Surface finish (Ra) values was calculatedand the percentage improvement in roughness was estimated as:■Ra = (Initial roughness – final roughness) × 100Initial roughness4. 9 ObservationsDesign data is obtained by using the DX 7 software. By putting the range values of theprocess parameters we obtained the standard and the run denotes the run which we have toperform i.e. for 1st experiment we have to perform the experiment using 12th row’sparameters. Here the response value taken is (■Ra) in Table 3.
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME316Table.3 ObservationsStd RunFactor 1 Factor 2 Factor 3 Reponce 1A: B: C: D:Size Current Iron Powder ■Ra(mesh) (amp) (%age) (gm)1 12 62.26 0.35 64.05 28.212 11 160.32 0.35 64.05 35.233 20 62.26 0.62 64.05 20.014 3 160.32 0.62 64.05 28.35 14 62.26 0.35 75.95 23.256 18 160.32 0.35 75.95 21.907 17 62.26 0.62 75.95 35.738 10 160.32 0.62 75.95 35.439 6 28.00 0.50 70.00 21.6110 2 200 0.50 70.00 34.7511 15 112.00 0.30 70.00 26.0112 5 112.00 1.0 70.00 28.2313 9 112.00 0.50 60.00 24.0814 1 112.00 0.50 90.00 23.1315 7 112.00 0.50 70.00 20.8816 19 112.00 0.50 70.00 20.0117 16 112.00 0.50 70.00 19.5518 4 112.00 0.50 70.00 19.4519 8 112.00 0.50 70.00 18.1220 13 112.00 0.50 70.00 18.225 RESULTS & DISCUSSIONSIt is not always necessary that all the input process parameters have significantcontribution in surface response. Some of the parameters may be very much significant thanother parameters. In Central rotatable Composite Design, the combination of the inputparameters in actual experiments is such that only one experiment is conducted at extremevalue for each variable. Therefore it is not much worthy to do analysis at extreme values tosee the effectiveness of input variables. Moreover in central run experiments, sameexperiments are repeated many times so they also cannot be taken to see the effect.From the design data using Design expert v.7 software, response curves were drawn.From Figure 2, (1) the %age of iron powder in the FMAB increases (from 64% to 76%)resulting increase in the %age improvement in surface roughness (■Ra). (2) as the abrasivesize increases (from 63 to 166), the %age improvement in surface roughness (■Ra) increases.
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME317Fig. 2 Effect of % of iron powder & Abrasive size on ■RaFig.3 Effect of % of Current & Abrasive size on ■RaFigure 3 represent (1) as the value of Current in the FMAB increases (from 0.3 to 0.6 amp)resulting increase in the %age improvement in surface roughness (■Ra). (2) as the abrasivesize increases (from 63 to 166), the %age improvement in surface roughness (■Ra) increases.It can be seen in Figure 4, (1) as the value of iron %age in the FMAB increases (64 to 76)resulting increase in the %age improvement in surface roughness (■Ra). (2) as the currentincreases (0.38 to 0.62), the %age improvement in surface roughness (■Ra) increases.Fig. 4 Effect of % of Iron powder & Current on ■Ra
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME3185. CONCLUSIONSAll the three individual parameters, mesh size of abrasive, current and percent composition ofFe powder in MAP have significant effect on the surface roughness in ferromagnetic workpiece Fe percent has higher contribution to ■Ra. In case of ferromagnetic work piece if the Fepercent in MAP is high then,The conclusions regarding %age Improvement in Surface finish are as follows1. Due to this the rigidity of FMAB will be more in ferromagnetic case and it will make morecontribution to finishing process. Current has high contribution in ■Ra.2. In surface finish experiments % of iron powder is the most significant factor for work-piece material.3.In case of ferromagnetic work-piece, percent composition of iron powder has more effectthan the mesh size of abrasives.4. With increase in mesh size of abrasive, percent improvement in surface roughness valuealso increases.5. With increase in current of power supply the percent improvement in surface roughnessvalue increases.REFERENCES Jain V.K, “Advance Machining Processes” Allied Publishers Pvt. Ltd. 2002. Jeong-Du Kim, Min-Seog Choi, Simulation for the prediction of surface-accuracy inmagnetic abrasive machining, Journal of Materials Processing Technology 53 (1995) pp 630-642. Hitomi Yamaguchi*, Takeo Shinmura, Study of an internal magnetic abrasive finishingusing a pole rotation system Discussion of the characteristic abrasive behavior, Journal of theInternational Societies for Precision Engineering and Nanotechnology 24 (2000) 237–244. Jain V.K, Kumar P., Behera P.K., Jayswal S.C., “Effect of working gap andcircumferential speed on the performance of magnetic abrasive finishing process”, Wear, Vol.250 (2001), pp.384-390. Yuri M.Baron ,Sung Lim Ko, Elena Repnikova, Experimental Verification of Deburringby Magnetic Abrasive Finishing Method, (2001). Geeng-Wei Chang, Biing-Hwa Yan ,Tzong Hsu , Study on cylindrical magnetic abrasivefinishing using unbonded magnetic abrasives, International Journal of Machine Tools andManufacture Volume 42, Issue 5 , April 2002, Pages 575-583. Singh Dhirendra K., Jain V. K. and Raghuram V., Parametric study of magnetic abrasivefinishing process, Journal of Materials Processing Technology Volume 149, Issues 1-3 , 10June 2004, Pages 22-29. Shaohui Yin,Takeo Shinmura, Vertical vibration-assisted magnetic abrasive finishing anddeburring for magnesium alloy, International Journal of Machine Tools & Manufacture 44(2004) 1297–1303. Singh Dhirendra K., Jain V. K. and Raghuram V, R. Komanduri, Analysis of surfacetexture generated by a flexible magnetic abrasive brush, © 2005 Published by Elsevier.
International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 –6340(Print), ISSN 0976 – 6359(Online) Volume 4, Issue 2, March - April (2013) © IAEME319 Y. M. Baron , S. -L. Ko and J. I. Park, Characterization of the Magnetic AbrasiveFinishing Method and Its Application to Deburring, Key Engineering Materials Vols. 291-292 (2005) pp. 291-296. S.L. Ko, Yu M. Baron and J.I. Park , Micro deburring for precision parts using MAF,Journal of Materials Processing Technology ,Volumes 187-188, 12 June 2007, Pages 19-25. U. D. Gulhane, S. B. Mishra and P. K. Mishra, “Enhancement of Surface Roughness of316l Stainless Steel and Ti-6al-4v using Low Plasticity Burnishing: Doe Approach”,International Journal of Mechanical Engineering & Technology (IJMET), Volume 3, Issue 1,2012, pp. 150 - 160, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359. U. D. Gulhane, A. B. Dixit, P. V. Bane and G. S. Salvi, “Optimization of ProcessParameters for 316l Stainless Steel using Taguchi Method and Anova”, International Journalof Mechanical Engineering & Technology (IJMET), Volume 3, Issue 2, 2012, pp. 67 - 72,ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359. P.B.Wagh, R.R.Deshmukh And S.D.Deshmukh, “Process Parameters Optimization forSurface Roughness in EDM for Aisi D2 Steel by Response Surface Methodology”,International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 1,2013, pp. 203 - 208, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359.
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