Review of Superfinishing by the Magnetic Abrasive Finishing Process

Home , Abrasive machining, Superfinishing

High Speed Mach. 2017; 3:42–55

Review Article Open Access

Lida Heng, Yon Jig Kim, and Sang Don Mun* Review of Superfinishing by the Magnetic Abrasive Finishing Process

DOI 10.1515/hsm-2017-0004 In the conventional lapping process, loose abrasive Received May 2, 2017; accepted June 20, 2017 particles in the form of highly-concentrated slurry are often used. The finishing mechanism then involves actions Abstract: Recent developments in the engineering indus- between the lapping plate, the abrasive, and the work- try have created a demand for advanced materials with su- piece, in which the abrasive particles roll freely, creating perior mechanical properties and high-quality surface fin- indentation cracks along the surface of the workpiece, ishes. Some of the conventional finishing methods such as which are then removed to finally achieve a smoother sur- lapping, grinding, honing, and polishing are now being re- face [1]. The lapping process typically is not used to change placed by non-conventional finishing processes. Magnetic the dimensional accuracy due to its very low material re- Abrasive Finishing (MAF) is a non-conventional superfin- moval rate. Grinding, on the other hand, is used to achieve ishing process in which magnetic abrasive particles inter- the surface finish and dimensional accuracy of the work- act with a magnetic field in the finishing zone to remove piece simultaneously [2]. In grinding, fixed abrasives are materials to achieve very high surface finishing and de- used by bonding them on paper or a plate for fast stock burring simultaneously. In this review paper, the working removal. Polishing is another finishing process used for principles, processing parameters, and current limitations smoothing a workpiece’s surface by an abrasive particle for the MAF process are examined via reviewing important and a work wheel. The conventional technique of polish- work in the literature. Additionally, future developments ing involves the use of fine abrasives in a liquid carrier on of the MAF process are discussed. a polishing pad. By this process, a rough surface with vis- Keywords: internal magnetic abrasive finishing; cylindri- ible irregularities can be transformed into a smooth sur- cal magnetic abrasive finishing; plane magnetic abrasive face to naked eyes [3]. Kuhar and Funduk [4] studied the finishing; surface roughness; removal weight effect of polishing techniques on the surface roughness of an acrylic denture. Their results concluded that the polishing technique produced the smoothest surface for an 1 Introduction acrylic denture. Honing is an internal finishing process using honing stones which are consisted of abrasive grains with a form of very fine powder. Honing is primarily used to Recent developments in industry have fueled the demand improve the geometric form of a surface, but may also im- for products with very high surface finish in addition to di- prove the surface texture [5]. Honing often is applied to in- mensional accuracy. However, it is very difficult to improve ternal cylindrical surfaces, such as automobile cylindrical the accuracy of such products with one simple finishing walls. There is another method called burnishing, which method. Therefore, many researchers have tried to adopt consists of pressing hardened steel rolls or balls into the different processing methods to improve the surface qual- surface of the workpiece and imparting a feed motion to ity of these products. Conventional methods for achieving the same surface [6]. Burnishing has provided very good high surface finish include lapping, grinding, honing, pol- results for finishing internal holes and tubes. ishing, and burnishing. Despite wide applications of these conventional finishing processes, there are several limitations on the surface finish and dimensional accuracy achievable by these *Corresponding Author: Sang Don Mun: Department of Mechan- conventional finishing processes. ical Design Engineering Chonbuk National University Jeonju-si, These problems include high cost needed to accu- South Korea; Email: [email protected] rately finish high strength materials, high energy con- Lida Heng: Department of Mechanical Design Engineering Chon- buk National University Jeonju-si, South Korea sumption, lower ecological safety, etc. In addition, the Yon Jig Kim: Department of Mechanical Design Engineering Chon- pressure applied on the workpiece surface is high, which buk National University Jeonju-si, South Korea

© 2017 L. Heng and S. D. Mun, published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License. Unauthenticated Download Date | 8/20/17 11:33 AM Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 43 may damage the finished surface [7]. Pranita et al. [8] 1.2 Advantages of MAF pointed out that the conventional finishing processes (i.e., grinding, lapping, and honing) are not suitable to process Because MAF uses very low forces and loose abrasive par- parts with complex shapes, miniature sizes, or 3-D struc- ticles, the damages to the surface can be minimized. The tures economically and rapidly. Singh et al. [9] reported advantages of MAF over other alternative processes such that advanced engineering materials, such as silicon ni- as super finishing, lapping, and honing are listed below: tride, silicon carbide, and aluminum oxide, are difficult to • The simultaneous machining of mutually perpen- finish via conventional grinding and polishing techniques dicular surfaces (such as cylindrical and conical sur- to achieve high accuracy and with minimal surface de- faces), other combinations (such as finishing the fects, such as micro-cracks. Rampal et al. [10] reported that outer diameter and radii of a piston ring), and simi- the surface finish requirements for parts used for manu- lar parts is possible. facturing semiconductors, atomic energy parts, medical • Material surface is free of buns and thermal defects. instruments, and aerospace components are very high; • Low energy consumption. however, many of them, such as vacuum tubes, waveg- • Simple to implement. uides, and sanitary tubes, are difficult to process by con- • Ecologically safe. ventional finishing methods such as lapping, because of • Self-adaptability. their shapes. • Controllability. Yin and Shinmura [11] reported that it is difficult for • Substantial improvement in service characteristics conventional finishing processes using a solid tool tofin- such as wear resistance, as well as mechanical and ish complicated micro-curved surfaces of cast parts of physical characteristics. magnesium alloys because the solid tool may not be able • Nonferrous materials, such as aluminum and its al- to enter inaccessible and unseen areas. loys or brass and its alloys, can also be finished with ease. 1.1 Magnetic abrasive finishing (MAF) Sumit and Chhikara [17] showed that MAF can be used to efficiently produce mirror-like internal and external sur- The Magnetic Abrasive Finishing (MAF) process has sev- faces of good quality for tube-type workpieces. Deepak et eral advantages over the conventional finishing processes. al. [7] reported that the MAF process can be used to effi- MAF is a non-traditional precision machining process, in ciently produce mirror-like surfaces of good quality on the which the finishing process is completed using magnetic order of a few nanometers for flat surfaces, as well as inter- force and magnetic abrasives [12]. It was initially devel- nal and external surfaces for tube-type workpieces. Their oped as a machining process in the US in the 1930s, but study showed that surface finishing via MAF is better than was not further developed until after the 1960s [13]. Mag- that via conventional finishing processes, such as lapping, netic abrasive finishing was discussed in a patent in 1938 honing, and the abrasive flow finishing. by Harry P. Coats [14]. In the last decade, MAF has been Yin and Shinmura [11] reported that the vertical developed as a new finishing technology, in particular in vibration-assisted magnetic abrasive finishing process is the manufacturing of highly precise and sensitive instru- a better process than the conventional magnetic abrasive ments for medical, optics, electrical, and engine compo- finishing process for removing the micro-burr of magne- nents [15, 16], although it is still a useful and viable ma- sium alloys. chining method. In the following sections, the working principles, pro- In MAF, the workpiece is kept between the N-pole and cessing parameters, and current limitations for the MAF S-pole of the magnet, and the working gap between the process will be examined in details by citing important re- workpiece and the magnet is filled with magnetic abra- search work in the literature. sive particles [12]. These abrasive particles forms a flexible magnetic abrasive brush (FMAB), acting as a multipoint cutting tool due to the effect of the magnetic field inthe working gap. When a workpiece is inserted into such a processing field under a given rotational speed, feed, and vibration in the axial direction, surface and edge finishing are carried out via the magnetic brush.

Unauthenticated Download Date | 8/20/17 11:33 AM 44 Ë L. Heng and S. D. Mun

2 Principle of MAF

2.1 Process setup of MAF

2.1.1 Process setup of cylindrical MAF

Figure 1 shows a schematic diagram of the cylindrical magnetic abrasive finishing process setup, in which a cylindrical workpiece is inserted inside the gap between the two magnetic poles [12]. The gap between the workpiece and the magnet pole is filled with magnetic abrasive particles (MAPs), which are composed of ferromagnetic materials, Figure 2: Cylindrical magnetic abrasive finishing process [19]. such as iron particles, and non-magnetic abrasive pow- ders. The MAPs are joined magnetically between magnetic poles (N and S) along the lines of magnetic force and form 2.1.2 Process setup of internal MAF a flexible magnetic abrasive brush (FMAB). The cylindrical magnetic abrasive finishing process is achieved when the The magnetic abrasive finishing process can also be used cylindrical workpiece starts to rotate at the same time as for finishing internal surfaces. Much of the developments the cylindrical workpiece or magnetic pole is vibrating [12]. of this process were conducted in Japan in the late 1980s A close-up view of the cylindrical MAF process is shown in and 1990s. It was first proposed as an external finishing Figure 2 [19]. process for cylindrical objects by Shinmura et al. [13]. The internal magnetic abrasive finishing process is consisted of two subsystems: (i) the magnetic pole rotating system [20] and (ii) the workpiece rotating system [21]. In the process, magnetic abrasive particles introduced into the workpiece are attracted by the magnetic field to bear down on the inner surface of the workpiece [22]. These particles join each other along the lines of magnetic force due to dipole-dipole interaction and form an FMAB, which pushes against the workpiece surface and develops a finishing pressure [23]. This finishing pressure creates micro- indentations on the workpiece surface. The tangential force developed by the FMAB is the main cutting force responsible for micro-chipping. Abrasives generally rely on a difference in hardness between the abrasive and thema- terial being processed, the abrasive being the harder of the two substances. The required finishing pressure is applied by the magnetic field produced by the permanent magnet or electromagnets. A photograph and schematic of the internal magnetic abrasive finishing process setup are shown in Figures 3 and 4, respectively.

2.1.3 Process setup of plane MAF

Figure 5 shows a schematic diagram of a magnetic abra- Figure 1: Schematic diagram of the cylindrical magnetic abrasive sive finishing setup for plane surfaces. During the plane finishing process setup [18]. magnetic abrasive finishing process, the finishing action is generated via the application of a magnetic field across the gap between the surface of the workpiece and the ro-

Unauthenticated Download Date | 8/20/17 11:33 AM

Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 45

Figure 5: Schematic diagram of the plane magnetic abrasive finishing process setup [9].

Figure 3: Photograph of the internal magnetic abrasive finishing process setup [24].

Figure 4: Two-dimensional schematic of the abrasive behavior of the process [25]. Figure 6: Plane magnetic abrasive finishing [26]. tating magnetic pole. The magnetic field generated by the moval (in the form of chips), which gradually improves the magnetic pole forms the (self-adaptive) magnetic abrasive surface roughness via pole feeding. brush. The normal force acting on the workpiece surface, Figure 6 shows a plane MAF process, in which the fin- in combination with pole rotation, causes the material re- ishing action is generated via application of a magnetic

Unauthenticated Download Date | 8/20/17 11:33 AM

46 Ë L. Heng and S. D. Mun field across the gap between the workpiece surface and the rotating electromagnet pole. The enlarged view of the finishing zone in Figure 6 illustrates the forces acting on the work surface to remove material. The force due to the magnetic field is responsible for the normal force causing abrasive penetration inside the workpiece, while rotation of the magnetic abrasive brush (i.e., N-pole) results in the material removal in the form of chips. Because the basic schematics of most MAF processes are similar, as discussed above, the research on improving the MAF focuses on the optimization of the process parameters, to be discussed in the following sections.

2.2 Process parameters

The parameters of the MAF process are divided into two categories: (i) input process parameters (e.g., magnetic abrasive type, abrasive particles, magnetic device, workpiece material, working gap, grinding oil, rotational speed, and axial vibration) and (ii) output process parameters (e.g., surface roughness and removal weight). The magnetic abrasive type, abrasive particles, magnetic device, workpiece material, working gap, grinding oil, rotational speed, and axial vibration are known as the significant input parameters in the MAF process because they have significant influence on the MAF process. Surface Figure 7: Schematic diagram of the process parameters of MAF. roughness and removal weight are used to evaluate the performance of magnetic abrasive finishing for a cylindri- the surface roughness (Ry) improved most when 1-µm dia- cal surface, an internal surface, and a plane surface. The mond abrasive particles were used. In terms of the rate of input and output process parameters of the MAF process material removal, the best result was obtained with 3-µm are shown in Figure 7. diamond abrasive particles. Vahdati and Rasouli et al. [28] evaluated how process parameters affected MAF on a concave free-form surface of 2.2.1 Output process parameters an Al alloy workpiece via the RSM method. To perform the MAF process, unbonded magnetic abrasive powder was In the magnetic abrasive finishing process, the improve- used. ment of surface roughness and the material removal rate Iron powder with a mesh size of #400 and alumina are the essential performance process parameters. abrasive powder with a mesh size of #1200 in a weight ra- Yoon et al. [27] investigated the effect of the magnetic tio of 3/1 were stirred using a mechanical stirring machine pole arrangement on the surface roughness of STS 304 us- for 20 minutes until the mixture becames almost homoge- ing MAF with four different magnetic pole arrangements, nous. Their results show that the gap, rotational speed of ∘ ∘ which included N single, N-S 90 , N-S 180 , and N-S-N ar- the spindle, and feed rate are influential in magnetic abra- rangements. According to their results, the surface rough- sive finishing of a concave free-form surface of Al alloys. ∘ ∘ ness improved by N single, N-S 90 , N-S 180 , and N-S- They found that in concave areas of the surface, the sur- N arrangements were 50.9%, 70.6%, 63.6% and 75.5%, re- face roughness decreases from its initial 1.3 µm roughness spectively. to 0.2 µm. Im et al. [12] improved the removal weight and surface Wu and Zou et al. [29] improved the removal rate and roughness (Ry) of an STS 304 bar using the MAF process. surface roughness (Ra) of SUS304 stainless steel plate us- In their study, different grain sizes (1, 3, and9 µm) were ing ultra-precision MAF process with low frequency alter- used as the abrasive tools for comparison. They found that

Unauthenticated Download Date | 8/20/17 11:33 AM Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 47 nating magnetic field. In their study, the important process field [32]. In order to understand the mechanism of the ma- parameters such as grinding fluid, and rotational speed terial removal of the MAF process, it is necessary to con- of magnetic pole were applied to the finishing process for centrate on the distribution of magnetic field between the improving the finishing capabilities. Their results show magnetic pole and workpiece. that the higher removal weight and smoother finished sur- The ferromagnetic particles join each other magneti- face can be obtained when grinding fluid was used. Also, cally between magnetic pole and workpiece along the lines the improvement of surface roughness and material re- of magnetic force to form a flexible brush like tool. For ex- moval rate increase with the increase of rotational speed ample, at position, during finishing process, the normal of magnetic pole. They found that the surface roughness force (FN ) acts on f a ferromagnetic particle near the work of SUS304 stainless steel plate improved from 240.24 nm surface of workpiece. Due to the rotation of the workpiece, to 4.38 nm. a resistance cutting force (RT) acts on the ferromagnetic Kala and Kumar et al. [30] developed a new setup particles in the tangential direction of the rotational mo- using a four-pole electro-magnet and a set of permanent tion. The tangential force (FT) due to magnetic field, acts magnet mounted on a perpex disc for finishing copper al- in the opposite direction of resistance cutting force resis- loy workpieces. In their experiments, effect of voltage to tance (RT), returns the ferromagnetic particle to its origi- the electromagnet, rotational speed, mesh size, and pulse nal position. It is shown that a ferromagnetic particle will on time of ultrasonic vibration on surface roughness were transmit abrasion pressure to an abrasive beneath it, un- studied. It is concluded that by using ultrasonic vibrations til the one on the workpiece surface to perform the cutting with the above arrangement a surface finish in nanometer action. Moreover, due to the magnetic field strength gradi- level on a flat copper alloy (C70600) work piece could be ents in the working gap, the ferromagnetic particles exert achieved, improving from 200 nm to 56 nm in 10 min. a normal force (FN ) to the work surface, while simultane- Sato and Yamaguchi et al. [31] studied the internal fin- ously, a tangential force (FT) will act on the ferromagnetic ishing process for a capillary using magneto-rheological particles in the anti-direction of cutting resistance (RT). fluid. They used the Taguchi method to study the param- Tangential force (FT) will prevent ferromagnetic particles eters (e.g., the rotational speed of the spindle, feed speed, from flowing or dispersing out of the working gap, which amount of lubricant, gap, and amount of abrasive pow- ensures that the finishing process will be successfully per- der) regarding the surface of a stainless steel 304 work- formed. Figure 9 shows a schematic of the normal force piece with low curvature. They could decrease the sur- (FN ) and the tangential force (FT) of the magnetic force act- face roughness value of stainless steel from 0.158 µm to ing on magnetic abrasive particles during the cutting pro- 0.102 µm. cess. Similar to the conventional abrasive finishing process In order to understand the effects of the process pa- or a cutting process with a tool with a negative angle, the rameters, it is necessary to understand the finishing mech- asperities of workpiece are removed by the abrasive tools anisms of MAF. in the form of micro-chips.

2.2.2 MAF finishing mechanisms (A) Calculation of forces acting on a ferromagnetic particle in MAF In the MAF process, two types of forces generated by a FMAB are responsible for finishing: (i) the normal force re- Figure 10 shows the schematic view of forces acting on a sponsible for packing the magnetic abrasive particles and ferromagnetic particle in MAF. The forces acting on a fer- providing micro-indentations into the workpiece and (ii) romagnetic particle in the magnetic field at position “B” is the tangential force responsible for micro-chipping due to the sum of two forces, Fx and Fy, on a ferromagnetic par- rotation of the FMAB [9]. A theory of the material removal ticle at the outside finishing gap of workpiece and mag- assumes that the normal force and the tangential force ex- netic poles (Figure 8). The force, Fx, acts along the direc- erted by the FMAB onto the surface of the workpiece are tion of line of magnetic force and it presses the abrasive combined to remove the material from the peaks of the sur- particle onto the surface of the workpiece. The force, Fy, is face asperities. This process is repeated as the contact be- in the direction of the magnetic equipotential line. These tween the brush and the surface continues during the fin- two forces, Fx and Fy, are given by [33] as ishing operation. (︂ dH )︂ (︂ dH )︂ Figure 8 illustrates how magnetic forces acting on fer- F = χFPµ VH & F = χFPµ VH (1) x o dX y o dY romagnetic particles are distributed within the magnetic

Unauthenticated Download Date | 8/20/17 11:33 AM 48 Ë L. Heng and S. D. Mun

Figure 8: Schematic diagram showing distribution of magnetic field and dispersion of forces acting on ferromagnetic particle [32]. Figure 10: Schematic view of forces acting on ferromagnetic particle in MAF [34].

As shown in Figure 10, FN and FT can be calculated from Fx and Fy based on the angle θ which is determined based on the location of the ferromagnetic particle.

2.2.3 Magnetic abrasive type

Magnetic abrasive particles can be the bonded type or the unbonded type [35]. Bonded magnetic abrasive particles are prepared by sintering ferromagnetic particles and abrasives, whereas unbonded magnetic abrasive particles are a mechanical mixture of ferromagnetic parti- Figure 9: Schematic diagram showing the normal force (FN ) and the tangential force (FT ) of the magnetic force acting on magnetic cles and abrasive powder with a small amount of lu- abrasive particles during cutting process. bricant [36]. Some experimental investigations have re- vealed that unbounded magnetic abrasives yield higher MRR while bonded magnetic abrasives produce a better Where x defines the direction of the line of magnetic force, surface finish [37]. Figures 11 and 12 show the structure y defines the direction of the magnetic equipotential line, FP model of a single bonded type and an unbonded type of χ is the susceptibility of the ferromagnetic particles, µo magnetic abrasive, respectively [35, 39]. is the permeability of vacuum, V is the volume of the fer- Heng et al. [38] applied the unbonded type of magnetic romagnetic particles, H is the magnetic field strength at abrasive to the MAF process for finishing the surface of point “B”, and dH and dH are the gradients magnetic field dX dY Mg alloy bars 50 mm in length and 3 mm in diameter. In strength in the x and y directions, respectively. their study, the unbonded type of magnetic abrasive con- As shown in Figure 10 that, the normal force, FN , along sists of 0.85 g of iron particles (#200), 0.2 g of three sizes the N-N direction and the tangential force, FT, along the T- of diamond abrasive particles (0.5, 1, and 3 µm), 0.01 g of T direction are given by [34], carbon nanotube (CNT) particles, and 0.2 ml of light oil. FN = FXcosθ + FY sinθ & FT = −FX sin θ + FY cos θ They found that the surface roughness (Ra) was improved (2)

Unauthenticated Download Date | 8/20/17 11:33 AM Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 49

Figure 11: Structural model of the single a bonded magnetic abrasive particle (Dmap=Diameter of magnetic abrasive particle; ds=diameter of abrasive particle) [35]. to 0.02 µm after 20 seconds by the unbonded type of magnetic abrasive. Chang et al. [18] studied cylindrical MAF using un- Figure 12: Structural model of the unbonded type of magnetic abra- bonded magnetic abrasives. They used the unbonded type sive [39]. of magnetic abrasive to finish the surface of SKD11, HRC55 (HV600). In their study, the unbonded magnetic abrasive ticles (0.01-0.04 µm) to finish the surface of zirconia ce- is a mechanical mixture of a SiC abrasive and ferromag- ramic bars. The surface roughness and diameter were sig- netic particle with a SAE30 lubricant. They found that the nificantly improved by the mixture of CNTs and diamond best surface roughness at 0.042 µm Ra could be obtained abrasive particles. They found that the surface roughness when the SiC abrasive particles were used. Sharma and of microscale-diameter zirconia ceramic bars could im- Singh [14] used the bonded type of magnetic abrasive to prove from 0.18 µm to 0.02 µm (Ra) by the mixture of CNTs finish brass tubes, SS 304, and SS 316 materials. Intheir and diamond abrasive particles. study, the bonded magnetic abrasive particles were pre- Yin and Shinmura [11] used 1 g of WA magnetic abra- pared by sintering ferromagnetic powder (iron) and abrasive (80 µm) mixed with 4 g of iron particles (330 µm) to im- sive powder (Al2O3) at a very high pressure, and the man- prove the removal volume and surface roughness of mag- ufacturing process employed determines the surface fin- nesium alloys, and they showed that the surface rough- ish level. According to the results, they found that the best ness of magnesium alloy could improve from 2.5 µm to surface roughness value on a cylindrical component was 0.7 µm (Ry) via the use of WA magnetic abrasive particles. improved from 0.257 µm to 0.075 µm Ra over a machining Chang et al. [18] used a SiC abrasive mixed with steel duration of 3 minutes with abrasive powder (Al2O3). grit to improve the material removal and surface roughness of an SKD11 material. They showed that the best surface roughness of SKD11 material could be reduced to 2.2.4 Abrasive particles characteristics 0.042 µm via the use of SiC magnetic abrasive particles. Among them, CNT particles and diamond particles In the MAF process, the abrasive particles are a critical (PCD) are the best abrasive particles for improving the sur- parameter because they are directly related to the cut- face roughness and removal weight of material due to their ting or polishing the surface of the material. The mag- superior mechanical properties [36]. Table 1 lists the me- netic abrasive tools consist of ferrous particles mixed with chanical properties of the abrasive particles. As shown fine abrasive particles (diamond (PCD), aluminum oxide in Table 1 that CNT particles have the excellent mechani- (Al2O3), silicon carbide (SiC), cubic boron nitride (CBN), cal properties followed by diamond particle (PCD), Al2O3, carbon nanotubes (CNTs), etc.), and such particles are SiC, and Boron. called ferromagnetic abrasive particles or Magnetic Abra- sive Particles (MAPs) [40]. Park et al. [41] used a mixture of 16 wt% diamond abrasive (1 µm) and 2 wt% CNT par-

Unauthenticated Download Date | 8/20/17 11:33 AM 50 Ë L. Heng and S. D. Mun

Table 1: Properties of abrasive used in MAF process [38, 42]. Singh and Singh [46] investigated the effect of magnetic abrasives on the internal finishing of brass tubes us- Abrasive Thermal Elastic Strength ing the MAF method. The workpieces were finished via a Types Conductivity Modulus (GPa) poles rotation system. (W/mK) (GPa) The rotation of the poles consists of small permanent Boron 100-200 370-400 3.3-4.0 magnets around the workpiece, which causes rotation of SiC 70-110 210-400 2.9-4.0 the magnetic field on the finishing surface. Al2O3 30 380 1.5 Kala and Pandey [47] demonstrated the application PCD 350 1050 4.0 of double disc magnetic abrasive finishing (DDMAF) pro- CNT 1800-6600 600-1200 20-50 cess, on planar paramagnetic workpieces (copper alloy and stainless steel) of different mechanical properties like flow stress, hardness, shear modulus, etc. In their study, 2.2.5 Magnetic devices the arrangement of the four poles with Nd-B-Fe type permanent magnet disc has been used to improve the surface The magnetic devices of the MAF process typically have of copper alloy and stainless steel. From the experimental three configurations: (i) MAF with a permanent magnet, results, it was found that the surface roughness of the cop- (ii) MAF with a direct current, and (iii) MAF with an alter- per alloy improved from 0.37 µm Ra to 0.05 µm Ra and the nating current [43]. surface roughness of stainless steel improved from 0.33 µm Ra to 0.07 µm Ra. MAF with permanent magnet has been success- (A) MAF with a permanent magnet fully improved the surface roughness of various workpiece shapes, including cylindrical workpieces, tube work- A permanent magnetic finishing mechanism was used by pieces, plate workpieces, and capillary tubes. The most Lin et al. [44]. Their experimental data was collected using significant improvement in surface roughness is found the Taguchi experimental design. The optimal parametric when MAF with permanent magnetic used to improve the conditions for processing the stainless SUS304 material surface of cylindrical workpiece. were applied in a two-stage process comprised of rough finishing that involved MAF, followed by precise finishing of the surface. From the experimental results, it was found (B) MAF with a direct current that the surface roughness of the stainless SUS304 material could improve from 2.670 µm Rmax to 0.158 µm Rmax Yamaguchi and Shinmura et al. [48] proposed the internal via the use of MAF with permanent magnet. MAF process using a stationary pole system. In their study, Im et al. [12] proposed MAF for micro-machining of an a SUS304 stainless steel disk was supported as a workpiece STS 304 cylindrical bar. The magnetic pole area is com- inside a vessel placed over a pole. A direct current (DC) posed of a Fe-Nd-B permanent magnet and a magnetic was used for generating the magnetic field, and the exper- field-assisted process with a mixture of iron particles, dia- iments were performed on the SUS304 stainless steel disk mond paste, and light oil. From their experimental results, ( 80 × 1 mm) with mixed-type magnetic abrasive iron par- it was found that the surface roughness (Ry) of STS 304 bar ticles (2.4 g) and an excitation current of 2 A. was improved to 0.06 µm in a finishing time of 30 second. Jain et al. [49] investigated the effect of the work- Shinmura and Aizawa [45] described the internal fin- ing gap and circumferential speed on the performance of ishing process of a SUS304 stainless steel sanitary tube via the MAF process. Their experimental work was performed magnetic abrasive machining, in which a suitable concen- with a stainless steel cylindrical workpiece ( 48 × 50 mm) trative magnetic field is induced in the inner working re- and an input current of 2.5 A. A loosely bonded powder is gion of the tube by the N-S poles of a permanent magnet. prepared for experimentation by homogeneously mixing In their study, a magnetic abrasive composed of allumina magnetic powder (Fe powder of 300 mesh size (51.4 µm)), particles (Al2O3) and iron particles with a mean diameter abrasive powder (Al2O3 of 600 mesh size (25.7 µm)), and a of 80 µm, as well as a machining fluid (15 wt%), is sup- lubricant called servospin-12 oil. plied. From the experimental results, it was found that the surface roughness of the sample improved from 0.4 µm Rmax to 0.1 µm Rmax in a finishing time of 10 minutes.

Unauthenticated Download Date | 8/20/17 11:33 AM Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 51

(C) MAF with an alternating current Chang et al. [18] investigated the finishing performance of steel grit on a harder workpiece using an un- Wou and Zou [50] studied the mechanism of the MAF pro- bonded magnetic abrasive. They concluded that the work- cess using a low frequency alternating magnetic field. In piece that had an HRC61 hardness yields a better surface this study, they compared the magnetic field to the finish- roughness and higher material removal than the working characteristics. The finishing time was 60 minutes. The piece that had HRC55 hardness. workpiece was a SUS304 stainless steel plate with a size of 80 mm × 90 mm × 1 mm. The direct magnetic field is 1.9 A, and the alternating magnetic field is 1.9 A. The finishing 2.2.7 Working gap force was measured in an alternating magnetic field and a direct magnetic field. The experimental results indicated In the MAF process, a decrease in the working gap in- that the alternating magnetic field may produce a fluctuat- creases the material removal weight and improves the sur- ing finishing force, and the force is greater than that ofthe face finish of the workpiece. direct magnetic field. At a low value of the working gap, the magnetic abra- In another work, Wu and Zou [51] proposed an ultra- sive brush is stronger, and it can take deeper cuts to re- precision plane MAF process by using an alternating mag- move a larger amount of material from the workpiece. netic field. The selected workpiece was a C2801 brass plate, This effect will further escalate with an increase inthe with a size of 80 mm × 90 mm × 1 mm. The compound circumferential speed. Jain et al. [49] evaluated the effect magnetic finishing fluid consists of electrolytic iron pow- of the working gap and the circumferential speed on ma- der (average diameter of 6 µm), WA abrasive (#200), and terial removal and surface finish improvement, showing an oily finishing fluid with an excitation current of3A. that higher speeds and smaller working gaps produce a Yamaguchi et al. [52] proposed a new precision inter- better surface finish. Exceptions were found for working nal machining process that controls the surface integrity of gaps smaller than 0.5 mm because of the restrained space, the internal surface of components used in critical appli- which compromises abrasive renovation. Singh et al. [53] cations such as high-pressure gas or liquid piping systems. applied Taguchi’s design of experiments to determine im- This process utilizes an alternating magnetic field to con- portant parameters influencing the surface quality gener- trol the force and the dynamic motion of the tools needed ated. Experimental results indicated that for a change in for finishing. surface roughness, the voltage and the working gap were MAF with direct current and magnetic abrasive with found to be the most significant parameters, followed by alternating current has been used successfully for improv- the grain mesh number and the rotational speed. Givi et ing the surface roughness and removal weight of cylin- al. [54] investigated the effects of some parameters on alu- drical workpieces, tube workpieces, and plate workpieces. minum surface plate finishing, such as rotational speed of MAF with alternating current is not a common practice as the permanent magnetic pole, working gap between the it is difficult to maintain and control the alternating mag- permanent pole and the workpiece, number of the cycles, netic field to finish the surfaces. But still, it has been used and the weight of the abrasive particles. Analysis of vari- for finishing and modification of surfaces. ance (ANOVA) has been used to determine significant fac- tors in the MAF process. The authors found that the working gap has a significant effect on the surface roughness 2.2.6 Workpiece material because for lower gap values, increasing in the gap value strongly decreases ∆Ra, but for higher gap values, ∆Ra de- The mechanical properties of the workpiece material are creases slowly. important to MAF in terms of surface roughness and removal weight. Sharma and Singh [14] studied the effects of various 2.2.8 Grinding oil parameters on MAF. MAF was applied on workpieces with hardnesses of 45, 50, and 55 RC with the same finishing Grinding fluid plays a vital role in MAF; they are commonly conditions. used in the finishing and machining processes to reduce Their results showed that a heavily improved finish- the friction force and the high temperature that occurs being occurs for the workpiece with a hardness of 55 RC with tween the surface finish of the workpiece and the abrasive Al2O3 and ferrite abrasives. tool.

Unauthenticated Download Date | 8/20/17 11:33 AM 52 Ë L. Heng and S. D. Mun

Moreover, grinding oil is an important component of fectively using the MAF technique [7]. In particular, when compound magnetic finishing fluid, which is the carrier the workpiece is a micro-scale material, the MAF process of magnetic particles, affecting the distribution of abra- becomes impossible because the pressure or the finishing sives and playing a role on lubrication and cooling in pro- force generated by the magnetic flux density can damage cess [29]. During the finishing process, the friction force the surface of the workpiece. Furthermore, surface finish- that exists between the relative motion of the workpiece ing is negligible on ferromagnetic materials, such as nickel and abrasive tool can make the surfaces rough or less and cobalt alloys. This is due to the workpiece being mag- smooth. The high temperature generated during the finish- netized in the presence of a magnetic field, thus strongly ing process affects the tool wear, thus causing dimensional attracting magnetic abrasive particles to it. deviation and premature failure of the abrasive tool [55]. Sihag et al. [57] reported that MAF has the limitation Therefore, in order to reduce both the friction force of low efficiency and low MRR, especially when applied to and the high temperature generated in the cutting or fin- hard materials. ishing process, grinding oils are used as grinding oils for Kang et al. [24] developed high-speed internal finish- applying to the abrasive tools mixtures [56]. ing and cleaning of flexible capillary tubes via MAF. When the tube diameter becomes smaller, it is very difficult to completely remove burrs from the inner surface of the tube 2.2.9 Rotational speed and axial vibration using non-traditional techniques. Deepak et al. [7] studied the effect of rotational motion Rotational speed and axial vibration are known as the on the MAF of a flat workpiece. One serious limitation of most critical parameters in the finishing process. Chips almost all such processes is a low material removal rate. can be removed from the surface of a workpiece by pro- Laroux [19] reported that the MAF media can impreg- ducing a relative motion between the workpiece and the nate the workpiece surface. abrasive tools. Mahajan and Tajane [6] proposed that the SiC abrasives can be seen in the surface when electron RPM of the workpiece is the most significant factor for probe micro-analysis, energy dispersive X-ray analysis, or a ferromagnetic workpiece material. The percentage im- related Auger laboratory analyses are used. When SiC is provement of the surface roughness value increases as the abrasive, MAF can impart a mirror finish, but it will be the RPM of the workpiece increases, but it starts reduc- a darker color than when SiC is not used. ing after reaching an optimum value due to abrasive particles scattered by increasing the centrifugal force beyond a certain limit. However, without the axial vibration (both 4 Future developments amplitude and frequency) and with only the rotation of the workpiece, circumferential grooves will form. Im et Despite much technical advancement in the development al. [12] improved the surface of a STS 304 stainless steel of MAF processes in recent years, some limitations still re- bar ( 3 (150 mm) by MAF at a workpiece revolution speed main. of 30,000 RPM with 0 Hz and 12 Hz of vibration. The results To overcome these limitations, new potential research show that in the case of 0 Hz vibration, the surface rough- regarding such processes should be explored. Some ad- ness improved drastically in the initial phase of process- vanced techniques must be applied to the MAF process. ing, and then declined until it became worse than the ini- First, research should be performed to obtain high di- tial condition after approximately 60 seconds of process- mensional accuracy (e.g., removal weight, change in diam- ing. Conversely, in the case of 12 Hz vibration, the surface eter, and roundness) and surface accuracy via the ultra- roughness improved until the 30 second time point, after precision magnetic abrasive machining technique instead which it remained approximately the same. of MAF. Second, possible adaptation of the advance principle into the development of new micro-finishing techniques 3 Current limitations of the MAF could be explored for the surface finish of micro-materials, process wire materials, which are being used in medical devices such as pacemaker, defibrillator and cochlear implant. Especially for complex biomaterial shapes such as knee Despite the potential advantages of MAF processes, nu- joint, hip joint and other artificial joints. Third, the appli- merous limitations still exist. Geometries, such as a wrin- cation of finishing temperature (e.g., cryogenic, room, and kled surface of a workpiece, remain difficult to finish ef-

Unauthenticated Download Date | 8/20/17 11:33 AM Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 53 high temperatures) could be applied to the finishing pro- of material removal by fixed abrasive lapping of various glass cess to improve the finishing capability. Finally, the usage substrates. Wear. 2013, 302, 1334–1339. of abrasive nano-techniques in a magnetic abrasive mix [2] Naresh, K.; Himanshu, T.; Sandeep, G.: Optimization of cylindrical grinding process parameters on C40E steel using taguchi could also be explored. technique. Int. Journal of Engineering Research and Applica- tions. 2015, 5, 100–104. [3] Ong, N. S.; Venkatesh, V. C.: Semi-ductile grinding and polishing of pyrex glass. Journal of Materials Processing Technoloy. 5 Concluding remarks 1998, 83, 261–266. [4] Kuhar, M.; Funduk, N.: Effects of polishing techniques on the This paper reviews the working principles, processing pa- surface roughness of acrylic denture base resins", Journal of rameters, and current limitations for the MAF process and Prosthetic Dentistry. 2005, 93, 76–85. has highlighted future developments of the MAF process. [5] Rajkumar, S.; Sasikkumar, M.; Ramachandran, R. V.; Sabarig- uru, T.; Vinothkumar, M.: Design and implementation of reduc- The conclusions of this study are summarized as follows. ing stick mark in honing machining process by using universal The MAF process has been shown to successfully joint. Internal Journal of Modern Trends in Engineering and Sci- improve the surface accuracy and dimensional accuracy ence. 2015, 2, 1–4. of various workpiece shapes, including cylindrical work- [6] Mahajan, D.; Tajane, R.: A review on ball burnishing process. pieces, tube workpieces, plate workpieces, capillary tubes, International Journal of Scientific and Research Publications. 2013, 3(11) 1–8. and concave surface workpieces. [7] Deepak, B.; Walia, R. S.; Suri, N. M.: Effect of rotational motion The MAF process can be successfully used for the fin- on the flat work piece magnetic abrasive finishing. International ishing of various materials, such as Mg alloys, Al alloys, Journal of Surface Engineering & Materials Technology. 2012, STS 304, zirconia ceramics, SS 305, SS 316, and brass. 2(1), 50–54. The critical parameters, such as magnetic abrasive [8] Pranita, A. D.; Azar, R. I.; Swapnali, R. G.: Review on advanced type and particles, magnetic flux density, workpiece mate- finishing processes. 4th International on Recent innovation in Science Engineering and Management. 2016, 577–581. rial, finishing gap, grinding oil, rotational speed, and axial [9] Singh, D. K.; Jain, V. K.; Raghuram, V.: Experimental investiga- vibration, are found to be effective for the MAF process. tions into forces acting during a magnetic abrasive finishing The MAF process can be used with the bonded or un- process. International Journal of Advanced Manufacturing Tech- bonded type of magnetic abrasives. MAF with unbounded nology. 2006, 30, 652–662. magnetic abrasives yields higher MRR, while bonded mag- [10] Rampal, E. R.: Comparing the magnetic abrasives by investigat- ing the surface finish. Journal of Engineering, Computer &Ap- netic abrasives produce a better surface finish. plied Science, 2012, 1(1), 20-24. The MAF process has three system configurations, [11] Yin, S.; Shinmura, T.: Vertical vibration-assisted magnetic abra- which include MAF with a permanent magnet, MAF with sive finishing and deburring for magnesium alloy. International a direct current, and AMF with an alternating current. Journal of Machining Tools and Manufacturing. 2004, 44, 1293– Despite the potential advantages of MAF processes, 1303. numerous limitations still exist. These limitations include: [12] Im, I. T.; Mun, S. D.; Oh, S. M.: Micro machining of an STS 304 bar by magnetic abrasive finishing.: Journal of Mechanical Science 1) geometries such as wrinkled surfaces, micro-scale ma- and Technology. 2009, 23(7), 1982–1988. terials, wire materials, and complex-shaped materials, 2) [13] Shinmura, T.: Study on magnetic abrasive finishing. CIRP ferromagnetic materials, such as nickel and cobalt alloys, Annals-Manufacturing Technology. 1990, 39(1), 325–328. and 3) low material removal rates. [14] Sharma, M.; Singh, D. P.: To study the effect of various parame- The ultra-precision magnetic abrasive machining ters on magnetic abrasive finishing. IJRMET. 2013, 3, 325–328. [15] Yamaguchi, H.; Shinmura, T.; Kaneko, T.: Development of a new technique could be used instead of MAF for achieving a internal finishing process applying magnetic abrasive finish- better improvement of the material removal weight. ing by use of pole rotation system. International Journal of the Japan, Society for Precision Engineering. 1996, 30(4), 317–322. Acknowledgement: This work was supported by [16] Sato, T.; Yamaguchi, H.; Shinmura, T.; Okazaki, T.: Study of sur- a research program of the National Research face finishing process using magneto-rheological fluid (MRF). Foundation (NRF) of Korea in 2016 (Project No. Journal of Japan Society for Precision Engineering. 2006, 72(11), 1402–1406. 2016R1D1A1B03932103). [17] Sumit, Y.;Chhikara, G.: Modern magnetic abrasive finishing process. International Journal of Enhanced Research in Science Technology & Engineering. 2014, 3(6), 460–462. [18] Chang, G. W.; Yan, B. H.; Hsu, R. T.: Study on cylindrical magnetic References abrasive finishing using unbonded magnetic abrasives. Inter- national Journal of Machine Tools and Manufacture. 2002, 42, [1] Cho, B. J.; Kim, H. M.; Moon, D. J.; Park, J. G.: On the mechanism 575–583.

Unauthenticated Download Date | 8/20/17 11:33 AM 54 Ë L. Heng and S. D. Mun

[19] Laroux, K. G.: Using magnetic abrasive finishing for deburring [34] Judal, K. B.; Yadava, V.: Modeling and simulation of cylindrical produces parts that perform well and look great. Alluring and electro-chemical magnetic abrasive machining of AISI-420 mag- Deburring. 2008, 60. netic steel. Journal of Materials Processing Technology. 2013, [20] Yamaguchi, H.; Kang, J.: Study of ferrous tools in internal sur- 213, 2089–2100. face and edge finishing of flexible capillary tubes by magnetic [35] Jayswal, S. C.; Jain, V. K.; D, P. M.: Modeling and simulation abrasive finishing. Transactions of NAMRI/SME. 2010, 38, 177– of magnetic abrasive finishing process. International Journal of 184. Advanced Manufacturing Technology. 2005, 26, 477–490. [21] Verma, G. C.; Kala, P.; Pandey, P. M.: Experimental investiga- [36] Rao, R. V.: Modeling and optimization of nano-finishing pro- tions into internal magnetic abrasive finishing of pipes. Inter- cesses. International Research and Development. 2011, 285– national Journal of Advanced Manufacturing Technology. 2017, 316. 88, 1657–1668. [37] Jain, V. K.: Abrasive finishing process. Advanced Machining Pro- [22] Yamaguchi, H.; Shinmura, T.: Development of a new internal fin- cess. 2004, 57-88. ishing process applying magnetic abrasive finishing by use of [38] Heng. L.; Yang, G. E.; Wang, R.; Kim, M. S.; Mun, S. D.: Effect of pole rotation system. International Journal of the Japan Society carbon nano tube (CNT) particles in magnetic abrasive finishing for Precision Engineering. 1996 (30), 317–322. of mg alloy bars. Journal of Mechanical Science and Technology. [23] Singh, P.; Singh, L.: Optimization of magnetic abrasive finish- 2015, 29, 5325–5333. ing parameters with response surface methodology. Proceed- [39] Judal, K. B.; Yadava, V.: Review of research work in magnetic ings of the International Conference on Research and Innova- abrasive finishing. Proceedings of National Conference on Re- tions in Mechanical Engineering. Lecture Notes in Mechanical cent Advances in Manufacturing (RAM-2010), SVNIT Surat. 2010, Engineering. 2014, 30, 273–286. 59–65. [24] Kang, J.; Andrew, G.; Yamaguchi, H.: High-speed internal finish- [40] Jain, V. K.: Magnetic field assisted abrasive based micro-/nano- ing of capillary tubes by magnetic abrasive finishing. 5th CIRP finishing. Journal of Materials Processing Technology. 2009, Conference on High Performance Cutting, Procedia CIRP 1. 2012, 209, 6022–6038. 1, 414–418. [41] Park, N. J.; Heng. L.; Wang, R.; Kim, M. S.; Mun, S. D.: Ultra- [25] Shinmura, T.; Yamaguchi, H.: study on a new internal finishing high-precision machining of microscale-diameter zirconia ce- process by the application of magnetic abrasive machining" (in- ramic bars by means of magnetic abrasive finishing. Applied tern finishing of stainless steel tube and clean gas bomb), The Mechanics and Materials. 2016, 851, 98–105. Japan Society of Mechanical Engineers. 1995, (38)4, 798–804. [42] Yu, M. F.; Lourie, O.; Dyer, M. J.; Moloni, K.; Kelly, T. F.; Ruoff, [26] Patel, K. B.; Patel, K. M.: Magnetic abrasive finishing of R. S.: Strength and breaking mechanism of multiwalled carbon AISI52100. International Journal of Trend in Research and De- nanotubes under tensile load, Science. 2000, 287(5453), 637– velopment Volume. 2014, 1(1), 1–8. 640. [27] Yoon, s., Tu, J. F.; Lee, J. H.; Gyun, E. Y.; Mun, S. D.: Effect of the [43] Kumar, H.; Singh, S.; Srivastava, A.: Parametric investigations magnetic pole arrangement on the surface roughness of sts 304 into Internal surface modification of brass tubes with alter- by magnetic abrasive machining. International Journal of Preci- nating magnetic field. Procedia Manufacturing. 2016, 5, 1234– sion Engineering and Manufacturing. 2014, 15(7), 273–286. 1248. [28] Vahdati, M.; Rasouli, S.: Evaluation of parameters affecting [44] Lin, C. T.; Yang, L. D.; Chow, H. M.: Study of magnetic abra- magnetic abrasive finishing on concave freeform surface ofal sive finishing in free-form surface operations using the Taguchi alloy via RSM method. Advances in Materials Science and Engi- method. Int Adv Manuf Technology. 2007, 34, 122–130. neering. 2016, 2016(12), 1–14. [45] Shinmura, T.; Aizawa. T.: Study on internal finishing of a non- [29] Wu, J.; Zou, Y.; Sugiyama, H.: Study on ultra-precision magnetic ferromagnetic tubing by magnetic abrasive machining process. abrasive finishing process using low frequency alternating mag- Bulletin, Japan Society for Precision Engineering. 1989, 23(1), netic field. Journal of Magnetism and Magnetic Materials. 2015, 37-41. 386, 50–59. [46] Singh, S.; Singh. L.: Effect of magnetic abrasives in internal fin- [30] Kala, P.; Kumar, S.; Pandey, P. M.: Polishing of copper alloy us- ishing of brass tubes using MAF method. Journal of Academia ing double disk ultrasonic assisted magnetic abrasive polish- and Industrial Research (JAIR), 2014, 23, 689–692. ing. Materials and Manufacturing Process. 2013, 28(2), 200– [47] Kala, P.; Pandey, P. M.: Comparison of finishing characteristic of 206. two paramagnetic materials using double disc magnetic abra- [31] Sato, K.; Yamaguchi, H.; Shinmura, T.; Okazaki, T.: Study of in- sive finishing. Journal of Manufacturing Process. 2015, 17, 63– ternal finishing process for capillary using magneto-rheological 77. fluid. Journal of the Japan Society for Precision Engineering. [48] Yamaguchi, H.; Shinmura, T.: Study of the surface modification 2009, 75(5), 612–616. resulting from an internal magnetic abrasive finishing process. [32] Shinmura, T.; Takazawa K.; Hatano, E.: Study on magnetic abra- Wear. 1999, 225(229), 246–255. sive finishing-effect of various types of magnetic abrasives on [49] Jain, V. K.; Kumar, P.; Behera, P. K.; Jayswal, S. C.: Effect of work- finishing characteristics. Bulletin of the Japan Society of Preci- ing gap and circumferential speed on the performance of mag- sion Engineering. 1987, 21(2), 139–141. netic abrasive finishing process. Wear. 2001, 250, 384–390. [33] Smolkin, M. R.; Smolkin, R. D.: Calculation and analysis of the [50] Wu, J.; Zou, Y.: Study on mechanism of magnetic abrasive fin- magnetic force acting on a particle in the magnetic field of sep- ishing process using low-frequency alternating magnetic field. arator. Analysis of the equation used in the magnetic methods International Conference on Electromechanical Control Technol- of separation. IEEE Transactions on Magnetics. 2006, 42(11), ogy and Transportation (ICECTT 2015). 2015, 395, 985–989. 3682–3693.

Unauthenticated Download Date | 8/20/17 11:33 AM Review of Superfinishing by the Magnetic Abrasive Finishing Process Ë 55

[51] Wu, J.; Zou, Y.: Study on an ultra-precision plane magnetic abra- [55] Nurul, A. M. J.; Kamaleshwaran, T.; Ahamd, F. M.; Azwan, I. A.: sive finishing process by use of alternating magnetic field, Ap- A study of surface roughness & surface integrity in drilling pro- plied Mechanics and Materials. 2013, 395, 985–989. cess using various vegetable-oil based lubricants in minimum [52] Yamaguchi, H.; Shinmura, T.; Takenaga, M.: Development of a quantity lubrication. Australian Journal of Basic and Applied Sci- new precision internal machining process using an alternating ences. 2014, 8(15), 191–197. magnetic field, Precision Engineering. 2003, 27, 51–58. [56] Brinksmeier, E.; Meyera, D.; Huesmann, C. A. G.; Herrmann, [53] Singh, K. D.; Jain, V. K.; Raghuram, V.: Parametric study of mag- C.: Metalworking fluids-mechanisms and performance. CIRP An- netic abrasive finishing process. Journal of Materials Process- nals - Manufacturing Technology. 2015, 64, 605–628. ing Technology. 2004, 149, 22–29. [57] Sihag, N.; Kala, P.; Pandy, P. M.: Chemo assisted magnetic [54] Givi, M.; Tehrani, A. F.; Aminollah. M.: Statistical analysis of abrasive finishing: experimental investigations. Procedia CIRP. magnetic abrasive finishing (MAF) on surface roughness. Ko- 2015, 26, 539–543. rean Society for Technology of Plasticity. 2010, 1252, 1160–1167.

Unauthenticated Download Date | 8/20/17 11:33 AM