Behrad Mir

Khamesee

Mir Behrad Khamesee

Thamir Al-Dulaimi

CiteSeerX

 
 
Thamir Al-dulaimi *, Mir Behrad Khamesee 
  
Department of Mechanical and Mechatronics Engineering, University of Waterloo 
200 University Ave. West, Waterloo, Ontario, Canada, N2L 3G1 
thamir.al-dulaimi@uwaterloo.ca; khamesee@uwaterloo.ca 
 
Introduction 
Surface finishing is the final operation in manufacturing 
processes and it costs around 15% of the total 
manufacturing cost [1]. A high quality surface with very 
low values of surface roughness and high accuracy are 
required for some products in many applications. These 
characteristics are required especially for products with a 
complex shape which are made from advanced materials 
such as alloys of hard materials, glass, and ceramics.  
Magnetic field, on the other hand, has assisted a wide 
spectrum of manufacturing techniques in finishing, 
cleaning, deburring, and burnishing for difficult to 
machine materials. Magnetic field has been employed in a 
number of manufacturing processes to control the 
effective parameters of these processes. Moreover, it’s 
used to overcome the limitations of traditional finishing 
processes in terms of accuracy and cost, due to the high 
strength rigid tools. Magnetic Abrasive Flow Machining 
(MAFM), Magnetic Float Polishing (MFP), 
Magnetorheological Abrasive Flow Finishing (MRAFF), 
and Magnetic Abrasive Finishing (MAF) are some 
examples for these manufacturing processes. [2-4].  
Magnetic Abrasive Finishing (MAF) technique is one of 
the advanced and nonconventional finishing processes, in 
which magnetic field is used to produce a high quality 
finished surface efficiently and economically [2]. In MAF 
technique, a workpiece is placed in a magnetic field 
which is produced by a permanent magnet or an 
electromagnet. The working gap between the workpiece 
and the magnetic source fills with the Magnetic Abrasive 
Particles (MAPs). Applying a relative motion between the 
magnetic source and the workpiece makes MAPs scratch 
the surface of the workpiece and remove a thin layer with 
a Micro or Nano scale in a form of fine chips. In 
Magnetic Abrasive Finishing (MAF) cutting force is 
controlled by the magnetic field.  Thus, the formation of 
microcracks, which are mainly caused by the normal 
stresses, will be minimized due to the controlled forces 
applied on the abrasive particles. 
 
 
 
Process Principles and Experimental Set-up 
The new set-up uses a rotating magnetic field to control 
the finishing process for a flat plate. The first attempt of 
using a rotating magnetic field in MAF process has been 
conducted by Shinmura et al. They applied a rotating 
magnetic field to finish external [5] and internal [6] 
surfaces of a cylindrical workpieces. The workpieces 
were installed on the table of a vertical milling machine. 
A rotating magnetic field was produced by electrifying 
three-coils arranged in the direction of 120̊ interval with a 
three phase AC current. Most of the previous work in the 
literature uses a mechanical power to produce a rotating 
motion for the workpiece or the magnetic source. That 
motivated us to propose a new stationary setup. The 
general principle of the new setup is shown in Fig. 1. The 
proposed setup is a stationary system that depends on a 
rotating magnetic field to move MAPs on the workpiece 
surface. This magnetic field is produced by electrifying 
the electromagnets in a specific pattern. This system does 
not need machine equipment or any type of motor. The 
magnetic force Fm acting on MAPs in the working area 
has a magnitude of: 
 
Fm=µov(M·  )H                 (1) 
 
where µo represents the magnetic permeability in vacuum, 
v represents the volume of the magnetic abrasive particle, 
M represents the magnetization of the magnetic abrasive 
particle in the working area, H represents the magnetic 
flux intensity, and 	is the gradient notation.  
The proposed system in this study contains a software and 
many hardware components. The software component 
represents a MATLAB-Simulink file. Its primary purpose 
is to simulate the system based on a mathematical model 
that governing the main parameters depending on this 
application. The hardware components contain a dSPACE 
machine which serves as a data acquisition device. The 
data source comes from the Simulink file. Secondly, an 
amplifier and power supply which supplies the dSPACE 
device and L298 Dual Full-Bridge Drives. 
FORMATION AND CONTROL OF A ROTATING MAGNETIC FIELD IN MAGNETIC 
ABRASIVE FINISHING
*Affiliated also with University of Baghdad, Baghdad, Iraq
Proceedings of the ASME 2016 Conference on Information Storage and Processing Systems 
ISPS2016 
June 20-21, 2016, Santa Clara, CA, USA 
ISPS2016-9549
1 Copyright © 2016 by ASME
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Fig. 1 The proposed system concept. 
 
The L298 Dual Full-Bridge Drives control the direction 
of the current which then controls the polarity of the 
electromagnet (coils): either North (N) or South (S) Pole. 
The third part of the hardware components is the physical 
system which contains four-cylindrical electromagnets. 
Each electromagnet contains a coil with 1000 turns of a 
copper wire (AWG 22) around an iron core. The diameter 
of the coil is 40mm and the height is also 40mm. The iron 
core diameter is 20mm and the height is 50mm. The 
electromagnetic coils are inclined with respect to the 
vertical axis with an angle of 30̊. 
 
Control 
To be able to perform experiments and test the proposed 
concept, a control module which controls the 
electromagnets is essential. Fig. 2 shows a flow chart of 
the communication from the MATLAB file to the 
physical system. In this application, the electromagnets 
are controlled through a dSPACE device.  
 
Fig.  2 Flow chart of the system communication. 
  
The use of L298 Dual Full-Bridge Drives is to solve the 
problem of residual magnetism for the iron core of the 
electromagnet. This phenomenon happens to 
ferromagnetic material when it is constantly being 
charged in a single direction of current, obtaining a single 
pole facing the particles. The function of L298 Dual Full-
Bridge Drives is to manipulate the direction of the current 
passing through the coil and control its polarity with 
North (N) or South (S) Pole.   
 
MATLAB Simulink  
Simulink is needed to program the desired signal and thus 
control the electromagnets’ excitation, for example, the 
timing for on and off signals of the electromagnets. The 
challenge involves designing a signal such that the pattern 
of the magnetic field generated at each coil can produce a 
Flexible Magnetic Abrasive Brush (FMAB) in the 
working gap with the presence of MAPs as shown in   
Fig. 3, and move MAPs from point A to point B 
horizontally (not vertically) on the workpiece surface to 
perform the finishing process.  
 
 
Fig. 3 Flexible Magnetic Abrasive Brush (FMAB). 
 
The output signal from Simulink + dSPACE is an analog, 
while the L298 Dual Full-Bridge Drives work with a 
digital signal. Therefore, Pulse Width Modulation (PWM) 
technique is used to convert the analog signal into a 
digital signal.  
 
Fig. 4 Simulink Block Diagram for PWM. 
 
The algorithm of conversion from analog signal to digital 
signal through PWM is incorporated into the overall 
Simulink file for the four-coil configuration shown         
in Fig. 5. It is reduced into a simple block circled by an 
orange rectangle. 
Simulink 
file 
Physical 
system 
dSPACE 
controller & 
L298 Dual Full-
bridge drives 
Flexible Magnetic 
Abrasive Brush (FMAB) 
Workpiece 
Electromagnetic 
Pole 
2 Copyright © 2016 by ASME
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Fig. 5 MATLAB simulink model. 
 
 On the left side of Fig. 5 above, the four blocks circled 
by a purple rectangle are the general pattern of the signal 
for each coil. In other words, this pattern dictates when 
the current passes through the coil and when it does not. 
With four-coil configuration, MAPs need to move from 
one point to another point in a circular path in order to 
perform the finishing process.  The ideal pattern ensures 
that MAPs move in a circular or semicircular path on the 
workpiece surface, and there is no residual magnetism 
within each coil. To make MAPs move, only two 
neighboring coils will be activated. For example, Coil 1 
and 2, at time 1, will have North Pole and the others will 
be neutral (not activated). At time 2, the next pair of coils, 
Coil 2 and 3, will have South Pole. Therefore, Coil 2 will 
change from North Pole to South Pole. The general 
pattern is summarized in Table I. The coils’ actuated 
signals are programmed and represented by the blocks 
encircled by the purple rectangle. It is important to note 
that there is attraction force to the magnetic particles 
regardless of which pole the coil has. The alternation of 
poles is to minimize residual magnetism at the core. To 
further avoid magnetization of the electromagnets, the 
general pattern signal, illustrated in Fig. 6, entered a 
function block that converts a +1 signal or a -1 signal into 
a high frequency sinusoidal wave that changes from +1 
and -1. 
Table I. The general pattern of coils activation. 
 
Note: Signal for North Pole=+1, Neutral (no current supply) 
=0, and South Pole=-1 
 
Fig. 6 General pattern for 4-electromagnets configuration. 
Conclusion 
The developed setup for abrasive finishing uses rotational 
magnetic fields, which does not require any mechanical 
moving parts to perform the finishing process. The 
pattern of coils’ excitation was tested with 2 Hz 
frequency 28 volts and a rotating magnetic field was 
obtained. It was observed that the particles can move on 
the workpiece surface according to the movement of the 
magnetic field.   The reliability of this setup will be 
validated by applying this technique to finish surfaces of 
different materials. 
 
Acknowledgment 
The authors would like to thank University of Baghdad, 
Iraq for partially funding of this research. They also thank 
Mr. Chi-Hsiang Liao for his support in building the 
simulink model for this study. 
 
References 
[1] S. Dhull, Harwider, and R.S. Walia, “Experimental 
study of process parameters for magnetic assisted AFM 
incorporating the drill bit helical flow effect,” 
International Journal of Research (IJR), vol. 3, Issue 01, 
January 2016. 
 [2] Jinzhong Wu, Yanhua Zou, and Hitoshi Sugiyama, 
“Study on finishing characteristics of magnetic abrasive 
finishing process using low-frequency alternating 
magnetic field,” Int. Jornal of Advance Manufacturing 
Technology, vol. 9, October 2015, pp. 1-10. 
[3] V.K. Jain, “Micro manufacturing process,” CRCpress, 
Taylor &Franci Group, 2013. 
 [4] Y. Zou, “Internal finishing of micro tubes by the 
magnetic abrasive finishing,” Jr. of Japanese society of 
abrasive technology, vol. 56(2), pp. 86–89, 2012.  
[5] T. Shinmura, E. Hatano and K. Takazawa, "The 
development of magnetic-abrasive finishing and its 
equipment by applying a rotating magnetic field," 
JSFE, vol. 29(258), pp. 4437-4443, 1986.  
[6] H. Yamaguchi, T. Shinmura, and M. Takenaga, 
"Development of a New Precision Internal Machining 
Process Using an Alternating Magnetic Field," 
Precision Engineering, vol. 27, pp. 51-58, 2003. 
3 Copyright © 2016 by ASME
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Formation and Control of a Rotating Magnetic Field in Magnetic Abrasive Finishing

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Formation and Control of a Rotating Magnetic Field in Magnetic Abrasive Finishing

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