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MAJOR PROJECT REPORT ON
“METALLURGICAL POLISHING SETUP USING
MAGNETIC ABRASIVE FINISHING ”
GUIDE:- SUBMITTED BY:-
Under the Guidence of :- Khushdeep Singh 1136952 (7M4)
Dr. Lakhvir Singh Harpreet Singh 1136929 (7M2)
Jagraj Singh 1136940 (7M2)
Harmeet Singh 1136924 (7M2)

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INDEX
Sr No. Module Page No.
1 Abstract 3
2 Objective 4
3 Introduction 5-6
4 Literature Review
 Magnetic Materials
 Shape of Magnets
 Strength of Magnets
 Wheel Material
 Workpiece Movement Mechanism
A. Work-piece Up and Down Movement
B. Work-piece rotation
 Electronic Controller
7-12
5
5.1
5.2
5.3
5.4
5.5
Design
Electric Motor
Non-Magnetic Wheel
Magnetic abrasives
Tool Holder
Magnets
13-19
6 Working 20
7 Results and Discussion 21

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1. Abstract
Finishing and Polishing plays a vital role in effective working of any component and
Imparting compressive residual stress to a surface improves the fatigue structural integrity of
components, which is particularly important or components used in such critical
applications as high-pressure gas or liquid piping systems. The recent increase in the use of
hard, high strength and temperature resistant materials in engineering necessitated the
development of newer machining techniques. Conventional machining or polishing methods
are not readily applicable to the materials like carbides; ceramics etc. Conventional
machining processes when applied to these newer materials are uneconomical, Produce poor
degree of surface finish and accuracy, Produce some stress , highly insufficient .Metallurgical
polishing or Magnetically Assisted Abrasive Polishing and Finishing (MAAF) processes are
most suitable for obtaining quality finish on metallic and non-metallic surfaces. In these
processes, the cutting forces are generated and controlled by magnetic wheel . In spite of
remarkable results of Metallurgical polishing processes, the major constraint towards
commercial adoption of this technology is the non-availability of magnetic abrasives. The
manufacturing techniques for preparing magnetic abrasives are time consuming and
complicated therefore the existing magnetic abrasives are very costly. The aim of the present
study is to develop and explore the usage of alternative magnetic abrasives. In the present
work, magnetic abrasives were prepared by mixing ferromagnetic powder, abrasive powder
and a special type of adhesive for bonding.
Keyword: Rotating Wheel having Magnets, Magnetic abrasives, Tool holder, Work-piece,
Electric motor, Work-piece movement mechanism.

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2.OBJECTIVE
For the polishing of any material Sand paper is used before this machine. It takes too much
time as well as too much human effort for the polishing and it does not achieve higher
accuracies. The final Surface obtained is not very fine in nature. With the development of this
machine, it becomes possible to achieve higher accuracy and better surface finish. It also
takes very less time as compared to previous method. Human effort is negligible because the
presence of the machine. It also requires very less handling as compared to the old manual
method. This machine is mainly used by the Engineers who deals with Research and
Development Department.
Main objectives of the system are-
 Better surface finish
 Reduced operational time.
 Increased accuracy and reliability.
 Increased operational efficiency.
 Less human effort
 Easy handling

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3. Introduction
Metallurgical polishing (MP) is one of the Non traditional or advanced polishing processes,
which produces a high level of surface quality and is primarily controlled by a magnets. In
Metallurgical polishing, the work piece is kept inside the tool holder. The working gap
between the work piece and Non-Magnetic sheet ( i.e Steel or Plastic) is filled with magnetic
abrasive particles. A magnetic abrasive flexible brush (MAFB) is formed, acting as a
multipoint cutting tool, due to the effect of the magnetic wheel rotation. When inserting a
cylindrical work piece in such a operation of giving revolution, feed and movement in axial
direction, surface and edge finishing are carried out by magnetic brush. In the application of
ferromagnetic substance of work, for instance, work piece is also magnetized and the
magnetic force acts on the top of the brush between the work piece and the abrasive grains
resulting in pressing the abrasive grains to work surface. The metallurgical polishing process
removes a very small amount of material by indentation and rotation of magnetic abrasive
particles in the circular tracks.
Polishing or Final finishing operations in manufacturing of precise parts are always of
concern owing to their most critical, labour intensive and least controllable nature. In the era
of magnetic surface finishing, deterministic high precision finishing methods are of utmost
importance and are the need of present manufacturing scenario. The need for high precision
in manufacturing was felt by manufacturers worldwide to improve inter-changeability of
components, improve quality control and longer wear/fatigue life.
New advanced metallurgical polishing and finishing processes were developed in last few
decades to overcome limitations of traditional finishing processes in terms of higher tool
hardness requirement and precise control of finishing forces during operation. This helped in
polishing harder materials and exercising better in process control over final surface
characteristics. Another limitation relaxed by some advanced polishing processes using
loose abrasives is to finish complicated geometries by enhancing reach of abrasive particles
to difficult-to-access regions of the work-piece surface. In this way, newly developed
finishing and polishing processes are to a large extent helpful in meeting requirements of 21st
century manufacturing.
Relative motion between the magnetic/abrasive particle mixture and the work-piece is
essential for material removal. There are several options for achieving the necessary motion.
A common setup is the rotation of the magnetic pole tip. This is done by either rotating the
entire permanent magnet setup or by rotating only the steel pole. Another method which is
commonly utilized in internal finishing is the rotation of the work-piece , this is unfortunately
limited to axial symmetric work-pieces. Selection of the motion is according to the
requirements and according to the work-piece shape and size. In this machine we use the
combination of both types i.e. both workpiece and wheel rotates.

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Metallurgical polishing is a surface polishing technique in which a magnetic wheel is used to
force abrasive particles against the target surface. As such, polishing of conventionally
inaccessible surfaces (e.g., the inside surface of a long curved pipe) is possible. Abrasive
particles assited Metallurgical polishing processes have been developed for a wide variety of
applications including the manufacturing of medical components, fluid systems, optics, dies
and molds, electronic components, micro-electromechanical systems, and mechanical
components. But this project is mainly concern with the metrology, which this is used for
polishing the specimen of different kinds of metals and non-metallic materials. These
polished specimens are used to check the grain structure of the material to check the effect of
different kinds of parameters on the work-piece like temperature, different forces etc.

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4. Literature Review
In literature mainly we study Abrasive particles, Magnets, wheel for fitting magnets, Work-
piece movement mechanism, Tool holder. About these mainly we study:
Magnetic Material: In magnetic material we study different kind of strong magnetic
materials and finally we select Neodymium because this is one of the strong magnets
available in the market. Neodymium is a permanent magnet made from
an alloy of Neodymium, iron and boron to form the Nd2Fe14B tetragonal crystalline structure.
Neodymium magnets are the strongest type of permanent magnet commercially available.
They have replaced other types of magnet in the many applications in modern products that
require strong permanent magnets. In practice, the magnetic properties of neodymium
magnets depend on the alloy composition, microstructure, and manufacturing technique
employed. Some important properties used to compare permanent magnets are:
 Remanence (Br)- which measures the strength of the magnetic field.
 Coercivity (Hci)- The material's resistance to becoming demagnetized.
 Curie Temperature (TC)-The temperature at which the material loses its magnetism.
Neodymium magnets have higher Remanence, much higher Coercivity but often lower Curie
temperature than other types.
Neodymium magnet also a negative points as the stronger magnetic fields can be hazardous
to mechanical and electronic devices; they can erase magnetic media such as floopy disks and
credit cards, and magnetize watches at a greater distance than other types of magnet. It also
have highly susceptible to corrosion.
Neodymium Rod magnets

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Shape of Magnet: There are many shapes of magnets available to suit a wide range of
purposes. You should choose the shape of your magnet according to how you plan to use it -
some shapes are easy to mount because they feature a thread or centre hole (Pots), whilst
others can easily be inserted into dowel-drilled holes (Rods) or set in resin (Discs or Blocks).
Different kinds of magnets are:
 Bar Magnet
 Discs Magnet
 Horseshoe Magnet
 Ring Magnet
 Spheres Magnet
 Rod Magnets
 Ring Magnets
 Pot Magnets
 Threaded Magnets
 Tube Magnets etc.
In this project we choose Rod Magnet due to strength and fitting wise. Rod magnets have a
magnetic length which is larger than their diameter. This enables the magnets to generate
very high levels of magnetism from a relatively small surface pole area. These magnets have
high 'Gauss' values because of their greater magnetic lengths and deep depth of field, making
them ideal for activating reed switches, Hall Effect sensors in security and counting
applications. They are also ideal for educational, research and experimental uses.
Dimensions: we use 7 Rod magnets , which are fitted in the Aluminium wheel with
adhesives. Dimensions of magnets are-
Length- 30mm
Diameter- 25mm
Strength of Magnet: A magnet is a material or object that produces a magnetic field. This
magnetic field is invisible but is responsible for the most notable property of a magnet: a
force that pulls on other ferromagnetic materials, such as iron and attracts or repels other
magnets. Strength of magnet depends upon the flux density per unit area. Mainly magnetic
strength we measure in Tesla or Gauss. The tesla (symbol T) is the SI derived
unit of magnetic flux density, commonly denoted as B. One tesla is equal to 1000 Gauss. We
estimate the required strength of magnet and let magnets of 5000 gauss or 0.5 tesla.
Wheel material: Wheel material play an important role in performance the project. First we
think about wheel of wood which was rejected due safety reasons. The first requirement of
wheel was it should be non-magnetic material. From study we select aluminium wheel
because it is non-magnetic, light-weight, easy to machine, low cost. One of the best known
properties of aluminium is that it is light, with a density one third that of steel, 2.700 kg/m3.
The low density of aluminium accounts for it being lightweight but this does not affect its
strength. Unlike most steel grades, aluminium does not become brittle at low temperatures.
Instead, its strength increases. At high temperatures, aluminium’s strength decreases. At
temperatures continuously above 100°C, strength is affected to the extent that the weakening
must be taken into account. Aluminium is easily worked using most machining methods –

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milling, drilling, cutting, punching, bending, etc. Furthermore, the energy input during
machining is low. Features facilitating easy jointing are often incorporated into profile
design. Fusion welding, Friction Stir Welding, bonding and taping are also used for joining.
Aluminium reacts with the oxygen in the air to form an extremely thin layer of oxide, this
layer is dense and provides excellent corrosion protection. The layer is self-repairing if
damaged.Anodising increases the thickness of the oxide layer and thus improves the strength
of the natural corrosion protection. Aluminium is extremely durable in neutral and slightly
acid environments.In environments characterised by high acidity or high basicity, corrosion is
rapid.
Aluminium Wheel after Casting
Work-piece Movement mechanism:
There are Two Types of Work-piece Movements. One is Up and Down movement to make
the contact between Work-piece and Abrasive particles and second is to rotate the work-piece
through 90 degree after one minute. Second type movement is requied to achieve the better
surface finish.

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A. Workpice Up and Down Movement: This type of movement is required to make the
contact between job and abrasive particles. For this purpose , mechanism is shown in
the below diagram. This is made up of Stainless Steel Because Steel is non-magnetic
in nature and it will not effect the operation.
Work-piece Up and Down Movement Mechanism

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B.Work-piece Rotation: For the rotation of Work-piece, we study about step controller
motors, D.C. motors, servo motors. From these, Problem in servo motor is that it cannot
handle large weight, the same problem was in step controller motor. D.C motor can be used
to handle heavy weight than servo and step controller motors. We buy a D.C motor of 12V
and a controller which can rotate dc motor in desired rotation and speed, one electronic unit is
used to rotate the tool at 90 degree.
D.C. Geared Motor
Electronic controller : We use a Electronic controller for the rotation of work-piece through
90 Degrees.In this electronic controller, There is a PC Circuit and In this circuit programming
is used to make the motor rotate through 90 degree. There is also a Speed controller in this
circuit to adjust the speed of dc motor according to the requirement. This Circuit is
programmed in such a way that it rotate the motor through 90 degree after 1 minute. By
Rotating the workpiece through 90 degree , better surface finish can be achieved.

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Electronic Circuit for Rotation
Tool holder: Tool holder is used to hold the specimen which is to be polished. But there was
one problem that it should be non-magnetic. We try to make a tool holder of aluminium but
its strength was low so it was rejected . After that we make a steel tool holder. But we face
some problems in steel tool holder like welding , cutting, drilling and other machining
operations, but there is another problem in this tool holder that it is heavy and we try to make
it light. For this we make a tool holder as shown in the diagram .In this Tool holder job
is held by the Four Screws.

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5. Design
Main parts or equipments are used in this machine are tool holder, controller, magnetic
wheel, electric motor, magnetic abrasives etc.
5.1 Electric Motor
An Electric motor is an electric machine that converts electrical energy into
mechanical energy.
In normal motoring mode, most electric motors operate through the interaction between an
electric motor’s magnetic field and winding currents to generate force within the motor. In
certain applications, such as in the transportation industry with traction motors, electric
motors can operate in both motoring and generating or braking modes to also produce
electrical energy from mechanical energy.
Found in applications as diverse as industrial fans, blowers and pumps, machine tools,
household appliances, power tools, and disk drives, electric motors can be powered
by alternating current (AC) source, such as from the power grid, inverters or generators.
Small motors may be found in electric watches. General-purpose motors with highly
standardized dimensions and characteristics provide convenient mechanical power for
industrial use.
Devices such as magnetic solenoids and loudspeakers that convert electricity into motion but
do not generate usable mechanical power are respectively referred to as actuators and
transducers. Electric motors are used to produce linear force or torque (rotary).Actual motor
used have 1500 rpm and require 220 volt for operation. Wheel is mounted on this motor gh
Rotates with high velocity.
Electric Motor

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Actual Motor Used
5.2 Non- Magnetic Wheel
It is casting wheel of aluminium having attach a series of magnets. The magnets are attach on
the wheel to attract magnetic abrasives. Wheel rotate with the help of electric motor and
results in rotation of magnets . Magnetic abrasives are attracted towards the wheel and
placed on the non magnetic sheet.
This aluminium wheel having 190 mm diameter and 60 mm thickness . A hole is drawn in
the shaft of the wheel to fix on the rotating shaft. One hole having internally threaded is
drawn in the shaft to prevent the slip of wheel on the shaft. In this wheel 7 holes are drill of
32 mm diameter and 24 mm depth to fix the magnets in a ring. These magnets are fix in this
wheel with a strong adhesive.
During casting the weight of the wheel was 5.5 kg, which was left approximately of 4.5 kg
due to machining allowances. One advantage of this wheel is that it minimize the magnetic
effect under the wheel which decreases the load on the motor.

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After Casting
Machining of Casted aluminium wheel

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5.3 Magnetic Abrasives
The mainly used abrasive media is a Silicon based polymer, hydrocarbon gel and the abrasive
grains. The abrasive required is essentially magnetic in nature for the proper machining
process to take place. These magnetic abrasives attract towards magnetic wheel and
accumulate on magnetic path and by the rotation of the wheel these abrasives rotates at speed
of wheel.
The grain or grit size is most important in determining a wheel’s ability to achieve the
required surface finish and remove stock. The size is designated by a number which increases
as grain size decreases. For example 10 grit has a median size of about 2.0mm and 60 grit
0.25mm.Larger grain sized Abrasives are used for the cutting as well as for finishing and
Small grain sized are used for Polishing.
These are very fine particles it seems like a powder with a naked eye. The size of these
particles is in nano meters so the preperation of these particles is a costlier process. The
hardness is depends upon the material used for example to cut the very hard metal we need
diamond particles.
The abrasive we use is called bonded abrasives. Size of these abrasives varies from 75 to 350
micron.
4.4 ToolHolder
In the study of tool holder first we prefer A collet is a holding device—specifically, a
subtype of chuck—that forms a collar around the object to be held and exerts a strong
clamping force on the object when it is tightened, usually by means of a tapered outer collar.
It may be used to hold a workpiece or a tool and it attain the required gap between the work-
piece and abrasives. Shape of this is depend upon that every type of shape of work-piece
should adjust.
An external collet is a sleeve with a (normally) cylindrical inner surface and a conical outer
surface. The collet can be squeezed against a matching taper such that its inner surface
contracts to a slightly smaller diameter, squeezing the tool or workpiece whose secure
holding is desired. Most often this is achieved with a spring collet, made of spring steel, with
one or more kerf cuts along its length to allow it to expand and contract.
Tool holder which is used in this project is made of stainless steel of 204 grade.

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In the selection of tool holder we study a lot of things. Shape of the tool holder is of box type.
Four volts are attached to these holder for passing the nuts to clamp the work piece.
We face many problems in toll holder like firstly we make a tool holder of steel in box shape.
But it was too heavy to rotate for motor and was not clamp work piece accurately. Then now
in this tool holder we use aluminium. Four externally threaded nut of 2.5 inch are used. A
coin type aluminium is attached to nuts and is freely move in between the two strips which is
easily clamp the work piece.
4.5 Magnets
A Magnet is a material or object that produces a magnetic field. This magnetic field is
invisible but is responsible for the most notable property of a magnet: a force that pulls on
other ferromagnetic materials, such as iron, and attracts or repels other magnets.

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Magnet is the major component in the working of the project. We use Neodymium material
of the magnet .
Dimensions: 30 mm diameter
25 mm height
Rod magnet
Strength of the magnet is about 5000 gauss. Seven magnets are attached in the holes of
aluminium wheel. These magnets are arrange in chain shape because the strength of the chain
is greater than ring magnet.

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Fitting of magnets in wheel

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6. Working
Hold the work piece in the tool holder and adjust its position. Put the abrasive particles on the
plastic sheet mounted on the stand. Lower down the vertical arm or motor and ensure a that
work piece will touch the magnetic particles but not plastic sheet.
Switch ON the power supply of electric motor then motor will move at high speed. Adjust the
position of work piece if require. When motor start then when wheel will rotate and due to
attraction of magnetic abrasives, abrasive moves on plastic sheet along the rotation of the
wheel.
These magnetic abrasives will contact with work piece continuously . Abrasive particles are
held together by the magnetic field, in the form of flexible magnetic abrasive brush. The
abrasive particles of the flexible magnetic abrasive brush remove the peaks of the
irregularities on the surface of the work-piece being polished. After one minute, the motor
along work piece and tool holder will rotate at 90 degree then again it stay for one minute and
this process will continuously repeated. As a result approximate 30 min our work piece will
polished at nano level. We can check the Surface roughness with the instruments like Digital
Surtronic Instrument.

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7. Results and Discussions
Effects of different process parameters (circumferential speed of the workpiece, and working
gap) on material removal, absolute change in surface finish value (_Ra), and percent
improvement in surface finish, are studied. This _Ra value is always found to be positive
hence surface finish is improved in all cases. Percent improvement in surface finish is defined
as the ratio of (_Ra ×100) and original surface finish.
In general, material removal increases with increase in circumferential speed (Fig. 5a). At
low value of working gap, magnetic abrasive brush is stronger and can take deeper cuts to
remove more amount of material from the work-piece. This effect will further escalate with
the increase in circumferential speed. Percent improvement in surface finish starts increasing
as the circumferential speed of work-piece increases and reaches to a maximum value before
it starts decreasing.
Analysis of forces acting during operation would reveal why the rate of increase in material
removal goes down in case of higher working gaps. On some of these aspects, work is in
progress in this Lab. Abrasive powder becomes blunt after a certain period of time and needs
replacement. At low working gap, the replacement of abrasive particles is needed very
frequently. On the other hand, the magnetic force becomes weaker as the working gap
increases. Percent improvement in surface finish initially increases with increase in working
gap and attains a maximum before it starts decreasing. It is necessary to main a Specific gap
between work-piece and abrasive particles.