This document provides information about different types of grinding machines. It discusses cylindrical grinders, surface grinders, and other specialized grinders. The key points are: - Grinding machines use an abrasive wheel to remove a thin layer of material from the workpiece through friction. - Cylindrical grinders can grind external or internal cylindrical surfaces and include plain, universal, and centerless varieties. - Surface grinders grind flat surfaces and include reciprocating and rotary table styles. - Other grinders include belt grinders, bench grinders, and specialized grinders for tasks like thread grinding and crankshaft grinding.

1. 1
Presentation
on
GRINDING MACHINE
In partial fulfillment of the subject
MANUFACTURING ENGINEERING – III
(3351903)
Prepared by
1. VAHAB SHEKH : [176920319031] / Diploma Mechanical / 5th
2. MIRAJ BHAYANI : [176920319002] / Diploma Mechanical / 5th
3. TAHIR TARKESHA : [176920319035] / Diploma Mechanical / 5th

2. GRINDING MACHINES
2
• Grinding machine is a power operated machine tool where, the work piece is fed
against constantly rotating abrasive wheel to remove thin layer of material from
work.
• Grinding is a surface finishing operation where very thin layer of material is
removed in the form of dust particles.
• Thickness of material removed is in range of 0.25 to 0.50 mm.
• Tool used is a abrasive wheel.
• Grinding is a surface finishing operation where very thin layer of material is
removed in the form of fine dust particles. (thickness 0.25-0.5mm)
• Grinding can be defined as a material removal process by the abrasive action
between rotating abrasive wheel & the work piece.
• Grinding machine is a power operated machine tool where, the work piece is
fed against a constantly rotating abrasive wheel which is also called as
Grinding wheel so that a thin layer of material is removed from the work piece.

3. • The work piece is fed against a
constantly rotating abrasive wheel
so that a thin layer of material is
removed from the it.
• Work piece is fed against the
rotating abrasive wheel.
• Due to action of rubbing or friction
between the abrasive particles and
work piece material is removed....
Types of Grinding On the basis of
quality of grinding, it is classified
as rough grinding and
precision grinding.
PRINCIPLE OF GRINDING
3

4. WORKING PRINCIPLE
4
Fig. Working Principle

5. INTRODUCTION
5
• A grinding machine, often shortened to grinder, is any of various power tools or
machine tools used for grinding, which is a type of machining using an abrasive
wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a
small chip from the work piece via shear deformation.
• Grinding is used to finish work pieces that must show high surface quality (e.g.,
low surface roughness) and high accuracy of shape and dimension. As the
accuracy in dimensions in grinding is on the order of 0.000025 mm, in most
applications it tends to be a finishing operation and removes comparatively little
metal, about 0.25 to 0.50 mm depth. However, there are some roughing
applications in which grinding removes high volumes of metal quite rapidly. Thus,
grinding is a diverse field.

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• The grinding machine consists of a bed with a fixture to guide and hold the work
piece, and a power-driven grinding wheel spinning at the required speed. The
speed is determined by the wheel’s diameter and manufacturer’s rating. The user
can control the grinding head to travel across a fixed work piece, or the work
piece can be moved while the grind head stays in a fixed position.
• Fine control of the grinding head or tables position is possible using a vernier
calibrated hand wheel, or using the features of numerical controls.
• Grinding machines remove material from the work piece by abrasion, which can
generate substantial amounts of heat. To cool the work piece so that it does not
overheat and go outside its tolerance, grinding machines incorporate a coolant.
The coolant also benefits the machinist as the heat generated may cause burns.
In high-precision grinding machines (most cylindrical and surface grinders), the
final grinding stages are usually set up so that they remove about 200 nm (less
than 1/10000 in) per pass - this generates so little heat that even with no coolant,
the temperature rise is negligible.'

7. GRINDING PROCESS
7
Fig. Grinding Process

8. TYPES OF GRINDING MACHINE
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• Belt grinder
• Bench grinder
• Cylindrical grinder
• Surface grinder
• Tool and cutter grinder
• Jig grinder
• Gear grinder
• Centreless grinder
• Planetary internal grinder

9. BELT GRINDER
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• Belt grinder, which is usually used as a machining method to process metals
and other materials, with the aid of coated abrasives. Sanding is the
machining of wood; grinding is the common name for machining metals. Belt
grinding is a versatile process suitable for all kind of applications like
finishing, deburring, and stock removal

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Fig. Belt Grinder

11. BENCH GRINDER
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• Bench grinder, which usually has two wheels of different grain sizes for
roughing and finishing operations and is secured to a workbench or floor
stand. Its uses include shaping tool bits or various tools that need to be
made or repaired. Bench grinders are manually operated.

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Fig. Bench Grinder

13. CYLINDRICAL GRINDER
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• Cylindrical grinder, which includes both the types that use centers and the
centreless types. A cylindrical grinder may have multiple grinding wheels.
The work piece is rotated and fed past the wheel(s) to form a cylinder. It is
used to make precision rods, tubes, bearing races, bushings, and many
other parts.
• It is a process of grinding curved surfaces.
• Surface may be straight or tapered.
• Work piece is mounted on two centers, one is tailstock centre and the other
is headstock centre.
• Head stock center may or may not revolve.

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Fig. Cylindrical Grinder

15. 15
• Centreless grinding is a machining process that uses abrasive cutting to remove material
from a workpiece Centreless grinding differs from centered grinding operations in that
no spindle or fixture is used to locate and secure the workpiece the workpiece is secured
between two rotary grinding wheels, and the speed of their rotation relative to each other
determines the rate at which material is removed from the workpiece
• This machine is used to produce external cylindrical surface. The surfaces may be
straight, tapered, steps or profiled. Broadly there are three different types of cylindrical
grinding machine as follows:
1. Plain center type cylindrical grinder
2. Universal cylindrical surface grinder
3. Centreless cylindrical surface grinder

16. PLAIN CENTER TYPE CYLINDRICAL GRINDER
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• Figure illustrates schematically this machine and various motions required for grinding
action. The machine is similar to a center lathe in many respects. The workpiece is held
between head stock and tailstock center. A disc type grinding wheel performs the grinding
action with its peripheral surface. Both traverse and plunge grinding can be carried out in
this machine as shown in Fig.

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A: rotation of grinding wheel
B: work table rotation
C: reciprocation of worktable
D: infeed
Fig. Plain centre type cylindrical grinder

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Fig. Cylindrical (a) traverse grinding and (b) plunge grinding
A: rotation of grinding wheel B: workpiece rotation C: reciprocation of worktable D: infeed

19. UNIVERSAL CYLINDRICAL SURFACE GRINDER
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• Universal cylindrical grinder is similar to a plain cylindrical one except that it is more
versatile. In addition to small worktable swivel, this machine provides large swivel of head
stock, wheel head slide and wheel head mount on the wheel head slide.
• This allows grinding of any taper on the workpiece. Universal grinder is also equipped
with an additional head for internal grinding. Schematic illustration of important features of
this machine is shown in Fig.

20. SURFACE GRINDER
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• Surface grinder which includes the wash grinder. A surface grinder has a "head" which is
lowered, and the work piece is moved back and forth past the grinding wheel on a table
that has a permanent magnet for use with magnetic stock. Surface grinders can be
manually operated or have CNC controls. Rotary surface grinders or commonly known as
"Blanchard" style grinders, the grinding head rotates and the table usually magnetic but
can be vacuum or fixture, rotates in the opposite direction, this type machine removes
large amounts of material and grinds flat surfaces with noted spiral grind marks. Used to
make and sharpen; burn-outs, metal stamping die sets, flat shear blades, fixture bases or
any flat and parallel surfaces.
• It is machine basically used to grind flat surface.
• Job is mounted to a table which moves longitudinally as well as in transverse direction.
• Manual feed or power feed.
• Protective guard for safety.
• Internal pump and piping arrangement for coolant
• Work piece can clamped in two ways
• Manual clamps.
• Magnetic chuck.

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Fig. Surface Grinder

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A: swiveling wheel head
B: swiveling wheel head slide
C: swiveling head stock
D: rotation of grinding wheel
Fig. important features of universal cylindrical grinding machine

23. SPECIAL APPLICATION OF CYLINDRICAL GRINDER
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• Principle of cylindrical grinding is being used for thread grinding with specially formed
wheel that matches the thread profile. A single ribbed wheel or a multi ribbed wheel can
be used as shown in Fig. 6.22.
A: rotation of grinding wheel
B: rotation of workpiece
C: Down feed
D: Longitudinal feed of wheel
Fig. Thread grinding with (a) single rib (b) multi-ribbed wheel

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• Roll grinding is a specific case of cylindrical grinding wherein large work pieces such as shafts,
spindles and rolls are ground.
• Crankshaft or crank pin grinders also resemble cylindrical grinder but are engaged to grind
crank pins which are eccentric from the centre line of the shaft as shown in Fig. 6.23. The
eccentricity is obtained by the use of special chuck.
A: rotation of wheel
B: rotation of crank pin
Fig. Grinding of crank pin

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• Basically there are four different types of surface grinding machines characterized by the
movement of their tables and the orientation of grinding wheel spindles as follows:
 Horizontal spindle and reciprocating table
 Vertical spindle and reciprocating table
 Horizontal spindle and rotary table
 Vertical spindle and rotary table

26. • illustrates this machine with various
motions required for grinding action.
A disc type grinding wheel performs
the grinding action with its peripheral
surface. Both traverse and plunge
grinding can be carried out in this
machine as shown in Fig.
HORIZONTAL SPINDLE RECIPROCATING TABLE
GRINDER
26
A: rotation of grinding wheel, B: reciprocation of worktable,
C: transverse feed, D: down feed

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A: rotation of grinding wheel B: reciprocation of worktable C: transverse feed D: down feed Fig.
Surface grinding (a) traverse grinding (b) plunge grinding

28. VERTICAL SPINDLE RECIPROCATING TABLE
GRINDER
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• This grinding machine with all working motions is shown in Fig. 6.14. The grinding
operation is similar to that of face milling on a vertical milling machine. In this machine a
cup shaped wheel grinds the workpiece over its full width using end face of the wheel as
shown in Fig. 6.15. This brings more grits in action at the same time and consequently a
higher material removal rate may be attained than for grinding with a peripheral wheel.
• The face of a wheel (cup, cylinder, disc, or segmental wheel) is used on the flat surface.
Wheel-face grinding is often used for fast material removal, but some machines can
accomplish high-precision work. The workpiece is held on a reciprocating table, which can
be varied according to the task, or a rotary-table machine, with continuous or indexed
rotation. Indexing allows loading or unloading one station while grinding operations are
being performed on another.

29. Fig. Vertical spindle reciprocating table
surface grinder
Fig. Surface grinding in Vertical spindle
reciprocating table surface grinder
A: ROTATION OF GRINDING WHEEL B: RECIPROCATION OF WORKTABLE C: DOWN FEED OF
GRINDING WHEEL
29

30. HORIZONTAL SPINDLE ROTARY TABLE GRINDER
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• Surface grinding in this machine is shown in Fig. 6.16. In principle the operation is same
as that for facing on the lathe. This machine has a limitation in accommodation of
workpiece and therefore does not have wide spread use. However, by swiveling the
worktable, concave or convex or tapered surface can be produced on individual part as
illustrated in Fig .
• The periphery (flat edge) of the wheel is in contact with the workpiece, producing the flat
surface. Peripheral grinding is used in high-precision work on simple flat surfaces; tapers
or angled surfaces; slots; flat surfaces next to shoulders; recessed surfaces; and profiles

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A: rotation of grinding wheel
B: table rotation
C: table reciprocation
D: down feed of grinding wheel
Fig. Surface grinding in Horizontal spindle rotary table surface grinder
A: rotation of grinding wheel
B: table rotation
C: table reciprocation
D: down feed of grinding wheel
Θ: swivel angle
Fig. Grinding of a tapered surface in horizontal spindle rotary table surface grinder

32. VERTICAL SPINDLE ROTARY TABLE GRINDER
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• The principle of grinding in this machine is shown in Fig. The machine is mostly
suitable for small work pieces in large quantities. This primarily production type
machine often uses two or more grinding heads thus enabling both roughing and
finishing in one rotation of the work table.
A: rotation of grinding wheel
B: work table rotation
C: down feed of grinding wheel
Fig. Surface grinding in vertical spindle rotary table surface grinder

33. TOOL AND CUTTER GRINDER
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• A tool and cutter grinder is used to sharpen milling cutters and tool bits along
with a host of other cutting tools.
• It is an extremely versatile machine used to perform a variety of grinding
operations: surface, cylindrical, or complex shapes. The image shows a
manually operated setup, however highly automated Computer Numerical
Control (CNC) machines are becoming increasingly common due to the
complexities involved in the process.
• Tool and cutter grinder and the D-bit grinder. These usually can perform the
minor function of the drill bit grinder, or other specialist tool room grinding
operations.

34. 34
Fig. Tool and Cutter Grinder

35. GEAR GRINDER
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• Gear grinder, which is usually employed as the final machining process when
manufacturing a high-precision gear. The primary function of these machines is
to remove the remaining few thousandths of an inch of material left by other
manufacturing methods (such as gashing or hobbing).
• Gear cutting is any machining process for creating a gear. The most common
gear-cutting processes include hobbing, broaching, milling, and grinding. Such
cutting operations may occur either after or instead of forming processes such as
forging, extruding, investment casting, or sand casting.
• Gears are commonly made from metal, plastic, and wood. Although gear cutting
is a substantial industry, many metal and plastic gears are made without cutting,
by processes such as die casting or injection molding. Some metal gears made
with powder metallurgy require subsequent machining, whereas others are
complete after sintering. Likewise, metal or plastic gears made with additive
manufacturing may or may not require finishing by cutting, depending on
application

36. 36
Fig. Gear Grinder

37. CENTRE LESS GRINDING MACHINE
37
• It is used to grind curved surface work piece which are long and slender.
• Work piece rests on a work-rest blade and is backed by a second wheel called
as regulating wheel.
• Grinding wheel pushes the work piece down the work-rest blade against the
regulating wheel.

38. 38

39. • This machine is used for grinding
cylindrical and tapered holes in
cylindrical parts (e.g. cylindrical liners,
various bushings etc ). The workpiece
is rotated between supporting roll,
pressure roll and regulating wheel and
is ground by the grinding wheel as
illustrated in
A: grinding wheel rotation B: workpiece rotation
C: wheel reciprocation
CENTERLESS INTERNAL GRINDER
39

40. • Planetary internal grinder is used
where the workpiece is of irregular
shape and can not be rotated
conveniently as shown in Fig.
below. In this machine the
workpiece does not rotate.
Instead, the grinding wheel orbits
the axis of the hole in the
workpiece.
PLANETARY INTERNAL GRINDER
40

41. ABRASIVES
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• An abrasive is a material, often a mineral, that is used to shape or finish a workpiece
through rubbing[1] which leads to part of the workpiece being worn away by friction. While
finishing a material often means polishing it to gain a smooth, reflective surface, the
process can also involve roughening as in satin, matte or beaded finishes. In short, the
ceramics which are used to cut, grind and polish other softer materials are known as
abrasives.
• Abrasives are extremely commonplace and are used very extensively in a wide variety of
industrial, domestic, and technological applications. This gives rise to a large variation in
the physical and chemical composition of abrasives as well as the shape of the abrasive.
Some common uses for abrasives include grinding, polishing, buffing, honing, cutting,
drilling, sharpenin, lapping, and sanding (see abrasive machining
• Abrasive is the material employed for sharpening, grinding and polishing operations.
• Natural abrasive – emery, corundum, quartz, sandstone, diamond, etc.
• Artificial abrasive – carborundum, aloxite, alundum, etc.

42. EXAMPLES OF BONDED ABRASIVES
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Fig: A variety of bonded abrasive used in abrasive machining processes

43. COMMON GRINDING WHEELS
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Fig: Common Type of Grinding Wheels made with conventional abrasives. Note that each wheel has
a specific grinding face grinding on other surfaces is improper and unsafe

44. APPLICATIONS OF ABRASIVES
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 Corundum : is a natural mineral which consists of aluminium oxide. Hardest natural
substance after diamond.
 Used for shaping, finishing and polishing other tools.
 Emery : natural abrasive consisting of aluminium oxide and little amount of iron oxide.
 Silicon carbide : synthetic abrasive harder than aluminium oxide.
 Used to grind metals like iron, brass and soft bronze.
 Used in non metals like wood and leather industries.

45. 45
• Zirconia aluminia : it is a mixture of zirconium oxide and aluminium oxide.
• Used in casting and foundry industries.
• Cubic boron nitride : is made up of boron nitride with a cubic crystalline
structure.
• Used for hard coating material.
• Diamond

46. BONDING
46
Bond:
• Vitrified bond:
• Vitrified bond is suitable for high stock removal even at dry condition.
• It can also be safely used in wet grinding.
• It can not be used where mechanical impact or thermal variations are like to occur.
• This bond is also not recommended for very high speed grinding because of possible
breakage of the bond under centrifugal force
• Resin bond:
• Conventional abrasive resin bonded wheels are widely used for heavy duty grinding
because of their ability to withstand shock load.
• This bond is also known for its vibration absorbing characteristics and finds its use
with diamond and CBN in grinding of cemented carbide and steel respectively.

47. • Resin bond is not recommended with alkaline grinding fluid for a possible
chemical attack leading to bond weakening.
• Fiberglass reinforced resin bond is used with cut off wheels which requires
added strength under high speed operation.
• Shellac bond:
• At one time this bond was used for flexible cut off wheels.
• At present use of shellac bond is limited to grinding wheels engaged in fine
finish of rolls.
• Oxychloride bond:
• It is less common type bond, but still can be used in disc grinding operation.
• It is used under dry condition.
47

48. • Rubber bond:
• Its principal use is in thin wheels for wet cut-off operation.
• Rubber bond was once popular for finish grinding on bearings and cutting tools.
• Working
• Work piece is clamped to the table by operating magnetic chuck.
• Required grade of grinding tool is fixed to spindle.
• Grinding operation is carried out be operating both table traverse wheel and
vertical feed hand wheel.
• Clamps are used to hold any work piece or a work-holding device on the table.
Alternatively they may be held on a magnetic chuck.
• It is a special device used to remove the magnetic power from an object. In
grinding whenever a job is ground by holding it on the magnetic chuck, the job will
also get some magnetic power.
48

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