GRINDING

SUBMITTED BY

AVINASH SNEHI (1214340049)

ME-1 3rd YEAR

OBJECTIVE

• Objective of this presentation is to share info related to

Grinding Machines and its processes.

CONTENTS

Ginding Process

Its purposes

Grinding Wheels

Grinding Wheel Wear

Categories of Grinding Machine

INTRODUCTION TO

GRINDING PROCESS

• The Grinding process is used to produce a high surface

finish with a close tolerance and for machining hard

materials.

• The process is a variation of polishing and uses abrasive

materials held together by an adhesive in the form of a

solid wheel.

Hand Grinding Machine

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Purposes for GRINDING

• Removal of excess material

• Production of high surface finishes

• Machining very hard materials

• Good form and locational accuracy

GRINDING WHEELS

• A grinding wheel consists of abrasive particles and

bonding material. The bonding material holds the

particles in place and establishes the shape and structure

of the wheel.

• The wheel is generally made from a matrix of coarse

particles pressed and bonded together to form a solid

circular shape,various profiles and cross sections are

available depending on the uses for the wheels.

GRINDING WHEEL

GRINDING

WHEELS

FUNCTIONS OF A GRINDING

WHEEL

• To remove materials from a workpiece

• Each grains acts as a cutting tool

• It is a cheap formation process

• The only self sharpening cutting tool

• Considered as a abrasive machining

STANDARD MARKING SYSTEM

ABRASIVES

• Abrasives are the intended for actual cutting action hence

they are the hard substances.

• A small nonmetallic hard particles having sharp edge.

• Capable of removing small amount of material from

surface through cutting process

ABRASIVES

Abrasives are classified as

• Aluminum Oxides

• Ceramic

• Silicon carbide

• Super Abrasive-DIAMOND

• Tungsten Carbide

Bond

• It is a material used as GLUE to hold the abrasive grains

together.Bond has no cutting action.The bonding

materials commonly used are

• Metal

• Resin

• Rubber

• silicate

TYPES OF GRINDING WHEEL

GRINDING WHEEL WEAR

• Grinding wheel wear is an important consideration because it

adversly affects the shape and accuracy of ground surfaces as

in the case with cutting tools.

TYPES OF WEAR

• Attritious Wear

• Grain Fracture

• Bond Fracture

ATTRITIOUS WEAR

• The cutting edges of a sharp grain become dull.

• Wear are caused by the interaction of the grain with the

workpiece involving both physical and chemical

reactions.

• These reactions involve diffusion,chemical degradation or

decomposition of the grain.

• Attritious wear is low when the two materials are chemically

inert with respect to each other.

• The more the inert the materials,the lower will be the tendency

of reaction.

• This wear based on the reactivity of the grain and the

workpiece and their relative mechanical properties such as

hardness and toughness.

GRAIN FRACTURE

Because abrasive grains are brittle,their fracture in grinding

are important.

• If the wear is excessive,the grain become dull.

• Grinding become inefficient and produces undesirably

high temperatures.

• New sharp cutting edge are produced continuously during

grinding.

BOND FRACTURE

• The strength of bond is a significant parameter in grinding.

• If the bond is too strong sharp grain along the circumference of

the grinding wheel can begin to the contact of workpiece thus

process becomes insufficient.

• If the bond is too weak the grain will dislodged easily,wear rate

is of wheel is increases then dimensional accuracy becomes

difficult.

GRINDING MACHINES AND

OPERATIONS

• A grinding machine is a machine tool used for producing

very fine finishes or making very light cuts using an

abrasive wheel as the cutting device.

• A distinguishing feature of grinding machines is the

rotating abrasive tool.

• Grinding machine is employed to obtain high accuracy

along with very high class of surface finish on the

workpiece.

CATEGORIES OF GRINDING

MACHINE

1. Surface Grinding

2. Cylindrical Grinding

3. Internal Grinding

4. Centered Grinding

5. Centerless Grinding

CYLINDRICAL GRINDING

• In this operation, the external or internal cylindrical

surface of a workpiece are ground. In external

cylindrical grinding (also center-type grinding) the

workpiece rotates and reciprocates along its axis

although for large and long workparts the grinding

wheel reciprocates.

• In internal cylindrical grinding, a small wheel grinds

the inside diameter of the part. The workpiece is held

in a rotating chuck in the headstock and the wheel

rotates at very high rotational speed. In this operation,

the workpiece rotates and the grinding wheel

reciprocates.

CENTERED GRINDING

• Centered grinding is used to grind multi-diameter shafts

• Its also controls their concentricity

CENTRELESS GRINDING

• Centerless grinding is a process for continuously grinding

cylindrical surfaces in which the workpiece is supported

not by centers or chucks but by a rest blade. The

workpiece is ground between two wheels. The larger

grinding wheel does grinding, while the smaller

regulating wheel, which is tilted at an angle regulates the

velocity of the axial movement of the workpiece.

SURFACE GRINDING

• Surface grinding is an abrasive machining process in

which the grinding wheel removes material from the plain

flat surfaces of the workpiece.

• the spindle position is either horizontal or vertical.

• the relative motion of theworkpiece is achieved either by

reciprocating the workpiece past the wheel or by rotating

it.

CLASSIFICATIONS

1. Horizontal Spindle with Reciprocating Table

2. Horizontal Spindle with Rotary Table

3. Vertical Spindle with Reciprocating Table

4. Vertical Spindle with Rotary Table

REFERENCES

• K.M.MOEED

• WIKIPEDIA

THANKS...