Machining Lab Manual

MACHINING TECHNOLOGY
Lab Manual
Submitted to:
Submitted by:
MECH-2015
Muhammad Nawaz Shareef University of Engineering and
Technology, Multan

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Table of Contents
Experiment No.01................................................................................................................. 3
To study the different parts of Lathe machine, milling machine, grinding machine, drilling machine,
their functions & types................................................................................................................... 3
Lathe machine ........................................................................................................................... 3
Milling Machine........................................................................................................................ 4
Grinding Machine...................................................................................................................... 7
Experiment No.02............................................................................................................... 10
To Study the Lathe Machine Tools, Accessories, their uses & Limitations while working on lathe
machine....................................................................................................................................... 10
Experiment No.03............................................................................................................... 14
To Study and perform Various Lathe machine operations using lathe machine tools on a given
Work piece. ................................................................................................................................. 14
3.1 Turning Operation........................................................................................................ 18
3.3 Taper turning Operation ............................................................................................... 20
3.4 Knurling Operation ...................................................................................................... 21
3.5 Drilling Operation ........................................................................................................ 22
3.6 Thread Cutting Operation............................................................................................. 23
Experiment No.04............................................................................................................... 25
To Study and perform various milling machine operations using different milling machine tools on
a given Work piece. ..................................................................................................................... 25
To Study and perform drilling/tapping/reaming machine operations using different drilling machine
tools on a given Work piece......................................................................................................... 28
Drilling/Tapping/Reaming Machine Operations ....................................................................... 31
Experiment No.06............................................................................................................... 32
To study and perform grinding machine operations using different grinding machine tools on a
given Work piece......................................................................................................................... 32
Surface Grinding Operation ..................................................................................................... 33
Experiment No.07............................................................................................................... 35
To Study and perform shaper/planner machine operations on a given Work piece. ....................... 35
Flat Surfaces Operation............................................................................................................ 36
Experiment No.08............................................................................................................... 37
To study the different parts of CNC machining centre, CNC turning centre, their functions & types.
.................................................................................................................................................... 37
Experiment No.09............................................................................................................... 39
To Study and perform various machining operations of CNC machines on a given Work piece.... 39
Experiment No.10............................................................................................................... 40

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To Study an overview of CNC programming, CNC tools, work holding devices of CNC machines
and control panel of CNC machines............................................................................................. 40

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Experiment No.01
Objective
To study the different parts of Lathe machine, milling machine, grinding machine, drilling
machine, their functions & types.
Introduction
Machining is the process of converting the given work piece into the required shape
and size with help of a machine tool. The most widely used machine tool is lathe. In simple
words machining is the process of removing certain material from the work piece.
Lathe machine
Lathe is the machine tool which is used to perform several operations on the work
piece. Lathe is useful in making several parts which is further assembled to make new
machine. Hence lathe is known as “mother of machines”.
BASIC WORKING PRINCIPLE OF LATHE
In lathe, the work piece is held in the chuck, a work holding device. The cutting tool is
mounted in the tool post. The chuck is rotated by means of power. When the chuck rotates,
the work piece also rotates. The tool is moved against the rotating work piece by giving small
amount of depth of cut. The material is removed in the form of chips. Continuous feed and
depth of cut is given until the required dimensions are obtained in the work piece.
Parts of Lathe machine
1. Bed
It is the base of the machine. On its left side, the head stock is mounted and on its
right it has movable casting known as tailstock. Its legs have holes to bolt down on the
ground.
2. Head stock
It consists of spindles, gears and speed changing levers. It is used to transmit the
motion to the job. It has two types one is the headstock driven by belt and the other one is the
gear driven.
3. Carriage
Carriage is used to carry a tool to bring in contact with the rotating work piece or to
with draw from such a contact. It operates on bed ways between the headstock and tail stock.
4. Saddle

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It is an ‘H’ shaped part fitted on the lathe bed. There is a hand wheel to move it on the
bed way. Cross slide, compound rest, tool post is fitted on this saddle.
5. Apron
It is the hanging part in front of the carriage. It accommodates the mechanism of hand
and power feed to the cutting tool for carrying out different operations
6. Lead screw
It is a long screw with ACME threads. It is used for transmitting power for automatic
feed or feed for thread cutting operation.
Types of Lathe
There are different types of lathe machines, they are
1. Centre lathe
2. Tool room lathe
3. Bench lathe
4. Capstan lathe
5. Turret lathe
6. Automatic lathe
Milling Machine
Milling is the machining process of using rotary cutters to remove material from a
work piece advancing (or feeding) in a direction at an angle with the axis of the tool. It covers
a wide variety of different operations and machines, on scales from small individual parts to
large, heavy-duty gang milling operations. It is one of the most commonly used processes in
industry and machine shops today for machining parts to precise sizes and shapes.

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Parts of Milling Machine
There are mostly two types of milling machine used in mechanical industries. First
one is horizontal milling machine and other one is vertical milling machine. The basic parts
of these machine described as follow.
1. Base
It is the foundation part of a milling machine. All other parts are jointed on it. It
carries the entire load so it should have high compressive strength so it is made by cast iron.
2. Column
Column is another foundation part of milling machine. It is mountain vertically on the
base. It supports the knee, table etc.
3. Knee
Knee is the first moving part of milling machine. If is mounted on the column and
moves along the slide ways situated over the column. It is made by cast iron and moves
vertically on slide ways It moves up and down on sideways which change the distance
between tool and work piece It is driven by mechanically or hydraulically.
4. Table
Table is situated over the knee. It is the part of machine which holds the work piece
while machining. It is made by cast iron and have T slot cut over it. The work piece clamp
over it by using clamping bolts.
5. Spindle
Spindle is the main part of the machine which hold tool at right place in vertical
milling machine and hold arbor in horizontal milling machine. It is a moving part which is in
rotary motion.
6. Arbor
It is a mechanical part on which is used as extension part of the spindle in horizontal
milling machine. It is fitted on the spindle whenever required. It holds the tool and moves it
in correct direction.
7. Ram
Ram is work as overhanging arm in vertical milling machine. One end of the arm is attached
to the column and other end to the milling head

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Types of milling
1. Plain milling machine
2. vertical milling machine
3. universal milling machine
4. simplex milling machine
5. triplex milling machine

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Grinding Machine
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. This wheel can be made up of
various sizes and types of stones, diamonds or of inorganic materials. For machines used to
reduce particle size in materials processing see grinding.
Parts Grinding Machine
1. Guard.
2. Work rest.
3. Wheel.
Types Grinding Machine
1. Belt grinder
2. Bench grinder
3. Cylindrical grinder
4. Surface grinder
Drilling Machine
It is the simplest and accurate machine used in production shop.The work piece is
held stationary ie. Clamped in position and the drill rotates to make a hole.

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Parts of Drilling Machine
1. Spindle
The spindle holds the drill or cutting tools and revolves in a fixed position in a sleeve.
2. Sleeve
The sleeve or quill assembly does not revolve but may slide in its bearing in a
direction parallel to its axis.
3. Column
The column is cylindrical in shape and built rugged and solid. The column supports
the head and the sleeve or quill assembly.
4. Head
The head of the drilling machine is composed of the sleeve, a spindle, an electric
motor and feed mechanism. The head is bolted to the column.
5. Worktable
The worktable is supported on an arm mounted to the column. The worktable can be
adjusted vertically to accommodate different heights of work or it can be swung completely
out of the way

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Types of Drilling Machine
1) Based on Construction
i. Portable,
ii. Sensitive,
iii. Radial,
iv. up-right,
v. Gang,
vi. Multi-spindle
2) Based on Feed
I. Hand driven
II. Power driven
Comment

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Experiment No.02
Objective
To Study the Lathe Machine Tools, Accessories, their uses & Limitations while working on
lathe machine.
Lathe Machine Tools
For making a finished job on lathe machine, various types of cutting tools are used.
One of them is single point cutting tool which is used to perform several operations on the
work piece. Various types of cutting tools are
1. Facing Tool
It is used for facing the longitudinal ends of the job. Its shape is like a knife.
2. Rough Turning Tool
It is used to remove excess material from the work piece in quick time. It can be used
to give large depth of cut and work at coarse feed.
3. Finishing Tool
It is used for getting smooth finish on the work piece. Its point is a little more round.

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4. Parting Tools
It is used to cut the jobs into tw o parts. It is also used for grooving.
5. Form Turning Tool
It is used for jobs which require both convex and concave turning.
6. Thread Cutting Tool
It is used for making internal or external threads on the work piece. The tool nose is
designed with a definite profile for taking threads.
7. Drill Tool
It is used for making holes of various diameters onthe job. Drill bit of various sizes of
diameter are available.
8. Boring Tool
It used for enlarging the drill hole.
9. Knurling Tool
Drawing slanting or square projecting lines on the surface of a job is known as
knurling. It is used for making better grip on the surface of a job.

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Tool Materials
1. The single point cutting tools are made of high speed steel. (H. S. S).
2. General purpose hand cutting tools are usually made from carbon steel or tool steel.
3. Carbide tipped tools fixed in tool holders, are mostly used in production shops.
Lathe Accessories
A number of lathe accessories extend the usefulness of a standard lathe. These
include.
1. Steady Rest
Long, thin work pieces present special problems for the lathe operator. A steady rest
solves these problems by supporting the work piece either at the end or in the middle.
2. Follower rest
A long, thin work piece tends to deflect away from the cutting tool during a cut. The
deflection is greater in the middle of the work piece than at either end, which results in a
diameter that is not uniform. A follower rest keeps the work piece from deflecting away from
the cutting tool by supporting it in the immediate area of the cut.

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3. Taper attachment
Normally, a lathe machines only parallel or perpendicular to the axis of the lathe
spindle. A taper attachment allows a lathe to cut a taper by causing the carriage and the cross-
slide to move at the same time.
4. Tool post grinder
A tool post grinder consists of a grinding wheel and motor that can be attached to the
compound rest in place of the normal tool post. Simple cylindrical external or internal
grinding can be performed on a lathe with this attachment.
Limitations
The size and shape limitations depend heavily on the machine being used. On most
lathes there is an outer diameter limit of 8" and a length limit of 42". Parts any bigger can not
be made on the lathes in the machine shop.

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Experiment No.03
Objective
To Study and perform Various Lathe machine operations using lathe machine tools on a
given Work piece.
Theory
Operations which can be performed in a lathe machine.
1. Turning
2. Taper turning
3. Chamfering
4. Thread cutting
5. Facing
6. Forming
7. Knurling
8. Parting-off
9. Drilling
10. Reaming
11. Boring
12. Counter boring
13. Tapping
Turning
This operation is adopted in order to cut the metal parallel to the axis. Turning is done
to decrease the diameter of the metal.
Taper Turning
The taper turning is an operation of producing a conical surface by gradual reduction
in the diameter of a cylindrical work piece.
Chamfering

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Chamfering removes the burrs and sharp edges, and thus makes the handling safe.
Chamfering can be done by a form tool having angle equal to chamfer which is generally
kept at 45°
Thread cutting
Threading is the act of cutting of the required form of threads on the internal or
external cylindrical surfaces.
Facing
The facing is a machining operation by which the end surface of the work piece is
made flat by removing metal from it. Facing is done to decrease the length of the metal.
Forming
The forming is an operation that produces a convex, concave or any irregular profile
on the work piece.
Knurling
The knurling is a process of embossing (impressing) a diamond-shaped or straight-
line pattern into the surface of work piece. Knurling is essentially a roughening of the surface
and is done to provide a better gripping surface.

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Parting-off
Parting or cutting off is the operation of cutting away a desired length of the work
piece, i.e., dividing the work piece in two or more parts.
Drilling
Drilling is the operation of producing a cylindrical hole in the work piece.
Reaming
Holes that are produced by drilling are rarely straight and cylindrical in form. The
reaming operation finishes and sizes the hole already drilled into the work piece.
Boring
The boring operation is the process of enlarging a hole already produced by drilling.

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Counter Boring
Counter boring is the operation of enlarging one end of an existing hole concentric
with the original hole with square bottom. It is done to accommodate the heads of bolts, studs
and pins.
Tapping
In the existing holes, to perform the internal threads, tapping process is used. After the
completion of the drilling process tapping is operated.

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3.1 Turning Operation
Aim
Perform a turning operation on the given cylindrical work piece.
Apparatus
1. Lathe with standard accessories.
2. Work piece
Material
Mild Steel round rod
Tools
Steel rule, outside calipers, tool holder with key, chuck key, HSS cutting Tool bit.
Theory
Lathe removes undesired material from a rotating work piece in the form of chips
with the help of a tool which is traversed across the work and can be fed deep in work. The
tool material should be harder than the work piece.
RPM Calculated using the following formula
rpm = π × d2
4
Turning Time Calculation
Time to turn = Length of the job to be turned × no of cut min
Feed × rpm
Procedure
1. First of all the given work piece is fitted the chuck using a chuck key.
2. Adjust the machine to run the job to a required cutting speed.
3. Fix the cutting tool in the tool post and centering operation is performed so that the
axis of the job coincides with the lathe axis.
4. Give the feed and depth of cut to the cutting tool.
5. Check the dimensions by using venire calipers.
6. After this operation, the diameter of the work piece is to be reduced according to the
given dimensions by turning process.

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3.2 Facing Operation
Aim
Perform a Facing operation on the given cylindrical work piece.
Tools
Steel rule, tool holder with key, chuck key, HSS cutting Tool.
Theory
Facing is the process of removing metal from the end of a work piece to produce a flat
surface. Most often, the work piece is cylindrical, but using a 4-jaw chuck you can face
rectangular or odd-shaped work to form cubes and other non-cylindrical shapes.
Procedure
4. Give the feed to the cutting tool with the help of cross slide hand wheel.
5. Check the dimensions by using scale calipers
6. After this operation, the length of the work piece is to be reduced according to the
given dimensions by facing process.

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3.3 Taper turning Operation
Aim
To perform Taper turning operation by Compound Rest Swiveling method on the
given cylindrical work piece
Tools
Steel rule, outside calipers, tool holder with key, chuck key, HSS cutting Tool bit.
Theory
Cutting Tapers on a lathe is common application. A number of methods are available
for cutting tapers on a lathe.
They are:
1. Compound rest Swiveling Method.
2. Using form tools.
3. Tail stock offset method.
4. Taper attachment method.
The amount of taper in a work piece is usually specified by the ratio of the difference
in diameters of the taper to its length. This is termed as conicity and is designated by the
letter K.
Conicity K = (D-d)/(2xl)
Where,
D – large Diameter
d – Small diameter
l – Length of taper
Procedure
4. Facing and turning operations are performed to get the required diameter on the work
piece.
5. Compound rest is set on the required half taper angle and is locked by the cutting rod
is adjusted to a fixed position.
6. Give the feed to the cutting tool with the help of compound rest hand wheel.

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3.4 Knurling Operation
Aim
To perform Knurling Operation on the given cylindrical work piece.
Tools
Steel rule, Knurling tool, tool holder with key, chuck key.
Theory
It is process of making serrations on the work piece. Knurling tools of different shape
and size are used to make grip on the work piece. It has two hardened steel rollers. The tool is
held in tool post and pressed against the rotating work piece. Work piece is rotated at lower
speed and small amount of feed is given.
Procedure
2. Set knurling tool at right angles to work piece and tighten it securely
3. Adjust the machine to run the job to a required speed.
4. Start lathe and then force knurling tool into work until diamond pattern come to point.

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3.5 Drilling Operation
Aim
To perform Knurling Operation on the given cylindrical work piece
Tools
Steel rule, Knurling tool, tool holder with key, chuck key.
Theory
The tailstock of a lathe can be used for drilling, with the aid of a drill chuck
attachment. The drill chuck has a morse taper shaft which can be push into the shaft of the
tailstock, locking it in position.
Procedure
2. Fix the drilling tool in the tailstock and centering operation is performed so that the
4. Give the feed to the drilling tool with the help of tailstock hand wheel.
5. After this operation, a round hole will be produce in work piece.

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3.6 Thread Cutting Operation
Aim
To obtain a Right Hand Screw threaded work piece of given dimensions.
Apparatus
1. Lathe with standard accessories.
2. Work piece
Material
Mild Steel round rod
Tools
Steel rule, thread micrometer, tool holder with key, chuck key, HSS cutting Tool bit.
Theory
Thread cutting on the lathe is a process that produces a helical ridge of uniform
section on the work piece. This is performed by taking successive cuts with a threading tool
bit the same shape as the thread form required. To cut a correct thread on the lathe it is
necessary first to make calculations so that the thread will have proper dimensions. The
following formulas will be helpful when calculating thread dimensions.
d = P x 0.750
Where:
d = Single Depth
P = Pitch
p = 1 / n
n = Number of threads per inch (TPI)
In feed Depth = .75 / n
Procedure
2. Fix the drilling tool in the tailstock and centering operation is performed so that the
axis of the job coincides with the lathe axis
3. Set the speed to about one quarter of the speed used for turning.
4. Set the quick change gearbox for the required pitch in threads. (Threads per inch)
5. Set the tool bit and right angles to the work, using a thread gage.
6. Move the threading tool up to the part using both the compound and the cross feed
7. The work piece is removed from the chuck and all the dimensions are measured and
checked

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Experiment No.04
Objective
To Study and perform various milling machine operations using different milling machine
tools on a given Work piece.
Theory
A milling machine is a machine tools that resinous metal from the work which is fed
against a retailing multipoint cutter. The cutter rotates at a high speed and because of the
multiple cutting edges it removes metal at a very fast rate. Milling can perform various
operations to convert the work piece into desire shape. It is a very useful machine and mostly
used in die making industries. The most popular operation done on milling machine is
described below.
Plain Milling
As the name implies, this operation used to get place surface. In this milling, the
cutting tool axis is parallel to the machining surface or the face of the machining surface.
This operation is very common and done on almost all jobs. This can be carried out on every
milling machine.
End Milling
This operation is also used to get plain surface. In this operation, the cutting tool axis
is perpendicular to the machining surface or the face of the machining surface. It is also used
to slot cutting on the milling axis.
Gang Milling
As the name is gang, in this milling operation more than one milling cutters are used
to machining. It is a horizontal milling operation, more than one cutter with different shape
and sizes are fixed at the arbor, which cut the desire shape in one pass. This milling operation
can save most of time of milling.

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Straddle Milling
In this operation, two or more parallel vertical surface machined in a single pass. In
this milling the work piece is situated between the two cutters which can machined the
surface vertically. The cutter are fixed on the same arbor and cut the metal in one pass.
Slotting
In this operation slots are cut by a cutter on the work piece. The slots are in various
shapes like circular, rectangular etc. and sizes according to the requirement.
Face Milling
It is a method of producing a flat surface at right angles to the axis of the cutter.
Form Milling
Formed milling cutters shaped to the contour to be cut are used to perform this
operation. This operation is accomplish by using convex, concave and corner rounding
milling cutters.

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Slotting Operation
AIM
To perform the Slotting on milling machine
Tools and Equipment
Milling machine, key slot milling cutter, vernier caliper
Material
M/S block
Procedure
1. Hold the work piece in the table of the milling machine using the vice.
2. Place parallels under the work piece to raise the surface to be milled above the level
of the vise jaws
3. Raise the table to the required position.
4. Adjust the cutting speed and feed.
5. Start the machine after selecting the proper speed and feed.
6. Mark the dimensions on the work piece.
7. Perform the Slotting operation.
Comment

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Experiment No.05
Objective
To Study and perform drilling/tapping/reaming machine operations using different
drilling machine tools on a given Work piece.
Theory
The drilling machine or is one of the most common and useful machine employed in
industry for producing forming and finishing holes in a work piece. The unit essentially
consists of.
1. A spindle which turns the tool (called drill) which can be advanced in the work piece
either automatically or by hand.
2. A work table which holds the work piece rigidly in position.
Working principle
The rotating edge of the drill exerts a large force on the work piece and the hole is
generated. The removal of metal in a drilling operation is by shearing and extrusion.
Drilling Machine Operations
Drilling
Drilling is the operation of cutting a round hole by a rotating tool called drill. Before the
process of drilling, the center of the hole is positioned on the work piece. Two lines at right angles to
each other are drawn. A center punch is used to mark the center point at the meeting of two lines.
The rotating drill is pressed at the center point scribed on the work piece to produce the hole.

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Boring
It is the operation of enlarging a hole that has already been drilled or bored with a
single point tool. It also rectifies the error of drilling.
Reaming
The process of sizing and finishing the already drilled hole is called as Reaming. The
tool used for reaming is known as a reamer. It is a cylindrical tool having many cutting edges.
Reamer cannot drill a hole. It simply follows the path of an previously drilled hole. It
removes a very small volume of metal.
Tapping
It is the operation of forming internal threads by means of a tool called tap.
Counter Boring
It is the operation of enlarging one end of a drilled hole. The enlarged hole is
connected to the original one and it is flat at the bottom. It is done to set bolt head and nuts
below the surface.
Counter Sinking

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The top of the drilled hole is beveled to accommodate the conical seat of a flat head
screw and counter sunk rivets; the operation is called counter sinking.

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Drilling/Tapping/Reaming Machine Operations
Aim
To perform drilling, reaming and tapping operations on the given M.S Flat work
piece.
Apparatus
1. Drilling Machine with standard accessories
2. Work piece
Material
M/S block
Procedure
1. The given work piece is first fitted to get required length, breadth and thickness wet
chalk is applied on four sides and with the scribber lines are drawn to get center hole
at required location.
2. The centers are punched with a Punch and hammer.
3. The work piece is fixed firmly in the vice of the Drilling Machine
4. Drill bit is fixed firmly in the chuck and drilling is performed giving uniform depths.
5. The drill bit is removed from the drill chuck and is replaced by a reamer.
6. The reaming operation is performed on the hole which has been previously drilled.
7. The work is removed from the vice for performing tapping operation.
8. The job is fixed firmly in a bench vice.
9. Tap is fixed in the tap handle and pressure applied on the taps to obtain internal
thread.
Comments

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Experiment No.06
Objective
To study and perform grinding machine operations using different grinding machine tools on
a given Work piece.
Theory
Grinding is the process of removing the surface of a hard material using a wheel made
from or covered in hard grit. Grinding is a finishing process used to improve surface finish,
abrade hard materials, and tighten the tolerance on flat and cylindrical. CNC grinding
machine is the use of abrasive on the work piece surface grinding machine. The majority of
grinders are ground using high-speed rotating grinding.
Grinding Operations
Selecting which of the following grinding operations to be used is determined by the
size, shape, features and the desired production rate.
Internal Grinding
Is used to grind the internal diameter of the work piece. Tapered holes can be ground
with the use of internal grinders that can swivel on the horizontal.
Form Grinding

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Is a specialized type of cylindrical grinding where the grinding wheel has the exact
shape of the final product.
Cylindrical Grinding
Cylindrical grinding (also called center-type grinding) is used to grind the cylindrical
surfaces and shoulders of the work piece.
Surface Grinding
Surface grinding is used to produce a smooth finish on flat surfaces.
Surface Grinding Operation
AIM
To perform the fine surface Grinding operation on given work piece.
Apparatus
Surface grinding machine, steel rule

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MATERIAL
M.S Flat Block
Procedure
1. Mark the require dimensions on the work piece.
2. Hold the work piece in the magnetic chuck.
3. Adjust the grinding wheel on to the work piece.
4. Start the machine and perform grinding operation.
5. Reduce the required thickness on the work piece by grinding operation. Perform fine
finishing operation on the work piece.
Comments

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Experiment No.07
Objective
To Study and perform shaper/planner machine operations on a given Work piece.
Theory
Shaper is a reciprocating type of machine tool. It is used for machining the surfaces.
The surface may be horizontal and vertical indeed. The shaper has the main parts such as
base, table, column, cross-rail, ram and tool head. The work is held on the table by using
correct work holding device. A single tool is in vertical position of the cutting stroke (forward
bias) the feed is given at the end of each cutting stroke during the return stroke, no metal is
cut. The cutting stroke takes place at slow speed and the return stroke takes place at a faster
speed. The faster feed rate is obtained using quick return.
Shaper Machine Operations
1. V-block in shaping machine by single point tools
2. Straight tooth of spur gears can be made in shaping machine
3. Slots
4. Steps
5. Flat Surfaces

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Flat Surfaces Operation
Procedure
1. Hold the work piece in a vice or holding device.
2. Set the planning tool in the tool head with minimum overhang. Raise the table up to
required position.
3. Adjust the length and position of the stroke.
4. Adjust the cutting speed and feed.
5. Perform planning operation on the work piece.
6. Mark the dimensions on the work piece.
Chips
Comments

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Experiment No.08
Objective
To study the different parts of CNC machining centre, CNC turning centre, their functions &
types.
Theory
The term “machining center” describes almost any CNC milling and drilling machine
that includes an automatic tool changer and a table that clamps the work piece in place. On a
machining center, the tool rotates, but the work does not. The orientation of the spindle is the
most fundamental defining characteristic of a machining center.
Difference between NC and CNC
Difference between NC and CNC is clarified in this experiment where NC is old
technology and program is fed to the machine through magnetic tapes. NC has no storage
memory while CNC is new technology and program is fed through computer
Codes
Generally G codes are writen in and performed by the CNC processor and operate the
motion control part of the control, the M codes are MACHINE codes, these operate most of
the basic electrical control functions such as Coolant, Tool changers, safety circuits etc, the
M,S& T codes are written in a separate PLC processor, both processors usually communicate
with each other over a common bus.
The tool changer and spindle are both configured to suit a particular machine specifics.
CNC Turning

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CNC Center
Types of CNC Turning
CNC chucking center
Holds part in some form of jaw chuck. Some have dual spindles (work both ends).
CNC universal turning center
Can use continuous bar feed system to machine and cut off parts from bar.Some have dual
tool turrets.
3-Axis Center Machine
A 3-axis milling machine consists of a vertical spindle and a horizontal spindle, but in
all cases, the milling machine is parallel to the table during machining.
The 4-axis milling machine generally has the same features as the 3-axis milling
machine, except that it’s equipped with a turntable, which is a real asset in fields of
mechanical production such as aviation or automotive.
A 5-axis milling machine always has three linear axes as well as two rotary axes,
which may vary according to the chosen model. In terms of the position of the rotary axes,
there are three models, which are two axes on the machine head, two axes on the table, or a
single axis on the table.
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39 | P a g e
Experiment No.09
Objective
To Study and perform various machining operations of CNC machines on a given Work
piece.
Step To Use the Machine
Steps for Successful CNC Machining
Step 1
Determine how the part will be machined
Step 2
List the tooling to be used.
Step 3
List the operations to be carried out.
Step 4
List the coordinates required for each operation.
Step 5
Write the CNC program.
Step 6
Load the CNC program. Check the CNC program. Proof / Test run the CNC program.
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40 | P a g e
Experiment No.10
Objective
To Study an overview of CNC programming, CNC tools, work holding devices of CNC
machines and control panel of CNC machines.
Parts of CNC Machine
Storage Memory
CNC has storage memory and it is easy to modify program.
Control Panel
The brain of the cnc machine, all the cnc program are stored inside this panel, cnc
machinists control the whole machine through the keys on this panel. CNC machinist’s
stat/stop the machine move axis by pressing different keys on this panel.
Tool Turret
The tool are mounted on the tool turret which are used for component machining.
Tool turrets vary in shapes and number of tools that can be mounted on them
Foot Switch or Foot Pedals
Foot switches are used to actual the chuck and tailstock quill. Through these pedals
cnc machinist’s open and close the chuck to grip the component, the same way tailstock quill
is taken to forward position or reversed through theses pedals

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How CNC Machine Works
1. First the part program is inserted into the MCU of the CNC.
2. In MCU all the data process takes place and according to the program prepared, it
prepares all the motion commands and sends it to the driving system.
3. The drive system works as the motion commands are send by MCU. Drive system
controls the motion and velocity of the machine tool.
4. Feedback system, records the position and velocity measurement of the machine tool
and sends a feedback signal to the MCU.
5. In MCU, the feedback signals are compared with the reference signals and if there are
errors, it corrects it and sends new signals to the machine tool for the right operation
to happen.
6. A display unit is used to see all the commands, programs and other important data. It
acts as the eye of the machine.
Application of CNC Machine
Almost every manufacturing industry uses CNC machines. With increase in the
competitive environment and demands, the demand of CNC usage has increased to a greater
extent. The machine tools that comes with the CNC are late, mills, shaper, welding etc. The
industries that are using CNC machines are automotive industry, metal removing industries,
industries of fabricating metals, electrical discharge machining industries, wood industries
etc.
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Machining Lab Manual

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