Basic Industrial Training Report

National Diploma in Engineering Sciences
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INSTITUTE OF ENGINEERING TECHNOLOGY
KATUNAYAKE-SRI LANKA
NATIONAL DIPLOMA IN ENGINEERING SCIENCES
TRAINING REPORT
BASIC INDUSTRIAL TRAINING PROGRAMME
AT
JINASENA (PVT) LTD -EKALA
BEST CAN MACHINERIES (PVT) LTD – JA-ELA
SUBMITTED BY: K.B.S.MADHUSHA FERNANDO
ADMISSION NO: MG/15/10262
FIELD: MECHANICAL (GENERAL) ENGINEERING
DURATION: 25/08/2016– 31/08/2017

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PREFACE
This training report is based on basic industrial training period of National Diploma in
Engineering Sciences which I currently following at Institute of Engineering Technology at
Katunayake.
It is a great pleasure to have my basic training at Jinasena (Pvt) Ltd and Best can machineries
(Pvt) Ltd. I got a golden opportunity to improve my practical skills in mechanical as well as
electrical field. And also I got a great chance to have knowledge about management part.
This training period of 11 months which started from 25th August 2016 to 31th August 2017,
really helped me to have a general idea about mechanical, electrical engineering and
maintenance and, it guides me to put a foundation to my future career. These two organizations
are good training places not only for trainees, but also those who have a specific knowledge
about their field to improve their skills.
It is pleasure to say that I was able to work with different kinds of employees, from top
management to labor. They also satisfied that helping us to improve our knowledge in every
possible time during their working hours.
This training report contains all my experience I had at my training as an industrial trainee. I
have included all those things which I learnt while I attend myself on projects, breakdowns and
preventives. I have presented this report best of my knowledge and fullest effort.
Mrs. K.B.S.Madhusha Fernando
Mechanical (General) Engineering
Institute of Engineering Technology
Katunayake.

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ACKNOWLEDGEMENT
I am very much appreciated in obtaining Jinasena (Pvt) Ltd and Best can Machineries (Pvt) Ltd
as my Basic Industrial Training that expanded for a period of 11 months.
It’s due to the enormous support of various personalities from different backgrounds that I
succeeded in achieving expected objectives.
At first I extend my gratitude to Mr. Wijith Subasinghe Production Manager of Jinasena and
Mr.Aravinthanathan the director of Best can machineries for its, because of their organization
facilitated industrial trainees in this way. Also Special thanks go to NAITA and its officials for
their service in the field of industrial training.
I’m grateful to Head of Department –Mechanical (Training) Mr.Senavirathne and
Mr.Dhanushka for his dedication & determination in finding us the training establishments &
evaluating, guiding us throughout the particular period.
I would like to thank,
Mr.Nishan Jinasena Mr. Prabath
Director – Jinasena (Pvt) Ltd RND of Jinasena (pvt) Ltd
Mr. M.H. Rodrigo Mr.R.C.Kaushalya
General Manager – Jinasena (Pvt) Ltd Workshop Engineer of BCM
Mr. Prabath Sanjeewa
Electrical Engineer

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Content
Jinasena (Pvt) Ltd .........................................................................................................................8
Contact Details ....................................................................................................................................9
Introduction .........................................................................................................................................9
History.................................................................................................................................................9
Divisions............................................................................................................................................11
Best Can Machinery (Pvt) Ltd...................................................................................................... 12
Introduction .......................................................................................................................................13
Casting....................................................................................................................................... 14
What is casting ..................................................................................................................................14
What are the limitations in Casting ...................................................................................................15
Types of materials used for Casting..................................................................................................15
Limitations to selection of materials .................................................................................................15
Basic requirements of casting process...............................................................................................15
Mould Cavity.....................................................................................................................................16
Types of Moulds................................................................................................................................16
Casting Terminology.........................................................................................................................18
Sand Casting......................................................................................................................................20
Sand Molding Techniques.................................................................................................................22
Patterns for Sand Casting ..................................................................................................................23
Cores..................................................................................................................................................24
Centrifugal Casting............................................................................................................................25
Melting Furnaces...............................................................................................................................26
Casting Defects..................................................................................................................................29
Pouring process .................................................................................................................................30
Lathe machine............................................................................................................................ 31
Types of Lathe...................................................................................................................................31
Specify main parts.............................................................................................................................33
Size of a lathe ....................................................................................................................................36
Operating condition in a lathe ...........................................................................................................36
Machining operation done in lathe....................................................................................................38
Thread cutting....................................................................................................................................48

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Drilling Machine......................................................................................................................... 53
Introduction .......................................................................................................................................53
Working Principle .............................................................................................................................53
Construction ......................................................................................................................................53
Types Of Drilling Machine ...............................................................................................................54
Operation Of Drilling Machine .........................................................................................................56
Milling ....................................................................................................................................... 58
Introduction .......................................................................................................................................58
Types of milling ................................................................................................................................58
Milling Operations ............................................................................................................................59
Milling machines...............................................................................................................................62
Indexing.............................................................................................................................................69
CNC Machines............................................................................................................................ 73
What is a CNC Machine?..................................................................................................................73
Types Of CNC Machine....................................................................................................................73
Operational Features Of CNC Machines...........................................................................................74
Basic CNC Principles........................................................................................................................75
CNC lathe,Drilling and Milling Machines ........................................................................................77
CNC Programming Basics ................................................................................................................78
CAD/CAM ........................................................................................................................................81
CNC Machines-Advantages/Disadvantages......................................................................................81
Work Holding Devices................................................................................................................. 82
Lathe Centers.....................................................................................................................................82
chuck .................................................................................................................................................82
Faceplates..........................................................................................................................................83
Rest....................................................................................................................................................84
Vices..................................................................................................................................................86
Super Quick-Change Toolpost ..........................................................................................................88
Welding ..................................................................................................................................... 89
Introduction .......................................................................................................................................89
Gas Welding......................................................................................................................................89
Arc Welding ......................................................................................................................................90
Resistance Welding...........................................................................................................................90
Soldering ...........................................................................................................................................91
Brazing ..............................................................................................................................................91
TIG welding(Gas Tungsten Arc Welding)........................................................................................92
Mig Welding......................................................................................................................................94

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Types Of Flames ...............................................................................................................................98
Types of Joints...................................................................................................................................98
Welding defect ..................................................................................................................................99
Ultrasonic Welding..........................................................................................................................100
Metal Cutting Techniques......................................................................................................... 102
Hack saw blades..............................................................................................................................102
Plasma Cutting Machines................................................................................................................103
Grinding Machine............................................................................................................................104
Electrical Discharge Machining........................................................................................................106
Accessories......................................................................................................................................106
Basic Definitions.............................................................................................................................106
Types Of Edm .................................................................................................................................107
How edm works?.............................................................................................................................107
Applications.....................................................................................................................................109
Advantages and Disadvantages .......................................................................................................109
AC Induction Motors ................................................................................................................ 111
Stator ...............................................................................................................................................111
Rotor................................................................................................................................................112
Principle of Operation .....................................................................................................................113
Slip ..................................................................................................................................................113
Speed...............................................................................................................................................113
Induction motor starting methods....................................................................................................114
Motor Protection..............................................................................................................................119
Plastic Injection Molding .......................................................................................................... 122
Injection Unit...................................................................................................................................123
Reciprocating Screw Injection Molding Machine...........................................................................124
Plastic Defects.................................................................................................................................126
Safty In Workshops .................................................................................................................. 129
Safety Items.....................................................................................................................................129
Safety Signs.....................................................................................................................................129
Project Report.......................................................................................................................... 130
Introduction .....................................................................................................................................131
Addressing the Issues and Reason for Implementation...................................................................131
How we Plan of Innovating and Automating the Casting Division ................................................132
Equipment Used for Automation Process .......................................................................................133
How the Bottom Pouring Ladle will be used for the Automation Process......................................134
Modifications for Small Thermal Mass Ladle for Effective Use of the Bottom Pouring Ladle .....134

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The Advantages of the Bottom Pouring Ladle................................................................................134
Bottom Pouring Ladle Technical Drawing with Parts Labelled......................................................135
The Importance of Pre-Heating.......................................................................................................136
Type of Preheater to be used for Specified Ladle ...........................................................................136
Motorized Post-Mounted (Column) Jib Crane................................................................................137
Details of Jib Crane.........................................................................................................................138
Conveyors........................................................................................................................................138
Advantages and Disadvantages of both Casting Processes.............................................................140
Production Before Automation Process ..........................................................................................141
Production After Automation Process.............................................................................................142
SEQUENCE 1.................................................................................................................................142
SEQUENCE 2.................................................................................................................................142
SEQUENCE 4, 5.............................................................................................................................144
Improvements and Rectifications that have to be made for the Automation Process .........................146
References............................................................................................................................... 148
Conclusion ............................................................................................................................... 149
CERTIFICATION......................................................................................................................... 150
CERTIFICATION......................................................................................................................... 151

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Jinasena (Pvt) Ltd

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Contact Details
 Head Office
No: 186, Elvitigala Mawatha, Colombo 08, Srilanka.
+94 112 688 966
jinasena@jinasena.com.lk
 Ekala Factory
9,Gampaha Road,Ekala, Ja-ela, Sri Lanka
Introduction
 Jinasena is a diversified organization manufacturing and trading a range of products.
 These products are escorted with unmatchable services to the customer, ensuring
comprehensive customer satisfaction.
 Jinasena deals with five product lines and provides presales and after-sales services for
these products.
History
 Jinasena Limited was founded in 1905 as a bicycle-repair shop but soon moved into
machinery repairs.
 Its founder, C.Jinasena, was a man of vision. He was a chartered engineer by profession
and was educated in the UK.
 Sri Lanka at that time was known as Ceylon and was under colonial rule. Engineering
– like many areas of enterprise – was the sole preserve of the British.
 When Jinasena Limited moved from servicing and repairing machinery used
extensively in the tea and rubber industries into manufacturing these very same
machines, it was like David going up against Goliath.
 Jinasena Limited was the first Ceylonese owned engineering company – and by 1932,
it was rated among the five leading engineering companies in the island.
 In 1950, the son of the founder T. S. Jinasena designed and manufactured the first
Jinasena Centric Water Pump.
 After years of servicing and repairing foreign water pumps, and gaining first-hand
knowledge of their shortcomings vis-à-vis local conditions, the Jinasena Centric Water
Pump was designed to overcome these problems and provide users with trouble-free
performance.
 The original water pump was fitted with a Hoover motor; but in 1967, a foundry was
set up – and in 1973, a factory dedicated to manufacturing electric motors was
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 Jinasena Electrical Motors benefits from its technical agreements with German firm,
Messrs. E. Blum Gmbh, as a result of which it has access to the latest developments in
designing and manufacturing electric motors and a virtual guarantee of meeting the
highest international standards.
 Its factory comprises machine, winding and assembly shops, and state of-the-art testing
facilities.
 Jinasena Group also has interests in diverse fields, including hotel operations,
generators, pneumatic rubber tyres, garments and agricultural machinery
 Its agricultural machinery centers around a mission to design and manufacture
mechanized farming equipment that is suited to farming conditions in Sri Lanka – in
particular, the relatively small paddy fields in rural areas.
 The range of tractors, threshers, reapers, choppers and weeders really began to make
their presence felt when the brand quickly gained the trust of the rural Sri Lankan
farmer, who is traditionally extremely skeptical about the mechanization of time-tried
methods.

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Divisions
 Ekala factory is consisted with different divisions for multi purposes. Those are;
1. Casting Division
2. Machining Division (CNC & Lathe)
3. Winding Division
4. Motor Assembly Division
5. Pump Assembly Division
6. Plastic Division
7. Die & Mould Division
8. Project division
9. Jinasena Agricultural machineries (JAM) division
10. Automobile Division

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Best Can Machinery (Pvt) Ltd.

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Introduction
Best Can Machinery (PVT) Ltd. have been established under Reg. No PV 3839 in 2008 at
49/B,Thudella East, Jaella. Mr. Aravinthanathan is the director of this company. He is a
mechanical engineer. Now this company is in Tudella area. There are around 10 employees
working in this company. This company mainly targeting repairing & manufacturing can
industry machines, but also any kind of mechanical jobs are done in here.
Tinpak, Rhino Roofing, Wichy Plantation, CBL Foods, Sun cable are some of the customers
of this Company. In this company, they own CNC Milling Machine, CNC Plasma Cutter, 3
Milling Machines 4 Lathes, Shaper, Hydraulic Press, & A Heat Treatment furnace.
They are doing gear wheel cutting, Heat treating, circular grinding, plasma cutting, CNC
machining, designing & manufacturing molds, manufacturing punch & dies & designing &
Fabricating any kind of machines. Most of time companies bring the jobs very difficult or jobs
they can’t do so the costing is also high. To do the costing using a job scan software to examine
the labour hours, machining hours & material cost, & AOD sys system & a tool issuing system.

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Casting
What is casting
Casting is a process which basically involves pouring of molten metal into a mold cavity where,
upon cooling down & solidification, it takes the shape of the cavity
Where Cast products are used
All the pump body parts are made at Jinasena casting Limited..
Where cast products are not used
Example : Some of alloyes metal parts such as rotors, rotor shfts…etc can‘t be made from
casting.
Why Casting is so important ?
 Intricate of shapes
 May be cast in a single operation
 Some metals can only be cast to shape
 Resistance to working stress
 Construction may be simplified, no assembly.
 Mass production at high production rates.
 Very large, heavy metal objects may be cast
 Good engineering properties

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What are the limitations in Casting
 Surface finish & dimensional accuracy.
 Limitations in toughness & strength.
 Limitations in making thin & complex structures.
 Shrinkage & porosity.
 Casting defects
Types of materials used for Casting
 Ferrous metals: Cast iron, Wrought iron, Alloy cast iron, Steel, etc.
 Non-ferrous metals: Copper alloys, Aluminium alloys, Magnesium alloys, Tin alloys,
etc.
Limitations to selection of materials
 Fluidity
 Shrinkage
 Ease with which properties can be controlled
Basic requirements of casting process
 Mould Cavity
 Melting Process
 Pouring Techniques
 Solidification Process
 Mould Removal
 Cleaning, Finishing & Inspection

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Mould Cavity
 Should be of desired shape & size
 Ability to compensate shrinkage of the solidifying metal
 Must be able to reproduce the desired detail
 Must have refractory characteristics
Types of Moulds
 Expandable Moulds
 Permanent moulds
 Composite moulds
Expendable Moulds
 Usually made of sand, plaster, ceramics, etc & mixed with various binders or bonding
agents.
 After the casting has solidified, the mould is broken up to remove the casting
 Preferred for production of smaller quantities

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Types of Expendable Moulds
 Expendable mould with re-usable pattern
 Expendable mould with disposable pattern
In JCL most of the casting parts are made from this type of mould. Because of low cost and
can be recycling.
Example: Sand Mould
Permanent Moulds
 Usually made of metals
 Used repeatedly
 Designed in such a way that the casting can be easily removed
 Generally restricted to large production
Permanat molds are used to make cores of expendable molds

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Composite moulds
 Made of two or more different materials, such as sand, graphite & metal
 Combined advantages of each material
Advantages of Permanent Moulds
 Good surface finish
 Good dimensional accuracy
 High strength & thermal conductivity
Casting Terminology
•Pattern
–Approximate duplicate of the casting, when the pattern is withdrawn, its imprint
provides the mould cavity.
•Core
–Placed into a mould cavity to form the interior surfaces or features of castings.
•Mouldingmaterial
–Readily formed aggregate material, which is packed around the pattern.
•Flask
–Rigid wood or metal frame that hold the mouldingaggregate.
•Cope
–Top half of the pattern, flask, mould or core of a two-part mould.
•Drag
–Bottom half of any of the above features
 Core print
–Region that is added to the pattern, core, or mould & is used to locate & support
the core within the mould.
 Mould cavity
–Combination of mould material & core produce a shaped hole.
 Riser
–An extra void created in the mould to hold molten metal, that acts as a reservoir
of liquid that can flow into the mould cavity to compensate for any shrinkage.
 Gating system
–Network of connected channels used to deliver the molten metal to the cavity.
 Vent
–Additional channels to provide an escape for the gasses that are originally
present in the mould or generated during the pour.

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•Parting line
–Interface that separates the cope & drag halves of mould, flask, core or pattern.
 Draft
–Taper on a pattern or casting that permits it to be withdrawn from the mould.
 Core box
–Mould or die used to produce cores.
 Sprue
–Vertical portion of the gating system.
 Choke
–Cavity in the mould at the base of the Sprueto allow the metal to flow
smoothly.
 Runners
–Horizontal channels.
 Gate
–Controlled entrance.

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Sand Casting
 Most common & the most versatile among other casting processes.
 Sand casting consists of,
Sequential steps in making the sand casting Mould making Machines

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Sands used in sand casting
This is the green soil mixture used in jinasena casting limited.
 Silica sand - 55 kg
 Red sand - 3 kg
 Bentonite - 5.5 kg
 Carbon dust - 9kg
 Normal soil (can be found by recycling mold and core)-250 kg
This ingredients were added to the automated soil mixing machine(Require water percentage
were auomaticaly added in the machine)
 Desired properties
 Refractoriness
 Cohesiveness
 Permeability
 Collapsibility
Checking steps of green soil mixture ejects from the Machine
 160g green soil sample were compressed (SHATTER INDEX TESTER);
equation { 160-x * 100} ;where x is filted falled down soil sample after
compressing.
160
 Moisture should be closely 3.06%
 Permability 25%-30%
Types of sand-moulds
 Green-sand mould
 Skin-dried mould
 Dry-sand mould
 Other types

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Sand Molding Techniques
(a)Sand is squeezed between two halves of the pattern
(b)Assembled moulds pass along an assembly line for pouring

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Patterns for Sand Casting
•Used to mould the sand mixture into the shape of the casting
•Factors affecting selection of pattern material
o Size & shape of the casting
o Desired dimensional accuracy
o Quantity of castings required
o Moulding process
•Types of pattern material
o Wood
o Metal
o Plastic
Making Patterns

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Cores
 Horizontal & Vertical cores
 Core prints
 Chaplets
DDH500 pump
Core prints & chaplets to support cores
Steps of making an investment casting
1.Making of pattern
2.Attaching the patterns to a central wax sprue, to form a casting cluster
3.Building the shell
4.Melting of the wax
5.Pouring metal
6.Breaking of mould
7.Disassembling castings

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Characteristics of Investment casting
 Unlike plastic patterns (i.e. polystyrene), wax can be recovered & reused.
 Good surface finish
 Close dimensional tolerances
 Can produce intricate shapes
Centrifugal Casting
•Utilizes the inertia forces caused by rotation to distribute the molten metal into the mould
cavities
Types of centrifugal casting are,
 Semi-centrifugal casting
 Centrifuging
Semi-centrifugal casting
centrifuge casting

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Melting Furnaces
Selection of a furnace depends on,
 Economic consideration
 Composition & melting point of the alloy
 Capacity & control of the furnace atmosphere
 Environmental consideration
 Type of charge material used
Types of furnaces available are
 Cupolas
 Crucible furnaces
 Electric arc furnaces
 Induction furnaces
 Levitation melting
In the past cupola furnace was used in jcl. now induction furnace is replaced for it due to
environmental pollution
Induction furnaces
How does it works ?
 Electromagnetic Induction
The energy transfer to the object to be heated occurs by means of electromagnetic
induction.
Any electrically conductive material placed in a variable magnetic field is the site
of induced

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electric currents, called eddy currents, which will eventually lead to joule heating
Features Of Induction Furnace
 An electric induction furnace requires an electric coil to produce the charge. This
heating coil is eventually replaced.
 The crucible in which the metal is placed is made of stronger materials that can resist
the required heat, and the electric coil itself cooled by a water system so that it does not
overheat or melt.
 The induction furnace can range in size, from a small furnace used for very precise
alloys only about a kilogram in weight to a much larger furnaces made to mass produce
clean metal for many different applications.
 The advantage of the induction furnace is a clean, energy-efficient and well-
controllable melting process compared to most other means of metal melting.
 Foundries use this type of furnace and now also more iron foundries are replacing
cupolas with induction furnaces to melt cast iron, as the former emit lots of dust and
other pollutants.
 Induction furnace capacities range from less than one kilogram to one hundred tons
capacity, and are used to melt iron and steel, copper, aluminum, and precious metals.
 The one major drawback to induction furnace usage in a foundry is the lack of refining
capacity; charge materials must be clean of oxidation products and of a known
composition, and some alloying elements may be lost due to oxidation (and must be re-
added to the melt).
Construction Of Induction Furnace
 There are many different designs for the electric induction furnace, but they all center
around a basic idea.
 The electrical coil is placed around or inside of the crucible, which holds the metal to
be melted. Often this crucible is divided into two different parts. The lower section

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holds the melt in its purest form, the metal as the manufacturers desire it, while the
higher section is used to remove the slag, or the contaminants that rise to the surface of
the melt.
 Crucibles may also be equipped with strong lids to lessen how much air has access to
the melting metal until it is poured out, making a purer melt
The advantages of this furnace are ;
 Higher Yield. The absence of combustion sources reduces oxidation losses that can be
significant in production economics.
 Faster Startup. Full power from the power supply is available, instantaneously, thus
reducing the time to reach working temperature. Cold charge-to-tap times of one to two
hours are common.
 Flexibility. No molten metal is necessary to start medium frequency coreless induction
melting equipment. This facilitates repeated cold starting and frequent alloy changes.
 Natural Stirring. Medium frequency units can give a strong stirring action resulting in
a homogeneous melt.
 Cleaner Melting. No by-products of combustion means a cleaner melting environment
and no associated products of combustion pollution control systems.
 Compact Installation. High melting rates can be obtained from small furnaces.
 Reduced Refractory. The compact size in relation to melting rate means induction
furnaces require much less refractory than fuel-fired units
 Better Working Environment. Induction furnaces are much quieter than gas furnaces,
arc furnaces, or cupolas. No combustion gas is present and waste heat is minimized.
 Energy Conservation. Overall energy efficiency in induction melting ranges from 55 to
75 percent, and is significantly better than combustion processes.
 It can direct heat the metal
 Induction heating is a rapid, clean, non-polluting heating.Easy to use
The disadvantages of this furnace are;
 Refining in Induction Furnace is not as intensive or effective as in Electric Arc Furnace
(EAF).
 Life of Refractory lining is low as compared to EAF
 The induction coil is cool to the touch; the heat that builds up in the coil should
constantly cooled with circulating water.
 Removal of S & P is limited, so selection of charges with less impurity is required.
 Installing and maintaining cost is very high
 Current leak may be caused for more injuries because of high voltage

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Casting Defects
 Metallic projection
 Cavities
 Porosity
 Discontinuities
 Defective surfaces
 Incomplete casting
 Incorrect dimensions or shapes
 Inclusion
To test the quality of a melted cast iron a triangular pyramidal sand mold is used
upper small silver layer should be less than 3 mm if it was a correctly melted cast iron.specify
CE meter is fixed with a inductive furnace.when the liquid cast iron sample was placw to a
gauge it can measured c,si content and temperature of a mixture.
To increase the quality of a melted cast iron the folloing ingredients were added;

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 Flat cobulant
 Silican carbide
 Graphite(carbon)
 Manganese
 Cac2
Pouring process
In jinasena casting devision ,pouring process is done by manual hands. Molten liquid Metal
was poured into the crucible and then two or four workers took it and go where the moldes
are to be filled. Molds are existed 2 hoursin case of hardening
In here there are lots of safety issues should be considered deeply.
 Still use traditional system
 No safety wears
 Works have to handle crucible by hand

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Lathe machine
Types of Lathe
Engine lathes (center lathe). These are probably the most popular among the lathe machines.
In fact, no machine shop is seen without this type of lathe. The good thing about engine lathes
is that it can be used in various materials, aside from metal. Moreover, the set-up of these
machines is so simple that they are easier to use. Its main components include the bed,
headstock, and tailstock. These engine lathes can be adjusted to variable speeds for the
accommodation of a wide scope of work. In addition, these lathes come in various sizes.
Capstan and Turret Lathes. These types of lathes are used for machining single work pieces
sequentially. This means that several operations are needed to be performed on a single work
piece. With the turret lathes, sequential operations can be done on the work piece, eliminating
errors in work alignment. With this set-up, machining is done more efficiently.
Correspondingly, time is saved because there is no need to remove and transfer the work piece
to another machine anymore. Used in mass production, Semi-automatic, Wide range of
operations can be performed.
Capstan and Turret lathe which have multiple tools mounted on turret either attached to the
tailstock or the cross-slide, which allows for quick changes in tooling and cutting operations.
Used when many duplicate parts required
Equipped with multisided tool post (turret) to which several different cutting tools mounted
Employed in given sequence
Special Purpose Lathes. As the name implies, these lathes are used for special purposes such
as heavy-duty production of identical parts. In addition, these lathes also perform specific
functions that cannot be performed by the standard lathes. Some examples of special purpose

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lathes include the bench-type jewelers’ lathes, automatic lathes, crankshaft lathes, duplicating
lathes, multispindle lathes, brake drum lathes, and production as the among others.
Bed is mainly support the whole machine
Carriage is assembly that moves the tool post and cutting tool along the ways
Carriage Hand wheel is a wheel with a handle used to move the carriage by hand by means of
a rack and pinion drive
A chuck is a clamping device for holding work in the lathe
Apron is the front part of the carriage assembly on which carriage hand wheel is mounted
Cross slide is a platform that moves perpendicular to the lathe axis under control of the cross
slide hand wheel is mainly support the whole machine
Cross slide hand wheel is a wheel with handle used to move the cross slide in and out.
Half nut lever is the lever to engage the carriage with lead screw to move the carriage under
power
Lead screw is a precision screw that runs the length of the bed. it is used to drive the carriage
under power for turning and thread cutting operations.
Swing is a dimension representing the largest diameter work piece that a lathe can rotate
Tailstock is a cast iron assembly that can be slide along the ways and be locked in place. used
to hold long work in place or mount a drill chuck for drilling into end of the work
Ram is a piston type shaft that can be moved in and out of the tailstock by turning the tailstock
hand wheel.
Tool is a cutting tool used to remove metal from the work piece and usually made of high speed
steel or carbide.
Ways is a precision ground surfaces along top of the bed on which saddle rides. The ways are
precisely aligned with the centerline of the lathe

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Specify main parts
 Bed
 Base of the lathe
 Supports all major components of the lathe machine.
 Large mass and made from gray cast iron
 Three main parts of the lathe –headstock, tailstock and carriage are mounted on the
bed of the lathe.
 Top of the bed has two guide ways or slide ways to provide support and sliding
surfaces for the carriage and for the tailstock
 Headstock
 Secured permanently at the left hand end of the lathe.
 It supports the spindle bed and is equipped with the power driving mechanism for the
spindle. The spindle speed can be set through speed selector knobs. The spindle is
hollow to facilitate holding of long work pieces.
 The work holding devices such as chucks, centers and collets are attached to the spindle.
o The spindle rotates on two large bearings housed on the headstock casting.
o A hole extends through the spindle so that a long bar stock may be passed
through the hole.
o The front end of the spindle is threaded on which chucks, faceplate, driving
plate and catch plate are screwed. The front end of the hole is tapered to receive
live center which supports the work.
o On the other side of the spindle, a gear known as a spindle gear is fitted. Through
this gear, tumbler gears and a main gear train, the power is transmitted to the
gear on the lead screw.
 Tailstock

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 Located at the right hand end of the bed
 Can be moved along the guide ways and can be clamped in any position on the
bed.
 Also called loose headstock
 Main purpose is to hold the dead center and to support the long work pieces
during machining.
 It has a quill, into which the dead Centre, drills, reamers can be fixed.
 The quill can move in and out with the help of hand wheel.
The uses of tailstock
 It supports the other end of the long work piece when it is machined between
 It is useful in holding tools like drills, reamers when performing drilling,
reaming
 The dead center is offset by a small distance from the axis of the lathe to turn
tapers by set over
 It is useful in setting the cutting tool at correct height aligning the cutting edge
with lathe
 Carriage
The carriage slides along the guide ways between headstock and tailstock and consists of an
assembly of the cross-slide, tool post, the compound rest and the apron.
Main function is to hold the cutting tool and move it to give longitudinal and cross feed to it.
The cross-slide moves radially in and out, thus controlling the radial position of the cutting
tool.
The compound rest, also called compound slide is mounted on the top of the cross slide and
has circular base graduated in degrees. It is used for obtaining angular cuts and short tapers.
Compound rest swivels the tool for positioning and adjustment. The tool post is located at the
top of the compound rest to hold the tool and to enable it to be adjusted to a convenient working
position. The apron is equipped with mechanisms for both manual and mechanized movements
of the carriage and the cross-slide, by means of a lead screw and feed rod.
Saddle:

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It is an “H” shaped casting. It connects the pair of bed guide ways like a bridge. It fits over the
bed and slides along the bed between headstock and tailstock. The saddle or the entire carriage
can be moved by providing hand feed or automatic feed.
Cross slide:
Cross-slide is situated on the saddle and slides on the dovetail guide ways at right angles to the
bed guide ways. It carries compound rest, compound slide and tool post. Cross slide hand wheel
is rotated to move it at right angles to the lathe axis. It can also be power driven. The cross slide
hand wheel is graduated on its rim to enable to give known amount of feed as accurate as
0.05mm.
Compound rest:
Compound rest is a part which connects cross slide and compound slide. It is mounted on the
cross-slide by tongue and groove joint. It has a circular base on which angular graduations are
marked. The compound rest can be swiveled to the required angle while turning tapers. A top
slide known as compound slide is attached to the compound rest by dove tail joint. The tool
post is situated on the compound slide.
Tool post:
This is located on top of the compound slide. It is used to hold the tools rigidly. Tools are
selected according to the type of operation and mounted on the tool post and adjusted to a
convenient working position
Apron
The apron is bolted to the front of the saddle. The apron houses the gears and control for the
carriage and the feed mechanism
Feed rod and lead screw
The feed rod is powered by a set of gears from the head stock. It rotates during the operation
of the lathe and provides mechanized movement to the carriage by means of gears, a friction
clutch, and a keyways along the length of the feed rod.
The lead screw is also powered by the gears from the headstock and is used for providing
specific accurate mechanized movement to the carriage for cutting threads on the work piece.
The lead screw has a definite pitch.
A split nut in the apron is used to engage the lead screw with the carriage. In some lathes, the
lead screw performs the functions of feed rod and there is no separate feed rod. Similarly a
lathe not meant for thread cutting will not have a lead screw.
(Speed of the lead screw/Speed of the work)= (Pitch of the screw to be cut/Pitch of the lead
screw)

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Size of a lathe
The size of a lathe is expressed or specified by the maximum size that can be handled by the
lathe
The swing diameter over bed.(This is the largest diameter of work that will revolve without
touching the bed and is twice the height of the center measured from the bed of the lathe.)
The swing diameter over carriage. (This is the largest diameter of work that will revolve over
the lathe saddle and is always less than the swing diameter over bed.)
The distance between centers. (This is the maximum length of work that can be mounted
between the lathe centers.
The maximum bar diameter (This is the maximum diameter of bar stock that will pass through
the hole of the head stock spindle).
The length of bed.(This indicates the approximate floor space occupied by the lathe)
Operating condition in a lathe
 Cutting speed
 Feed
 Depth of cut
Cutting speed
In a lathe, for the turning operation, cutting speed is the peripheral speed of the work
piece past the cutting tool.
Expressed in meters/minute.
Cutting speed= m/min
Where D= diameter of the work piece in mm.

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N=rpm of the work
Depth of Cut
Perpendicular distance between machined surface and uncut surface of the Work-piece
d = (D1 – D2)/2 (mm)
Feed
f – the distance the tool advances for every rotation of workpiece (mm/rev)
 The feed of a cutting tool in a lathe work is the distance the tool advances for each
revolution of the work.
 Feed is expressed as mm/revolution.
 Increased feed reduces cutting time. But increased feed greatly reduces the tool life.
 The feed depends on factors such as size, shape, strength of the work material and
method of holding the component, the tool shape, the rigidity of the machine, depth of
cut, power available etc. Coarser feeds are used for roughing and finer feeds for
finishing cuts
d Depth
of Cut
DD 21
f
Feed
DD 21

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Machining operation done in lathe
 Straight turning
 Taper turning
 Chamfering
 Drilling
 Reaming
 Boring
 Counter boring
 Taper boring
 Internal thread cutting
 Tapping
 Parting off
 Thread cutting
 Facing
 Knurling
 Filing
 Polishing
 Grooving
 Forming

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Turning
Excess Material is removed to reduce Diameter
Rough Turning: is the term used for the process of heavy stock removal in order to save
machining time.
Finish Turning operation in the order to bring the job to a correct size and provide a fine finish
on it.
Cutting Tool: Turning Tool
A depth of cut of 1 mm will reduce diameter by 2 mm
Facing
 Flat Surface/Reduce length

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 Machining at the end of job
 Flat surface or to Reduce Length of Job
 Turning Tool
 Feed: in direction perpendicular to work-piece axis
 Length of Tool Travel = radius of work-piece
 Depth of Cut: in direction parallel to work-piece axis
 Rough facing: Cross feed-0.5-0.7mm & DOC- up to 5mm
 Fine facing: C.F-0.1-0.3mm & DOC-0.5mm.
Knurling
 Produce rough textured surface
 For Decorative and/or Functional Purpose
 Knurling Tool
 Handles of many components, instruments and tools, gauges and heads of small screws
etc., are usually provided with rolled depressions on them to provide a better grip in
comparison to a smooth surface.
 The indentation –KNURLS
 Surface – KNURLED
 The operation performing these knurls-KNURLING
Depth of
cut
Feed
WorkpieceChuck
Cutting
speed
Tool
d
Machined
Face

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Grooving
 Produces a Groove on work piece
 Shape of tool
 shape of groove

 Also called Form Turning
Parting off or cutting off
 It is the operation employed for cutting away a desired length from the bar stock.
 Parting Tool – similar to square grooving tool but have a longer point(to reach the center
of the job)
 Feed- Cross feed
Knurling tool
Tool post
Feed
Cutting
speed
Movement
for depth
Knurled surface
Shape produced
by form tool Groove
Grooving
tool
Feed or
depth of cutForm tool

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Chamfering
 Beveling sharp machined edges
 Similar to form turning
 Chamfering tool – 45°
 Avoid Sharp Edges
 Make Assembly Easier
 Improve Aesthetics
Drilling
 Work is held in a suitable device, such as a chuck or face plate and the drill is held in
the sleeve or barrel of the tail stock.
 In the case of blind holes, the required depth is marked on the drill.
Feed
Parting tool
Feed
Drill
Quill
clamp moving
quill
Tail stock clamp
Tail stock

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Tapers and taper turning
A taper may be defined as a uniform increase or decrease in diameter of a piece of work
measured along its length.
In a lathe taper turning means to produce a conical surface by gradual reduction in diameter
from a cylindrical work piece.
 Taper:
The common methods of expressing the taper are.
1. Taper per foot: the difference in inches of end diameters per foot length of the job.
2. Taper per inch: the difference in inches of end diameter per inch length of the job
3. Taper 1 in X: For this units should be uniform, such as a taper 1 in 20 means either a taper
of I inch on 20 inches or a taper of 1 Foot over a 20 feet length.
Taper Turning
From the geometry
Tanα=
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.
L
DD
2
tan 21 

 C
B
A L
D
90°
 2D1

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This is termed as the CONICITY and it is designated by the letter K.
K=
Methods
 Form Tool
 Swiveling Compound Rest
 Simultaneous Longitudinal and Cross Feeds
 Taper Turning Attachment
 Tailstock set over
Taper turning using a form tool
 Shape of the tool is remain same as the shape of the component to be produced.
 Accuracy of taper produce depends on accuracy of taper present on tool
 Width of tool must be greater than or equal to the length of work piece to be taper
turned.
 Maximum length of component which can be taper turned is 20 mm( small lengths)
only
 Only external taper turning is possible.
 Limitation-
This method is limited only for short length taper. Because the metal is
removed by the entire cutting edge, and only increase in the length of the taper will
necessitate the use of a wider cutting edge. This will require excessive cutting pressure,
which may distort the work due to vibration and spoil the work piece.

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Taper turning by swiveling the compound rest
 The compound rest has a circular base graduated in degrees, which can be swiveled at
any angle.
 While turning a taper, the base of compound rest is swiveled through an angle equal to
the half taper angle. The tool is then fed by hand.
 Once the compound rest is set at the desired half taper angle, rotation of the compound
slide screw will cause the tool to be fed at that angle and generate a corresponding taper.
 The movement of the tool in this method being purely controlled by hand, this gives a
low production capacity and poorer surface finish. The setting of the compound rest is
done by swiveling the rest at the half taper angle, if this is already known. If the
diameter of the small and large end and length of taper are known, the half taper angle
can be calculated.
1. Calculate the compound rest angle for turning short taper of 1:16.
sol.
Let α be the angle at which the compound rest will be set
tan α =
2. Calculate the compound rest angle to turn a short taper of 1mm per 12mm.
Sol. Given taper: 1 mm per 12mm
162
1
l2
dD


 .Ans91.1
32
1
tan 01






 

04167.0
122
1
2
tan 




l
dD
 Ans0
386.2

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Taper turning by combining feeds
 Taper turning by combining feeds is a more specialized method of turning taper.
 In certain lathes both longitudinal and cross feeds may be engaged
simultaneously causing the tool to follow a diagonal path which is the resultant
of the magnitude of the two feeds.
 The direction of the resultant may be changed by varying the rate of feeds by
change gears provided inside the apron.
Tail stock off-set
There are 2 methods for tapering on the job.
1. The job revolves in position: Perfect alignment with the head stock spindle and the two
centers, while tool moves along a straight line which is inclined at an angle (taper angle
ALPHA) to the center line of the job.
2. An alternative method can be to shift the center line of the work at an angle ALPHA from
the original position and move the tool parallel to the axis of the spindle.
 Of the above 2, it is the second condition which is accomplished by setting over the tail
stock.
 The nut of the clamping bolt of the tail stock is loosened.
 The dead center is shifted from the original position by a predetermined amount of set
over.
 Graduations provided on the flat surface of the tailstock, facing the head stock, help in
adjusting the required set over.

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The length of work is 300 mm, the amount of taper is
1: 25. Find the tail stock set over required
mm
Taper turning by a taper attachment
 The principle of turning taper by a taper attachment is to guide the tool in a straight path
set at an angle to the axis of rotation of the work piece, while the work is being revolved
between centers or by a chuck aligned to the lathe axis.
 A taper turning attachment consists essentially of a bracket or frame which is attached
to the rear end of the lathe bed and supports a guide bar pivoted at the centers. The bar
having graduations in degrees may be swiveled on either side of the zero graduation
and is set at the desired angle with the lathe axis.
 When the taper turning attachment is used, the cross slide is first made free from the
lead screw by removing the binder screw. The rear end the cross slide is then tightened
with the guide block by means of a bolt.
 When the longitudinal feed is engaged, the tool mounted on the cross slide will follow
the angular path, as the guide block will slide on the gear bar at an angle to the lathe
axis.
50
1
252
1
tan 

 6
50
1
300 

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 The required depth of cut is given by the compound slide which is placed at right angles
to the lathe axis.
 The guide bar must be set at half taper angle and the taper on the work must be
converted in degrees. The maximum angle through which the guide bar may be
swiveled is 10 degree to 12 degree on either side of the center line.
 If the diameters D,d and the length L of the taper are specified, the angle of swiveling
the guide bar can be determined from equation
tanα=
The advantage of using a taper turning attachment are-
1-The alignment of live and dead centers being not disturbed, both straight and taper
turning may be performed on a work piece in one setting without much loss of time.
2-once the taper is set, any length of a piece of work may be turned with in its limit.
3-very steep taper on a long work piece may be turned, which cannot be done by any
other method.
4-accurate taper on a large number of work pieces may be turned.
5-internal tapers can be turned with ease
Thread cutting
Cutting screw threads on a center lathe is known as screw-cutting.
Thread cutting consist in producing a helical form or thread on the revolving work piece.
Thread cutting can be considered as turning only since the path to be travelled by the cutting
tool is helical
Treads can be produced by means of taps and dies also, but the commonly used method on the
lathe is to cut the threads by means of the CUTTING TOOL.
Irrespective of the shapes and sizes, etc., there is one common factor in all the threads that is
the basis of generation of all threads is HELIX.
Another pre requisite of thread cutting is the tip or cutting edge of the tool should have an
included angle corresponding to the included angle of the particular type of the thread.
Elements Of Threds
PITCH (P): It is the distance from one point on the thread to the corresponding point on the
adjacent thread.
Major Diameter (D): It is the largest diameter of a screwed part, measured at right angle to
the axis of the piece.

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Minor Diameter (d): It is the smallest diameter of a screwed part, measured normal to the axis
of the piece.
Pitch Diameter (Pd): It is the Diameter of the imaginary cylinder of which the surface will
intersect the threads at such points where the widths of the threads is equal to the adjacent
widths of the spaces between them.
Depth of threads (t): It is the distance, measured normal to the axis of part, between the crest
and root of the thread.
t=(D-d)/2
Lead is the axial distance a point moves along the helix in one revolution.
In a single start helix, lead=pitch.
In a multi start helix, lead=pitch x number of starts.
There are two types of threads
1. Metric (thread angle 60*)
2. Inches (thread angle 55*)
Thread cutting in a Lathe
 For cutting treads – For every revolution of the spindle (work) the tool should move
parallel to the axis of the job by a distance equal to the LEAD of the screw.
 There will be a definite ratio between longitudinal feed of the tool and the speed of the
spindle.

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 The desired ratio is obtained with the help of lead screw by connecting it to the spindle
through a train of gears.
 On engaging the split half nut the movement of the carriage, and hence the tool is guided
by the lead screw.
 Gear ratio= (Driver teeth/ Driven teeth)=(Speed of the Lead screw)/(Speed of Work
)=(Pitch of the screw to be cut)/(pitch of the lead screw)
How to cut (external) threads in a lathe
Cutting threads is an indispensable part of machining. The 60º (metric) external thread is the
most common thread to be cut, and once you can cut it, no other thread (internal, external, whit
worth, acme, square, etc.) is beyond reach.
Tools required:
1. A bench grinder with course and fine stones
2. A sharpening stone
3. A 60º threading gage (‘fishtail gage’)
4. A thread pitch gage.
5. Lathe with threading gears or a quick-change gear box
Tool should be grinded to 60º using tool angle gauge (fishtail gage).
Tool post angle
Lathe setup
Start the lathe setup by setting the compound at 29.5º
Set up the work piece in the lathe and center it
Set the threading tool in the tool post
If necessary, turn the diameter to the major diameter of the thread which is going to cut using
facing tool. Many threads are specified by their major diameter. Length to be threaded is more
than two or three times the diameter .If the piece allows for it, cut a thread relief. A thread
relief is a section that is cut as deep as the thread, but wider than a pitch or two. This provides
a place to stop the advance of the cutter. Some designs allow for more thread relief than others

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– cut as large a thread relief as is practical for the piece you’re turning. Beginners should cut
0.1” or more if possible in the picture note that we are not threading to the shoulder – if we
were the thread relief would be cut right at the shoulder. This thread will stop in the thread
relief.
Set the threading tool in the tool post. Set the height to right on center, or a tiny bit below.
Now, using the ‘fishtail gage’ to square the cutter to the work. Note that the compound remains
at the previously set angle, and only the tool holder is moved to set the cutter straight on.
Advancing the cutter is done using the compound. Since the advance will be on the compound,
dial the compound back to make sure you have enough travel to get to the bottom of the thread.
(If run out before the thread is done, all is not lost – see ‘picking up a thread’ further down).
Run the cross-slide forward until the tool just touches the piece to be threaded. Now set the
cross-slide dial to zero. This is ‘home’ – before each pass we’ll return the cross-slide to zero.
Zero the compound dial.
Set the pitch by either changing the gears in your quadrant (the gears at the back of the lathe
headstock) or using a quick change gear box. Most lathes have a table showing the proper
settings either inside the quadrant cover (for those requiring change gears) or on the headstock,
for those with a quick change gearbox. Most modern lathes have a quick-change gear box, so
setting the pitch is done by levers or knobs. Set your lathe to the pitch you intend to thread.
Also, especially for beginners, set your lathe to the slowest speed you can – this may be limited
by your thread pitch.

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If you move the piece in the chuck, or you’re threading between centers and remove the piece,
or you need to take the piece to the mating work to check it out, your previous settings are lost.
Don’t despair, getting them back is easy, and is called “picking up a thread”. To pick up a
thread simply install the piece back in the lathe. The threading dial should be engaged and the
lathe set to the appropriate TPI. If you just took the piece out, none of that should have changed.
Now, with the cutter back so it won’t touch the work, start the lathe and engage the half-nut at
the appropriate mark. As the cutter advances, stop the lathe without disengaging the half-nut,
somewhere along the thread. Now advance the cross-slide close to the thread and advance the
compound and cross-slide until the bit steers neatly into the existing thread. At this point zero
the cross-slide and compound and you’re back where you
started, albeit with a
different setting on the compound. Back out the cross-
slide, return to the beginning of the thread and you’re ready to resume! Don’t let this process
scare you – it’s super easy.

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Drilling Machine
Introduction
The drilling machine or drill press 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.
Use:- Drilling machine is used to drill blind and through holes in work
pieces.
Construction
The machine has only a hand feed mechanism for feeding the tool into the
work piece. This enables the operator to feel how the drill is cutting and
accordingly he can control the down feed pressure. Sensitive drill presses are
manufactured in bench or floor models, i.e., the base of machine may be
mounted on a bench or floor. The main operating parts of a sensitive
machine/drill press are Base, Column, Table, and Drill Head.

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Types Of Drilling Machine
 Bench Drilling Machine
 Portable Drilling Machine
 Sensitive or Bench Drill
 Upright Drilling Machine(Single Spindle)
 Upright Drilling Machine(Turret Type)
 Radial Drilling Machine
 Multiple Spindle Drilling Machine
 Deep Hole Drilling Machine
 Gang Drilling Machine
 Horizontal Drilling Machine
 Automatic Drilling Machine
Bench Drilling Machine:- The simplest type of sensitive drilling machine is shown in
figure. This is used for light duty drilling work. This machine is capable to drill hole up to
12.5mm diameter
1. Motor:- An electric motor supplies the required driving force to stepped
pulley.
2. Base: - Base is the bottom part of machine in which the column is fitted
upright.
3. Feed handle: - Handle is provided to feed the drill in to the work piece.
A rake and pinion mechanism is provided to drive the chuck.
4. Column: - Column is the main cylindrical part of drill machine on
which the other components are mounted.
5. Belt guard:- Belt guard is provided to cover the belt and pulley drive mechanism to minimize
the hazard of accident.
6. Chuck:- Chuck is provided to hold the drill of different sizes up to 6.5 mm. Drill size of more
than 6.5 mm are to be fitted directly in the Morse taper of spindle

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7. Work Table: - Work pieces are mounted and held in position by the table. This table can be
tilted for drilling at an angle.
Portable Drilling Machine
It is a very small, compact and self-contained unit carrying a small electric motor
inside it. It is very commonly used for drilling holes in such components that
cannot be transported to the shop due to their size or weight or where lack of space
does not permit their transportation to the bigger type of drilling machine. In such
cases, the operation is performed on the site by means of the portable electric drill.
Sensitive or Bench Drill
This type of drilling machine is used for very light work. Its construction is very simple and
so is the operation. It consists of as shown in fig. of a cast iron having a fixed table over it.
Radial Drilling Machine
This machine is very useful because of its wider range of action. Its principal use is in drilling
holes on such work is difficult to be handled frequently. With the use of this machine], the tool
is moved to the desired position instead of moving the work to bring the latter in position for
drilling.

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Operation Of Drilling Machine
 Drilling
 Reaming
 Boring
 Counter Boring
 Counter Sinking
 Spot Facing
 Tapping
 Drilling: - It is the main operation done on this machine. It is the
operation of producing a circular hole in a solid metal by means of a
revolving tool called drill.
 Boring: - It is an operation used for enlarging a hole to bring it to the
required size and have a better finish.
 Counter sinking: - It is the operation used for enlarging the end of a
hole to give it a conical shape for a short distance.

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 Reaming :- It is the operation of finishing a hole to bring
it to accurate size and have a fine surface finish . This
operation is performed by means of a multi tooth tool
called reamer.
 Counter boring: - This operation is used for enlarging only
a limited portion of the hole is called counter boring.
 Tapping: - It is the operation done for forming internal
threads by means of the tool called tap.

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Milling
Introduction
 Milling is the process of machining flat, curved, or irregular surfaces by feeding the
work piece against a rotating cutter containing a number of cutting edges. The usual
Mill consists basically of a motor driven spindle, which mounts and revolves the milling
cutter, and a reciprocating adjustable worktable, which mounts and feeds the work
piece.
 Milling machines are basically classified as vertical or horizontal. These machines are
also classified as knee-type, ram-type, manufacturing or bed type, and planer-type.
Most milling machines have self-contained electric drive motors, coolant systems,
variable spindle speeds, and power-operated table feeds
 Milling is a process of producing flat and complex shapes with the use of multi-tooth
cutting tool, which is called a milling cutter and the cutting edges are called teeth.
 The axis of rotation of the cutting tool is perpendicular to the direction of feed, either
parallel or perpendicular to the machined surface. The machine tool that traditionally
performs this operation is called milling machine.
 Milling is an interrupted cutting operation in which the teeth of the milling cutter enter
and exit the work during each revolution. This interrupted cutting action subjects the
teeth to a cycle of impact force and thermal shock on every rotation. The tool material
and cutter geometry must be designed to withstand these conditions. Cutting fluids are
essential for most milling operations.
Types of milling
There are two basic types of milling
1. Down (climb) milling, when the cutter rotation is in the same direction as the motion of the
work piece being fed.
2. Up (conventional) milling, in which the work piece is moving towards the cutter, opposing
the cutter direction of rotation

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Comparison of Up and Down Milling
 Down milling, the cutting force is directed into the work table, which allows thinner
work parts to be machined. Better surface finish is obtained but the stress load on the
teeth is abrupt, which may damage the cutter.
 Up milling, the cutting force tends to lift the work piece. The work conditions for the
cutter are more favorable. Because the cutter does not start to cut when it makes contact
(cutting at zero cut is impossible), the surface has a natural waviness.
Milling Operations
Milling of Flat Surfaces
Peripheral Milling
 In peripheral milling, also called plain milling, the axis of the cutter is parallel to the
surface being machined, and the operation is performed by cutting edges on the outside
periphery of the cutter. The primary motion is the rotation of the cutter. The feed is
imparted to the work piece.
 In peripheral milling the axis of the cutter rotation is parallel to the work surface to be
machined.
Types of Peripheral Milling
Slab milling
The basic form of peripheral milling in which the cutter width extends beyond the work piece
on both sides
Slotting
Slotting, also called slot milling, in which the width of the cutter, usually called slotter, is less
than the work piece width.
The slotter has teeth on the periphery and over the both end faces. When only the one-side face
teeth are engaged, the operations is known as the side milling, in which the cutter machines the
side of the work piece
Straddle milling
Straddle milling, which is the same as side milling where cutting takes place on both sides of
the work.
In straddle milling, two slotters mounted on an arbor work together;
When the slotter is very thin, the operation called slitting can be used to mill narrow slots (slits)
or to cut a work part in two.

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The slitting cutter (slitter) is narrower than the slotter and has teeth only on the periphery.
Advantages of peripheral milling
 More stable holding of the cutter. There is less variation in the arbor torque
 Lower power requirements.
 Better surface finish.
Face milling
 In face milling, cutter is perpendicular to the machined surface. The cutter axis is
vertical, but in the newer CNC machines it often is horizontal. In face milling,
machining is performed by teeth on both the end and periphery of the face-milling
cutter.
 Face milling is usually applied for rough machining of large surfaces. Surface finish is
worse than in peripheral milling, and feed marks are inevitable. One advantage of the
face milling is the high production rate because the cutter diameter is large and as a
result the material removal rate is high. Face milling with large diameter cutters
requires significant machine power.
 In Face milling the axis of the cutter rotation is perpendicular to the work surface to be
machined.

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End milling
 In end milling, the cutter, called end mill, has a diameter less than the work piece width.
The end mill has helical cutting edges carried over onto the cylindrical cutter surface
are used to produce pockets, closed or end key slots, etc.
Milling of Complex Surfaces
Milling is one of the few machining operations, which are capable of machining complex two-
and three-dimensional surfaces, typical for dies, molds, cams, etc. Complex surfaces can be
machined either by means of the cutter path (profile milling and surface contouring), or the
cutter shape (form milling).
Form milling
In form milling, the cutting edges of the peripheral cutter (called form cutter) have a special
profile that is imparted to the work piece. Cutters with various profiles are available to cut
different two-dimensional surfaces. One important application of form milling is gear
manufacturing
Types of Form Milling

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Profile milling
In profile milling, the conventional end mill is used to cut the outside or inside periphery of a
flat part. The end mill works with its peripheral teeth and is fed along a curvilinear path
equidistant from the surface profile.
Surface contouring
The end mill, which is used in surface contouring has a hemispherical end and is called ball-
end mill. The ball-end mill is fed back and forth across the work piece along a curvilinear path
at close intervals to produce complex three-dimensional surfaces.
Similar to profile milling, surface contouring require relatively simple cutting tool but
advanced, usually computer-controlled feed control system.
Milling machines
The conventional milling machines provide a primary rotating motion for the cutter held in the
spindle, and a linear feed motion for the work piece, which is fastened onto the worktable.
Milling machines for machining of complex shapes usually provide both a rotating primary
motion and a curvilinear feed motion for the cutter in the spindle with a stationary work piece.
Milling Machine Types
Various machine designs are available for various milling operations. In this section we discuss
only the most popular ones, classified into the following types
 Column-and-knee milling machines
 Bed type milling machines
 Machining centers
Other Classifications
According to nature of purposes of use
 General Purpose Milling Machine
Conventional milling machines, e.g Up and down milling machines
 Single Purpose Milling Machine

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Thread, cam milling machines and slitting machine
 Special Purpose Milling Machine
Mass production machines, e.g., duplicating mills, die sinkers,
thread milling etc.
According to configuration and motion of the work-holding table / bed
Knee type
small and medium duty machines the table with the job/work travels over the bed
(guides) in horizontal (X) and transverse (Y) directions and the bed with the table
and job on it moves vertically (Z) up and down.
Bed type
Usually of larger size and capacity; the vertical feed is given to the milling head
instead of the knee type bed
According to the orientation of the spindle
Horizontal Milling Machine
 Horizontal spindle Feed
Vertical milling machine
 Vertical Spindle Feed
Universal milling machine
 Both Horizontal and Vertical spindle Feed
Column-and-knee milling machines
The column-and-knee milling machines are the basic machine tool for milling.
The name comes from the fact that this machine has two principal components, a
column that supports the spindle, and a knee that supports the work table.
There are two different types of column-and-knee milling machines according to
position of the spindle axis
 Horizontal &Vertical.
Bed type machines
In bed type milling machines, the worktable is mounted directly on the bed that
replaces the knee. This ensures greater rigidity, thus permitting heavier cutting
conditions and higher productivity. This machines are designed for mass
production.
Single-spindle bed machines are called simplex mills and are available in either
horizontal or vertical models. Duplex mills have two spindle heads, and triplex

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mills add a third spindle mounted vertically over the bed to further increase
machining capability.
Milling Machine Specifications
Horizontal Milling Machine Vertical Milling Machine

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Milling cutters
Classification of milling cutters according to their design
 HSS cutters: Many cutters like end mills, slitting cutters, slab cutters, angular
cutters, form cutters, etc., are made from high-speed steel (HSS).
 Brazed cutters: Very limited number of cutters (mainly face mills) are made with
brazed carbide inserts. This design is largely replaced by mechanically attached
cutters.
 Mechanically attached cutters: The vast majority of cutters are in this category.
Carbide inserts are either clamped or pin locked to the body of the milling cutter.

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Milling Cutter Nomenclature
The pitch refers to the angular distance between like or adjacent teeth.
The pitch is determined by the number of teeth. The tooth face is the forward facing
surface of the tooth that forms the cutting edge.
The cutting edge is the angle on each tooth that performs the cutting.
The land is the narrow surface behind the cutting edge on each tooth.
The rake angle is the angle formed between the face of the tooth and the centerline of
the cutter. The rake angle defines the cutting edge and provides a path for chips that are
cut from the workpiece.
The primary clearance angle is the angle of the land of each tooth measured from a line
tangent to the centerline of the cutter at the cutting edge. This angle prevents each tooth
from rubbing against the workpiece after it makes its cut.
o This angle defines the land of each tooth and provides additional clearance for
passage of cutting oil and chips.
The hole diameter determines the size of the arbor necessary to mount the milling cutter.
Plain milling cutters that are more than 3/4 inch in width are usually made with spiral
or helical teeth. A plain spiral-tooth milling cutter produces a better and smoother finish
and requires less power to operate. A plain helical-tooth milling cutter is especially
desirable when milling an uneven surface or one with holes in it.
Classification of milling cutters associated with the various milling
operations
Profile sharpened cutters
 surfaces are not related with the tool shape
 Slab or plain milling cutter : straight or helical fluted
 Side milling cutters – single side or both sided type

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 Slotting cutter
 Slitting or parting tools
 End milling cutters – with straight or taper shank
 Face milling cutters
Form relieved cutters
 Where the job profile becomes the replica of the tool-form
 Form cutters
 Gear (teeth) milling cutters
 Spline shaft cutters
 Tool form cutters
 T-slot cutters
 Thread milling cutter
Profile sharpened cutters
 The profile sharpened cutters are inherently used for making flat surfaces or
surface bounded by a number of flat surfaces only.
Slab or Plain milling cutters
 Plain milling cutters are hollow straight HSS cylinder of 40 to 80 mm outer
diameter having 4 to 16 straight or helical equi-spaced flutes or cutting edges and
are used in horizontal arbors to machine flat surface
Side and slot milling cutters
 These arbor mounted disc type cutters have a large number of cutting teeth at
equal spacing on the periphery.
Machining flat surface by slab milling Cutter
Side milling cutters

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End milling cutters
 The end milling cutter, also called an end mill, has teeth on the end as well as the
periphery
Face milling cutter
Form relieved cutters
Form of the tool is exactly replica of the job-profile to be made
Clearance or flank surfaces of the teeth are spiral shaped instead of flat
Used for making 2-D and 3-D contour surfaces

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T-slot & Gear milling cutters
Thread milling cutter
Indexing
 Indexing is the process of evenly dividing the circumference of a circular work
piece into equally spaced divisions, such as in cutting gear teeth, cutting splines,
milling grooves in reamers and taps, and spacing holes on a circle.
 The index head of the indexing fixture is used for this purpose.
Index Head
 The index head of the indexing fixture (Figure ) contains an indexing mechanism
which is used to control the rotation of the index head spindle to space or divide
a work piece accurately. A simple indexing mechanism consists of a 40-tooth
worm wheel fastened to the index head spindle, a single-cut worm, a crank for
turning the worm shaft, and an index plate and sector. Since there are 40 teeth in
the worm wheel, one turn of the index crank causes the worm, and consequently,

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the index head spindle to make 1/40 of a turn; so 40 turns of the index crank
revolve the spindle one full turn.
Index Plate
 The indexing plate (Figure) is a round plate with a series of six or more circles of
equally spaced holes; the index pin on the crank can be inserted in any hole in any
circle. With the interchangeable plates regularly furnished with most index heads,
the spacing necessary for most gears, bolt heads, milling cutters, splines, and so
forth can be obtained.
Sector
 The sector (Figure) indicates the next hole in which the pin is to be inserted and
makes it unnecessary to count holes when moving the index crank after each cut. It
consists of two radial, beveled arms which can be set at any angle
Index Plate Types
 Brown and Sharpe type consists of 3 plates of 6 circles each drilled as follows:
 Plate I - 15, 16, 17, 18, 19, 20 holes
 Plate 2 - 21, 23, 27, 29, 31, 33 holes
 Plate 3 - 37, 39, 41, 43, 47, 49 holes
 Cincinnati type consists of one plate drilled on both sides with circles divided as
follows:
 First side - 24, 25, 28, 30, 34, 37, 38, 39, 41, 42, 43 holes

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 Second side - 46, 47, 49, 51, 53, 54, 57, 58, 59, 62, 66 holes
Indexing Methods
Simple Indexing or Plain Indexing
 In simple or plain indexing, an index plate selected for the particular application,
is fitted on the worm shaft and locked through a locking pin’
 To index the work through any required angle, the index crank pin is withdrawn
from the hole of the index plate than the work is indexed through the required
angle by turning the index crank through a calculated number of whole
revolutions and holes on one of the hole circles, after which the index pin is
relocated in the required hole
 If the number of turns that the crank must be rotated for each indexing can be
found from the formula
 N = 40 / Z
 Where
 Z - No of divisions or indexings needed on the work
 40 – No of teeth on the worm wheel attached to the indexing plate,
since 40 turns of the index crank will turn the spindle to one full turn
 Suppose it is desired to mill a gear with eight equally spaced teeth. l/8th of 40 or
5 turns (Since 40 turns of the index crank will turn the spindle one full turn) of
the crank after each cut, will space the gear for 8 teeth. If it is desired to space
equally for 10 teeth, 1/10 of 40 or 4 turns would produce the correct spacing.
 The same principle applies whether or not the divisions required divide equally
into 40. For example, if it is desired to index for 16 divisions, 16 divided into 40
equals 2 8/16 turns. i.e for each indexing we need two complete rotations of the
crank plus 8 more holes on the 16 hole circle of plate 1(Plate I - 15, 16, 17, 18,
19, 20 holes)
Direct Indexing
 In direct indexing, the index plate is directly mounted on the dividing head spindle
( no worm shaft or wheel)
 While indexing, the index crank pin is withdrawn from the hole of the index plate
than the pin is engaged directly after the work and the indexing plate are rotated
to the desire number of holes
 In this method fractions of a complete turn of the spindle are limited to those
available with the index plate
 Direct indexing is accomplished by an additional index plate fastened to the index
head spindle. A stationary plunger in the index head fits the holes in this index

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plate. By moving this plate by hand to index directly, the spindle and the work
piece rotate an equal distance. Direct index plates usually have 24 holes and offer
a quick means of milling squares, hexagons, taps, and so forth. Any number of
divisions which is a factor of 24 can be indexed quickly and conveniently by the
direct indexing method.
Differential Indexing
 Sometimes, a number of divisions is required which cannot be obtained by simple
indexing with the index plates regularly supplied. To obtain these divisions, a
differential index head is used. The index crank is connected to the worm shaft
by a train of gears instead of a direct coupling as with simple indexing. The
selection of these gears involves calculations similar to those used in calculating
change gear ratio for lathe thread cutting.
 Gear Ratio I = 40/K ( K – Z)
Where
 K – a number very nearly equal to Z
 For example if the value of Z is 53, the value of K is 50
Indexing in Degrees
 Work pieces can be indexed in degrees as well as fractions of a turn with the usual
index head. There are 360 degrees in a complete circle and one turn of the index
crank revolves the spindle 1/40 or 9 degrees. Therefore, 1/9 turn of the crank
rotates the spindle 1 degree. Work pieces can therefore be indexed in degrees by
using a circle of holes divisible by 9. For example, moving the crank 2 spaces on
an 18-hole circle, 3 spaces on a 27-hole circle, or 4 spaces on a 36-hole circle will
rotate the spindle 1 degree.
 Smaller crank movements further subdivide the circle: moving 1 space on an 18-
hole circle turns the spindle 1/2 degree (30 minutes), 1 space on a 27-hole circle
turns the spindle 1/3 degree (20 minutes), and so forth.

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CNC Machines
What is a CNC Machine?
CNC : Computer Numerical Control, Conventionally, an operator decides and adjusts various
machines parameters like feed , depth of cut etc depending on type of job , and controls the
slide movements by hand. In a CNC Machine functions and slide movements are controlled by
motors using computer programs.
Types Of CNC Machine
There are many different types of CNC Machines used in industry, Such as:
 Mills and Machining Centers
 Lathes and Turning Centers
 Drilling Machines
 EDM Sinker and wire cut Machines
 Flame and Laser-Cutting Machines
 Water Jet Profilers
Types Of Cnc Machine Control Units
 Fanuc controll
 Siemens
 Gsk
 Mech 3 etc.
Program input
Different ways of data input are :
 MDI : Manual Data Input
 Program preparation with cad cam
 Program data transfer from pc to cnc m/c
 Program Data Transfer From Pc To Cnc Operations

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Operational Features Of CNC Machines
 For a CNC machine control unit (MCU) decides cutting
 speed, feed, depth of cut, tool selection , coolant on off and tool paths.
 The MCU issues commands in form of
 numeric data to motors that position slides and tool accordingly.
 A numerical control, or “NC”, system controls many machine functions and movements
which were traditionally performed by skilled machinists.
NC
 Numerical control developed out of the need to meet the requirements of high
production rates, uniformity and consistent part quality.
 Programmed instructions are converted into output signals which in turn control
machine operations such as spindle speeds, tool selection, tool movement, and cutting
fluid flow.
CNC

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 By integrating a computer processor, computer numerical control, or “CNC” as it is
now known, allows part machining programs to be edited and stored in the computer
memory as well as permitting diagnostics and quality control functions during the
actual machining.
 All CNC machining begins with a part program, which is a sequential instructions or
coded commands that direct the specific machine functions.
 The part program may be manually generated or, more commonly, generated by
computer aided part programming systems.
 Overview
Basic CNC Principles
All computer controlled machines are able to accurately and repeatedly control motion in
various directions. Each of these directions of motion is called an axis. Depending on the
machine type there are commonly two to five axes.Additionally, a CNC axis may be either a
linear axis in which movement is in a straight line, or a rotary axis with motion following a
circular path.
Motion control -the heart of CNC
 The most basic function of any CNC machine is automatic, precise, and consistent
motion control.
 Rather than applying completely mechanical devices to cause motion as is required on
most conventional machine tools, CNC machines allow motion control in a
revolutionary manner.
 All forms of CNC equipment have two or more directions of motion, called axes. These
axes can be precisely and automatically positioned along their lengths of travel.
 The two most common axis types are linear (driven along a straight path) and rotary
(driven along a circular path).

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Basic CNC Principles Coordinates System:
Absolute Coordinate System Incremental Coordinate System
Work Positioning:
 The method of accurate work positioning in relation to the cutting tool is called the
“rectangular coordinate system.” On the vertical mill, the horizontal base line is
designated the “X” axis, while the vertical base line is designated the “Y” axis. The “Z”
axis is at a right angle, perpendicular to both the “X” and “Y” axes.
 Increments for all base lines are specified in linear measurements, for most machines
the smallest increment is one ten-thousandth of an inch (.0001). If the machine is
graduated in metric the smallest increment is usually one thousandth of a millimeter
(.001mm).
 The rectangular coordinate system allows the mathematical plotting of points in space.
These points or locations are called “coordinates.” The coordinates in turn relate to the
tool center and dictate the “tool path” through the work.

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CNC lathe,Drilling and Milling Machines
 Automated version of a manual machine.
 Programmed to change tools automatically.
 Used for turning and boring wood, metal and plastic
How CNC machines Works:
 Controlled by G and M codes.
 These are number values and co-ordinates.
 Each number or code is assigned to a particular operation.
 Typed in manually to CAD/CAM by machine operators.
 G&M codes are automatically generated by the computer software.
Features of CNC Machines
 The tool or material moves.
 Tools can operate in 1-5 axes.
 Larger machines have a machine control unit (MCU) which manages operations.
 Movement is controlled by a motors.
 Feedback is provided by sensors.
 Tool magazines are used to change tools automatically
Tools
 Most are made from
 high speed steel (HSS),
 tungsten carbide or ceramics.
 Tools are designed to direct waste away from the material.
 Some tools need coolant such as oil to protect the tool and work.
Tool Paths, Cutting and Plotting Motions

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 Tool paths describes the route the cutting tool takes.
 Motion can be described as point to point, straight cutting or contouring.
 Speeds are the rate at which the tool operates e.g. rpm.
 Feeds are the rate at which the cutting tool and work piece move in relation to
each other.
 Feeds and speeds are determined by cutting depth, material and quality of finish
needed. e.g. harder materials need slower feeds and speeds.
 Rouging cuts remove larger amounts of material than finishing cuts.
 Rapid traversing allows the tool or work piece to move rapidly when no
machining is taking place.
CNC Programming Basics
 CNC instructions are called part program commands.
 When running, a part program is interpreted one command line at a time until
all lines are completed.
 Commands, which are also referred to as blocks, are made up of words which
each begin with a letter address and end with a numerical value.
Important things to know:
 Coordinate System
 Units, incremental or absolute positioning
 Coordinates: X,Y,Z,
 Feed rate and spindle speed
 Coolant Control: On/Off, Flood, Mist
 Tool Control: Tool and tool parameters
Programming consists of a series of instructions in form of letter codes Preparatory
Codes:
 G codes-Initial machining setup and establishing operating conditions
 N codes-specify program line number to executed by the MCU
 Axis Codes: X,Y,Z -Used to specify motion of the slide along X, Y, Z direction
 Feed and Speed Codes: F and S-Specify feed and spindle speed
 Tool codes: T –specify tool number
 Miscellaneous codes –M codes For coolant control and other activities
Programming Key Letters

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 O -Program number (Used for program identification)
 N -Sequence number (Used for line identification)
 G -Preparatory function
 X -X axis designation
 Y -Y axis designation
 Z -Z axis designation
 R -Radius designation
 F –Feed rate designation
 S -Spindle speed designation
 H -Tool length offset designation
 D -Tool radius offset designation
 T -Tool Designation
 M -Miscellaneous function
Explanation of commonly used G codes
 G00 –Preparatory code to control final position of the tool and not concerned with the
path that is followed in arriving at the final destination.
 G01 –Tool is required to move in a straight line connecting current position and final
position. Used for tool movement without any machining-point to point control. (linear
interpolation)
 G02 –Tool path followed is along an arc specified by I, J and K codes.( circular
interpolation)
Table of Important G codes
 G00 Rapid Transverse
 G01 Linear Interpolation
 G02 Circular Interpolation, CWG
 03 Circular Interpolation, CCW
 G17 XY Plane,
 G18 XZ Plane,G19 YZ Plane
 G20/G70 Inch units
 G21/G71 Metric Units
 G40 Cutter compensation cancel
 G41 Cutter compensation left
 G42 Cutter compensation right
 G43 Tool length compensation (plus)
 G43 Tool length compensation (plus)
 G44 Tool length compensation (minus)
 G49 Tool length compensation cancel
 G80 Cancel canned cycles
 G81 Drilling cycle
 G82 Counter boring cycle
 G83 Deep hole drilling cycle

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