Design of machines tool

2. Introduction to machine tool and
machining

3. Objectives
• Difference between machines and machine tool
• Definition of machining
• Introduction to machine tool
• Introduction to lathe machine
• Classification of lathe machine
• Working principle of lathe machine
• Lathe operations

4. Machine?????????
• Machine is defined as an assembly of mechanisms that are clustered
together to perform certain operations by utilizing electrical,
mechanical, hydraulic and/or pneumatic power.
• Total number of mechanisms exist within a machine may vary from
just few to few hundreds
• Accordingly size of a machine also varies.
• Some machines, irrespective of their size, are portable. For example, a
hand drill (small machine) and a large mining crane both are portable.

5. Machine Tool ????
• Machine tool is a
power operated,
 non-portable
 valuable machine that can perform multiple machining operations by
remove excess material from a pre-formed blank with the help of a
suitable cutting tool.

6. CHARACTERISTICS of machine tool
• It must be power driven (human operated machines are not
machine tools). The form of power at input to the machine tool can
be either electrical, mechanical, hydraulic, pneumatic or a non-
conventional one.
• It must be non-portable (portability irrespective of size). Thus
machine tools are always firmly installed with the shop floor.
• It must have sufficient value (value in terms of capability and
performance; not on the basis of cost).
• It can perform more than one machining or metal cutting
operations.
• It utilizes a cutting tool to shear off excess materials from
workpiece.
• Examples of machine tool include Lathe machine tool, Milling
machine tool, Shaping machine tool, Industrial drilling & boring
machine tool, etc. Therefore, all machine tools are basically
machines, but not vice versa.

7. MACHINING??????
• Machining is any of various
processes in which a piece
of raw material is cut into a
desired final shape and size
by a controlled material-
removal process.

8. i n t r o d u c t i o n to m a c h i n e t o o l s
• Machine Tools: Machining equipment that cuts, shears, punches,
presses, drills, grinds.
• Machine tools are generally the power driven metal cutting or metal
farming machines used to alter/change the
• Workpiece to the required shape and size by:
1. Cutting away the unwanted sections
2. Pressing, drawing, punching or shearing
3. Controlled electrical machinery process

9. G e n e r a t i o n o f M a c h i n e T o o l s
a) Machine tools are operated manually or with
automatic control.
b) The earlier machines used flywheels to stabilize their
motion and had complex system of gears and levers to
control the machine and the piece being worked on.
c) Machines continued to be improved and soon after
World War II, the numerical controlled (NC) machine
was developed.
d) The NC machines used a series of numbers punched
on paper tape or punch cards to control their motion.
e) Lately computers have been added and the
Computerized Numerical Control (CNC) machines have
allowed industry to produce parts quickly and
accurately.
f) The operating commands that control the machine
tool are executed with amazing speed, accuracy,
efficiency and reliability.

11. INTRODUCTION
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 Lathe is one of the most important machine tools in the
metal working industry. A lathe operates on theprinciple
of a rotating work piece and a fixed cutting tool.
 The cutting tool is feed into the work piece, which rotates
about its own axis, causing the work piece to be formed to
the desired shape.
 Lathe machine is also known as “the mother/father of the
entire tool family”.
 The lathe machine is one of the oldest and most important
machine tools. As early as 1569, wood lathes were in use
in France. The lathe machine was adapted to metal cutting
in England during the Industrial Revolution.

12. WORKING PRINCIPLE OF LATHE MACHINE
 The lathe is a machine tool which holds the work piece
between two rigid & strong supports called centers or in
a chuck or in face plate which revolves.
 The cutting tool is held and fed against the revolving
work. Cutting tool fed either parallel or at right angles to
the axis of w/p. Or may also at an angle .
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13. 10
Workpiece
Headstock center
(Live Centre)
Tailstock center
(Dead Centre)
Tool
Workpiece
Chip
Tool post
S
peripheral
speed (m/min)
N (rev/min)
D
Working Principle

14. BLOCK DIAGRAM OF LATHE MACHINE
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15. CLASSIFICATION OF LATHE MACHINE
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 Speed Lathe -
 Engine Lathe -
 Bench Lathe -
 Tool room Lathe -
 Capstan & Turret Lathe -
 Special purpose Lathe -
 Automatic Lathe -

16. SPEED LATHE
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 It is the simplest type lathe.
 Due to high speed of spindle it is called “Speed Lathe”.
 Speed of Spindle : 1200 to 3600 rpm.
 It is mainly used for metal spinning, polishing etc.

17. ENGINE OR CENTER LATHE
 In starting it was driven by steam engine, So it is called
as Engine lathe.
 Not production lathe, found in school shops, tool rooms,
and job shops.
 Primarily for single piece or short runs.
 Manually operated.
 Types :-
a) Belt driven lathe
b) Individual motor driven lathe
c) Gear head drive lathe
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18. BENCH LATHE
 It is small sized engine lathe mounted on bench.
 A bench top model usually of low power used to make
precision machine small & light weight work pieces.
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19. TOOL ROOM LATHE
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 Same as engine lathe.
 It is used for production of small & precision works like
tools, gauges, fixtures and accurate parts in tool room.
 Different speeds can achieved.
 Costly as compared to a same size engine lathe.

20. CAPSTAN & TURRET LATHE
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 Modified Engine lathe.
 Capstan lathes are used in mass production used for
light duty work pieces.
 Turret lathes are used in mass production and for
heavy duty work pieces.
 No tailstock.
 Instead of tailstock hexagonal turret is there.
 No time waste for re-setting of tools.

21. CAPSTAN & TURRET LATHE
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22. SPECIAL PURPOSE LATHE
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 Conventional/programmable lathe.
 Operated as standard lathe or programmable lathe to
automatically repeat machining operations.
 Computerized numerically controlled lathes.
 Cutting-tool movements controlled by computer-
controlled program to perform sequence of operations
automatically.

23. SPECIAL PURPOSE LATHE
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24. AUTOMATIC LATHE
 A lathe in which the work piece is automatically fed and
removed without use of an operator. It requires very less
attention after the setup has been made and the machine
loaded.
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25. CONSTRUCTION OF LATHE
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26. PARTS OF LATHE IN CONSTRUCTION
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 Main parts of lathe are :-
Bed
Head stock
Tail stock
Carriage
Feed mechanism
Screw cutting mechanism

27. CONSTRUCTION
Bed
 Made from cast iron or
nickel cast iron alloy.
 It supports head stock,
Tail stock & carriage.
 On top section are
machined ways
Guide and align major
parts of lathe
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28. CONSTRUCTION
HEAD STOKE
 Clamped on left-hand
end of bed
 Headstock spindle
 Hollow cylindrical
shaft supported by
bearings
 Provides drive through
gears to work-holding
devices
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29. CONSTRUCTION
HEAD STOKE
 Clamped on left-hand
end of bed
 Headstock spindle
 Hollow cylindrical
shaft supported by
bearings
 Provides drive through
gears to work-holding
devices
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30. CONSTRUCTION
TAILSTOKE
 Placed at right side of
lathe.
 To support long work
piece.
 Operations like
drilling, tapping,
reaming can done
using sleeve of
tailstock.
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31. CONSTRUCTION
CARRIAGE
 Used to move cutting tool along lathe bed
 Consists of four main parts
 Saddle
 Cross-slide
 Apron
 Compound rest
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32. CONSTRUCTION
FEED MECHANISM
 Three types of feed-
Longitudinal Cross
Angular
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33. CONSTRUCTION
CROSS SLIDE
 Fitted on the Saddle
 Moves cutting tool at right angles to lathe bed
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34. CONSTRUCTION
TOPSLIDE
 Fitted to top of Cross slide
 Carries tool post and cutting tool
 Can rotate to any angle
 Is used to turn tapers
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35. CONSTRUCTION
TOOLPOST
 Fitted on top slide and carries
the cutting tool or the cutting
tool holder
 Can adjust the height on some
types
 Can carry 4 different tool
holders
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36. CONSTRUCTION
TOOLHOLDER
 Used for holding cutting tool bits
 Available in Right hand, left hand and straight
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37. CONSTRUCTION
CUTTING TOOLS
 Can be High Speed Steel held in tool
holders
 Can be also Ceramic (Tungsten carbide)
bits held directly in tool post
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38. APRON MECHANISM
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39. OPERATIONS PERFORM ON LATHE
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 Straight turning
 Taper turning
 Facing
 Chamfering
 Thread cutting
 Grooving
 knurling
 Under cutting
 Filing
 Spinning
 Forming
 Polishing
 Solder turning
 Spring winding
 Boring
 drilling

40. OPERATION
TURNING
 To remove material from the outside diameter of a work-
piece to obtain a finished surface.
 Work piece become cylindrical.
 Motion of tool is parallel to the work piece surface.
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41. OPERATION
FACING
 To produce a flat surface at the end of the work- piece or
for making face grooves.
 To make side surface perpendicular via cutting tool
 Motion of tool is perpendicular to the work piece
surface.
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42. OPERATION
TAPER TURNING
 Dia. of cylindrical work piece decreasing or increasing
gradually is called as taper turning.
1 Types of taper turning:
2 By using form tool.
3By setting over tailstock center.
4 By swiveling the compound rest.
5 By using taper turning attachment.
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43. OPERATION
THREADING
 To produce external or internal threads on the work-
piece.
 Pointed form tool is fed linearly across surface of
rotating work part parallel to axis of rotation at a large
feed rate, thus creating threads.
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44. OPERATION
GROOVING
 Tool is fed radially into rotating work at some location to
cut off end of part, or provide a groove.
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45. OPERATION
CHAMFERING
 Cutting edge cuts an angle on the corner of the cylinder,
forming a "chamfer"
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46. OPERATION
BORING
 To enlarge a hole or cylindrical cavity made
by a previous process or to produce circular
internal grooves.
 Boring mills are used for large work pieces
 Boring produces circular internal profiles in
hollow work pieces
 Machines are available with
a variety of features
1 Horizontal boring machines
2 Jig borers
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47. OPERATION
KNURLING
To produce a regularly shaped roughness on the
work piece.
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48. THANK YOU
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