Hshhdbdbhshshndbbdhsbdnbxhxb

1. Machine Tools

2. Machine Tool
• Machine Tool is a device in which energy is expended in
removing excess material (in the form of chips) producing
finished surfaces of desired shape, size and finish with the aid
of a special device called cutting tool.
• Most versatile of all manufacturing processes in its capability
to produce a diversity of part geometries and geometric
features with high precision and accuracy.

3. Classification of Machine Tools
 Based on Production capability and application
 General Purpose Machine Tools
 Production Machine Tools
 Special Purpose Machine Tools
 Single Purpose Machine Tools
 Based on type cutting tools used
 Those using single point tools
 Those using multipoint tools
 Those using abrasive wheels

4. General Purpose Machine Tools
 Lathe
 Drilling Machine
 Milling Machine
 Shaper
 Planer
 Grinding Machine

5. Figure: Diagram of an engine lathe, showing its principal components
The Lathe
The main function of the lathe is
to remove the material from the
work piece and make the work
piece the desired shape and size.
During the travel of the lathe, the
work piece is rotated against the
tool to achieve material removal
and the direction of tool
movement becomes feed
Lathe is a machine tool which holds the work between two rigid and strong supports,
called centers, or in a chuck or face plate.
The cutting tool is rigidly held and supported in a tool post and is fed against the
revolving work.
While the work revolves about its own axis, the tool is made to move either parallel to
(Cylindrical surface) or at an angle with the axis (Tapered surface) to cut the desired
material.

7. Parts of a Lathe
 Bed The main parts of the lathe, all parts are bolted to the bed. It includes the
headstock, tailstock, carriage rails and other parts.
 Head stock (The headstock is usually located on the left side of the lathe and is
equipped with gears, spindles, chucks, gear speed control levers, and feed
controllers)
 Tailstock Usually located on the right side of the lathe, the work piece is supported
at the end
 Carriage The carriage is located between the headstock and the tailstock and
contains apron, saddle, compound rest, cross slide and tool post
 Apron
The apron is on the front of the saddle which has hand wheel and levers. It is used
to control the movement of carriage on the bed.
 Saddle
The saddle has H shaped. It is on the carriage which helps cross slide to move
back and forth on the machine.

8. Cross slide
Cross slide is on the carriage and moves on the saddle. It moves back and
forth to give depth of cut to the metal specimen by using hand wheel.
Compound rest:
Compound slide is on the cross slide which can rotate. It gives support to tool
post. It is used in taper turning by giving an angle.
Tool post:
Tool post is on the compound rest and used to clamp the cutting tool.
Lead Screw Lead screw is used to move the carriage automatically during
threading
Feed Rod It is used to move the carriage from left to right and vice versa
Chip Pan
It is present at the bottom of the lathe. Chip pan is used to collect the chips
that are produced during the lathe operation
Hand Wheel:
It is the wheel which is operated by hand to move cross slide, carriage,
tailstock and other parts which has hand wheel.

9. Lathe Basics
Headstock

10. Lathe Basics
Bedways

11. Lathe Basics
Carriage/Apron

12. Lathe Basics
Tailstock

13. Turning Operation
FIGURE : Schematic illustration of a turning operation
showing depth of cut, d, and feed, f. cutting speed is the
surface speed of the workpiece at the tool tip.

14. Lathe Operations
Figure: Various cutting operations that can be performed on a lathe.

15. Lathe Operations
Figure: Various cutting operations that can be performed on a lathe.

16. Accessories - Chucks
Figure: Three Jaw Chuck

18. Drilling
 Drilling is a process of producing round holes in a solid material or
enlarging existing holes with the use of multi-point cutting tools
called drills or drill bits.
 Drilling is an extensively used process by which blind or though
holes are originated or enlarged in a work piece.
 Various cutting tools are available for drilling, but the most common
is the twist drill.
 A variety of drilling processes are available to serve different
purposes.
 Drilling is used to drill a round blind or through hole in a solid
material.
 If the hole is larger than ~30 mm, a smaller pilot hole is drilled
before core drilling the final one.
 For holes larger than ~50 mm, three-step drilling is recommended

19. Types of Drilling Processes
 Core drilling is used to increase the diameter of an existing hole.
 Step drilling is used to drill a stepped (multi-diameter) hole in a
solid material.
 Counter boring provides a stepped hole again but with flat and
perpendicular relative to hole axis face. The hole is used to seat
internal hexagonal bolt heads
 Countersinking is similar to counter boring, except that the step
is conical for flat head screws.
 Reaming operation is usually meant to slightly increase the size
and to provide a better tolerance, surface finish and improved
shape of an initially drilled hole. The tool is called reamer.
 Center drilling is used to drill a starting hole to precisely define
the location for subsequent drilling operation and to provide
centre support in lathe or turning centre

20.  Gun drilling is a specific operation to drill holes
with very large length-to-diameter ratio up to 300.

21. Drilling Machines
 The drilling machine is also called drill press.
 The two common types of drilling machines are
i) Drill press ii) Radial drilling machine
 The drill press is relatively easy to set up and
use.
 The radial drilling machine is more versatile and
suitable to drill multiple holes in a heavy job.

23.  Various other types of drilling machines are
available for specialized jobs.
These may be portable, bench type, multiple –
spindle, gang, multiple drills or automatic
drilling machines.
 the size of the drilling machine is usually
specified by the largest diameter of the hole
that can be drilled on it.
multiple – spindle gang automatic drilling machines
multiple drills
portable

24. Common type of drill bits

25. Milling Machines Types & Milling
operations

26. Introduction
 Milling machines are used to produce parts having
flat as well as curved shapes.
 Milling machines are capable of performing the
usual flat, horizontal and vertical machining
operations and can be used to do many other
machining operations like gear teeth cutting,
drilling, reaming, boring, slotting, tapping, keyway
cutting, cam milling and so forth.
 In this process, the work-piece is normally fed into a
rotating cutting tool known as milling cutter.
 Equally spaced peripheral teeth on the cutter come
in contact with the work piece intermittently and
machine the work piece.

27.  Milling is a process of producing flat and complex shapes
with the use of multi-point (or multi-tooth) cutting tool.
 The axis of rotation of the cutting tool is perpendicular to
the direction of feed, either parallel or perpendicular to
the machined surface
 Milling is usually an interrupted cutting operation since
the teeth of the milling cutter enter and exit the work-
piece 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

28. The Milling Process
Figure depicts two basic types of milling operations:
 down milling, when the cutter rotation is in the same direction as the
motion of the work-piece being fed, and in the up milling in which
the work-piece is moving towards the cutter, opposing the cutter
direction of rotation

29. Up milling and down milling
 In down milling, the cutting force is directed on to the work table, which allows
thinner parts to be machined without susceptibility to breakage. Better surface
finish is obtained in down milling but the stress load on the teeth is abrupt,
which may damage the cutter.
 In down milling, though the cut starts with a full chip thickness, the cut gradually
reduces to zero. This helps in eliminating the feed marks present in the case of
up milling and consequently better surface finishing. This is also known as climb
milling. It also allows greater feeds per tooth
 In up milling, the cutting action tends to lift the work-piece and hence, proper
fixture is required in this operation
 Each tooth of the cutter starts the cut with zero depth of cut, which gradually
increases and reaches the maximum value as the tooth leaves the cut.
 The chip thickness at the start is zero and increases to the maximum at the end
of the cut.
 The surface becomes slightly wavy, as the cut does not begin as soon as the
cutter touches the work piece

33. Other Machine Tools using
Single Point Cutting Tools
Shaping
Planing

34. Introduction to Shaping and Planing
Shaping: where the workpiece is fed
right angles to the reciprocating
cutting tool between successive
strokes of the tool. It is suitable for
small to medium size jobs
Planing: where the workpiece is
reciprocated and the tool is fed at
right angles to the cutting motion.
suitable for medium to large size

35. Shaper Machine
 The main functions of shaping machines are to produce flat
surfaces in different planes.
 The cutting motion provided by the linear forward motion of
the reciprocating tool.
 The intermittent feed motion provided by the slow transverse
motion of the job along with the bed result in producing a flat
surface by gradual removal of excess material layer by layer in
the form of chips.
 The vertical infeed is given either by descending the tool holder
or raising the bed or both.
 Straight grooves of various curved sections are also made in
shaping machines by using specific form tools
 The single point straight/form tool is clamped in the vertical
slide which is mounted at the front face of the reciprocating
ram.
 whereas the work-piece is directly or indirectly through a vice is
mounted on the bed.

36. on a flat plain a straight line called
Generatrix (G) is traversed in a
perpendicular direction called
Directrix (D) resulting a flat surface.
Cutting motion (CM)
Feed motion (FM)

37. Shaper
FIGURE: The most widely used shaper is the
horizontal push-cut machine tool

38. Common Shaping / Planing Geometry
FIGURE: Types of surfaces commonly machined by shaping and planing.

39. Grinding Machines : Operations

40. Introduction
 Finishing process are different from other
manufacturing processes.
 The distinction between the finishing processes and
other manufacturing processes is that the finishing
processes are intended to improve the surface
smoothness and do not significantly change the
dimensions of the part. Rather they are meant to
achieve the closer dimensional tolerance.
 The machining and finishing processes for these
objectives include abrasive machining, honing,
lapping, super finishing, burnishing, buffing and
polishing.

41. abrasive machining honing
lapping
buffing
Polishing

42. Abrasive Machining or Grinding
 Grinding is the most common form of abrasive machining. It is
a chip forming metal cutting operation
 It is a material cutting process which engages an abrasive tool
whose cutting elements are grains of abrasive material known
as grit.
 These grits are characterized by sharp cutting points, high
hot hardness, chemical stability and wear resistance
 For grinding, generally, a rotating wheel is used as a tool.
 The grits are held together by a suitable bonding material
to give shape of an abrasive tool
 In grinding, the high circumferential speed of the grinding
wheel causes high friction and chips become red hot and fly as
sparks.

44. Advantages
• dimensional accuracy
• good surface finish
• good form and locational accuracy
• applicable to both hardened and unhardened material
• grinding can produce surface finish up to 2 microns and dimensional
tolerances as small as 0.0025mm.
Applications
• surface finishing
• slitting and parting
• descaling, deburring
• stock removal (abrasive milling)
• finishing of flat as well as cylindrical surface
• grinding of tools and cutters and re-sharpening of the same

46. NumericalControl (NC) Fundamentals
What is Numerical Control (NC)?
 Numerical Control (NC) A machine tool is operated by a
series of coded instructions that include numbers, letters of
the alphabet, and symbols that the machine control unit
(MCU) can read.
 These coded instructions are changed into electrical pulses
that the machine’s motors and controls follow to run
manufacturing functions on a work piece.
 Numerical control (NC) points to the method of
controlling the manufacturing operations by numerical
instructions in the form of directly inserted coded in
machine tools

47. Advantages of NC over conventional systems:
 Flexibility with accuracy,
 repeatability,
 reduced scrap,
 high production rates,
 good quality.
 Reduced tooling costs.
 Easy machine adjustments.
 More operations per setup,
 less lead time,
 accommodate design change,
 reduced inventory.
 Rapid programming and program recall,
 less paperwork.
 Faster prototype production.
 Less-skilled operator,
 multi-work possible.

48. Limitations of NC:
Relatively high initial cost of equipment.
Need for part programming.
Special maintenance requirements.
More costly breakdowns.

49. What is CNC
 CNC machining is a manufacturing process in which pre-programmed
computer software dictates the movement of factory tools and
machinery. The process can be used to control a range of complex
machinery, from grinders and lathes to mills and routers.
 In a CNC machine, all the numerical functions are managed by the
computer. The computer stores the programs which are required to
operate the machine. The computer also gives the display of various
parameters of the machine-like spindle speed, feed rate, etc. It
consists of electronic in instrumentation to measure the output

50. Difference between NC and CNC
 The earliest NC machines performed limited functions and
movements controlled by punched tape or punch and cards.
 As the technology evolved, the machines were equipped with
increasingly powerful microprocessors (computers) with the
addition of these computers, NC machines become CNC machines.
 NC machine described as a machine that is controlled by a set of
instructions in the form of numbers, letters, and symbols. The set of
instructions is called a program.
 Whereas in the CNC machine, it is described as the machine which
is used to control the motions of the workpiece and tool with the
help of prepared program in the computer. The program is written
in alphanumeric data

51. Difference between NC and CNC
 In the NC machine, the modification in the program is difficult. As
compared to the CNC machine, the modification in the program
is very easy.
 The NC machine is required for a highly skilled operator. Whereas
in the CNC machine, a less skilled operator can also operate the
machine.
 The cost of the NC machine is less. As compared to the CNC
machine, the cost of the machine is very high.
 In the NC machine, the accuracy is less as compared with the job.
Where the CNC machine has high accuracy

53. Advantages of CNC over conventional NC:
·Control using software (executive) rather than hard-wired
·Increased flexibility (variety of mixed operations & functions)
·Elimination of tape reader (or tape read only once per program)
·Part program storage (computer memory (multiple programs) &
storage media)
·Display shows instructions being executed & other operational data
·Greater accuracy (faster control solutions)
·More versatility (e.g., program editing (at the machine),
reprogramming, tool path plotting, metric conversion, cutter dimension
compensation)
·Fixed (subroutine) cycles (e.g., pocket milling, pecking)
·Manual data input (MDI) (even while another program is running) and
remote data transfer
·System integration capability (connect to robots & other computer- or
microprocessor- based equipment, create cells)
·Machine diagnostics (gives error message or identifies problem)

55. Introduction of
3D Printing

56. What is 3D Printing
 3D Printing is a process for making a physical object from a three-
dimensional digital model, typically by laying down many successive
thin layers of a material. It brings a digital object (its CAD
representation) into its physical form by adding layer by layer of
materials.
 There are several different techniques to 3D Print an object. 3D Printing
brings two fundamental innovations: the manipulation of objects in
their digital format and the manufacturing of new shapes by addition
of material.

58. 3D Printing

59. 3D Printing Technology
 The starting point for any 3D printing process is a 3D digital model,
which can be created using a variety of 3D software programmes —
in industry this is 3D CAD.
 The model is then ‘sliced’ into layers, thereby converting the design
into a file readable by the 3D printer.
 The material processed by the 3D printer is then layered according
to the design and the process.
 there are a number of different types of 3D printing technologies,
which process different materials in different ways to create the final
object.
 Functional plastics, metals, ceramics and sand are, now, all routinely
used for industrial prototyping and production applications.
 There is also a growing number of entry level machines that have
been adapted for foodstuffs, such as sugar and chocolate

60. How it Works
 The different types of 3D printers each employ a different
technology that processes different materials in different ways. It is
important to understand that one of the most basic limitations of 3D
printing — in terms of materials and applications — is that there is
no ‘one solution fits all’
 For example some 3D printers process powdered materials (nylon,
plastic, ceramic, metal), which utilize a light/heat source to
sinter/melt/fuse layers of the powder together in the defined shape.
 Perhaps the most common and easily recognized process is
deposition, and this is the process employed by the majority of
entry-level 3D printers. This process extrudes plastics, in filament
form through a heated extruder to form layers and create the
predetermined shape

61. Additive manufacturing vs 3D
Printing vs Rapid Prototyping
 Between the terms 3D printing and additive manufacturing, there is no
difference. 3D printing and additive manufacturing are synonyms for
the same process.
 Additive Manufacturing is a suitable name to describe the technology
that is used in building 3D objects by adding materials layer by layer.
The term “additive” refers to the method of adding and building the
product repeatedly
 Both terms reference the process of building parts by joining material
layer by layer from a CAD file.
 This is as opposed to a traditional manufacturing process, like CNC
Machining, where a part is built by subtracting material from a block of
material.
 3D printing and additive manufacturing can be used regardless if the
parts are fabricated in plastic, metal, or rubber.

62. Additive manufacturing vs 3D Printing vs
Rapid Prototyping (contd.)
 The term rapid prototyping is different from 3D printing/additive
manufacturing.
 Rapid prototyping is the technique of fabricating a prototype model
from a CAD file.
 In other words, 3D printing/additive manufacturing is the process,
and rapid prototyping is the end result.
 Rapid prototyping is one of many applications under the 3D
printing/additive manufacturing umbrella.