1. Finishing Machine Tools
Cutting Machine Tools
Lathe
Milling Machine
Shaper
Drilling machine
Finishing Machine Tools
Grinding
Honing
Lapping c c c

2. Machine Tools: Lathe

3. Working Principle of lathe
Introduction
Most versatile and widely used machine tools
Main function: to remove metal from a job to give it the required shape and size.
The job is securely and rigidly held in the chuck or in between centers on the lathe machine and then turn it against a single point cutting tool which will remove metal from the job in the form of chips.
Besides the simple turning operation as described above, lathe can be used to carry out other operations also, such as drilling, reaming, boring, taper turning, knurling, screw/thread cutting, grinding etc.
Working Principle of lathe

5. Machine Tools: Lathe

6. Lathe Components: Lathe Bed
Headstock:
It contains drive mechanism with necessary speed change arrangement to achieve different speeds.
Work holding devices such as chuck is mounted on it.

7. Lathe Components: Lathe Bed
Function: Provides platform for entire machineCarriage, tail stock can slide along the bed by means of guide ways.
Made from cast iron using casting process

8. Lathe Components: Lathe Bed
Chuck:
Function: Holds the work piece
Three Jaw Chuck:
All the three jaws move simultaneously
Used in coaxial turning
Four Jaw Chuck:
Each jaw can move independently
Used in eccentric turning

9. Lathe Components: Carriage

10. Lathe Components: Carriage

11. Carriage: Function: Used to move tool post in desired direction.
It has three independent degrees of freedom.
Apron(4) provides motion parallel to lathe bed,
Cross slide(3) provides motion perpendicular to lathe bed,
Compound rest(2) provides motion inclined to lathe axis in a horizontal plan
Three calibrated wheels are used to control the motion of the tool within fraction of a millimeter

12. Lathe Components: Tail Stock
Function: Used to hold drill, centre mount
Longitudinal motion of the drill can be controlled using a calibrated wheel
Entire tail stock can be moved along the lathe bed and this motion can be synchronized with lead screw

13. Lathe Components: Lead Screw
Function: Used to move carriage, tailstock at constant speed along lathe bed (threading operation)
Rotational speed of lead screw is synchronized with chuck speed
Half nut mechanism is used to engage/ disengage lead screw with the carriage
Lead Screw

14. Lathe Components: Gearbox
Function:
Provides velocity reduction between drive motor and chuck
Used to change the speed of chuck
It is used to synchronize rotational speed chuck with lead screw speed

17. Types of lathe machine Speed Lathe Bench lathe Engine Lathe
Tool room Lathe
Capstan & Turret
Automatic Lathe

26. Lathe Operations: Turning
Turning: Turning is a lathe operation in which diameter of work piece is reduced by keeping length constant
Depth of cut is given in radial direction
Feed is given in axial direction
Work piece rotates towards operator

27. Lathe Operations: Taper Turning
Taper Turning: It is a lathe operation in which diameter of work piece can be varied along the length of work piece
Depth of cut is given in radial direction
Feed is given the direction which inclined at certain angle with axial direction
Taper turning

28. Lathe Operations: Eccentric Turning
Eccentric Turning: It is the process of reducing the diameter of a part of work piece which is radial eccentric to main body of the work piece
Four jaw chuck is used for eccentric turning. The jaws are adjusted in such a way that axis of part to be turned becomes collinear with chuck axis

29. Lathe Operations: Eccentric Turning

30. Lathe Operations: Contour Turning
Contour Turning: It is a turning process in which tool is moved axial direction not along straight path but along curved profile to produced an axisymmetric part of complicated shape
It is difficult to control path followed by tool manually so these operations are done programmable CNC machine
Contour turning

31. Lathe Operations: Form Turning
Form Turning: It is a turning process in which complicated axisymmetric parts are produced using a tool whose cutting edge has same profile of as that of desired part
Excessive heat is generated in form turning as compared to other turning processes because cutting edge has line contact as compared to point contact
Feed is not given in axial
direction
Tool cost will be high
Form turning

32. Lathe Operations: Facing
Facing: It is a lathe operation in which the length of cylindrical work piece is reduced by removing a layer of material on the flat face of cylinder.
Depth of cut is given in axial direction
Feed is given in radial direction
Depth of cut
Facing

33. Lathe Operations: Boring
Boring: It is a lathe operation in which already existing hole is enlarged
It is always preceded by drilling operation
It is similar to turning except the fact that turning is performed on external surface where as boring is performed on internal surface
Boring Tool
Boring

34. Lathe Operations: Threading
Threading: It is a lathe operation threads are produced on internal or external cylindrical surface
It is similar to turning except feed (axial tool speed) is much higher
Carriage is always moved with the help lead screw in threading so that feed is perfectly constant
A definite velocity ratio is maintained in between chuck and lead screw depending upon pitch of thread to be cut.
Threading

35. Lathe Operations: Chamfering
Chamfering: It is a lathe operation in which sharp edge of a component is smoothened by making cut at 450
Chamfering

36. Lathe Operations: Grooving and Parting
Grooving: It is a lathe operation in which narrow groove is made on cylindrical surface
Parting/Cutoff: It is a lathe operation in which a cylindrical specimen is cut into parts.
Grooving and parting operations use similar tool
Cutoff
Grooving

37. Lathe Operations: Knurling
Knurling: It is a lathe operation in which crossed helical markings are produced on cylindrical surface of a work piece to increase grip
It is not a machining operation because material is not removed during the knurling
Knurling tool has two cylinders with helical protrusions on it. The two helices will be opposite to each other
When the knurling tool is pressed against the rotating cylindrical surface desired pattern is produced because of plastic deformation

38. Spinning

39. Some Important Points Regarding Lathe operations
Increase in cutting speed improves surface finish however increase in depth cut and/or feed deteriorates surface finish
Increase in cutting speed, depth of cut and feed increases heat generated and reduces tool life (because at higher temperature the tool becomes soft and wear rate increases)
Depth of cut and feed are perpendicular to each other
Work piece/chuck always rotates towards operator

40. Basic Lathe Operations

41. Drilling on lathe

42. Machine Tools: Drilling Machine

43. Drilling Machine: Hand Drilling Machine
It is also known as portable drilling machine
Accuracy of drilled hole depends on operator skill

44. Machine Tools: Drilling Machine
Sensitive Drilling machine

45. Drilling Machine: Pillar Drilling Machine
It is also known as upright drilling machine or vertical drilling machine
Base: Supports entire drilling machine. Usually made of Cast Iron.
Column: Vertical part mounted on base. Supports work piece holder table and drill driving system.
Work table: Supports work piece. Moves Up and down along the column. Can swing around column
Drilling head: Mounted on column, consists drill driving system, feed mechanism.
Spindle: Holds drill in correct position and transmits rotary motion to drill

46. Upright or vertical Drilling machine (Round column section pillar machine)

47. Drilling Machine: Radial Drilling Machine
It is very similar to column drilling machine except that it has an additional degree of freedom
The spindle can move along radial direction with respect to column
It is more versatile than column drilling machine

48. a) Gang Drilling machine b)Multi-spindle Drilling Machine

49. Drill Bit

51. Operations on Drilling Machine: Drilling
It is a process of producing circular hole inside a work piece
Drill Bit

52. Operations on Drilling Machine: Reaming
It is a process accurately sizing or smoothening already existing hole
Radial increment is very small. Reaming is often performed as finishing operation which follows after drilling operation
Reamer

53. Operations on Drilling Machine: Boring
It is a process of enlarging already existing hole to meet desired size
Radial increment is large as compared to reaming operation
Boring Cutter

54. Operations on Drilling Machine: Counter Boring
It is a process of enlarging the opening of already existing hole by making a cylindrical step within the hole
The cylindrical step is produced so that it can accommodate bolt head within it
Counter Boring Tool

55. Operations on Drilling Machine: Spot Facing
Spot facing is similar to counter boring except the depth of step produced is very shallow
The shallow step is produced so that it can accommodate washer
Counter Boring Tool can be used perform Spot Facing

56. Operations on Drilling Machine: Counter Sinking
It is a process of chamfering edge of circular hole to produce conical opening is called counter sinking
The conical opening is produced so that it can accommodate a screw head within it
Countersinking Tool

57. Operations on Drilling Machine: Tapping
It is a process of producing internal threads within already existing hole
Tapping Tool

58. Operations on Drilling Machine: Trepanning
It is process of producing a large circular hole inside a work piece by removing material along the circumference of the hole to be produced
There are two types of trepanning tools viz.
Multipoint hollow Trepanning tool
Single point trepanning tool
Working of single point trepanning tool is similar to that of a drafting compass
Multipoint Trepanning Tool

59. Operations on Drilling Machine: Trepanning
Single Point Trepanning Tool

60. Machine Tools: Grinding Machine
Grinding: It is process of imparting the good surface finish and High dimensional accuracy to the components with negligible removal of material using rotary abrasive wheel (Grinding wheel)

61. Machine Tools: Grinding Machine
Principle of operation/Grinding Mechanism:
Mechanism for material removal is Abrasion and Erosion
Wheels are made up of fine grain abrassive (SiC )
Each abrasive particle acts like a separate cutting tool
Material is removed in the form of microchips

62. Grinding Machine: Surface Grinding
Surface Grinding: It is a grinding process in which material is removed from flat surface with help of movable grinding wheel.
Worktable: 2 feeds
Grinding wheel: vertical feed(Depth of cut)
Horizontal spindle/ Peripheral surface grinding machine

63. Vertical spindle/ Wheel face grinding machine
Fig A
Fig B
Vertical spindle/ Wheel face grinding machine

64. Grinding Machine: Cylindrical Grinding
Cylindrical Grinding: It is a grinding process in which material is removed on the curved surface of a cylinder which is fixed rigidly in between two centers
Depth of cut is radial where as feed is in axial direction

65. Applications: Cylindrical Grinding machine
Bed, Worktable, Headstock, Tailstock, Wheel Head
Applications:
Cylindrical Grinding machine

66. Internal Grinding machine
Bed, Headstock, Tailstock, Chuck, Wheel Head
Internal Grinding machine

67. Grinding Machine: Centreless Grinding
Centreless Grinding: It is a grinding process in which material is removed on the curved surface of a cylinder without fixing the cylinder in between the centers

68. Grinding Machine: Centreless Grinding
Important Points Related to Centreless Grinding:
Both grinding wheel as well as regulating wheel rotate in same direction and the work piece rotates in opposite direction
The speed of grinding wheel is such that it pushes component downwards against the work post
The axis of regulating wheel is slightly inclined to the axis of grinding wheel so that it produces a component of its peripheral speed along the axis of work piece. This axial velocity component is responsible for feed of the work piece
The peripheral speed of grinding wheel, regulating wheel and work piece will not be same in general. (The grinding wheel has the highest speed)

69. Centreless Internal Grinding

70. Thank you…!