THERMAL AND ELECTRICAL BASED MACHINING OPERATIONS

1. THERMAL AND ELECTRICAL
ENERGY BASED PROCESSES
UNIT -2

2. ELECTRICAL ENERGY BASED
PROCESSES

3. EDM-Principle
• A thin wire of round shape used as an electrode, which is
supplied to the work area through a pair of wheels. With the
aid of current a high power spark is produced between wire-
electrode and work piece. Due to this high amount of heat is
produced nearly to 10000 degree Celsius. This heat energy
used to melt and vaporize the work material. Then with the
supply of dielectric fluid the molten stage materials are flushed
away, likewise the machining is carried out in the work piece.

4. .

5. Specifications
Voltage = 250 V
GAP = 0.005 – 0.05 mm
Temperature = 10000 degree celcius
Spark occur = 10 – 30 micro seconds
Current density = 15 – 500 A

6. Di electric Fluid – Flushing Method
1. Pressure Flushing
2. Suction Flushing
3. Side Flushing

7. Pressure Flushing
Di electric Fluid – Flushing Method

8. Suction Flushing
Di electric Fluid – Flushing Method

9. Side Flushing
Di electric Fluid – Flushing Method

10. Functions of Dielectric Fluid

11. Electrode (Tool)
• Graphite ( Non Metallic)
• Copper (Metallic)
• Coppre - Tungsten

12. POWER GENERATING CIRCUITS
Types

13. 1. Relaxation Circuit
• Commonly used
• Simplicity
• Less cost

15. Dis-advantages

16. 2. R-C-L Circuit
• MRR increases with the decrease of R
Capacitor charging
time is the problem
in R-C circuit.
So to overcome this
, inductance (L) is
introduced in the
circuit

17. Rotary Pulse Generator
• R-C and R-C-L yield low MRR
• Rotary Pulse Generator over come Drawback
of above to circuits
• It give high MRR
• It give good Surface finish
• It give low tool wear
• It provide better control in all Parameters

18. Rotary Pulse Generator
• Here Capacitor is discharged through the diode during first half
cycle.
• In the next half cycle sum of voltages is given with charged
capacitor to the circuit.
• So high spark produced
• It results high MRR
Draw Back
•Poor Surface Finish

19. Controlled Pulse Generator Circuit

20. PROCESS PARAMETERS
.
EDM

21. 1. Operating Parameters
2. Taper
3. Surface finish
4. Current Density
PROCESS PARAMETERS

22. Advantages
of EDM

23. Dis-advantages of EDM

24. Applications of EDM

25. Wire – Cut EDM (WEDM)
Travelling Wire Cut EDM (TWEDM)

26. Disadvantages of WEDM
• High Capital cost
• Cutting Rate is slow
• Not suitable for large work pieces

27. Applications of WEDM
• In the manufacturing of
Gears
Tools
Rotors
Turbine Blades
Cams

28. Wire Cut EDM Vs EDM

30. Characteristi
cs of EDM

31. THERMAL ENERGY BASED PROCESSES

32. PRINCIPLE
Here the machining is done by usage of heat
energy.
The heat energy is focused on a particular
portion for melt & Vaporize the work material
Example :
1. Electron Beam Machining (EBM)
2. Laser Beam Machining (LBM)
3. Plasma Arc Machining (PAM)

33. ELECTRON BEAM MACHINING (EBM)

34. ELECTRON
BEAM
MACHINING
(EBM)

35. PRINCIPLE - EBM

36. TYPES OF EBM

41. Process parameters

42. Process parameters
1.Control of current

43. Process parameters
2.Control of Spot Diameter

47. Process parameters
3.Control of Focal Distance of magnetic lens

48. LASER BEAM MACHINING
Photon Emission

49. PRINCIPLE OF LASER BEAM PRODUCTION

50. 1.Spontaneous Emission
2.Stimulated Emission

51. ACCURACY

52. TYPES OF LASER
1. Gas lasers
2. Solid lasers
3. Liquid lasers
4. Semi Conductor lasers

53. SOLID LASER
RUBY LASER
Synthetic Ruby rod made up of crystal of aluminium oxide

54. LASER BEAM MACHINING

55. .

56. .

57. MACHINING APPLICATIONS OF LASER
1. Laser in Metal Cutting
2. Laser in Drilling
3. Laser in Welding
4. Laser in Surface Treatment
5. Trimming
6. Blanking
7. Micromachining applications

58. Laser in Surface Treatment
A thin layer of cobalt alloy coating is applied on
Turbine blade for heat and Wear Resistance.
A thin Ceramic coating is applied on metal
Surface for heat and Wear Resistance.
Its also used to seal the micro cracks which are
usually present in hard – Chromium
electroplates

59. Advantages of LBM
1. All Kind of metals are machined
2. Micro holes are possible
3. Soft materials like rubber can be machined
4. No tool wear and contact with w/p
5. Automated process
6. Controlling of beam is easy

60. 1. High initial Cost
2. Operating cost is high
3. Required skilled labours
4. Rate of production is low
5. Need safety equipments
6. Life of flash lamp is low
7. The machined holes are not straight and round
Disadvantages of LBM

61. PLASMA ARC MACHINING
OR
PLASMA JET MACHINING

62. WORKING PRINCIPLE

63. Plasma arc
machining

64. ACCURACY

65. GASES USED IN PAM

66. Direct Arc Plasma
Torch
TYPES OF PLASMA ARC TORCHES

67. In-Direct Arc Plasma Torch
.

68. Advantages of PAM

69. Dis-Advantages of PAM

70. Applications of PAM