Types of unconventional machining processes

1. 20ME503PE
Unconventional Machining Processes

2. Unconventional Machining Processes
2
• UNIT 1 – Introduction and Mechanical
Energy Based Processes
• UNIT II – Thermal and Electrical Energy
Based Processes
• UNIT III - Chemical and Electro-Chemical
Energy Based Processes
• UNIT IV - Advanced Nano Finishing Processes
• UNIT V - Recent Trends in Non-Traditional
Machining Processes

3. UNIT I -INTRODUCTION AND
MECHANICAL ENERGY BASED
PROCESSES
3

4. Conventional Machining Processes
4
• In conventional machining processes, metal is
removed by using some sort of tool which is
harder than the workpiece and it is subjected
to wear.
• Tool and workpiece are in direct contact

5. DEMERITS OF CONVENTIONAL
MACHINING PROCESS

6. UNCONVENTIONAL
MANUFACTURING
PROCESS
6
Non –Traditional Machining Process
or
Un-Conventional Machining Process
Unconventional Forming Process

7. UNCONVENTIONAL MACHINING
PROCESS
7

8. UNCONVENTIONAL FORMING
PROCESS
8

9. Traditional or Conventional Machining
9

10. Need for Unconventional Machining
10
• Greatly improved thermal, mechanical and chemical properties
of modern materials – Not able to machine thru conventional
methods. (Why???)
• Ceramics & Composites – high cost of machining and damage
caused during machining – big hurdles to use these materials.
• In addition to advanced materials, more complex shapes, low
rigidity structures and micro-machined components with tight
tolerances and fine surface finish are often needed.
• To meet these demands, new processes are developed.
• Play a considerable role in aircraft, automobile, tool, die and
mold making industries.

11. Need for Unconventional Machining
11
• Very high hardness and strength of the material. (above 400 HB.)
• The work piece is too flexible or slender to support the cutting or
grinding forces.
• The shape of the part is complex, such as internal and external
profiles, or small diameter holes.
• Surface finish or tolerance better than those obtainable
conventional process.
• Temperature rise or residual stress in the work piece are
undesirable.

12. CLASSIFICATION

13. 13

14. 14
Unconventional Machining Processes -
Classification
Electrical

15. Mechanical Based Processes
15
AJM - Abrasive Jet Machining
WJM – Water Jet Machining
AWJM – Abrasive Water Jet Machining
USM – Ultrasonic Machining

16. 16
Electrical Based Processes
Electrical
EDM - Electrical Discharge Machining
WCEDM - Wire Cut Electrical Discharge Machining

17. 17
Chemical & Electrochemical Based Processes
ECM - Electro –Chemical Machining
ECD - Electro Chemical Deburring
ECG – Electro –Chemical Grinding
ECH – Electro – Chemical Honing

18. 18
Thermal Based Processes
LBM - Laser Beam Machining
PAM – Plasma Arc Machining
EBM - Electron Beam Machining
IBM – Ion Beam Machining

19. SELECTION OF MACHINING METHODS
19

20. PROCESS SELECTION
20
Based on the following points
1. Physical Parameters
2. Shapes to be machined
3. Process Capability or Machining Characteristics
4. Economic Considerations

21. Physical Parameters
21

22. Shapes to be
machined
22
.

23. 23
Process Capability
or
Machining Characteristics
1. Material Removal rate
2. Tolerance Maintained
3. Surface Finish
4. Depth of surface
Damage
5. Power required for
machining

24. 24
Process Economy

25. MRR – Material Removal Rate
25

26. Tolerance
26
. Engineering tolerance
is the permissible
limit or limits of
variation in
manufacturing

27. Surface Roughness / Finish
27
. Surface texture is one of the important factors that control
friction and transfer layer formation during sliding.

28. LIMITATIONS
Of
Un Conventional Machining
28
1. More expensive process
2. Low Material Removal Rate (MRR)
3. AJM, CHM , PAM and EBM are not commercially
economical Process

29. ADVANTAGES
of UCM
29
• High Accuracy and surface finish in process
• Less Rejected pieces
• Increase productivity
• Tool material need not be harder than work piece material.
• Easy to machine harder and brittle materials
• There is no residual stresses in the machined material

30. MECHANICAL ENERGY BASED
PROCESSES

31. MECHANICAL ENERGY METHODS
• Abrasive Jet Machining (AJM)
• Water Jet Machining (WJM)
• Ultrasonic Machining (USM)

32. Abrasive Jet Machining (AJM)

34. Abrasive Jet Machining

35. Arrangement of Abrasive Jet
Machining (AJM)
.

36. Construction details
.
Gas
Used
Nitrogen , Carbon di-oxide ,
compressed air
Abrasive Particles
Used
Aluminium oxide
(10,25&50microns)
Silicon Carbide(25&50microns)
Glass Powder , Dolomite and
Specially Prepared sodium
bicarbonate
Nozzle
Tungsten Carbide ,
Synthetic Sapphire (Ceramic)

37. .
.

38. Construction details
• Aluminium oxide (Al2O3 ) - 10 to 50 microns
• Silicon Carbide (SiC) - 25 and 50 Microns
• Glass Powder - 0.3 to 0.6 mm
Abrasive Particle Sizes

40. .
• .
The Shape and Size of Cut is controlled by a
movement adjusting mechanism given to
work piece or Tool
Cam Mechanism
Pantograph
Mechanism

41. AJM

42. MRR - PARAMETERS

43. MASS FLOW RATE

44. Abrasive Grain Size
OR

45. Gas Pressure

46. Velocity of Abrasive particles

47. Mixing Ratio

48. Stand off Distance

49. Stand of distance

50. Advantages
1. We can cut all kind of materials
2. No heat produced in process , so no thermal damage
3. Very thin and brittle material can be machined
4. Low initial investment
5. Good Surface Finish
6. Intricate holes can be cut in hard and brittle material

51. Disadvantages
1. Low MRR
2. Soft Material cannot be machined
3. Machining accuracy is poor
4. Nozzle Wear Rate is High
5. Abrasive Powder cannot be reused
6. Embedding of Abrasive particle in work piece is the high
damage thing in this process
7. It requires Dust Collection System

52. Application

53. Characteristics
of AJM

54. .
WATER JET
MACHINING

55. Introduction

56. Principle

57. PARTS
Pump
Accumulator
Control Valve
Regulating Chamber
Nozzle

58. .
.
Pump or
Intensifier
Used to Increase the water Pressure
Up to 1500 – 4000 N / mm2

59. .
.
Accumulator
Used to Store the water
Used to avoid water Pulsation

60. .
.
Nozzle
Used to Increase the velocity of water jet
Made up of Sintered Diamond, Tungsten Carbide and
Synthetic Sapphire
Nozzle Exit Diameter 0.05 – 0.35mm
Velocity of Water Jet From Nozzle 920 m/s

61. .
.
Regulating
Chamber
Used to Control the flow of water jet to Nozzle

62. WJM

63. PROCESS PARAMETERS

64. MRR

65. MRR

66. MRR

67. .

68. .

69. ADVANTAGES

70. DIS-ADVANTAGES

71. APPLICATION

72. .
.

73. .

74. Hydro-dynamic jet Machining
Abrasive Water jet Machining

75. Hydro-dynamic
jet Machining
Abrasive Water jet
Machining

76. Characteristics of AWJM

77. ULTRASONIC
MACHINING
PROCESS
USM
.

78. .
.
Ultrasonic
Waves of High
Frequency

79. Sound
.INFRA SONIC
WAVES
ULTRA SONIC
WAVES
AUDIBLE
WAVES

80. SUITABLE

81. PRINCIPLE

83. .
Ultrasonic
Generator
Used to convert the current from low
frequency to high frequency

84. Abrasive Slurry

85. .
Transducer
Used to convert
Electrical energy
into Mechanical
Vibrations

86. .
Tool Holder
Made up of Titanium alloy , Monel ,
Aluminium, Stainless steel

87. .
Tool
Material
Low Carbon Material
and Stainless steel
The tool is brazed,
soldered or Fastened
mechanically to the
transducer through a
tool holder

88. Working of USM

89. Transducer
convert the high
frequency
electrical energy
into Mechanical
Vibrations
Oscillator convert the
Low frequency electrical
energy into high
frequency electrical
energy
20 – 30 HZ
Vibrations are
transferred to
tool material
Abrasive Slurry
Passed
Between the
vibrating tool
and work piece
The
refrigeration
system used
to cool the
abrasive
slurry to 5 –
6 Degree
celcius

90. COMPARISON

91. TRANSDUCER

92. TYPES OF TRANSDUCER

93. MAGNETOSTRICTIVE TRANSDUCER
.
Change in length is independent of
the direction of the magnetic field
But depend only on the
magnitude of the field and
Nature of the material

94. MAGNETOSTRICTIVE TRANSDUCER

95. MAGNETOSTRICTIVE TRANSDUCER
LT battery used to
heat the filament
So electrons are
produced
Those electrons
are accelerated
by HT Battery
So AC current
Produced in the
circuit

96. So Rod start
to vibrate
due to
magnetostric
tive effect
This vibrations rod
create Ultrasonic
Waves , which sent out
MAGNETOSTRICTIVE TRANSDUCER

97. MAGNETOSTRICTIVE TRANSDUCER
The Longitudinal Extension
and contraction of the Rod AB
produce an EMF in the coil L2

98. Resonance
Frequency of the
oscillatory circuit
Frequency of Vibrating
Rod
=
Resonance will occur when
At resonance , the rod vibrates vigorously and ultrasonic
waves are produced at high frequencies

99. Advantages –
Magnetostrictive Transducer

100. Disadvantages –
Magnetostrictive Transducer

101. PIEZOELECTRIC TRANSDUCER
Its more efficient than magnetostrictive transducer
The modern USM are of this type.

102. PIEZOELECTRIC
effect
crystal

103. Definition - Piezoelectric
• Piezoelectric transducers are a type of electro
acoustic transducer that convert the electrical
charges produced by some forms of solid
materials into energy.
• The word "piezoelectric" literally means
electricity caused by pressure.

104. Circuit

105. Arrangement of the circuit

106. Working LT battery used to
heat the filament
So electrons are
produced
Those electrons are
accelerated by HT Battery
So AC current
Produced in the
circuit
This AC current Passes
through L1 and L2 and
its transferred to
Secondary circuit
This AC current passed to the plates A and B and it make the
Crystal to vibrate due to the principle of inverse piezoelectric
effect. The vibrations of crystal creates Ultrasonic waves

107. Resonance

108. Advantages – Piezoelectric transducer
Disadvantages – Piezoelectric transducer
1. Piezoelectric quartz is high cost
2. Cutting and shaping of crystal is very complex.

109. CONCENTRATOR or HORN

110. STRAIGHT AND TAPER ROD AS HORN

111. HORN

112. NODAL POINT
CLAMPING

113. FEED MECHANISM

114. .
1. Its high sensitive
2. Compact in size

115. .
1. Feed rate is high

116. MRR
MRR Per unit time

117. Wear Ratio

118. Factors considered for MRR
in USM

119. Grain size of Abrasives

120. Abrasive material
It Depend on
1.The type of material to be machined
2. Requirement of Surface finish
For Machining - Tungsten Carbide
- Die Steel
Boron Carbide
Silicon Carbide
Abrasives
For Machining - Glass
- Ceramics
Aluminium oxide

121. Concentration of Slurry
Abrasive Slurry = Abrasive Particles + Water

122. Amplitude of Vibration
MRR increase with the increase of Amplitude of Vibration

123. Frequency
MRR increases with the increase of Ultrasonic wave
Frequency

124. Process Parameters

125. Tool Material
Lengthy tool causes overstresses
So tool should be short and rigid
Process Parameters

126. Process Parameters
Wear Ratio
1.5 : 1 For Tungsten Carbide Work Pieces
100 : 1 For Glass Work Pieces
50 : 1 For Quartz Work Pieces
75 : 1 For Ceramics
1 : 1 For Hardened tool steel Work Pieces

127. Abrasive Material and
Cutting Power
Process Parameters

128. Advantages of USM

129. Disadvantages of USM

130. Applications

131. Recent Development

132. UNIT-3
ELECTRICAL ENERGY BASED
PROCESSES

133. .

134. 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