The document discusses various unconventional machining processes. It covers mechanical energy based processes like abrasive jet machining, water jet machining and ultrasonic machining in Unit 1. Unit 2 discusses thermal and electrical energy based processes. Key processes covered are electrical discharge machining and electrochemical machining. Unit 3 focuses on chemical and electrochemical energy based processes like electrochemical machining. The document provides details on the working, parameters, advantages and applications of these various 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
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
13. Need for Unconventional Machining
13
• 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.
14. Need for Unconventional Machining
14
• 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.
20. 20
Chemical & Electrochemical Based Processes
ECM - Electro –Chemical Machining
ECD - Electro Chemical Deburring
ECG – Electro –Chemical Grinding
ECH – Electro – Chemical Honing
21. 21
Thermal Based Processes
LBM - Laser Beam Machining
PAM – Plasma Arc Machining
EBM - Electron Beam Machining
IBM – Ion Beam Machining
22. Mechanical based Unconventional Processes
22
USM – Through mechanical abrasion in a
medium (solid abrasive particles
suspended in the fluid)
WJM – Cutting by a jet of fluid
AWJM – Abrasives in fluid jet.
IJM – Ice particles in fluid jet.
Abrasives or ice – Enhances
cutting action.
27. Chemical & Electrochemical
based Unconventional Processes
27
CHM – uses Chemical
dissolution action in
an etchant.
ECM – uses Electrochemical
dissolution action in
an electrolytic cell.
29. PROCESS SELECTION
29
Based on the following points
1. Physical Parameters
2. Shapes to be machined
3. Process Capability or Machining Characteristics
4. Economic Considerations
43. ADVANTAGES
of UCM
43
• 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
67. 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
68. Dis-Advantages
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
77. .
.
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
106. 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
110. 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
112. 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
113. So Rod start
to vibrate
due to
magnetostric
tive effect
This vibrations rod
create Ultrasonic
Waves , which sent out
MAGNETOSTRICTIVE TRANSDUCER
115. 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
120. 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.
123. 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
125. Advantages – Piezoelectric transducer
Disadvantages – Piezoelectric transducer
1. Piezoelectric quartz is high cost
2. Cutting and shaping of crystal is very complex.
137. 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
143. 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
151. 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
