unit 1 ucm
Post on 08-May-2015
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UNIT I INTRODUCTION
Syllabus
• Unconventional machining Process
• Need
• Classification
• Brief overview
WHAT IS UCM?
Conventional Machining Process
• Metal Removal ?
• Nature of Contact ?
• Scrap ?
Demerits
• Disposal of Waste
• By products of chips
• Work holding Devices for larger cutting force
• Heat Generation
• Not possible without chips
Unconventional Manufacturing process
• Unconventional Manufacturing process
1. Unconventional Machining process
or
Non Traditional Machining Process
2. Unconventional Forming process
Unconventional Manufacturing process
Machining process
• Metal Removal
• No Direct Contact b/w
tool and work piece
Forming process
• Metals are formed
• Releases large amount of
Energy in very short time
interval
NEED FOR UCM
Need
• Machining – produces finished products with high degree of
accuracy
• Conventional machining
• Utilizes cutting tools (harder than workpiece material).
• Needs a contact between the tool and workpiece.
• Needs a relative motion between the tool and workpiece.
Need
• The need for higher productivity, accuracy and surface quality
• Improve the capability of automation system and decreasing their
sophistication (decreasing the investment cost) requirements
• Very hard fragile materials difficult to clamp for traditional
machining
• When the work piece is too flexible or slender
• When the shape of the part is too complex
• Internal and external profiles, or small diameter holes.
CLASSIFICATION
12
Unconventional Machining Processes – Based on Energy
13
Unconventional Machining Processes – Based Mechanism
14
Unconventional Machining Processes – Based on Energy used for Removal
15
Unconventional Machining Processes – Based on Transfer of Energy
16
Mechanical Based Processes
1. Working principles
2. Equipment used
3. Process parameters
4. MRR
5. Variation in techniques used
6. Applications
AJM
WJM
AWJM
USM
17
Electrical Based Processes
1. Working principle
2. Equipment used
3. Process parameters
4. Surface finish & MRR
5. Electrode/Tool
6. Power & Control circuits
7. Tool wear
8. Dielectric
9. Flushing
10. Applications
Electrical
EDM
WEDM
18
Chemical & Electrochemical Based Processes
1. Working principles
2. Etchants & Maskants
3. Techniques of applying maskants
4. Process parameters
5. Surface finish & MRR
6. Electrical circuits in case of ECM
7. Applications
CHM
ECM
ECG
ECH
19
Thermal Based Processes
1. Working principles
2. Equipment used
3. Types
4. Beam control techniques
5. Applications
LBM
PAM
EBM
SELECTION PROCESS
Selection Process
• Selection Process is based of following parameters– Physical Parameter– Shapes to be Machined– Process Capability – Economic consideration
Physical ParameterParameter ECM EDM EBM LBM PAM USM AJM
Potential, V 5- 30 50-500 200 x 103 4.5 x 103 250 220 220
Current, A 40,000 15-500 0.001 2 600 12 1.0
Power, kW 100 2.70 0.15 20 220 2.4 0.22
Gap, mm 0.5 0.05 100 150 7.5 0.25 0.75
Medium ElectrolyteDie electric
fluidVacuum Air Argon Nitrogen
Abrasive grains
Work Material
M/C diffTungsten carbide
All Mtl All Mtl All MtlTungsten carbide
HSS
Shapes to be Machined
Process Machines
Holes ( Micro, Small, deep,Shallow)
LBM, EBM,ECM, USM & EDM
Precision Work USM & EDM
Horning ECM
Etching ECM & EDM
Grinding AJM & EDM
Deburring USM & AJM
Threading EDM
Profile Cut PAM
Process Capability or Machining Characteristics
Process MRR
( mm3/s )Surface Finish
(μm)Accuracy
(μm)Power (kW/
cm3/ min
LBM 0.10 0.4 – 6.0 25 2700
EBM 0.15 - 40 0.4 – 6.0 25 450
EDM 15 - 80 0.25 10 1.8
ECM 27 0.2 -0.8 50 7.5
PAM 2500 Rough 250 0.90
USM 14 0.2 – 0.7 7.5 9.0
AJM 0.014 0.5- 1.2 50 312.5
Process Economy
Process Capital Cost Tool & FixturesPower
RequirementEfficiency
EDM Medium High Low High
CHM Medium Low High Medium
ECM V. High Medium Medium V. Low
AJM V. Low Low Low Low
USM High High Low Medium
EBM High Low Low V. High
LBM Medium Low V. Low V. High
PAM V. Low Low V. Low V. Low
Conventional
V. Low LowLow
V. Low
Limitation
• More Expensive
• Slow Process
• Commercial
Compiled ByD.Vasanth kumar
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