I_Unit_Introduction_to_Unconventional_Ma.ppt

fds

1. ME 6004
Unconventional Machining Processes
Dr.D.ELIL RAJA
Associate Professor
Department of Mechanical
St.Joseph’s Institute of Technology

2. Manufacturing Technology I
Metal casting (Sand casting and other casting processes)
Materials Joining (Arc welding, TIG, EBW, PAW, etc.)
Bulk deformation (Metal Forming – Forging, Rolling, Extrusion)
Sheet metal processes (Shearing, bending, drawing, etc.)
Manufacturing of plastic materials (Injection molding, etc).
Manufacturing Technology II (Material removal process)
Metal Cutting or Mechanical Abrasion
Centre lathe and special purpose lathes
Shaper, Planer, Slotter, Milling, Drilling, Broaching, Gear cutting, etc.
Grinding, Honing, Lapping, etc.
CNC and DNC
Introduction

3. Introduction – Contd.
3
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.
Absence of any of these elements – makes the process a
unconventional or nontraditional one.
Big boon to modern manufacturing industries.
The need for higher productivity, accuracy and surface
quality – led to combination of two or more machining
actions, called hybrid machining processes.

4. History of Machining
4
In ancient days – hand tools (stones, bones or stick).
Later – hand tools of elementary metals (bronze or iron)
Till 17
th
Century – tools were either hand operated or driven
mechanically by very elementary methods.
Wagons, ships, furniture, etc. – were produced.
Introduction of water, steam and electricity – power driven
machine tools
Caused a big revolution in 18
th
and 19
th
centuries.
1953 – Numerical control machine tools – enhanced the
product productivity and accuracy.

5. 5

6. Traditional or Conventional Machining
6

7. Metal Cutting Processes
7

8. Abrasive Machining
8
Cylindrical grinding
Flat surface grinding

9. Abrasive Machining
9
Centreless grinding

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. 12
Unconventional Machining Processes -
Classification
Electrical

13. Mechanical Based Processes
13
1.Working principles
2.Equipment used
3.Process parameters
4.MRR
5.Variation in techniques used
6.Applications
AJM
WJM
AWJM
USM

14. 14
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

15. 15
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

16. 16
Thermal Based Processes
1.Working principles
2.Equipment used
3.Types
4.Beam control techniques
5.Applications
LBM
PAM
EBM

17. Mechanical based Unconventional Processes
USM – thru 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.
17

18. Thermal based Unconventional Processes
Thru – melting & vaporizing
Many secondary phenomena –
surface cracking, heat
affected zone and striations.
Heat Source:
Plasma – EDM and PBM.
Photons – LBM
Electrons – EBM
Ions – IBM
Machining medium: different
for different processes.
18

19. Chemical & Electrochemical based
Unconventional Processes
CHM – uses Chemical dissolution
action in an etchant.
ECM – uses Electrochemical
dissolution action in an
electrolytic cell.
19