Module 1 ntm

Introduction to Non-traditional machining

1. 18ME641
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2. TSN, JSSATEB
Module 1 : Introduction

3. “It is the process of removing excess
material from the work piece to obtain the
desired shape and size”

Classification
1.Conventional (Traditional machining process)
2.Non Conventional(Non Traditional machining
process)


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4. Conventional Machining
•Conventional machining makes use of a hard,
and sharp cutting tool to shape materials.

•There are different types of machine designed to
hold and move the cutting too against a rigidly
held work piece materials or vice versa, to
remove excess material from the work piece.

•Eg: Lathes, Drilling machine, Grinding Machine
etc
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5. Non Traditional Machining
•Non Traditional machining makes use of various
forms energy sources in order to remove excess
materials from the work piece.

•There are a variety of non traditional process
based on the forms of energy sources like Light(
Laser), Sound( Ultrasonic Process), Magnetism,
Plasma, Electrical sparks, Chemical Dissolution
…


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6. Cont..
“Machining process where tool and work
piece does not make contact with each other
but the required machining process is done”

“ Group of process that removes the excess
material by various technique involving
mechanical, thermal, electrical and chemical
energy but do not uses sharp cutting tool “
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7. Cont…
Process that removes excess of material by
various techniques involving mechanical,
thermal, electrical or chemical energy.


Ex: EDM, ECM, AJM, PAM,
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8. NTM characteristics
•Material removal may occur with chip formation
or even no chip formation may take place.
Eg: In AJM, chips are of microscopic size and in case of
ECM material removal occurs due to electrochemical
dissolution at atomic level.

•In NTM, there may not be a physical tool present.
Eg: In laser jet machining, machining is carried out by
laser beam. However in Electrochemical Machining there
is a physical tool that is very much required for
machining.

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9. Cont..
•In NTM, the tool need not be harder than the work
piece material.
Eg: In EDM, copper is used as the tool material to
machine hardened steels.

•NTM processes do not necessarily use mechanical
energy for material removal.
•They use different energy domains to provide
machining.
Eg: USM, AJM, WJM mechanical energy is
used to machine material. EDM,LBM
used other source of engery
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10. Need for Non Traditional Machining
•The strength of steel alloys has increased five
folds due to continuous R & D effort.

•In aero-space requirement of High strength at
elevated temperature with light weight leads to
development and use of hard titanium alloys,
nimonic alloys, and other HSTR alloys.

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11. Cont…
•The ultimate tensile strength has been improved
by as much as 20 times.

•Development of cutting tools which has
hardness of 80 to 85 HRC which cannot be
machined economically in conventional
methods
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12. Cont..
•Technologically advanced industries like
aerospace, nuclear power, wafer fabrication,
automobiles has ever increasing use of High –
strength temperature resistant (HSTR) alloys and
It is no longer possible to use conventional process
to machine these alloys.

•Production and processing parts of complicated
shapes (in HSTR and other hard alloys) is
difficult, time consuming and uneconomical by
conventional methods of machining.

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13. Cont..

•Innovative geometric design of products and
components made of new exotic materials with
desired tolerance, surface finish cannot be
produced Economically by conventional
machining.

•If Work piece material are too brittle like glass,
ceramics, heat treated alloys, it is no longer
possible to use conventional process to machine
these alloys.



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14. Cont..
•Intricate shaped blind hole – Eg: square hole of 15
mm x15 mm with a depth of 30 mm with a
tolerance of 100 microns.
•Difficult to machine material – Eg: Inconel, Ti-
alloys or carbides, Ceramics, composites , HSTR
alloys etc.,
•Low Stress Grinding – Electrochemical Grinding
is preferred as compared to conventional grinding
•Deep hole with small hole diameter – Eg: ϕ 1.5
mm hole with l/d = 20
•Machining of composites



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15. Comparison
Conventional Process
•The cutting tool and
work piece are always
in physical contact with
relative motion with
each other, which
results in friction and
tool wear.

Non Conventional
Process
•There is no physical
contact between the tool
and work piece, In
some non traditional
process tool wear
exists.

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16. Conventional Process

•Material removal rate is
limited by mechanical
properties of work
material.
Non Conventional
Process

•NTM can machine hard
to cut materials like
titanium, ceramics,
nimonics, SS,
composites,
semiconducting
materials
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17. Cont..
Conventional Process
•Relative motion
between the tool and
work is typically rotary
or reciprocating. Thus
the shape of work is
limited to circular or
flat shapes.
•In spite of CNC
systems, production of
3D surfaces is still a
difficult task.
Non Conventional
Process
•Many NTM are capable
of producing complex
3D shapes and cavities
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18. Cont..
Conventional Process
•Machining of small
cavities, slits , blind
holes or through holes
are difficult


Non Conventional
Process
•Machining of small
cavities, slits and
Production of non-
circular, micro sized,
large aspect ratio, shall
entry angle holes are
easy using NTM
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19. Cont..
Conventional Process

•Use relatively simple
and inexpensive
machinery and readily
available cutting tools
Non Conventional
Process

•Non traditional
processes requires
expensive tools and
equipment as well as
skilled labour, which
increase the production
cost significantly
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20. Cont..
Conventional Process
•Capital cost and
maintenance cost is low
•Traditional processes are
well established and
process is well
understood
•Conventional process
mostly uses mechanical
energy
Non Conventional Process
•Capital cost and
maintenance cost is high
•Mechanics of removal of
Material in some NTM
process are still under
research
•Most NTM uses energy
in direct form Eg: laser,
Electron beam in its
direct forms are used in
LBM & EBM
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21. Cont..
Conventional Process
•Surface finish and
tolerances are limited
by machining
inaccuracies


•High metal removal
rate.
Non Conventional
Process
•High surface finish(up
to 0.1 micron) and
tolerances (25
Microns)can be
achieved

•Low material removal
rate.
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22. Classification of NTM processes

Based on the nature of energy used for material
removal.

•Mechanical Processes
•Electrochemical Processes
•Electro-Thermal Processes
•Chemical Processes



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23. 1. Mechanical Processes

⎯ Abrasive Jet Machining (AJM)
⎯ Ultrasonic Machining (USM)
⎯ Water Jet Machining (WJM)
- Abrasive Water Jet Machining (AWJM)
- Abrasive Flow Machining (AFM)
- Magnetic Abrasive Finishing (MAF)
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24. Cont…
2. Electrochemical Processes

⎯ Electrochemical Machining (ECM)
⎯ Electro Chemical Grinding (ECG)
⎯ Electro Jet Drilling (EJD)

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25. Cont…
3. Electro-Thermal Processes
⎯ Electro-discharge machining (EDM)
⎯ Laser Jet Machining (LJM)
⎯ Electron Beam Machining (EBM)
⎯ Plasma Arc Machining (PAM)
4. Chemical Processes
⎯ Chemical Milling (CHM)
⎯ Photochemical Milling (PCM)
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26. Cont…
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27. I. Mechanical Energy Processes
•Material removal is due to the application of
mechanical energy in the form of high frequency
vibrations or kinetic energy.
•Erosion of work material by a high velocity
stream of abrasives or fluid (or both) is the
typical form of mechanical action
•Ultrasonic machining
•Water jet cutting
•Abrasive water jet cutting
•Abrasive jet machining

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28. II. Electrochemical Machining Processes
•Electrical energy is used in combination with
chemical reactions, to remove material
•Reverse of electroplating
•Work material must be a conductor

–Electrochemical machining (ECM)
–Electrochemical deburring (ECD)
–Electrochemical grinding (ECG)



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29. III. Thermal Energy Processes
•The material is removed through the controlled,
localized heating of the work piece. It result into
material removal by melting and evaporation.
•Thermal energy is applied to small portion of work
surface, causing that portion to be removed by
fusion and/or vaporization
- EDM, Wire EDM
- EBM
- Laser beam machining
- Plasma arc machining

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30. IV. Chemical Machining (CHM)
Material removal through contact with a strong
chemical etchant.

Chemical etchants selectively remove material from
portions of work part, while other portions are
protected by a mask
–Chemical milling
–Chemical blanking
–Chemical engraving
–Photochemical machining

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31. Selection Of Process
To make efficient use of modern machining process,
it is necessary to know the exact nature of the
machining process

The correct selection of the NTM methods must be
based on the following aspects.
i) Physical parameters of the process
ii) Shape to be machined
iii) Process capability
iv) Economics of the processes
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32. Physical parameters of the process
•PAM and ECM require high power for fast
machining.

•EBM and LBM require high voltages and require
careful handling of equipment.

•EDM and USM require medium power .

•EBM can be used in vacuum and PAM uses oxygen
and hydrogen gas.
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33. TSN, JSSATEB

34. Shape to be machined
The different shapes can be machined by NTM.

•EBM and LBM are used for micro drilling and
cutting.
•USM and EDM are useful for cavity sinking and
standard hole drilling.
•ECM is useful for fine hole drilling and contour
machining.
•PAM can be used for cutting and AJM is useful
for shallow pocketing
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35. TSN, JSSATEB
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36. Process capability
•EDM which achieves higher accuracy, has the
lowest specific power requirement.
•ECM can machine faster and has a low thermal
surface damage depth.
•USM and AJM have different material removal rates
combined with high tool wear and are used non
metal cutting.
•LBM and EBM are, due to their high penetration
depth, can be used for micro drilling, sheet cutting
and welding.
•CHM is used for manufacture of PCM and other
shallow components.
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37. Process capability

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38. Economics of the processes
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39. Advantages NTM
1.Difficult to machine the materials in
conventional machining, can be machined with
non conventional process.
2.Machining of materials for the complex shapes
is possible with non conventional process.
3.Economical for mass production for long
duration.
4.High strength, high hardness and heat resisting
materials can be machined with non
conventional process.
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40. Cont…

5. High accuracy and surface finish

6. Material removed without mechanical contact with the
work piece (ECM,EDM,LBM,CHM).

7. Material removal rate is independent of work piece
hardness (ECM,LBM,EDM)

8.Cutting forces are independent of work piece
hardness.(ECM,LBM,EDM,CHM)

9. Tool material need not be harder than the work piece
material.(ECM,LBM,EDM,CHM,USM)



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41. Cont…
10.Tool wear is not a problem (ECM,LBM,CHM)
11.Ability to machine any material. (LBM)
12. Burr-free machining (ECM,EDM,CHM)
13. Stress- free machining. (ECM,ECG,CHM)
14.Uniform material removal over the entire area
simultaneously.(ECM,CHM)
15.Superior surface integrity possible
(ECM,CHM,ECG)

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42. Cont…

16. Intricate shaped and fragile materials can be
machined.(USM)

17. Finely focused micro machining

18.Micro- hole drilling at shallow entrance angles
possible.(EDM,ECM,LBM,EBM)

19. Easy compatibility with numerical control and
mini- computer controls.(ECM,EDM,LBM,EBM)
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43. Limitations:
1.Work piece and tool must be electrically
conductive (e.g. EDM,ECM)

2.Depth of cut is limited(e.g. LBM)

3.Recast or heat affected zones(HAZ) of surfaces
produced may be troublesome(e.g.
EDM,LBM,EBM)


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44. Cont…
4. Compatibility of the process with the metallurgical
state of the work piece materials can be studied
before using a particular non-traditional
machining process for production work.

5. There may be taper in the sidewalls of holes or
cavities(e.g. EDM,LBM)

*Most of these limitations can be overcome and
controlled, so that the advantages can be obtained
with good product quality assurance.
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45. Applications
USM:
•Drilling and machining of cavities / holes in
conductive and non-conductive materials like
glass and ceramics etc.

•Threading of various glass and ceramic materials.

•Hard materials and precious stones such as
synthetic ruby for the preparation of jewels to
watches and timer are successfully machined by
this method.

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46. AJM

• Abrasive water jet cutting is highly used in
aerospace, automotive and electronics industries
(PCB cutting).

•In aerospace industries, parts such as titanium
bodies for military aircrafts, engine components
(aluminium, titanium, heat resistant alloys),
aluminium body parts and interior cabin parts are
made using abrasive water jet cutting.

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47. Cont…
•In automotive industries, parts like interior trim
(head liners, trunk liners, door panels) and fiber
glass body components and bumpers are made by
this process.

•Similarly, in electronics industries, circuit boards
and cable stripping are made by abrasive water jet
cutting.
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48. LBM

•Laser beam machining is used to perform
precision micro- machining on all materials
such as steel, ceramic, glass, diamond, graphite
etc.
•It is used for cutting, drilling, welding of
materials, marking, scribing, heat treating of
surfaces and selectively clad materials.
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49. PAM

•Pipe industry – preparing pipe edges for
welding.

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50. EBM

•EBM is more popular in industries like aerospace,
insulation, food processing, chemical, clothing,
etc.

•It is very useful in those cases where number of
holes (simple as well as complex shaped) required
in a work piece may range from hundreds to
thousands (perforation of sheets, etc).

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51. Cont…

•This Process is also used for drilling thousands of
holes (diameter < 1.00 mm) in very thin plates
used for turbine engine combustion domes.


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52. TSN, JSSATEB

53. Cont…


•Many thousand holes (diameter < 1.0 mm) in a
cobalt alloy fiber spinning head of thickness
around 5 mm are drilled by EBM.

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54. TSN, JSSATEB

55. EDM

•Useful in machining of small holes, orifices,
slots in diesel fuel injection nozzles, airbrake
valves and aircraft engines etc.

•Blind cavities and narrow slots in dies,
minimum diameter hole can be produced.

•Mold making
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56. TSN, JSSATEB

57. CM
•Aviation Industries
•Printed Circuit Boards
•Jewellery
•Turbine Engines
•Pressure Vessel Bulkheads
•Chemical Milling => Production Of Blind
Holes, Pockets, Channels

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58. Questions
1.What is non-traditional machining/
unconventional machining/ modern machining
technique. How are they classified.
2.Differentiate between conventional (traditional)
and unconventional (non-traditional) or modern
machining processes. June/July 2016, June/July
2014, June/July 2013, Dec 2011
3.What are the applications of non-traditional
machining methods.
4. What are the advantages and disadvantages of
non-traditional machining.
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59. Cont…
5.Classify non-traditional machining processes
based on nature of energy employed in
machining.

6. Write a note on the source of energy harnessed
and mechanism of material removal in non-
traditional machining. June/July 2011

7. Explain the need for development of non-
traditional machining. June/July 2011
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60. Cont…
8. Classify the modern machining processes. Dec
2011)
9. Explain the principle of modern machining process.
10.What are the factors to be considered while
selecting a process? Dec 2011
11.Explain the need to develop modern machining
processes. Dec 2012
12.Explain parameter to select to employ the new
machining methods. Dec 2012
13.Give the broad classification of non-traditional
machining processes. Dec 2012)
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61. Cont…
14.Justify the need of unconventional
manufacturing process in today’s industries.
June/July 2013
15.What are the basic factors upon which the
unconventional manufacturing processes are
classified? Explain. June/July 2013
16.Explain how the non-traditional machining
processes are classified. June/July 2014
17.List the unconventional machining processes
under mechanical energy thermal and chemical
energy category. Dec 2014, Jan2015
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62. Cont…
18. Differentiate between conventional (traditional)
and non-traditional machining processes with
examples. Dec 2014,Jan 2015)
19.Make a comparison between traditional and non-
traditional machining process in terms of cost,
application, scope, machine time and limitations.
Dec 2014, Jan 2015
20. List and explain the various factors to be
considered for selection of machining processes.
June/July 2015
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63. Cont…
21.Classify various non-traditional machining
process based on energy source used with giving
suitable examples. June/July 2015

22. Based on the various parameters of machining,
compare the conventional and non-conventional
machining processes. June/July 2015

23.How modern machining processes are
classified? June/July 2016
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64. Cont…
24.What are the essential physical process
parameters for an efficient use of modern
machining processes ? June/July 2016

25.Why Non-traditional machining (NTM)
processes are selected for manufacturing?
June/July 2016

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