2. Overview
• Need for NTM processes
• Classification of NTM processes
• Process capability and the operating parameters for NTM
processes
• Overview of Manufacturing sector
• Comparison with the conventional processes
5. Need of NTM
Machining
Un-conventional = Non-traditional = Un-traditional
Manufacturing
Un-conventional ?
Very popular and wide applications
Sometimes only feasible solutions
6. Need of NTM
Limitations of Conventional processes
• Machining invariably uses K.E., i.e., forces and motions.
– Forces are accompanied by friction, heat, vibration,
deflection etc. These lead to tool wear, inaccuracy
(precise and miniature features not possible), poor
surface finish, surface integrity (surface cracks,
residual stresses, hot spots), low MRR.
– Motions limit the shape and size of the realizable
features.
Eg.: Square holes, small but deep holes required in
turbine blades, simple features in deep areas were the
rotating tool cannot reach.
NTM use simpler motions with special tools.
7. Need of NTM
HSHTR (turbine blades, aerospace alloys, refractory
metals)
Un-usual and complex part geometries
Avoiding surface damage
Metals and
Shape
Non-metals
Complexity
machining
Avoid Surface Precision and
Damage Miniaturization
Miniaturization Productivity
8. Need of NTM
• Non circular blind holes • Inaccessible/ critical area
de-burring
• Normal size but deep
• Super finishing of inner
hole drilling lateral surface of a shell
• Micro drilling • Finishing of fragile
• Three dimensional components
contour in a die • Holes along a curved axis
• Micro & Nano
• Elliptical piston machining components of special
& finishing materials
AND MANY MORE
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9. NTM DEFINED
A group of processes that remove excess
material by various techniques involving
mechanical, thermal, electrical, or chemical
energy (or combinations of these energies)
but do not use a cutting tool and its physical
contact with the work piece in the
conventional sense
Absence of tool-workpiece contact or relative motion, makes the
process a nontraditional
10. Machining Accuracies
• Nanomachining processes
include atom, molecule, or
ion beam machining, and
atom or molecule deposition.
• These techniques can
achieve 1-nm tolerances
that can be measured using
a scanning electron
microscope (SEM), a
transmission electron
microscope, an ion analyzer,
or electron diffraction
equipment
12. Classification of NTM processes
• Mechanical - erosion of work material by a high velocity
stream of abrasives or/& fluid is the typical form of
mechanical action
• Electrical - electrochemical energy to remove material
(reverse of electroplating)
• Thermal – thermal energy usually applied to small portion
of work surface, causing that portion to be removed by
fusion and/or vaporization
• Chemical – chemical etchants selectively remove material
from portions of workpiece, while other portions are
protected by a mask
17. Mechanism of processes
Mechanism of
Energy type Energy source Processes
material removal
Mechanical motion of tool / Conventional
Mechanical Plastic shear job machining
Mechanical /Fluid motion AJM, USM
Electrochemical Ion displacement Electric current ECM
Mechanical and Plastic shear and ion Electric current and
ECG
electro-chemical displacement mechanical motion
Chemical Corrosive reaction Corrosive agent CHM
Electric spark EDM
High speed electrons EBM
Thermal Fusion and vaporization
Powerful radiation LBM
Ionized substance IBM, PAM
19. Characteristics of NTM processes
Process Characteristics Operating Form of Energy
parameters
CHM • Sharpening of hard Chemical properties Etching
material of the reagent
• Used as honing process
• Higher MRR than
grinding
EDM • Shaping and cutting V = 50-380, A = 0.1- Series of sparks
complex parts made of 500,
hard materials MRR ~ 300
• White layer mm^3/min
• Expensive tooling and 0.03 and above
equipment
USM • Brittle fracture V=220, A= 12 amp Small amplitude
• Abrasive embedding AC, Gap = 0.25 and high frequency
20. Characteristics of NTM processes
Process Characteristics Operating Form of Energy
parameters
WEDM • Simple or complex Varies with material Series of sparks
contour cutting and thickness
• Expensive equipment
LBM • Cutting and hole V= 4500, air PHOTONS
making on thin material medium
• HAZ 0.5-7.5 m/min
• No need of vacuum
• Expensive equipment
• Low efficiency
EBM • Small hole and slot V = 1,50,000 KE of electrons
making 1-2 mm^3/min
• Need vacuum
• Expensive equipment
• HAZ
21. Characteristics of NTM processes
Process Characteristics Operating Form of Energy
parameters
AJM • Suitable for all material V = 110, I = 1.5 A, Abrasive propelled
• Tapered surface Gap = 0.76 at in high speed air
generated
• Effect of standoff
distance
IBM • Costly process High velocity ions
• Less efficiency (more energy)
• Very slow
PAM • HAZ V= 100, I=500 DC PLASMA
• Rough surface Gap= about 150
• Heavy work
ECM • Less tool wear V =10, I=10,000 A
• Oxide layer Electrical and
Chemical
22. Shape applications
Feature Suitable processes
Holes • For holes not less than 0.130 mm; EBM, EDM, LBM
• Large and deep holes; EDM and ECM (well above 20 L/D)
• For improving the geometry of holes, conventional processes like
reaming and boring can be combined with the processes
Through • USM, ECM, and EDM
cavities • Trepanning tool
• Generally EDM and USM and suitable for precision small cavities
while ECM is best for large cavities
Pocketing • Same as a through holes but have a flat at the bottom
• Trepanning tool usage is not possible
• ECM, CHM, and EDM are the principle processes
• CHM is suitable for large surface area
Arrayed • Arrayed microholes- beam processes
structures • Arrayed protrusions- EDM, ECM, CHM
Taper ECM is good as less tool wear occurs
24. Material applications
Process applicability
USM AJM ECM CHM EDM EBM LBM PAM
Metals and Alloys
Aluminum C B B A B B B A
Steel B B A A A B B A
Super alloys C A A B A B B A
Titanium B B B B A B B B
Refractories A A B C A A C C
Non-Metals
Ceramic A A D C D A A D
Plastic B B D C D B B C
Glass A A D B D B B D
A Good C Poor
B Fair D Inapplicable
27. Limitations of conventional processes
• Machining processes that involve chip formation have
a number of limitations
– Large amounts of energy
– Unwanted distortion
– Residual stresses
– Burrs
– Delicate or complex geometries may be difficult or
impossible
28. Advances in NTM processes
• Hybrid processes
• Automation
• Micro-fabrications
• Proper decision support by use of modern tools (FEA,
AHP etc.).
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29. Advantages of NTM
– Complex geometries are possible
– Extreme surface finish
– Tight tolerances
– Delicate components
– Easy adaptability for automation
– Little or no burring or residual stresses
– Brittle materials with high hardness can be
machined
– Microelectronic or integrated circuits are possible
to mass produce
– Manufacturing otherwise impossible shapes
– Production of functionally gradient materials
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30. Research issues in NTM
• Creating, improving unit operations
• Scaling up/down manufacturing capabilities
• Novel manufacturing concepts
• Understanding, responding to health, safety,
environmental issues
• Process monitoring and control
• “Application – Process- Material” system development
• Metrology
• Characterizations
36. Various work samples machined by USM
1- The first picture on the left is a plastic sample that has inner grooves that are machined using USM.
2- The Second picture (in the middle is a plastic sample that has complex details on the surface
3- The third picture is a coin with the grooving done by USM
