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• 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
Overview
Dimensional Range
Precision or miniaturization?
Very popular and wide applications Sometimes only feasible solutions
Need of NTM
Un-conventional Non-traditional Un-traditional= =
Machining
Manufacturing
Un-conventional ?
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), poorsurface finish, surface integrity (surface cracks,residual stresses, hot spots), low MRR.
– Motions limit the shape and size of the realizablefeatures.Eg.: Square holes, small but deep holes required inturbine blades, simple features in deep areas were therotating tool cannot reach.
NTM use simpler motions with special tools.
Need of NTM HSHTR (turbine blades, aerospace alloys, refractory metals)Un-usual and complex part geometriesAvoiding surface damage
Shape Complexity
Metals and Non-metals machining
Avoid Surface Damage
Precision and Miniaturization
Miniaturization Productivity
8
• Non circular blind holes• Normal size but deep
hole drilling• Micro drilling• Three dimensional
contour in a die• Elliptical piston machining
& finishing
• Inaccessible/ critical area de-burring
• Super finishing of inner lateral surface of a shell
• Finishing of fragile components
• Holes along a curved axis• Micro & Nano
components of special materials
AND MANY MORE
Need of NTM
A group of processes that remove excessmaterial by various techniques involvingmechanical, thermal, electrical, or chemicalenergy (or combinations of these energies)but do not use a cutting tool and its physicalcontact with the work piece in theconventional sense
NTM DEFINED
Absence of tool-workpiece contact or relative motion, makes the process a nontraditional
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
Classification of Conventional Processes
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 areprotected by a mask
NTM Processes
Single Action Hybrid
Classification of NTM processes
Single Action Mechanical and Chemical and electrochemical Processes
Single Action Thermal Processes
Hybrid Processes
Mechanism of processesEnergy type Mechanism of
material removal Energy source Processes
Mechanical Plastic shearMechanical motion of tool /job
Conventionalmachining
Mechanical /Fluid motion AJM, USMElectrochemical Ion displacement Electric current ECMMechanical and electro-chemical
Plastic shear and iondisplacement
Electric current andmechanical motion ECG
Chemical Corrosive reaction Corrosive agent CHM
Thermal Fusion and vaporization
Electric spark EDMHigh speed electrons EBMPowerful radiation LBMIonized substance IBM, PAM
Hybrid NTM processes
Characteristics of NTM processes Process Characteristics Operating
parametersForm of Energy
CHM • Sharpening of hardmaterial• Used as honing process• Higher MRR thangrinding
Chemical propertiesof the reagent
Etching
EDM • Shaping and cuttingcomplex parts made ofhard materials• White layer• Expensive tooling andequipment
V = 50-380, A = 0.1-500,MRR ~ 300mm^3/min0.03 and above
Series of sparks
USM • Brittle fracture• Abrasive embedding
V=220, A= 12 ampAC, Gap = 0.25
Small amplitudeand high frequency
Characteristics of NTM processes Process Characteristics Operating
parametersForm of Energy
WEDM • Simple or complexcontour cutting• Expensive equipment
Varies with materialand thickness
Series of sparks
LBM • Cutting and holemaking on thin material• HAZ• No need of vacuum• Expensive equipment• Low efficiency
V= 4500, air medium
0.5-7.5 m/min
PHOTONS
EBM • Small hole and slotmaking• Need vacuum• Expensive equipment• HAZ
V = 1,50,0001-2 mm^3/min
KE of electrons
Characteristics of NTM processes Process Characteristics Operating
parametersForm of Energy
AJM • Suitable for all material• Tapered surface
generated• Effect of standoff
distance
V = 110, I = 1.5 A,Gap = 0.76
Abrasive propelledat in high speed air
IBM • Costly process• Less efficiency
• Very slow
High velocity ions (more energy)
PAM • HAZ• Rough surface• Heavy work
V= 100, I=500 DCGap= about 150
PLASMA
ECM • Less tool wear• Oxide layer
V =10, I=10,000 AElectrical and
Chemical
Shape applicationsFeature 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 likereaming and boring can be combined with the processes
Throughcavities
• USM, ECM, and EDM• Trepanning tool• Generally EDM and USM and suitable for precision small cavitieswhile 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 structures
• Arrayed microholes- beam processes• Arrayed protrusions- EDM, ECM, CHM
Taper ECM is good as less tool wear occurs
Material applications
Material applicationsProcess 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
B Fair
C Poor
D Inapplicable
Process variants Basic process Variant process
USM • Ultrasonically Assisted Machining (UAM)• Rotary ultrasonically Assisted Machining (RUM)
AJM • Abrasive Flow Machining (AFM)• Orbital Grinding (OG)• Abrasive Water Jet Machining (AWJM)
ECM • Electro-Chemical Grinding (ECG)• Electro-Chemical Discharge Grinding (ECDG)• Electro-Chemical Deburring (ECD)• Electro-Chemical Honing (ECH)• Shaped Tube Electrolytic Machining (STEM)
EDM • Wire Electrical Discharge Machining (WEDM)• Wire Electrical Discharge Grinding (WEDG)
CHM • Chemical Milling (CHM)• Chemical Engraving (CHE)• Chemical Blanking (CHB)• Photo-Chemical Machining (PCM)
26
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
• Hybrid processes• Automation• Micro-fabrications• Proper decision support by use of modern tools (FEA,
AHP etc.).
Advances in NTM processes
29
– 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
Advantages of 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
Research issues in NTM
Typical Parts Machined
Nonmetallic and tiny parts by WJM Metallic and very large
Ceramic Parts Bullet proof glass Rack and Pinion
WJM
Typical Parts Machined
EDM and WEDM
Typical Parts Machined
CHM
Typical Parts Machined
ECM
End
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
EDMing of insulating ceramics
EDMing of curved hole
Powder mixed EDM