1. RECENT TRENDS OF
“NON-CONVENTIONAL MICROMACHINING”
RECENT TRENDS OF
“NON-CONVENTIONAL MICROMACHINING”
Taha Ali El-Taweel
Production Engineering and Mechanical Design
Faculty of Engineering, Shebin El-Kom,
Menoufiya University
Taha Ali El-Taweel
Production Engineering and Mechanical Design
Faculty of Engineering, Shebin El-Kom,
Menoufiya University
By
2. INTRODUCTION
Electrochemical micro-machining (EMM)
Through-maskless - Through-mask
Micro-electrodischarge machining (MEDM)
Laser micro-machining (LMM)
Mask projection techniques - Direct writing techniques
Micro-ultrasonic machining (MUSM)
Chemical- micro machining (CMM)
Dry chemical etching - Wet chemical etching
FUTURE POTENTIAL
LAYOUT OF THE PRESENTATIONLAYOUT OF THE PRESENTATION
3. Thermal Action
- EDM
- LBM
- IBM
Mechanical Action
- USM
- WJM
- AJM
INTRODUCTIONINTRODUCTION
The need for fabricating parts from hardened high-
strength and heat-resistant metals and alloys has created
difficult machining problems for industry. To meet these
problems, non-conventional machining methods have
been developed. (no mechanical force)
Chemical Action
Chemical Milling
Electrochemical
Action
- ECM
Non-conventional Machining
5. NON-CONVENTIONAL MICROMACHININGNON-CONVENTIONAL MICROMACHINING
• Electrochemical micro-machining (EMM)
• Micro-electrodischarge machining (MEDM)
• Laser micro-machining (LMM)
• Ultrasonic micro-machining (USMM)
• Chemical micro-machining (CMM)
The unit of removal can be of the order of atomic
quantities through;
6. Electrochemical machining (ECM)Electrochemical machining (ECM)
Electrochemical machining
(ECM) Ion exchange is the metal
removal mechanism.
- Reverse of electroplating
- Workpiece must be electrically
conductive
- Electrolyte acts as a current
carrier
- High rate of electrolyte
movement; washes metal ions.
- ECM for the production of gas
turbine compressor blades
Principle of ECM machining
7. EMM through-maskless EMM through-mask
Electrochemical micro-machining
- Capillary drilling
- MEJM
- One-sided EMM
- Two-sided EMM
Electrochemical micro-machining (EMM)Electrochemical micro-machining (EMM)
Requires highly localized material removal induced
by the impingement of a fine electrolytic jet.
8. Electrochemical micro-machining (EMM)Electrochemical micro-machining (EMM)
EMM through-masklessEMM through-maskless
Micro electrochemical
jet machining (MEJM)
Capillary drilling workpiece
(anode)
nozzle
diameter
electrolyte jet
(cathode)
Insulation
glass tube
platinum
(cathode)
workpiece
(anode)
electrolyte
MEJM Capillary drilling
Removes material by
using an electrolyte jet
from a small nozzle,
which works as cathode
without advancement of
the jet.
Fine cathode tool in the
form of a capillary that is
advanced at constant
rate towards the
workpiece.
9. EMM through-maskEMM through-mask
Involves selective metal dissolution from unprotected areas
of a one- or two-sided photoresist-patterned workpiece.
The sample is held in a stationary
holder while the multi-nozzle
cathode, which is attached to the
table, moves at a constant speed
facing the sample
One-sided
Localized dissolution induced by
scanning two cathode
assemblies over a vertically held
work-piece providing movement
of the electrolyte
Two-sided
One-sided EMM Two-sided EMM
Electrochemical micro-machining (EMM)Electrochemical micro-machining (EMM)
10. Fabrication of micro-electronic
components
Ink-jet nozzle plates
Metal masks
Micro-hole drilling
Micro-surface production
Ink-jet nozzle
Photograph of micro holes
Cylindrical micropin DC current Pulse current
EMM applicationsEMM applications
Micro gear pattern
12. Electrodischarge machining (EDM)Electrodischarge machining (EDM)
Electrical Discharge Machining (EDM) is a non-conventional
machining technique in which the material is removed by the erosive
action of electrical discharges (sparks) provided by a generator.
Benefits
Widely accepted production technology
- 2% of worldwide machining.
High surface finishes
Hardness of material not a concern
Odd/Delicate shapes easier to produce
Small holes easy to produce
Heat treatment usually unnecessary
Drawbacks
Slower machining time
Surface integrity effects
14. Different Types of EDMDifferent Types of EDM
Die-sinking EDM
Wire EDM
Machinable material
» electrically conductive
» semiconductor
materials
Schematic illustration of EDM system Principle of WEDG
Can be made
»
micro shafts
»
micro holes
»
other complex
shapes
15. Micro-electrodischarge machining (MEDM)Micro-electrodischarge machining (MEDM)
It is required for micro-machining to maintain the
energy of a single discharge in the order of 10-6
J to10-7
J
E =1/2 (C + C') V 2
Reducing the discharge energy:
» By reducing the discharge voltage
» By reducing the total capacitance
(C + C')Effective discharge control can be achieved,
by Controlling parameters:
» Discharge current
» Open circuit voltage
» Off-time
» Polarity of electrode
Description of eroding pattern and
overlapping pattern of discharge
16. MEDM applicationsMEDM applications
. MEDM of ceramics
Cross-sectional shape on the TiN coating
and the EDMed surface
Micro-electrodes for and micro-pins
Fabrication of Micronozzle
Micro-hole drilling
positive polarity negative polarity
18. Laser machining (LM)Laser machining (LM)
– Heat treatment
– Welding
– Ablation
– Deposition
– Etching
– Focused beam milling
Laser applicationsLaser applications
Setup of the laser micro-machining
Highly focused optical energy of Laser is used to melt
and evaporate workpiece portions in a controlled
manner.
- Refectivity and thermal conductivity of workpiece are important
- Widely used in automotive and electronics industries due to its
accuracy, reproducibility, flexibility, ease of automation.
19. LMM applicationsLMM applications
» Micro-machining of electrostatic electron lenses
» Ink-jet printer nozzles
» Micro-hole drilling
» Micro-channels produced by mask projection
» Manufacturing of 3D structures
Example geometries in WC/Co
Ink-jet printer nozzles
Micro-channelsMicro-holes
20. Ultrasonic machining (USM)Ultrasonic machining (USM)
Ultrasound - above 20 kHz, can be
generated using peizoelectric or
magnetostictive effects
- A formed tool, with the shape of the
cavity to be machined is made to
vibrate against the workpiece surface
and between the two are placed
abrasive particles (slurry).
- The material is removed in the form
of grains by shear deformation,
brittle fracture of work material; and
by impact, cavitation and chemical
reaction
Principle of USM
21. Micro-ultrasonic machining (MUSM)Micro-ultrasonic machining (MUSM)
Micro USM procedure
MUSM toolsMUSM tools
The WEDG/EDM combination is used to
generate co-axial micro-tool first, which
MUSM of brittle materials carried out
Non-thermal, non-chemical and thus can produce a high-quality
surface finish
The machining procedure of microtool
22. MUSM applicationsMUSM applications
» Micro-hole drilling» Micro-hole drilling
The entrance The exit
Micro air turbine.Center
pin diameter 70 µm;
rotor diameter 350 µm
Finishing
» Manufacturing of 3D s
tructures
» Manufacturing of 3D s
tructures
» Finishing EDMed parts» Finishing EDMed parts
23. Chemical machining (CM))Chemical machining (CM))
# Chemical milling
# Chemical blanking
# Photochemical blanking
Used to make precise,
microscopic holes
microscopic grooves
Material removal from the surface by controlled chemical
dissolution using reagents, etchants- acids/alkalies
» Dry chemical etching
» Wet chemical etching
26. FUTURE POTENTIALFUTURE POTENTIAL
The use of ultra-short pulses
in EMM, MEDM & Laser to
machine the widest choice of
materials with very high
quality.
Studying the effect of
machining parameters on
surface integrity of micro
component.
Newest hybrid processes are
suggested for micro-
machining.
• EMM with Laser Assistance
(EMML)
• EMM with MEDM
• MUSM with EMM & MEDM
28. NanomachineryNanomachinery
Aerospace: Gyroscopes, transducers
Biomedical: DNA detection/separation devices
Molecular: sieves for protein sorting
Electronics: Flexible (paper like) displays,
nanowires
Automotive: Accelerometers, pressure sensors
Healthcare: Nanotherapeutic devices, catheters,
infusion pumps, intrauterine products
Industry Application ExamplesIndustry Application Examples
29. NanomachineryNanomachinery
Scanning probe microscopes have been used for
the machining of nanofeatures ranging from
~100 nm down to atomic dimensions
Various approaches used are based on
lithography, atomic and molecular level
manipulation and material transfer, material
modification by tip induced oxidation desorption
hydrogenation or decomposition mechanical
scratching of metals semiconductors and
polymers.
Nano Machining Using
SPM
Nano Machining Using
SPM
30. NanomachineryNanomachinery
Bottom-up processes Top-down processes
Contact printing, Imprinting
Template growth
Spinoidal
wetting/dewetting
Laser trapping/tweezer
Assembly and joining (Self-
and directed assembly)
Electrostatic (coatings and
fibres)
Colloidal aggregation.
Lithography (E-beam, ion
beam, Scanning probe,
optical near field)
Energy beam machining
(Laser, electron beam, ion
beam)
Erosive processes (electrical,
chemical, mechanical and
ultrasonic)
Typical nanomachining processes
*SEM micrographs were obtained for showing the fracture surfaces of specimens failed in air and argon.
*The first graph (3.a) shows the fracture surface in air. It can be seen, some inclusions as well as number of secondary cracks.
*The second graph (3.b) shows fracture surface in argon. It can be seen, the specimen has revealed more ductile manner, where primary and secondary striations are observed.
*The third graph (8.a) shows with high magnification the fracture surface failed in air. Some crystallographic fracture modes were observed. The size and density of striations yielded on the fracture surfaces indicate the amount of plasticity associated with crack growth.
*The forth graph (8.b) shows also with high magnification that the fracture surface failed in argon. It is clear, this surface exhibits more ductility than that tested in air.
*It can be seen that some cavities have nucleated very close to the crack tip and these nucleated cavities are linked together to form a very fine crack.
*Cavity nucleation and linkage were obvious to be the dominant fracture mechanism in the very early stages while local strain softening were believed to be the dominant mechanism at the very late stages of the fracture lifetime.
*It is suggested for bending fatigue testes that, the fatigue life of the specimens were consumed mostly by initiating a crack of a critical size and thus the propagation will consume short time duration.
