1. The document describes micro slit machining using electric discharge machining (EDM) with a modified rotary disk electrode.
2. Key findings include that a negative polarity workpiece, discharge current of 0.1 A, and pulse duration of 5 μs produced the highest material removal rate of 1.5 mm3/min for machining titanium alloy.
3. The modified EDM technique using a rotating disk electrode located below the workpiece improved debris removal and allowed high-precision micro slits with a width variation of ±1 μm to be produced in titanium alloy.
In this work, i have described the importance of TiO2 as a high dielectric material. Later the interface traps and their capture cross section were analyzed by DLTS.
Synthesis, Electrical and Optical Properties of Nickel Sulphate Hexa Hydrate ...IJERA Editor
L-Arginine doped Nickel SulphateHexa Hydrate (NSH) single crystalswere grown by slow evaporation
techniquefor different molar concentrations, viz., (0.2 to 1 mole% in steps of 0.2).The grown crystals were
subjected to various studies.XRD data were collected from powder samples of the crystals.ACelectrical
measurementswerecarriedoutatvarioustemperaturesrangingfrom40-750C. Resultsindicate anincrease
oftheelectricalparameterswiththeincreaseoftemperature.The dielectric value suggests that the L-Arginine doped
NSH single crystal is good for microelectronic application. The UV-Vis-NIR spectral studies were performed to
analyze the optical absorption of the grown crystals in the range 200 – 1100nm. Results obtained were
presented.
Temperature and strain sensitivity of long period grating fiber sensor revieweSAT Journals
Abstract
Long period grating fibers are special class of fibers which are produced by periodic modulation of the refractive index of the core. This perturbation leads to forward guiding mode to couple with co propagating cladding modes depending on the phase matching condition. This coupling causes the cladding modes to attenuate during propagation in the fiber and leads to dips in the attenuation bands at discrete wavelengths in the transmission spectrum. These bands are shifted when the LPG is exposed to temperature, strain, refractive index changes in surrounding environment etc. This forms the basis of LPG sensor. The properties of LPG are modified in order to achieve the required sensitivity towards any measurands as per the applications. The performance of LPG by modifying the properties of LPG is reviewed.
Keywords: Optical fiber, Optical fiber sensor, Fiber Bragg, Long period grating, Strain, Temperature
Er-Er interactions in yttrium-erbium compounds thin filmsRoberto Lo Savio
Er-doped materials are extensively studied in Si-based photonics, owing to the capability of Er ions to emit and absorb photons at discrete wavelengths, extending from the ultraviolet to the infrared. However the maximum Er amount that can be introduced as a dopant in a solid host is limited to about 10^20 at/cm3 owing to the low solid solubility. Such a limit can be overcome in mixed Y-Er compounds: given the strong similarities between Y and Er compounds, the Er amount can be varied with continuity in a wide range, extending from the low values typical of a doping condition to the extreme values of Er compounds (about 10^22 at/cm3). However the Er content increase certainly leads to the occurrence of Er-Er interactions that determine a strong modification of the emitting properties of the Er ions. We have studied the influence of such interactions in both oxide Y2-xErxO3 and disilicate Y2-xErxSi2O7 thin films, grown on c-Si substrates by rf magnetron co-sputtering. In both compounds the existence of two well-defined Er concentration regimes (defined as Er-doping and Er compound) has been demonstrated, with a threshold value of about 10^21 Er/cm3. Above this limit, the interactions between the excited Er ions and the Er population in the ground state lead to a fast depletion of the high-energy levels with a consequent refilling of the low-energy ones. Although the interactions occurring in both materials are exactly the same, their effects are different.
Y2-xErxO3 is a low phonon energy host, and then non-radiative phononic decays have low rates: Er-related optical emission both in the visible and in the infrared regions is then observed. In the doping regime a population inversion condition between the first two excited levels is achieved, opening the route for the realization of optical amplifiers, operating at 2.75 um. However when the Er amount is increased (compound regime) the interactions have a detrimental effect, since the condition of population inversion is lost.
In the high-phonon energy host Y2-xErxSi2O7 only Er-related emission at 1.54 um is observed for any x value. In this material the Er-Er interactions are demonstrated to produce a quantum cutting process in which it is possible to excite several Er ions with a single incoming excitation photon. In particular, in the Er-richest film (Er2Si2O7) maximum quantum cutting efficiencies of 400% have been reached. In this regime this material can be exploited therefore in Ge solar cells, thanks to the generation of several infrared photons at expenses of only one incident visible photon.
Method Development for Dynamic Light ScatteringHORIBA Particle
Dr. Jeff Bodycomb from HORIBA Scientific discusses method development for sizing by dynamic light scattering (DLS) and the SZ-100 Nanoparticle Analyzer. This presentation will be useful for those who use DLS to determine nanoparticle size including SZ-100 users and DLS users in general.
Topics to be covered include preparing suspensions, sample filtration (clarification), and particle concentration.
Erbium-rich thin film materials for optical communications in siliconRoberto Lo Savio
Presentation for the Ph.D. thesis defense.
It contains materials about the synthesis and the characterization of rare-earth compounds containing erbium.
In this work, i have described the importance of TiO2 as a high dielectric material. Later the interface traps and their capture cross section were analyzed by DLTS.
Synthesis, Electrical and Optical Properties of Nickel Sulphate Hexa Hydrate ...IJERA Editor
L-Arginine doped Nickel SulphateHexa Hydrate (NSH) single crystalswere grown by slow evaporation
techniquefor different molar concentrations, viz., (0.2 to 1 mole% in steps of 0.2).The grown crystals were
subjected to various studies.XRD data were collected from powder samples of the crystals.ACelectrical
measurementswerecarriedoutatvarioustemperaturesrangingfrom40-750C. Resultsindicate anincrease
oftheelectricalparameterswiththeincreaseoftemperature.The dielectric value suggests that the L-Arginine doped
NSH single crystal is good for microelectronic application. The UV-Vis-NIR spectral studies were performed to
analyze the optical absorption of the grown crystals in the range 200 – 1100nm. Results obtained were
presented.
Temperature and strain sensitivity of long period grating fiber sensor revieweSAT Journals
Abstract
Long period grating fibers are special class of fibers which are produced by periodic modulation of the refractive index of the core. This perturbation leads to forward guiding mode to couple with co propagating cladding modes depending on the phase matching condition. This coupling causes the cladding modes to attenuate during propagation in the fiber and leads to dips in the attenuation bands at discrete wavelengths in the transmission spectrum. These bands are shifted when the LPG is exposed to temperature, strain, refractive index changes in surrounding environment etc. This forms the basis of LPG sensor. The properties of LPG are modified in order to achieve the required sensitivity towards any measurands as per the applications. The performance of LPG by modifying the properties of LPG is reviewed.
Keywords: Optical fiber, Optical fiber sensor, Fiber Bragg, Long period grating, Strain, Temperature
Er-Er interactions in yttrium-erbium compounds thin filmsRoberto Lo Savio
Er-doped materials are extensively studied in Si-based photonics, owing to the capability of Er ions to emit and absorb photons at discrete wavelengths, extending from the ultraviolet to the infrared. However the maximum Er amount that can be introduced as a dopant in a solid host is limited to about 10^20 at/cm3 owing to the low solid solubility. Such a limit can be overcome in mixed Y-Er compounds: given the strong similarities between Y and Er compounds, the Er amount can be varied with continuity in a wide range, extending from the low values typical of a doping condition to the extreme values of Er compounds (about 10^22 at/cm3). However the Er content increase certainly leads to the occurrence of Er-Er interactions that determine a strong modification of the emitting properties of the Er ions. We have studied the influence of such interactions in both oxide Y2-xErxO3 and disilicate Y2-xErxSi2O7 thin films, grown on c-Si substrates by rf magnetron co-sputtering. In both compounds the existence of two well-defined Er concentration regimes (defined as Er-doping and Er compound) has been demonstrated, with a threshold value of about 10^21 Er/cm3. Above this limit, the interactions between the excited Er ions and the Er population in the ground state lead to a fast depletion of the high-energy levels with a consequent refilling of the low-energy ones. Although the interactions occurring in both materials are exactly the same, their effects are different.
Y2-xErxO3 is a low phonon energy host, and then non-radiative phononic decays have low rates: Er-related optical emission both in the visible and in the infrared regions is then observed. In the doping regime a population inversion condition between the first two excited levels is achieved, opening the route for the realization of optical amplifiers, operating at 2.75 um. However when the Er amount is increased (compound regime) the interactions have a detrimental effect, since the condition of population inversion is lost.
In the high-phonon energy host Y2-xErxSi2O7 only Er-related emission at 1.54 um is observed for any x value. In this material the Er-Er interactions are demonstrated to produce a quantum cutting process in which it is possible to excite several Er ions with a single incoming excitation photon. In particular, in the Er-richest film (Er2Si2O7) maximum quantum cutting efficiencies of 400% have been reached. In this regime this material can be exploited therefore in Ge solar cells, thanks to the generation of several infrared photons at expenses of only one incident visible photon.
Method Development for Dynamic Light ScatteringHORIBA Particle
Dr. Jeff Bodycomb from HORIBA Scientific discusses method development for sizing by dynamic light scattering (DLS) and the SZ-100 Nanoparticle Analyzer. This presentation will be useful for those who use DLS to determine nanoparticle size including SZ-100 users and DLS users in general.
Topics to be covered include preparing suspensions, sample filtration (clarification), and particle concentration.
Erbium-rich thin film materials for optical communications in siliconRoberto Lo Savio
Presentation for the Ph.D. thesis defense.
It contains materials about the synthesis and the characterization of rare-earth compounds containing erbium.
Novel Electric Discharge Machining method for better machining AbhishekGupta2133
Alternating Energy EDM is currently a developing type of machining, the results obtained are very enthusiastic.
The usage of the sintered electrode is the main reason for the astonishing results, and it's rotation make it even better.
WC i.e. Tungsten Carbide has high erosion tendency and low resistivity, whereas PCD i.e. Polycrystalline Diamond has low erosion and high resistivity, due to which plasma channel is more likely to form between WC with Workpiece instead of PCD with Workpiece as the gap between WC as well as PCD with Workpiece is same.
But after WC section gets eroded, the gap between WC section with Workpiece is not enough to create and sustain plasma channel, then plasma channel is formed between PCD section with Workpiece and due to low erosion tendency and high resistivity no significant material removal takes place only finishing operation takes place.
After eroding of PCD, Diamonds expose to workpiece and micro grind it.
Material Removal- WC section
Finishing- PCD section
Micro grinding- Diamonds (mechanically)
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
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journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Experimental Investigation of Process Parameters on Inconel 925 for EDM Proce...Vishal Kumar Jaiswal
Experimental Investigation of Process Parameters on Inconel 925 for EDM Process by using Taguchi Method
Research Paper Published by:
Vishal Kumar Jaiswal
M.Tech (Production and Industrial Engineering)
Paper Source:
http://www.ijsrd.com/articles/IJSRDV6I50198.pdf
http://ijsrd.com/Article.php?manuscript=IJSRDV6I50198
Improvement of Surface Roughness of Nickel Alloy Specimen by Removing Recast ...IJMER
In this investigation, experimental work and computational work are combined to obtain
improvement in the surface roughness of nickel alloy specimen, the machining is carried out by means
of CNC wire electric discharge machining (WEDM). Brass wire is used as the tool electrode and nickel
alloy (Inconel600) is used as the work piece material. The machining parameters such as Pulse-On time
(Ton), Pulse-Off time (Toff), Peak Current (Ip), and Bed speed are considered as input parameters for this
project. Surface roughness and Recast layer are considered the output parameters. The experiments
with the pre-planned set of input parameters are designed based on Taguchi’s orthogonal array. The
surface roughness is measured using stylus type roughness tester and the thickness of the Recast layer
is measured using Scanning Electron Microscope (SEM). The results obtained from the experiments are
fed to the Minitab software and optimum input parameters for the desired output parameters are
identified. The software uses the concept of analysis of variance (ANOVA) and indicates the nature of
effect of input parameters on the output parameters and confirmation is done by validation
experiments. Once the recast layer thickness is obtained Chemical Etching and abrasive blasting is
performed in order to remove the recast layer and again the surface roughness is measured by using
stylus type roughness tester. Finally from the obtained results it was found that there was significant
improvement in the Surface roughness of the nickel alloy material. In addition using regression
analysis this work is stimulated by computational method and the results are obtained.
A Literature Review On Dry Wire Electrical Discharge MachiningIJSRD
EDM in gaseous media is one of the fastest growing branches among institutions involved in the research and development of EDM as green manufacturing process Dry EDM is an environmental friendly machining process were liquid dielectric fluid is replaced by gaseous dielectric fluids. Present & past performance of dry EDM process using various types of gases & their mixtures as dielectric medium. Development of Dry EDM Technology enhance the performance parameters such as material removal rate (MRR), Low tool wear rate (TWR), thin recast layer.
Dynamic Monitoring Of Information in Large Scale Power GridsIJSRD
this document proposes the software model for detection and analysis of cascading faults in the operation of large scale power grids. Using data mining technologies, probable patterns can be detected for faults and proper mitigation measures can be taken. Firstly, the fault is detected by checking the stability of system. Then event sequences are calculated to best approximate the fault node. Then by analyzing the severity of vulnerability and region in which vulnerability would occur, proper ICT Technologies can make operators aware about the faults. Hence, speeding up the existing mechanisms. This model aims to solve problem of detection more efficiently than existing systems.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
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Palestine last event orientationfvgnh .pptxRaedMohamed3
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Introduction to AI for Nonprofits with Tapp NetworkTechSoup
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Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
1. Micro slit machining using EDM with a
modified rotary disk electrode(RDE)
H.M. Chow , B.H. Yan , F.Y. Huang
Department of Mechanical Engineering, National Central University, Chung-Li, 32054, Taiwan, ROC
Name : Wen-Chen Huang
ID : M9710108
Date : 2009/5/19
1
3. Abstract
• The effects of polarity, discharge current, pulse
duration and rotational speed on the material
removal rate (MRR), the electrode wear rate
(EWR), the expansion of slit, the surface profile and
the recast layer of micro slit machining are reported
and discussed.
3
4. Introduction
• MEDM equipment is too expensive to be able to be
used widely.
• WEDM suffers from the breakage susceptibility of
the superfine wire.
• This new application of RDE-EDM machining is
achieved by locating the rotating disk electrode
below the workpiece to improve the debris removal
rate.
• The benefits of this modified RDE-EDM also
include the obtain of an improved EDMed circuit
system that reduces the discharge current, and the
offering of a compact designation to stabilize RDE
vibration during machining. 4
5. Experimental procedure
• The modified RDE-EDM developed in this study
consists of a modified non-micro EDM machine (a
die-sinking EDM) with a RDE.
Fig. 1. Schematic diagrams of EDM with:
(a) a conventional RDE
(b) a modified RDE. Note that the relative position of the workpiece
and the RDE is reversed in the modified RDE-EDM. 5
6. Experimental procedure
The RDE-EDM experimental conditions
Conditions
Electrode size Cu, D=ø42 mm, t=25, 50, 75, 100 μm
Workpiece Ti–6Al–4V, t=0.45 mm
Polarity Negative ( - ), positive ( + )
Dielectric Kerosene
Peak current Ip (A) 0.06, 0.1, 0.5
High voltage (V) 280
Gap voltage (V) 25
Duty factor 0.55
Pulse duration τp (μs) 2, 5, 10, 20
Working time (min) 4
Revolutions of electrode (rpm) 0, 10, 20, 50, 150
Target depth 1.02mm
6
8. Results and discussion
Fig. 3. The material removal depth vs. Fig. 4. The electrode wear vs. the rpm
the rpm of the RDE electrode of the RDE electrode with the
with the discharge current as a discharge current as a parameter.
parameter.
8
9. Results and discussion
• (Fig. 3)The former was because the relative motion
between the electrode and the workpiece increased
the debris removal rate, whilst latter might be due
to the large centrifugal force at high rotational
speed that made it difficult for the dielectric fluid to
flow into the gap, thus decreasing the discharge
activity.
• The workpiece was located at the top of the RDE in
the present modified RDE-EDM, thus the debris
removal mechanism was increased not only by the
rotating electrode but also by the gravity of the
debris itself. 9
10. Results and discussion
Fig. 5. The effects of electrode thickness on the material removal depth,
the expansion of the slit, and the electrode wear.
10
11. Results and discussion
• At a discharge current Ip = 0.1A, the discharge
density was too high for an EDM process to be
stable.
• An optimized discharge density could be reached
by using a thicker electrode, the optimized
arrangement possibly allowing the use of a greater
material removal depth and therefore resulting in
less electrode wear.
11
12. Results and discussion
Fig. 6. The material removal depth vs. Fig. 7. The expansion of the slit vs.
the pulse duration for both the pulse duration for both
negative discharge polarity and negative discharge polarity and
positive discharge polarity. positive discharge polarity.
12
13. Results and discussion
• A higher MRR was observed with adopting the
RDE-EDM as the cathode.
• However, in handling the positive-polarity condition,
the dissociated carbons element in the dielectric
fluid tend to adhere to the anode (Ti alloy), which
may form a TiC recast layer by solid solubilization
and then diffuse gradually during sample melting
and solidification in the EDM process.
• This phenomenon may, somehow, reduce the
material removal rate. Furthermore, the melting
point of TiC (3150°C) is about twice that of Ti
(1660°C). It is more desirable to adopt a negative
polarity in a acquiring low EWR and a high MRR. 13
This practice is adopted in the present work.
14. Results and discussion
Fig. 8. Cross-sectional SEMs of micro slits obtained by both positive and
negative discharge polarities for: (a) the outlook of the slit; (b) the
14
bottom of the slit, and; (c) the surface of the slit.
15. Results and discussion
• (a)The depth of the slit was twice the depth with
negative polarity than it was with positive polarity.
• (b)The thermal effect area was smaller and the
recast layer was thinner with negative polarity.
• (c)More sub-crack surfaces are observed with
positive polarity, which is consistent with the lower
MRR associated with positive polarity.
• The deposit carbon reacts with Ti to form TiC which
has a high melting point above 3150°C and requires
a greater energy density to be removed with positive
polarity: this also accounts for lower MRR with
positive polarity. 15
16. Results and discussion
Fig. 9. The material removal depth vs. Fig. 10. The expansion of the slit vs.
the pulse duration with discharge pulse duration with discharge
current as a parameter (the current as a parameter ( the
negative discharge polarity is negative discharge polarity is
adopted). adopted).
16
17. Results and discussion
• Too-long a pulse duration (>6 μs) or too-high a
discharge current (0.5 A) result only in a lower
removal rate and worse surface conditions.
• Only a small slit expansion was obtained at the low
discharge current of 0.06 A and a pulse duration of
2–5 μs with negative polarity.
17
18. Results and discussion
Fig. 11. A photograph of a single-slit Fig. 12. Photograph of a multiple-slit
microstructure. The micro slit microstructure (with 10 slits)18
is compared with a hair.
19. Results and discussion
• The resultant width of the slit was 42 mm, and the
depth was 1.02 mm
• The tolerance of the slit width and slit depth is ±1
μm, and ± 5 μm, respectively.
• The uniform wear in the radial direction was
reduced to 0.02 mm after the carrying out of the
machining of the 10-slit microstructure process.
19
20. Conclusions
1. The modified RDE-EDM can improve MRR by
locating the workpiece above the RDE. EWR also
decreases uniformly around the periphery of the
disk electrode with this modified arrangement. The
position accuracy and vibrational stability of RDE
are improved over those of classical RDE-EDM to
achieve a high standard of micro slit machining.
20
21. Conclusions
2. Although Ti is known to be a difficult material to
cut, an MRR as high as 1.5 mm3 /min-1 is
demonstrated in this study with the modified RDE-
EDM, using the optimum working condition at 10–
20 rpm, a discharge current of 0.1 A, and a pulse
duration of 5 μs.
3. Optimized discharge current is essential because
the temperature during discharge is extremely
sensitive to the discharge current due to the small
area of the micro slit. A greater MRR and lower
EWR can be obtained by properly optimizing the
discharge current.
21
22. Conclusions
4. Negative polarity for the workpiece was adopted
for the present micro machining. A greater MMR
and lower EWR in the machining of the Ti alloy
process was observed under such working
polarity.
5. The finished surface of the slit shows less
cracking, less recast layer and a smaller
expansion of the slit with negative polarity which
later is recommended for further work in this and
similar fields. However, the cracking, the recast
layer, and the expansion of the slit all increase as
pulse duration increase.
22
23. Conclusions
6. The best working conditions are: Ip = 0.06 A;
τp = 2 μm, and; 20 rpm to obtain the smallest slit
width in these experiments. However the optimum
conditions may be different when applied to other
EDM processes. A preliminary calibration of each
EDM process to acquire the optimization is
therefore essential in applying this new technique.
23