meo16 a19

RECENT DEVELOPMENTS IN ELECTROCHEMICAL MICROMACHINING.

A TERM PAPER SUBMITTED IN FULFILLMENT OFTHE REQUIREMENTS FOR THE COURSE

NON-TRADITIONAL MACHINING (MEC442) IN MECHANICAL ENGINEERING

SUBMITTED BY SUBMITTED TO

M.GOPI KRISHNA Mr. JASVINDER SINGH10907035 (Assistant Professor)RME016A19 Dept. Of Mechanical Engineering

DEPARTMENT OF MECHANICAL ENGINEERING (2009-2013)

LOVELY PROFESSIONAL UNIVERSITY

JALANDHAR– 144403

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Acknowledgements

I place on record and warmly acknowledge the continuous encouragement, invaluable supervision, timely suggestions and inspired guidance offered by our guide Mr. JASVINDER SINGH, Mechanics department, in bringing this report to a successful completion.

I am grateful to Prof. Gurpreet Singh Phull, Head of the Department of Mechanical Engineering, for permitting me to make use of the facilities available in the department to carry out the project successfully. Last but not the least I express my sincere thanks to all of my friends who have patiently extended all sorts of help for accomplishing this undertaking.

Finally I extend my gratefulness to one and all that are directly or indirectly involve in the successful completion of this TERM PAPER work.

M.Gopi Krishna (10907035)

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Abstract

Electrochemical Micro-Machining appears to be very promising as a future micro and Nano machining technique since in many areas of applications it offers several advantages. In this paper, a review is presented on current research, development and industrial practice of micro-ECM for micro and Nano fabrication. New developments in the area of electrochemical micro-machining e.g. micro-electrochemical milling, wire-ECM, solid electrochemical machining, surface structuring and OFLL etc. have also been reported. Future trend of research in the area of utilization of anodic dissolution method for manufacturing of Nano range products are also highlighted. The electrochemical micro machining can effectively be used for high precision machining operations. Further research activities of ECM will open up many challenging opportunities for effective utilization of ECM in the micro machining and Nano fabrication domain.

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CONTENTS

Description Page no.

ACKNOWLEDGEMENT………………………………………….. 2ABSTRACT ………………………………………………………… 3CONTENTS…………………………………………………………. 4LIST OF FIGURES............................................................................. 5LIST OF TABLES.............................................................................. 5CHAPTER-1 INTRODUCTION………………………………….... 61.1 EXPERIMENTAL SET-UP AND PRINCIPLE OF ECM......................................................................................... 81.2 ECM MACHINE PARAMETER.................................................. 91.2.1 SERVOSYSTEM........................................................................ 91.2.2 ELECTROLYTE........................................................................ 91.2.3 TOOL FEED RATE................................................................... 101.2.4 TEMPERATURE CONTROL.................................................... 101.2.5 MATERIAL REMOVAL RATE............................................... 101.2.6 TOOL DESIGN........................................................................... 101.2.7 SURFACE FINISH..................................................................... 111.2.8 PUMPS........................................................................................ 111.3 ECM PROCESS PARAMETERS.................................................. 111.4 Development of Electrochemical Micromachining Setup ...... 121.4 FUNDAMENTAL.......................................................................... 121.4.1(A) Material removal in ECMM................................................... 12 (B) ANODIC REACTION........................................................... 12 (C) MASS TRANSPORT............................................................ 13 (D) ELECTROLYTE................................................................... 14

CHAPTER-2 2.0 DEVELOPMENTS IN ELECTROCHEMICAL MICROMACHINING......................................................................... 152.1 Micro electrochemical Milling ……………………………….. 162.2 Wire Electrochemical Machining …………………………….. 172.3 Solid electrochemical machining……………………………… 172.4 Oxide film laser lithography (OFLL) by EMM……………….. 182.5 Micro and Nanometer Scaled Surface Structuring……………. 182.6 EMM for nano-fabrication……………………………………... 19

CHAPTER-3 CONCLUSION............................................................... 20

CHAPTER-4 REFERENCES................................................................ 20

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LIST OF FIGURES:-No. Description. Page No

Figure 1:---------------------- Schematic View of EMM------------------- 6Figure 2:---------------------- Before Machining ------------------- 7Figure 3:---------------------- After Machining ------------------- 7Figure 4:---------------------- set up of ECMM ------------------- 8Figure 5:---------------------- Diffusion Layer Thickness------------------ 13Figure 6:---------------------- Micro Hemisphere step-1-------------------- 16Figure 7:---------------------- Micro Hemisphere step-2-------------------- 16Figure 8:---------------------- Micro Hemisphere step-3-------------------- 16Figure 9:---------------------- Schematic Arrangement wire ECMM----- 17Figure 10:--------------------- Ultra sonic Cleaning ------------------- 18Figure 11:--------------------- STM Based ECM ------------------- 19Figure 12:--------------------- Tungsten Tool -------------------- 19Figure 13:--------------------- Structure of Ni -------------------- 19

LIST OF TABLES:-

Table:-1 .......ECM PROCESS PARAMETERS-----------------------------11

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CHAPTER 1

1. Introduction Electrochemical machining (ECM) has seen a resurgence of industrial interest within

the last couple of decades due to its many advantages such as no tool wear, stress free and smooth surfaces of machined product and ability to machine complex shape in electrically conductive materials, regardless of their hardness.

When this ECM process is applied to the micromachining range for manufacturing ultra-precision shape, it is called electrochemical micro-machining (EMM).

Micromachining may literally mean the machining of the dimension between 1 and 999 mm.

However, as a technical term, it also means the smaller amount of machining that cannot be achieved directly by a conventional technique.

Advanced micro machining may consist various ultra precision activities to be performed on very small and thin work pieces in large numbers. Sometimes, when these things are performed with conventional machining techniques, the problem one usually encounters is high tool wear, rigidity and heat-affected zone.

In nonconventional machining most of the machining processes are thermal oriented, e.g. Electro Discharge machining(EDM), Laser beam machining (LBM), Electron beam machining (EBM) etc.

Chemical machining and Electrochemical machining are thermal free processes, but chemical machining cannot be controlled properly in the micro-machining domain.

ECM process is applied to the micro machining range of applications for manufacturing ultra precision shapes; it is called Electrochemical micro machining (EMM).

EMM appears to be a very promising micro machining technology due to its advantages that include high MRR, better precision and control, rapid machining time, reliable and environmentally acceptable.

In recent years, ECM has received much attention in the fabrication of micro parts Following Fig. shows the schematic view of EMM system set up, which consists of

pulsed DC power supply, machine controller, micro tool drive unit, mechanical machining unit and electrolyte flow system etc.

ECM works on the principle of Faradays law i.e. when two conductive electrodes are placed in an electrolyte maintained at low potential difference then there is discharge

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of electrons taking place. When the current is switched on, the electrolyte (NaCl+H2O) gets ionised according to the following relationship,

Thus in ECM of iron, using NaCl as the electrolyte, iron is removed as Fe(OH)2 and sodium chloride is recovered back.

The iron hydroxide produced during the process must be removedContinuously from the electrolyte by filtration before it is recirculated

To exploit full potential of EMM, research is still needed to improve accuracy and compactness.

Removal of material from the work piece during ECM can be calculated from Faraday‘s law of electrolysis as follows..

1.1 Set-up of ECMM

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The machining set-up of ECMM consists of various sub components as shown in Figure-2.

The sub systems are: 1) Work holding platform 2) tool feeding device3) Control system 4) Electrolyte flow system and 5) Power supply system.

Fig.4 Work holding platform consists of two rectangular platforms to hold the work,

which are made of acrylic because of its non-corrosive property. The work is placed in-between two detachable plates which are fastened together by means of screws.

The work holding platform is immersed inside the electrolyte tank during machining. The machining chamber filled with electrolyte, rests on the base and the electrolyte

re-circulation is carried out in the chamber itself. The chamber is clamped to the base. The feeding device actuated with stepper motor moves the tool by receiving the

signals from the control unit. The circumference of the tool is insulated by coating a thin film of wax and paint, to

avoid stray current effect. In the machining process flow of current is only at the tip, hence the tip of the tool is

not insulated or coated. The control system takes care of the entire machining process. It helps in maintaining the electrode gap at a desirable value for obtaining the required

shape. Ammeter is used to check the gap maintained between the tool and the work. When the tool electrode gets in contact with the work, the stepper motor moves it

upward gradually until the contact is broken. The required feed is controlled using number of passes. The tool moves four microns for a single step rotation of the stepper motor. The tool can be moved according to the amount of inter electrode gap required

between the tool and the work piece.

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A pumping system of electrolyte directs the electrolyte to the working zone with a medium velocity and drives out the material removed.

The electrolyte passes through the two nozzles with desired pressure in the machining chamber.

The material removed from the work is dissolved into the electrolyte. The electrolyte is filtered before re-circulated to the chamber by the pump. During the machining operation hydrogen gas is evolved at the tool. The gas bubbles formed act as a short circuiting medium creating micro sparks

which can erode the tool material. Hence, to avoid the micro spark generation, the electrolyte is pumped out at a

moderate pressure and removes the hydrogen gas generated. The different electrolytes that can be used for SDSS machining are HCl or mixture of

brine and H2SO4. The magnetic pump used to circulate the electrolyte is having the flow rate of 16 -

18 lit/min and head of 2.5m. Non continuous pulsed DC supply is used in ECMM. The AC power supply is converted to low voltage pulsed DC power supply using a

pulse rectifier. The voltage and current are set digitally according to the need for the machining. A protective fuse is provided to prevent the short circuit phenomena.

1.2 ECM MACHINE PARAMETERS:1.2.1 SERVO SYSTEM:

The servo system controls the tool motion relative to the work piece to follow the desired path.

It also controls the gap width within such a range that the discharge process can continue.

If tool electrode moves too fast and touches the work piece, short circuit occurs. Short circuit contributes little to material removal because the voltage drop between

electrodes is small and the current is limited by the generator. If tool electrode moves too slowly, the gap becomes too wide and electrical discharge

never occurs. Another function of servo system is to retract the tool electrode when deterioration of

gap condition is detected. The width cannot be measured during machining; other measurable variables are

required for servo control.1.2.2 ELECTROLYTE:

The electrolyte is essential for the electrolytic process to work. The electrolyte has three main functions in ECM. These three functions are:

1. It carries the current between the tool and the workpiece.2. It removes the products of machining from the cutting region.3. It dissipates heat produced in the operation.

Electrolytes must have high electrical conductivity, low toxicity and low corrosiveness.

The electrolyte is pumped at about 14kg/cm2 and at speed of at least 30 m/s.1.2.3 TOOL FEED RATE:

In ECM process a gap of about 0.01 to 0.07 mm is maintained between the tool and the work piece.

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For smaller gap, the electrical resistance between the tool and work is least and the current is maximum and accordingly maximum metal is removed.

The movement of the tool slide is controlled by a hydraulic cylinder giving some range of feed rate.

1.2.4 TEMPERATURE CONTROL: The temperature of the electrolyte must be constant so that variation in conductivity

will not occur. If the temperature of the electrolyte is low it means lower rate of metal removal and if

it is higher temperature may lead to the vaporization of the electrolyte. Therefore temperature of electrolyte must be maintained between 25° and 60°.

1.2.5 MATERIAL REMOVAL RATE: It is a function of feed rate which indicates the current passed between the work and

the tool. As the tool advances towards work, gap decreases and current increases which

increases more metal at a rate corresponding to tool advance. A stable spacing between tool and work is thus established. It may be noted that high feed rate not only is industrious but also produces best

quality of surface finish. However feed rate is restricted by removal of hydrogen gas and products of

machining. Metal removal rate is lower with low voltage, low electrolyte concentration and low

temperature.1.2.6 TOOL DESIGN:

As no tool wear takes place, any good conductor is applicable as a tool material, but it must be designed strong enough to withstand the hydrostatic force, caused by electrolyte being forced at high speed through the gap between tool and work.

The tool is made hollow for drilling holes so that electrolyte can pass along the bore in tool. Cavitations, stagnation and vortex formation in electrolyte flow must be avoided because these result a poor surface finish.

It should be given such a shape that the desired shape of job is achieved for the given machining condition.

Both external and internal geometries can be machined with an electrochemical machine.

Copper is often used as the electrode material. Brass, graphite, and copper-tungsten are also often used because of the ability to be

easily machined, they are conductive materials, and they will not corrode.There are two major aspects of tool design. These are :-

1. Determining the tool shape so that the desired shape of the job is achieved for the given machining conditions.2. Designing the tool for considerations other than e.g. electrolyte flow, insulation,

strength and fixing arrangements.

1.2.7 SURFACE FINISH:ECM can produce surface finish order of 0.4 μm by turning round of tool or work. Anydefect on tool face produce replica on work piece. Tool surface should therefore be polished.The finish is better in harder material. For optimum surface finish, careful electrode design,maximum feed rate, and surface improving additives in electrolyte are selected. Low

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voltage decreases the equilibrium machining gap and result in better surface finish andtolerance control. Low electrolyte concentration decreases the machining gap and gives thebetter surface finish. Low electrolytic temperature also promotes better surface finish.1.2.8 PUMPS:Single or multi-stage centrifugal pumps are used on ECM equipment. A minimum flow rate15 litres/ min per 1000 A electrolyzing current is generally required. A pressure of 5-30kg/cm2 meets most of the requirements of ECM application.

1.3 ECM PROCESS PARAMETERS

Table.1

1.4 Development of Electrochemical Micromachining (ECMM) Setup1.4.1 FUNDAMENTALS OF ECMM

ECMM works on the principle of faraday’s laws of electrolysis for the removal of material.

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The removed material is flushed out using electrolyte jet. The gap between the work piece and micro tool is accurately controlled and the tool is

fed accordingly. Finely, negative shape of tool is created in the workpiece. The way of material

removal, anodic reactions, mass transport and electrolyte circulation is described here.A. Material removal in ECMM

In the machining region where the workpiece directly faces the cathode tool, the anodic reaction rate is constant for a constant Inter- Electrode Gap (IEG) and the electrolyte conductivity.

The machining performance is influenced by various predominant process parameters, such as current density, IEG, electrolyte flow rate, concentration and type of electrolyte, and also the anode reactions.

If IEG is reduced, the resolution of machining shape becomes better. Material removal is maximum for small IEG. Experimental results have proved that the addition of a magnetic field causes increase

in material removal rate and accuracy. The material removal rate is expressed in terms of unit removal (UR) in the

micromachining domain. UR is defined as a unit of work piece removed during one cycle/pulse ofMachining.

B. Anodic reaction Depending on the operating conditions and metal electrolyte combinations, different

anodic reactions take place at high current densities. The rates of these reactions are dependent on the ability of the system to remove the

reaction products as soon as they are formed and supply fresh electrolyte to the anode surface.

All of these factors influence the machining performance, namely dissolution rate, shape control and surface finish of the workpiece.

The current efficiency of metal dissolution, ŋ is related to weight loss, Δw by

ŋ = ΔwZF/ Itawhere I is the applied current,

t is the machining time, F is Faraday’s constant, Z is the valence of metal dissolution and a is the mol. weight of the metal.

Actually, the dissolution valence v will influence the metal removal and is related to the UR as follows:

UR =I a ŋ/pZFAᵨwhere

ᵨis the density in g/m3, A is the surface area in m2 and p is the number of pulse/unit time.

Current efficiency for metal dissolution, which is a function of current density and local flow conditions, varies as a function of distance from the tool.

C. Mass transport Mass transport processes influence the EMM performance in several ways.

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First, they influence the maximum rate of an electrodissolution reaction, thus giving rise to a so called limiting current;

second, mass transport-controlled anodic reactions affect the morphology of dissolved surfaces; and finally, mass transport processes influence the macroscopic and microscopic current distribution on the workpiece.

An understanding of mass transport effects are, therefore, a prerequisite for the development of ECMM processes.

During anodic dissolution, the concentration at the anode surface can be significantly different from that of the bulk.

These concentrations are mainly determined by the rate of mass transport, transport mechanisms and diffusion layer thickness which play an important role in high-rate anodic dissolution process.

Metal ions produced at the anode are transported into the solution by convective diffusion and migration.

To maintain electroneutrality, electrolyte anions accumulate from the anode to be compensated by the rate of migration towards the anode.

The extent of ion build-up depends on the current density, metal dissolution efficiency, and hydrodynamic conditions.

The Nernst diffusion layer concept has been used frequently to obtain a simplified description of mass transport effects in high-rate dissolution of metals.

A stagnant diffusion layer of thickness ᵟ is thus assumed to exist at the anode as shown in fig.

Fig.5 Inside the diffusion layer, a concentration gradient exists and the transport occurs

exclusively by diffusion. Outside the diffusion layer, transport occurs by convection and the electrolyte

concentration is assumed to be constant. For an anodic reaction that is controlled by convective mass transport, the anodic

current density, I, is given by

Where D is the effective diffusion coefficient that takes into account the contributions from transport by migration, CS is the surface concentration, Cb is the bulk concentration, and

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ᵟ is the diffusion layer thickness. Current distribution and accuracy of the job can be affected by the mass transport

conditions. An increase in current density leads to an increase in the rate of metal dissolution at

the anode. In anodic dissolution, salt film mechanism and acceptor mechanism have been

identified for mass transport. In the salt film mechanism, the rate of transport of dissolution products from the

anode surface is rate limiting. In high rate anodic dissolution in neutral Nerst diffusion layer concept describing

mass transport at the dissolving anode surface. A typical anodic polarization curve exhibiting a limiting current is also included

electrolyte, the transport of reaction products away from the anode is rate limiting and salt film precipitation occurs at the surface of the anode.

In the acceptor mechanism, the limiting factor is the rate of transport towards the anode of acceptor types such as complexing ions; these varieties react with the dissolved metal ions to form hydrated complex ions.

In EMM, a smooth surface finish can be achieved only at limiting current density. If the current density is too high, it may cause the formation of heat-affected zones,

and it finally results in improper surface finish and low accuracy. The limiting current density is governed by convective mass transport; the anodic

limiting current density J is given by

where D is the effective diffusion coefficient, which takes into account the contribution from

transport by migration, Cs is the surface concentration, v is velocity flow rate.

D. Electrolyte The electrolyte completes the electric circuit between the tool and workpiece, and

allows the desired machining reactions to occur. It also carries away heat and reaction products from the machining zone. The electrolytes are classified into two categories: passivating electrolytes containing

oxidizing anions, e.g. sodium nitrate, sodium chlorate, and non-passivating electrolytes containing relatively aggressive anions such as sodium chloride. Passivating electrolytes generally give better machining precision.

The electrolyte must possess less throwing power to increase the accuracy. For neutral electrolyte, sodium nitrate is more advantageous than sodium chloride due

to its lower throwing power, and highly controlled metal removal, which increases the accuracy in machining.

Since the precipitate from reaction increases the possibility of short circuit between tool and workpiece, it is preferable to use fresh and clean electrolyte instead of re-circulated one.

The pH value of the electrolyte solution is chosen to ensure good dissolution of the workpiece material during the machining without affecting the tool.

Acidic electrolytes are preferable in micro ECM because they do not create insoluble reaction products.

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It is also usual to use neutral electrolyte such as sodium nitrate. Some chemicals like NaHSO4 can be added with specific concentrations that do not

affect the process adversely. It was also found that hydrochloric acid solution is useful in fine-hole drilling because

it dissolves the metal hydroxides as they are produced. Recently, it was reported that less toxic and dilute electrolyte, 0.1 M H2SO4 can be

applied for the machining of stainless steel with ultra-short pulses. Although resolution is improved at lower concentrations, there is a lower limit to

concentration that can be used. For example, an experiment was attempted unsuccessfully with an electrolyte

concentration of 0.01 M HCl . At this low ionic concentration, the ion- content in the small gap between the

electrodes is insufficient to supply the charge carriers necessary to complete the charging of the double layer capacitance.

It was possible to add small amounts of other ionic species such as NaCl or KCl to the 0.01 M HCl solution to increase the total electrolyte concentration and thus create an environment with enough solution conductivity to support electrochemistry.

For Ni the electrochemical reaction critical point was rather independent of high acid or chloride concentration, i.e. the chemical nature of the electrolyte, and depends mainly on bulk electrolyte conductivity and ionic strength.

CHAPTER 2

2.0 DEVELOPMENTS IN ELECTROCHEMICAL MICROMACHINING

Attempts have been made to utilize micro and nanoscopic anodic dissolution of metals for fabrication of micro and nano features. Principles of ECM have already been successfully demonstrated to machine micro scale features using ultra short pulses. Some of the latest

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Developments in this area are presented here in under.

2.1 Micro electrochemical Milling

Layer by layer micro machining can be achieved for fabricating 3D structure with good surface quality by utilizing controlled movement of the cylindrical micro tool in dilute acidic electrolyte. Figure shows a micro hemisphere on the top of a cylinder, machined in three steps e.g. rough cut for fabricating cylinder and hemisphere with 100 μm diameter on the cylinder and finally finish cut with very fast feed rate for fabricating final shape of the hemisphere with 60 μm diameter. Finish cut should be applied at high speed with short pulse on time. Not only short pulses but also dissolution time can localize electrochemical dissolution.

Fig.6Disk-type electrodes can be applied to machine microstructures without taper. Application of multiple electrodes increases productivity of micro ECM. For the multiple machining without taper, multiple disk-type electrodes are machined by Reverse EDM. Fig. 13 (a, b) shows dual micro columns fabricated on SS 304 work piece by dual disc type electrodes of WC, 45mm disc and 20 mm neck.

Fig.7 Fig.8

2.2 Wire Electrochemical Machining

Microware of less than 10 mm can be utilized as tool in wire ECM. In ECM, there is no tool wear during machining. Hence wire is not worn out and very thinner wire can be used and also wire feeding is not essential. Figure exhibits schematic arrangement of wire ECM.

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Wire ECM can be applied to fabricate micro grooves. Fig. 14 (b) shows microgrooves machined by wire ECM. Complex profile of micro-grooves can also be generated by wire-ECM.

Fig.92.3 Solid electrochemical machining

Solid electrochemical machining involves an anodic electrochemical reaction at the micro-contact between the metal substrate and ion conductor i.e. Na-_”-Al2O3 pyramid. The metal substrate is locally incorporated into the ion conductor in the form of metal ions via the micro contact under a DC bias source at 523 ~ 873 K below the melting temperature of the target metal. Solid electrochemical machining has also been performed using an ion conducting polymer coated tungsten needle microelectrode at ambient temperature. As is well known, Nafion has high proton conductivity at room temperature. Moreover, a variety of metal ions can travel in Nafion in place of protons. In contrast, the present development employs a tungsten (W) microelectrode coated with a polymer electrolyte layer, as depicted in Figure.

The shape of the apex of an ion conductor can be directly transferred to the metal surface because the solid electrochemical reaction proceeds only at the solid-solid micro contact of the polymer and target metal plate. Hence, the aspect ratio of the machined surface can be easily designed by the apex configuration of the polymer layer. It has been demonstrated that many different kinds of metal substrates can also be machined and submicron resolution can be achieved at room temperature as shown in Figure.

2.4 Oxide film laser lithography (OFLL) by EMM

Complex photo resist masking process in lithography can entirely be eliminated by the application of laser hybrid ECM. Titanium is anodized using sulfuric acid electrolyte. The oxide film is irradiated using a well-focused laser beam (10μm) to form a pattern on the oxide

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film of thickness 200-300nm on titanium base. Dissolution is localized at the irradiated areas, the remainder of the oxide film acting as a mask. The photo resist could be entirely eliminated. After anodic dissolution, the freestanding oxide film at the edge of machined cavities is removed by ultrasonic cleaning as shown in Figure.

Fig.10The OFLL technique is better adapted for fabricating multilevel structures since it does not require application of a photo resist. After fabrication of the first level, the sample is anodized again and the second level pattern is produced by selective laser irradiation of the oxide, followed by anodic dissolution of the irradiated areas.

2.5 Micro and Nanometer Scaled Surface Structuring

The surface topography of biomedical implants plays an important role for cell attachment and differentiation. Surface topography at the nanometer scale is thought to be at least as important for cell response as micrometer scale topography. For titanium, chemical etching in hot sulphuric and hydrochloric acid based electrolytes can produce roughness on a sub micrometer scale. By superposing this type of nano-roughness with electrochemical micro structuring one can produce surfaces with controlled roughness at two different scales. An example of such a surface is exhibited in Figure. The ability to fabricate well-defined surface topographies will be useful for better understanding of the complicated interactions of living cells with implant materials.

2.6 EMM for nano-fabrication

In Scanning Tunneling Microscope (STM) based ECM, reactions are confined to the tunneling region due to depletion of electrolyte in the tip-surface gap. Using STM based

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ECM micro-grooves with sub micron width can be fabricated with machining precision below 100 nm as shown in Figure.

Fig.11STM has also been used as tool for nano-structuring of electrode surface by the application of 500ps voltage pulses. A tungsten tool of complex shape with rounded features was produced by focused ion beam milling and utilized for single step electrochemical machining for generating nano-structures in Nickel using ultra short voltage pulses as shown in Figure. The structure of 400 nm was machined into the nickel surface in 105 seconds which is much faster than the time required to machine the tool itself.

Fig.12 Fig.13

CHAPTER 3CONCLUSION:-The term paper presents research achievements and industrial applications created in micro and nano scale machining using ECM. Results of recent research indicate the applications of

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electrochemical metal removal in micro and nano-machining offers many opportunities that have been unexplored till now. Further research activities in the area of ECM for effective utilization in micro and nano-fabrication require improvements in tool design and development, monitoring and control of the inter electrode gap, control of material removal and accuracy, efficient power supply, elimination of micro sparks in IEG and selection of suitable electrolyte which are expected to enhance the applications of ECM technology in modern manufacturing industries engage in ultra precision machining. Extensive research efforts and continuing advancements in this area will make the process more efficient and effective. The increasing demands for precision manufacturing of micro parts and nano-features for biomedical components, automotive components and IT applications will lead modern manufacturing engineers to utilize ECM technique more successfully considering its advantages. Electrochemical micro-machining will be more popular in the near future in the area of micro and nano fabrication due to its quality, productivity and ultimately cost effectiveness.

CHAPTER4REFERENCES:-

Bhattacharyya, B., and Munda, J., 2003, “Experimental investigation on the influence of electrochemical machining parameters on machining rate and accuracy in micro machining domain”, Int. J of Machine tools & Manufacture,43, pp. 1301-1310.

De Silva, and McGeough, J.A., 1998, “Process monitoring of electrochemical micro machining”, Int. J. of Materials processing technology, 76, pp. 165-169.

Masuzawa, T., and Tonshoff, H.K., 1997, “Threedimensional micro machining by machine tools”, Annals of CIRP, 46 (2), pp. 621-628.

Masuzawa, T., 2000, “State of the art of micro machining”, Annals of CIRP, 49 (2), pp. 473-487.

Taniguchi, N., 1983, “Current status in, and future trends of ultra- precision machining and ultrafine material processing”, Annals of CIRP, 32 (2), pp. 573-582.

Rajurkar, K.P., Zhu, D., McGeough, J.A., Kozak, J., and De Silva, A., 1999, “New developments in electrochemical

machining”, Annals of CIRP, 48 (2), pp. 567-579.

Datta, M., Shenoy, R.V., and Rominkiw, L.T., 1996, “Recent advances in the study of electrochemical micro machining”, Transactions of ASME, 118, pp. 29-36.

Van Osenbrugger, C., and de Regt, C., 1985, “Electrochemical micro machining”, Philips tech. rev., 42, pp. 22-32.

Datta, M., and Romankiw, L.T., 1989, “Applications of chemical and electrochemical micro machining in the electronic industry”, J. of electrochem. Soc., 136, pp. 285c.

http://www.intechopen.com/books/ cutting-edge-research-in-new-technologies/some-contributions-at-the-technology-of-electrochmical-micromachining-with-ultra-short-voltage-pulse

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