Fabrication of EDM Tool Using Rapid Prototyping and Electroforming

7/21/2019 Fabrication of EDM Tool Using Rapid Prototyping and Electroforming

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Fabrication of EDM Tool using Rapid Prototyping and

Electroforming

CAPSTONE PROJECT

Submittedin Partial Fulfillment of the

Requirement for Award of theDegree

Of

BACHELOR OF TECHNOLOGY

In

MECHANICAL ENGINEERING

By

Name Reg No.AKSHAY WAHI 11008401BALDEEP SINGH 11000061DAKSH SHARMA 11000476

RAJNISH MISHRA 11000737VARDHAN MAHENDRU 11001825

Under the Guidance

ofMr. HARPINDER SINGH

SANDHU

DEPARTMENT OF MECHANICAL ENGINEERING

LOVELY PROFESSIONAL UNIVERSITY

PHAGWARA, PUNJAB (INDIA) -144402

2014


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Lovely Professional University Jalandhar,

Punjab

CERTIFICATE

We hereby certify that the work which is being presented in the Capstone

project/Dissertation entitled Fabrication of EDM tool using Rapid Prototyping

and Electroforming in partial fulfillment of the requirement for the award of

degree of Bachelor of Technology/Master of Technology and submitted in

Department of Mechanical Engineering, Lovely Professional University, Punjab is

an authentic record of my own work carried out during period of

Capstone/Dissertation under the supervision of Mr. Harpinder Singh Sandhu,

Assistant Professor, Department of Mechanical Engineering, Lovely Professional

University, Punjab.

The matter presented in this dissertation has not been submitted by me

anywhere for the award of any other degree or to any other institute. .

Date: (Project Members)

Akshay Wahi

Baldeep Singh

Daksh Sharma

Rajnish Mishra

Vardhan Mahendru

This is to certify that the above statement made by the candidate is correct

to best of my knowledge.

SuperviserMr. Harpinder Singh Sandhu


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Acknowledgement

We avail this opportunity to convey our sincere thanks to Mr. Harpinder Singh

Sandhu, our project mentor who helped us to use our skill in the right way by giving

us and by rendering all the possible help from all the sides.

We would also like to thank Mr. Sarbjeet Singh, for his kind co-operation and

noble assistance. We also feel indebted to thank our HOS, Mr. Gurpreet Singh

Phullfor all the help and support without which this project would not have been

concluded.

Thanking You

PROJECT TEAM


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Contents

1.

Introduction

1. Electric Discharge Machining

1. History

2. Principle of EDM

3.

Electric setup of EDM

4.

Mechanism of MRR

5. Methodology

6. Important parameters in EDM

7. Effect of various parameters

8. Current research trends

2.

Rapid Prototyping

1.

Fused deposition Modelling

2.

Selective Laser Sintering

3.

Laminated Object Manufacturing

4. Stereolithography

5.

Why Rapid Prototyping?

6.

Methodology


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3. Electroforming

1. Methodology

2. Current Trends

3.

Applications

2.

Literature Review

3.

Objective of Study

4.

Full Methodology

1. Designing

2.

Fabrication of ABS Component

3.

Application of Conductive Paint

4.

Electroforming

5.

Testing on an EDM Machine

5. Results & Discussions

1. Electroforming Analysis

2. EDM Analysis

6.

Conclusion

7. References


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List of Figures

S.No. Figure Description

I The schematic diagram of vibration assembly

II The electrode setup fixed on the EDM machine

III Mechanism of MRR

IV Working Principle of FDM

V Working Principle of SLS

VI Working Principle of LOM

VII Working Principle of SLS

VIII CAD Drawing of the ABS component in Standard Orientation

IX Detailed sketch of the abs component


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X FDM produced ABS components

XI Brass Conductive Paint from Sugandh Corporation

XII Painting the work pieces using a paint brush

XIII Pieces after painting

XIV Fixture to hold the tool

XV Electroplating Setup

XVI Components after Electroplating with Copper

List of Tables

S. No. Table Description

A. Analysis of different parameters of Electroforming

B. Analysis of Electric Discharge Machining

Chapter 1: INTRODUCTION

1.1 Electric Discharge Machining

Electric discharge machining (EDM), sometimes colloquially also referred to as

spark machining, spark eroding, burning, die sinking or wire erosion, is a

manufacturing process whereby a desired shape is obtained using electrical

discharges (sparks). Material is removed from the work piece by a series of rapidly

recurring current discharges between two electrodes, separated by a dielectric liquid

and subject to an electric voltage. One of the electrodes is called the tool-electrode,or simply the tool or electrode, while the other is called the work piece-electrode,

or work piece.[1]

When the distance between the two electrodes is reduced, the intensity of the electric

field in the volume between the electrodes becomes greater than the strength of the

dielectric (at least in some point(s)), which breaks, allowing current to flow between

the two electrodes. This phenomenon is the same as the breakdown of a capacitor

(condenser) (see also breakdown voltage). As a result, material is removed from


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both the electrodes. Once the current flow stops (or it is stoppeddepending on the

type of generator), new liquid dielectric is usually conveyed into the inter-electrode

volume enabling the solid particles (debris) to be carried away and the insulating

properties of the dielectric to be restored. Adding new liquid dielectric in the inter-

electrode volume is commonly referred to as flushing. Also, after a current flow, a

difference of potential between the two electrodes is restored to what it was before

the breakdown, so that a new liquid dielectric breakdown can occur.

1.1.1 History

The history of EDM techniques goes as far back as the 1770swhen it was

discovered by English scientist, Joseph Priestly. He noticed in his experiments that

electrical discharges had removed material from the electrodes. Although it was

originally observed by Priestly, EDM was imprecise and riddled with failures

.During research to eliminate erosive effects on electrical contacts, the soviet

scientists decided to exploit the destructive effect of an electrical discharge and

develop a controlled method of metal machining. In 1943, soviet scientists

announced the construction of the first spark erosion machining. The spark generator

used in 1943, known as the Lazarenko circuit, has been employed for several years

in power supplies for EDM machines and an improves form is used in many

application. Commercially developed EDM techniques were transferred to a

machine tool. This migration made EDM more widely available and a more

appealing choice over traditional machining processes.

1.1.2 Principle of EDM

In this process the metal is removing from the work piece due to erosion case by

rapidly recurring spark discharge taking place between the tool and work piece.

Show the mechanical set up and electrical set up and electrical circuit for electro

discharge machining. A thin gap about 0.025mm is maintained between the tool and

work piece by a servo system. Both tool and work piece are submerged in a

dielectric fluid .Kerosene/EDM oil/deionized water is very common type of liquid

dielectric although gaseous dielectrics are also used in certain cases.


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Fig. I [1]


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Fig. II [1]

1.1.3 Electric setup of the Electric Discharge Machining

The tool is made up of cathode and work piece is of anode.When the voltage across

the gap becomes sufficiently high itdischarges through the gap in the form of the

spark in interval offrom 10 of micro seconds. And positive ions and electrons

areaccelerated, producing a discharge channel that becomesconductive. It is just atthis point when the spark jumps causingcollisions between ions and electrons and

creating a channel ofplasma. A sudden drop of the electric resistance of the

previouschannel allows that current density reaches very high valuesproducing an

increase of ionization and the creation of apowerful magnetic field. The moment

spark occurs sufficientlypressure developed between work and tool as a result of

which avery high temperature is reached and at such high pressure andtemperature

that some metal is melted and eroded. Suchlocalized extreme rise in temperature

leads to material removal.Material removal occurs due to instant vaporization of

thematerial as well as due to melting. The molten metal is notremoved completelybut only partially. As the potentialdifference is withdrawn, the plasma channel is no

longersustained. As the plasma channel collapse, it generates pressureor shock

waves, which evacuates the molten material forming acrater of removed material

around the site of the spark.


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1.1.4 Mechanism of MRR

The mechanism of material removal of most widely establishedEDM process is the

conversion of electrical energy it intothermal energy. During the process of

machining the sparks areproduced between work piece and tool. Thus eachsparkproduces a tiny crater, and crater formation shown in this Fig. inthe material

along the cutting path by melting and vaporization,thus eroding the work piece to the

shape of the tool.It is well-known and elucidated by many EDM researchers

thatMaterial Removal Mechanism (MRM) is the process oftransformation of

material elements between the work-piece andelectrode. The transformation are

transported in solid, liquid orgaseous state, and then alloyed with the contacting

surface byundergoing a solid, liquid or gaseous phase reaction.

Fig. III[1]


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1.1.5 Methodology

Concept of single variable at a time approach at a time is used tofind out the effect

of inputparameters on the machiningparameters viz; MRR, SR. A series of

experiments wereconducted to study the effects of various machining parametersofEDM. In each experiment, one input variable was variedwhile keeping all other

input parameter at fixed value. Studieshave been undertaken to observe the effect of

selectedparameters viz; discharge current, pulse on time, pulse off time,wire feed,

servo voltage o MRR and SR. Experiments werecarried out on D2 die steel material

as a work-piece electrodeand brass copper as a tool electrode. Distilled water has

beenused as a dielectric fluid throughout the tests.

1.1.6 Important parameters in EDM

On-time or pulse time: It is the duration of time (s) for whichthe current is allowedto flow per cycle. Material removal isdirectly proportional to the amount of energy

applied during thison-time.Off-time Or Pause time: It is the duration of time

between thesparks. This time allows the molten material to solidify and tobe wash

out of the arc gap.Arc Gap: It is the distance between the electrode and the

workpiece during the process of EDM. It may be called as the sparkgap.Duty Cycle:

It is the percentage of on-time relative to totalcycle time. This parameter is

calculated by dividing the on-timeby the total cycle time (on-time plus off-time).

The result ismultiplied by 100 for the percentage of efficiency or the socalled duty

cycle.Intensity: It points out the different levels of power that can besupplied by thegenerator of the EDM machine.Voltage (V): It is a potential that can be measure by

volt it isalso effect to the material removal rate and allowed to per cycle.Voltage is

given by in this experiment is 50 V.

1.1.7 Effect of Various Parameters on MRR and SR

Effect of peak current: To investigate the effect of peakcurrent on MRR and SR,

pulse-on time is varied while keepingother parameters like pulse-off time, servo

voltage, wire feedrate constant.At low pulse duration, the MRR is low and nearly

constant aslow discharge energy is produced b/w the working gap due toinsufficient

heating of work-piece and low pulse duration. Athigh pulse duration, MRR increases

with increase in peakcurrent because of the sufficient availability of discharge

energyand heating of the work-piece material. The small increase incutting speed at

high value of peak current and pulse duration isrelated to inferior discharge due to

insufficient cooling of thework material.The surface roughness is function of two

parameters, peakcurrent and pulse-on time, both of which are function of

powersupply. A rough surface is produced at high peak current and/orpulse-on time.

The reverse is also true. A finer surface texture isproduced at low value of peak


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current and/or pulse duration andvice versa. This is due to because pulse energy per

discharge iscan be expressed as follows: E= u(t).i(t)dtWhere, u(t) is the discharge

duration, i(t) is the dischargecurrent and E is the pulse energy per discharge. Since

thedischarge voltage u(t) stays constant during the discharge pulseduration and

discharge current. Thus from above formula ofdischarge energy we can say at low

value of discharge currentand/or pulse duration discharge energy will be low and at

highvalue discharge energy will be high. But higher dischargeenergy will worsen the

surface roughness because of increase indiameter and depth of the discharge craters

which is inagreement with work carried by Fuzhu Han Et.al. So in order tocontrol

the fine surface we must control the pulse energy perdischarge.Effect on time of

pulse: To observe the effect of pulse-on timeon MRR and SR value of peak current

is varied while keepingthe other parameter like pulse-off time, servo voltage, wire

feedrate fixed.The MRR increases with increase in pulse duration at all valueof peak

current. TheMRR is a function of pulse duration but atlow value of peak current, theMRR is low due to theinsufficient heating of the material and also after pulse

duration,the MRR increases less because of insufficient clearing ofdebris from the

gap due to insufficient pulse interval.Surface roughness increases with increase in

pulse duration atdifferent value of peak current but it is observed that

surfaceroughness at low value of pulse duration and high value of peakcurrent is less

than the at high value of pulse duration and lowvalue of peak current. This is due to

because at low pulseduration materials remove mainly by gasifying and formscraters

with ejecting morphology due to high value of peakcurrent and heat flux in the

ionized channel, which causes thetemperature of the work-piece to be raised or to beeasily exceedthe boiling point. On the other hand long pulse durationremoves

material mainly by melting and forms craters withmelting morphology due to low

value of peak current and heatflux in the ionized channel, which prevents the

temperature ofthe work-piece from reaching a high value Which is inagreement with

the work carried by others.Effect of pulse-off time: The MRR decreases when pulse-

offtime is increased as with long pulse-off time the dielectric fluidproduces the

cooling effect on wire electrode and work materialand hence decreases the cutting

speed.The surface roughnesschanged little even though the pulse-off time

changedcorresponding to a small value of pulse-on time. Mainly surfaceroughness

improves with increase in pulse-off time. The surfaceroughness is high at low value

of pulse-off time, this is due tobecause with a too short pulse-off time there is not

enough timeto clear the melted small particles from the gap b/w the toolelectrode

and work-piece and also not enough time for deionizationof the dielectric: arcing

occur and the surfacebecomes rougher. It is observed that surface roughness

firstdecreaseswith increase in pulse-off time and then increases withincrease in

pulse-off time. This is because more energy isrequired to establish the plasma

channel and there-for there ishigher electrode wear and higher surface


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toughness.Effect of servo voltage: The effect of servo voltage on MRRand Surface

roughness is observed by varying pulse durationwhile keeping other variablelike

pulse-off time, servo voltage,wire feed rate fixed.The MRR increases with increase

in servo voltage and then itstarts to decrease. This is due to increase in servo voltage

resultin higher discharge energy per spark because of large ionizationof dielectric

between working gap. Consequently, the MRRincreases. However, a too high

voltage result in high dischargeenergy per spark which causes unfavorable break

down ofdielectric and large amount of debris between the working gapwhich unable

the material removal rate increases.The surface roughness at low value of pulse

duration withincrease in servo voltage first increases up to 30V and thendecrease

with increase in servo voltage. At high value of pulseduration the surface roughness

continuously decrease withincrease in servo voltage. This is due to because at low

pulseduration the discharge energy is low so melted particles cannotflow out of the

machining zone and impinge on the work-piecematerial and surface roughnessincrease but with increase inmore servo voltage more energy is produced which

leads touniform melting and melted particles flushed out between theworking

gap.Effect of wire feed rate: The MRR increases less or remainsnearly constant with

increase in wire feed rate. The maximummaterial removal rate is obtained at wire

feed rate of 7m/min.

The MRR increases with increase in wire feed rate becausethere is less dissipation to

the surrounding and hence more heatgenerated at spark gap, leading to higher

material removal rate.For further increase in feed rate the cutting speed decrease

dueto the un-flushed debris between the working gap or unwantedmelted particles

between the working gap which form anelectrically conductive path between the

tool electrode andwork-piece, causing unwanted spark between the tool electrodeand

work-piece. Thus only a portion of energy is used in workmaterial removal which

reduces the cutting speed. This is inagreement with work carried out by

others.Surface roughness decreases with increase in wire feed atdifferent value of

pulse on time. With increase in wire feed ratearea of work-piece electrode is small in

comparison with thewire electrode and most heat is generated on the work-

pieceelectrode. So that uniform melting of the work-piece andvaporized or melted

material flush away by the dielectric fluidsufficiently. As a result finish surface isproduced by themachining which is in agreement with the work carried out bythe

others.The present study experimentally is calculated by thedistribution of input

discharge energy of electric dischargemachining, using heat transfer equations. The

results is obtainedby the especially of fraction of energy transferred to the

workpiece.In this work EDM with ultrasonic assisted cryogenically cooledtool

electrode has been successfully performed on M2 HSSwork piece material. The

electrode is wear ratio and surfaceroughness was significantly lower in UACEDM

process incomparison with conventional EDM process and materialremoval rate was


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at par with that of conventional EDM.In this process, the material removal

mechanism uses theelectrical energy and turns it into thermal energy through aseries

of discrete electrical discharges occurring between theelectrode and work piece

immersed in an insulating dielectricfluid. The thermal energy generates a channel of

plasma between the cathode and anode at a temperature in the range of 8000-

12,000oC, initializing substantial amount of heating andmelting of material at the

surface of each pole.

1.1.8 Current Research Trends in EDM

As far as EDM is concerned, two kinds of research trends are carried out by the

researchers viz modeling technique and novel technique. Modeling technique

includes mathematical modeling, artificial intelligence and optimization techniques

such as regression analysis, artificial neural network, genetic algorithm etc. The

modeling techniques are used to validate the efforts of input parameters on output

parameters since EDM is a complicated process of more controlled input parameters

such as machining depth, tool radius, pulse on time, pulse off time, discharge

current, offset depth, output parameters like material removal rate and surface

quality. Novel techniques deal with hour other machining principles either

conventional or unconventional such as ultrasonic can be incorporated into EDM to

improve efficiency of machining processes to get better material removal rate and

surface quality. Novel techniques have been introduced in EDM research since

1996.

1.2 Rapid Prototyping

'Rapid prototyping' is a group of techniques used to quickly fabricate a scale model

of a physical part or assembly using three-dimensional computer aided design

(CAD) data. Construction of the part or assembly is usually done using 3D printing

or "additive layer manufacturing" technology.

The first methods for rapid prototyping became available in the late 1980s and were

used to produce models and prototype parts. Today, they are used for a wide range

of applications and are used to manufacture production-quality parts in relatively

small numbers if desired without the typical unfavorable short-run economics. This

economy has encouraged online service bureaus. Historical surveys of RP

technology start with discussions of simulacra production techniques used by 19th-

century sculptors. Some modern sculptors use the progeny technology to produce

exhibitions. The ability to reproduce designs from a dataset has given rise to issues


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of rights, as it is now possible to interpolate volumetric data from one-dimensional

images.

As with CNC subtractive methods, the computer-aided-design - computer-aided

manufacturing CAD-CAM workflow in the traditional Rapid Prototyping processstarts with the creation of geometric data, either as a 3D solid using a CAD

workstation, or 2D slices using a scanning device. For RP this data must represent a

valid geometric model; namely, one whose boundary surfaces enclose a finite

volume, contain no holes exposing the interior, and do not fold back on themselves.

In other words, the object must have an inside. The model is valid if for each point

in 3D space the computer can determine uniquely whether that point lies inside, on,

or outside the boundary surface of the model. CAD post-processors will approximate

the application vendors internal CAD geometric forms (e.g., B-splines) with a

simplified mathematical form, which in turn is expressed in a specified data formatwhich is a common feature in Additive Manufacturing: STL (stereo-lithography) a

de facto standard for transferring solid geometric models to SFF machines. To

obtain the necessary motion control trajectories to drive the actual SFF, Rapid

Prototyping, 3D Printing or Additive Manufacturing mechanism, the prepared

geometric model is typically sliced into layers, and the slices are scanned into lines

[producing a "2D drawing" used to generate trajectory as in CNC`s tool path],

mimicking in reverse the layer-to-layer physical building process.

Rapid Prototyping has also been referred to as solid free-form manufacturing,

computer automated manufacturing, and layered manufacturing. RP has obvious useas a vehicle for visualization. In addition, RP models can be used for testing, such as

when an airfoil shape is put into a wind tunnel. RP models can be used to create

male models for tooling, such as silicone rubber molds and investment casts. In

some cases, the RP part can be the final part, but typically the RP material is not

strong or accurate enough. When the RP material is suitable, highly convoluted

shapes (including parts nested within parts) can be produced because of the nature of

RP.

There is a multitude of experimental RP methodologies either in development or

used by small groups of individuals. Some common RP Techniques that are

currently commercially available include Stereo-lithography (SLA), Selective Laser

Sintering (SLS), Laminated Object Manufacturing (LOM), Fused Deposition

Modeling (FDM), Solid Ground Curing (SGC), and Ink Jet printing techniques. For

this project, we have fabricated the components from FDM Technique.


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1.2.1 Fused Deposition Modeling

Developed by Stratasys Inc.-constructs parts based on deposition of extruded

thermoplastic materials called FDM process. The build material is heated to 0.5Cabove its melting point so that it solidifies about 0.1 s after extrusion and cold welds

to the previous layers. In this process, a spool of thermoplastic filament feeds into a

heated FDM extrusion head. The movement of the FDM head is controlled by

computer. Inside the flying extrusion head, the filament is melted into liquid by a

resistant heater. The head traces an exact outline of each cross-section layer of the

part. As the head moves horizontally in x and y axes the thermoplastic material is

extruded out a nozzle by a precision pump. The material solidifies in l/10 s as it is

directed on to the workplace. After one layer is finished, the extrusion head moves

up a programmed distance in z direction for building the next layer. Each layer is

bonded to the previous layer through thermal heating.

Fig. IV [2]

Factors to be taken into consideration are the necessity for a steady nozzle speed andmaterial extrusion rate, the addition of a support structure for overhanging parts, and

the speed of the head which affects the overall layer thickness.

1.2.2 Selective Laser Sintering

Developed by Carl Deckard and Joseph Beaman at the Mechanical engineering

department of university of Texas at Austin. SLS uses a carbon dioxide laser to

sinter successive layers of powder instead of liquid. In SLS processes, a thin layer of


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powder is applied by a counter-rotating roller mechanism onto the work place. The

powder material is preheated to a temperature slightly below its melting point. The

laser beam traces the cross-section on the powder surface to heat up the powder to

the sintering temperature so that the powder scanned by the laser is bonded. The

powder that is not scanned by the laser will remain in place to serve as the support to

the next layer of powder, which aids in reducing distortion. When a layer of the

cross-section is completed, the roller levels another layer of powder over the sintered

one for the next pass. (2)

Fig. V [2]

1.2.3. Laminated Object Manufacturing

The LOM processes produce parts from bonded paper plastic, metal or composite

sheet stock. LOM machines bond a layer of sheet material to a stack of previously

formed laminations, and then a laser beam follows the contour of part of a cross-

section generated by CAD to cut it to the required shape. The layers can be glued or


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welded together. The excess material of every sheet is either removed by vacuum

suction or remains as next layers support.(2)

Fig. VI [2]

1.2.4. Stereolithography

Invented by Charle Hull of 3D systems Inc. is the most commercially available andwidely used prototyping machine. This relies on a photosensitive monomer resin

which forms a polymer and solidifies when exposed to ultraviolet (UV) light. The

material used

is liquid photo-curable resin, acrylate. Under the initiation of photons, small

molecules (monomers) are polymerized into large molecules. Based on this

principle, the part is built in a vat of liquid resin.


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The prototype is created by tracing layer cross-sections on the surface of the liquid

photopolymer pool with a laser beam. The beam traces in parallel lines, or

vectorizing first in one direction and then in the orthogonal direction unlike the

contouring or zigzag cutter movement used in CNC machining. An elevator table in

the resin vat rests just below the liquid surface whose depth is the light absorption

limit. The laser beam is deflected horizontally in X and Y axes by galvanometer-

driven mirrors so that it moves across the surface of the resin to produce a solid

pattern. After a layer is built, the elevator drops a user-specified distance and a new

coating of liquid resin covers the solidified layer. A wiper helps spread the viscous

polymer over for building the next layer. The laser draws a new layer on the top of

the previous one. In this way, the model is built layer by layer from bottom to top.

When all layers are completed, the prototype is about 95% cured. Post-curing is

needed to completely solidify the prototype. This is done in a fluorescent oven

where ultraviolet light floods the prototype.

Fig. VII [2]


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1.2.5 Why Rapid Prototyping?

The reasons of Rapid Prototyping are: -

1.

To increase effective communication.2. To decrease development time.

3. To decrease costly mistakes.

4. To minimize sustaining engineering changes.

5. To extend product lifetime by adding necessary features and eliminating

redundant features early in the design.

Rapid Prototyping decreases development time by allowing corrections to a product

to be made early in the process. By giving engineering, manufacturing, marketing,

and purchasing a look at the product early in the design process, mistakes can be

corrected and changes can be made while they are still inexpensive. The trends in

manufacturing industries continue to emphasize the following:

1.

Increasing number of variants of products.

2. Increasing product complexity.

3. Decreasing product lifetime before obsolescence.

4.

Decreasing delivery time.

Rapid Prototyping improves product development by enabling better communication

in a concurrent engineering environment.

1.2.6 Methodology of Rapid Prototyping

The basic methodology for all current rapid prototyping techniques can be

summarized as follows:

1.

A CAD model is constructed, then converted to STL format. The resolutioncan be set to minimize stair stepping.

2. The RP machine processes the .STL file by creating sliced layers of the

model.

3.

The first layer of the physical model is created. The model is then lowered by

the thickness of the next layer, and the process is repeated until completion

of the model.


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4. The model and any supports are removed. The surface of the model is then

finished and cleaned.

1.3 Electroforming

Electroforming is a metal forming process that forms thin parts through electrode

position. The part is produced by coating a conductive layer of liquid metal skin

onto a base form, known as a mandrel, which is removed after forming. The

conductive layer reverse-plaques to the face of the master electroform, and the

mandrel can be parted without the metal coating sticking to it. Ergo, this is the

opposite of electroplating. Subsequent electroforming of mothers and sons can be

accomplished without reverse-plaques to the new parts because the master and

mother can be passivized without precluding conductivity. Passivation precludes

adhesion in either direction. This is in contradistinction to electroplating, in which

the electrodeposit's adhesion to the mandrel is of utmost concern. This process also

differs from electroplating in that the deposit is much thicker than the phases which

are plated and can exist as a self-supporting structure when the mandrel is

removed.[3]

1.3.1 Methodology

In the basic electroforming process, an electrolytic bath is used to deposit nickel or

other electro formable metals onto a conductive patterned surface, such as stainless

steel. Once the deposited material has been built up to the desired thickness, the

master electroform is parted from the premaster substrate. This process allows high-

quality duplication of the premaster and therefore permits quality productionat

low unit costs with high repeatability and excellent process control.

If the mandrel is made of a non-conductive material it can be covered with a

conductive coating. Technically, it is a process of synthesizing a metal object by

controlling the electro deposition of metal passing through an electrolytic solution

onto a metal or metalized form.

The object being electroformed can be a permanent part of the end product or can be

temporary (as in the case of wax), and removed later, leaving only the metal form,the electroform. New technologies have made it possible for mandrels to be very

complex. In order to facilitate the removal of the electroform from the mandrel, a

mandrel is often made of aluminum. Because aluminum can easily be chemically

dissolved, a complex electroform can be produced with near exactness.


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1.3.2 Current Trends

The main advantage of electroforming is that it reproduces the external shape of the

mandrel within one micrometer

Generally, forming an internal cavity accurately is more difficult than forming an

external shape, however the opposite holds true for electroforming because the

mandrel's exterior can be accurately machined.

Compared to other basic metal forming processes (casting, forging, stamping, deep

drawing, machining and fabricating) electroforming is very effective when

requirements call for extreme tolerances, complexity or light weight. The precision

and resolution inherent in the photographically produced conductive patterned

substrate, allows finer geometries to be produced to tighter tolerances while

maintaining superior edge definition with a near optical finish. Electroformed metal

is extremely pure, with superior properties over wrought metal due to its refined

crystal structure. Multiple layers of electroformed metal can be molecularly bonded

together, or to different substrate materials to produce complex structures with

"grown-on" flanges and bosses.

Tolerances of 1.5 to 3 nanometers have been reported.

1.3.3 Applications

In recent years, due to its ability to replicate a mandrel surface precisely atom-by-

atom with practically no loss of fidelity, electroforming has taken on new

importance in the fabrication of micro and nano scale metallic devices and in

producing precision injection molds with micro and nano scale feature for

production of nonmetallic micro molded objects.

A wide variety of shapes and sizes can be made by electroforming, the principal

limitation being the need to part the product from the mandrel. Since the fabricationof a product requires only a single pattern or mandrel, low production quantities can

be made economically.


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Chapter 2: Literature Review

A.E.J. Jon et al[4] describes the development, comparison and validation of a 3-D

model of the electroplating process. It is based on the current density distribution

that is generated using the Finite Element Method (FEM) and is used together with

Faraday's law of electrolysis and various material and electrolyte values to determine

the local plating depth. The quantity of material deposited or plated on to the

work surface is given by Faraday's Law. He verifies it by creating a current density

distribution model of a piston to determine the depth of plating and comparing the

result with Faradays law.

Kumar Sandeep et al[5] has done his research in the past decade for the

development of EDM. His study mainly focuses on the aspects related to the surface

quality and the metal removal rates which are the most important parameters from

the point of view of selecting the optimum condition processes as well as economic

aspects. He shows a series of experiments to depict the MRR as a function

parameters such as time of pulse, effect of servo voltage, pulse off time etc.

John H. Kuzmik et al [5]proposed their work on electroplating on plastics. The

plastic components he used were made up of ABS. he uses the electroless plating

methodology where he describes the various phases to cleanse, etch, preactivate andactivate the ABS components so that they are ready for electroplating.

Kwai Sang Chinet al[6] has worked on the implementation of Rapid Prototyping

Technology as an alternate manufacturing process in Hong Kong. He has

emphasized the critical decision factors in the implementation of Rapid Prototyping.

These factors are classified into four main aspects: - Managerial, Financial,

Technological and Organizational. Each of these factors is important for the

successful implementation of RP Methodology.

C.K. Chua et al[7] has done his research on the effectiveness of Rapid Prototyping,

as an alternate manufacturing process over Investment Casting. IC might beeconomical for the mass production of metal parts with complex and intricate

features, but in case of single part or small quantity production, the relatively long

lead times and the high tooling costs required for the manufacture of metal moulds

for the fabrication of parts can prove to be a hindrance. He has shown that the

application of RP technologies to fabricate complex sacrificial IC patterns can result

in significant reduction in the costs and lead times associated with single part or

small quantity production.


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Danial Ghodsiyeh[8] et al has published his paper on the effectiveness of Electric

Discharge Machining as a non-traditional machining process. He has conducted a

series of experiments machining specimens made up of titanium and zirconium, that

are difficult to machine. He was successful in machining intricate shapes in thespecimens, with intricate shapes, which were otherwise not possible by the use of

conventional machining methods. His research also includes the effect of various

parameters such as servo voltage, peak current, pulse off time, etc. on the material

removal rate and surface roughness of the finished product.

Saeed Daneshmand et al [9] has worked on the machining of NiTi, (an alloy of nickel and

titanium) using Electro Discharge Machining, which is very difficult to machine otherwise

using conventional methods owing to its high hardness and resistance to cyclic loading. His

experiments indicate that the parameters of discharge current, voltage, and pulse on time

have a direct impact on material removal rate (MRR), and with their increase, MRR

increases as well. Tool wear rate (TWR) diminishes with the increase of pulse off time and

discharge current. The analysis of results obtained for surface roughness indicates that

pulse on time and off time have the highest impact on the surface roughness of the

specimen.

Ludmila Novakova-Marcincinova et al [10] contributed by presenting basic

information about common and advanced materials used for realization of products

by Fused Deposition Modeling Rapid Prototyping technology (RPT) application.In

different RPT the initial state of material can come in either solid, liquid or powderstate. In solid state it comes in various forms such as pellets wires or laminates and

their current range materials includes paper, nylon, wax, resins, metals and ceramics.

Common materials used in FDM are ABS plus thermoplastic (Acrylonitrile

Butadiene Styrene), ABS-M30 thermoplastic (acrylonitrile butadiene styrene), ABS-

M30i thermoplastic (acrylonitrile butadiene styrene), ABSi thermoplastic, PC-ABS

thermoplastic (polycarbonate acrylonitrile butadiene styrene), PC thermoplastic

(polycarbonate), PC-ISO thermoplastic, PPSF/PPSU thermoplastic

(polyphenylsulfone). Some advanced materials are variety of ceramic and metallic

materials such as silicon nitrate, PZT, aluminum oxide, hydroxyapatite and stainless

steel for a variety of structural, electro ceramic and bio ceramic applications.

Nenad V. Mandich et al[11] stated that Electroplated chromium deposits rank

among the most important plated metals and are used almost exclusively as the final

deposit on parts. Without the physical properties offered by electroplated chromium

deposits, the service life of most parts would be much shorter due to wear, corrosion,

and the like. Parts would have to be replaced or repaired more frequently, or they

would have to be made from more expensive materials, thus wasting valuable

resources. The thickness of electroplated chromium deposits falls into two

classifications: decorative and functional. Decorative deposits are usually under 0.80


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mm in thickness. Functional hard chrome deposits have a thickness customarily

greater than 0.80 mm and are used for industrial, not decorative, applications. This

research is very useful in electroplating of components and favour many physical as

well as chemical properties.

Jie Liu et al[12]proposed that Dental glass-ceramic restoration materials haveexcellent physical and chemical, mechanical, aesthetic and biocompatibility

characteristic. This is a new forming process based on selective laser sintering (SLS)

technology which is proposed. The research showed that the composite powder of

epoxy resin binder E-12 and K2O-Al2O3-SiO2 series of dental glass ceramics, when

preheating temperature, layer thickness, laser power, scan speed and scan spacing

are, respectively, 30, 358C, 0.08 mm, 21W, 1,800 mm/s and 0.10 mm/s, the relative

densities of dental glass-ceramic parts are relatively high; the mechanical properties

and forming effect are excellent. The relative density and bending strength of SLS

parts under the optimized processing parameters are 37.40 per cent and 2.08 MPa,

respectively.

Prof. Deepa Yagnik[13] performed experiments about the use of RPT inAerospace industry.Aerospace industries are employing FDM technology for

endless applications as it gives most flexibility with a variety of thermoplastics

designed for aerospace applications. Aerospace icons like NASA & Piper Aircraft

employ the most exciting FDM (3D printing) applications in the world. NASAs

Human-Supporting Rover has FDM Parts. . Development of Gas Turbine Research

Establishment (GTRE) flagship product, the Kaveri jet engine, was commissioned

for the HAL Tejas aircraft (a light combat aircraft), which has an all-terraincapability that spans from hot deserts to the worlds highest mountain range.

V. Scott Gordon James M. Bieman et al[14] analyzed that with careful planning

and management, software developers can effectively use rapid prototyping. By

identifying effects mentioned in multiple sources, we are able to extract information

about software products and processes resulting from the use of prototyping, as well

as potential difficulties. They also how the RPT can be effectively used which can

be obtained by Performance issues Avoiding end-user misunderstandings

Improving code maintainability Avoid delivering a throw-away" Budgeting and the

prototype Completion and conversion of the prototype.

K.H. Ho et al[15]proposed work on the inception to the development of die-sinking EDM within the past decade. It reports on the EDM research relating to

improving performance measures, optimizing the process variables, monitoring and

control the sparking process, simplifying the electrode design and manufacture. A

range of EDM applications are highlighted together with the development of hybrid

machining processes. Factors such as Effect of electrical parameters Time domain

Pulse parameters Radio frequency Flushing of dielectric fluid Rotating the electrode

design and manufacture Rapid tooling manufacture.


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Chapter 3: OBJECTIVE OF STUDY

To fabricate an EDM tool of desired shape via alternate non-conventional methods using

concepts of Rapid Prototyping Technology and Electroforming on FDM produced ABS

components.

The procedure to be followed is as follows: -

1.

Making a CAD Model of the component of desired shape.

2.

Converting the file into .STL format

3. Fabricating the components via 3D printers using FDM Technique.

4.

Setting up the electroforming setup.

5.

Getting the components ready for electroforming by applying conductive paint.

6.

Initiating the Electroforming process and noting the effect of change of various

parameters on the thickness of metal plating in the component.

7.

Testing of the components by mounting them on an EDM machine and performing

the EDM process.


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Chapter 4: Full Methodology

Planning phase of the product to be manufactured went on for a week where we

discussed the various shapes suitable for our project. We came up with this model in

PRO ENGINEER Wildfire 5. This particular shape was chosen as it was an unusual

shape for an EDM tool and can be thoroughly studied during electroplating.


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Fig. VIII

Fig IX


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STL file of the design was given to GNA - Institute of Management and Technology

for the 3D printing through FDM process. It took just a couple of hours to complete

the whole process of 3D printing. Our order was ready the very next day.

Fig. X

Then we ordered brass conductive paint from Sugandh Corporation, Mumbai. They

dispatched the paint in about 10 days. By this time we made the whole setup of the

electroplating.


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Fig. XI

For the process of electroplating we bought the following items:-

1.

PVC coated tank

2.

H2SO4

3. Cu2SO4

4. Copper Plates (electrodes)

5. Copper Rods (for holding the components)

6.

Electrode Holder

7. Connecting Wires

8. Connecting Clips

9. Painting Brushes

By the time conductive paint reached we painted the FDM made pieces. We

applied two coatings of the paint on the pieces by regular drying them in

sunlight.


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Fig. XII


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Fig. XIII

Once the pieces were completely painted, we made the setup for electroplating.

Tank was filled with acidic aqueous solution of CuSO4to serve as the electrolyte

in the process and to complete the circuit of the setup.

Copper electrode holders were hanged using copper rods and connecting wires.

Copper electrodes were placed in the holders. We started with plating three

pieces at a time by hanging four electrodes on the sides of the pieces to be plated

as shown in the figures of the setup.

We took help from a group of electrical and electronics engineering students ofLPU who were working on the AC to DC rectifier whose voltage can vary

between 0-50 V and current can vary between 0-100 A.

Then the rectifier was connected with the setup using clips and connecting wires.

Work pieces were made cathode (negatively charged) and copper pieces were

made anode (positively charged).


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Fig. XIV

Fig. XV


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Initially 2V was given to the setup and work pieces were plated for 4 hours.

Then we plated all the pieces by varying voltage, current, concentration of the

solution, time.

Once all the pieces were plated we made a fixture to hold work piece in EDMmachine.

Fixture was made using a metal block as shown in the figure.

Fig. XVI

Then the piece was fixed on the fixture and was installed on the EDM machine.

Then a Die Steel flat (EN-31) was taken to get the impression of the work piece.

This particular grade of steel was chosen as it is very hard and is difficult to

machine using conventional machining methods. It took about 1 hour to get a

clear impression of depth 1 mm. We tried this process for different parameters

and noted the calculations. Here during EDM process, our work piece is now a

tool and die steel flat is a work piece.


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Chapter 5: Results and Discussions

5.1 Electroforming Analysis

S.No. Paint Applied Voltage Conc.

gm/Lt

Time Thickness

Obtained

Mass

Increased by

1. Fully Painted 3 200 7hrs 0.68mm 21.71gm

2. on the outer

surface

2 200 6hrs 0.32mm 6.85gm

3. on the inner

surface

2 200 6hrs 0.36mm 5.31gm


5. on the outer

surface

4 200 8hrs 1.07mm 32.37gm

6. On the outer

surface

4 210 6hrs 0.95mm 21.89gm

7. On the inner

surface

4 210 6hrs 0.89mm 12.71gm


9. On the outer

surface

3 210 8 0.55mm 5.73gm

10. Fully Painted 3 210 8 0.81mm 24.87gm


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5.2 EDM Analysis

S. No. Current

(Amp)

Voltage

(V)

Ton Weight of Electrode Wear

(g/hour)Etb Eta

1 5 30 4 41.73 41.41 0.64

2 5 50 6 43.56 42.86 0.81

3 8 30 5 31.4 30.66 1.48

4 8 40 6 31.3 30.41 1.77

Chapter 6: Conclusion


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After performing this project, we have successfully determined that our

methodology to fabricate EDM tool by Rapid Prototyping and Electroforming was

appropriate. We achieved a maximum thickness of about 900 microns, and thesurface finish was moderate. We optimized the surface finish by varying the

parameters such as voltage and achieved the best results accordingly. The work-

pieces were also successfully tested as electrodes/tools for EDM Process.

From the above results and discussions the following conclusions can be drawn: -

1. The thickness of the electroplated material depends on various parameters

specially voltage and concentration.

2. The surface finish of the electroplated component is best at low voltage and

low current, but in doing so the rate of deposition decreases and the process

takes more time for a particular thickness.

3. At the edges, dendritic structure formation takes place.

4.

The electrode wear increases with increase in current and voltage.

5. As predicted, the finished components used as electrodes for EDM did not

produce any negative results owing to the fact that their core was made up of

ABS. Only one component suffered great wear because of improper

electroplating on one edge.


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References

1. Kumar Sandeep: A Review on the Current Research Trends in Electrical

Discharge Machining.

2. D.T. Pham, International Journal of Machine Tools & Manufacture 38

(1998) 12571287

3.

Ken Osborne:Electroplating and Metal Protection, University of Auckland

4. A H. J. Jeon: Simulating electroplated micro surfaces in 3-D

5. John J. Kuzmik: Plating on Plastics.

6. Kwai-Sang Chin: Implementation of Rapid Prototyping Technology- A Hong

Kong Manufacturing Industry's Perspective.

7. C.K. Chua Rapid: Investment casting, direct and indirect approaches via

model maker II

8. Danial Ghodsiyeh: A Review on the Current Research Trends in Wire

0

0.5

1

1.5

2

0 20 40 60 80

Y-Wear rate(g/hr)

Y-Wear rate(g/hr)


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9. Electrical Discharge Machining (WEDM).

10.

Saeed Daneshmand: Influence of Machining Parameters on Electro

Discharge Machining of NiTi Shape Memory Alloys.

11.

Ludmila Novakova: Basic and Advanced Materials for Fused Deposition

Modeling Rapid Prototyping Technology.

12. Nenad V. Mandich and Donald I. Snyder: Electro deposition of chromium

13.

Jie Liu, Biao Zhang, Chunze Yan, Yusheng Shi: Rapid Prototyping Journal

Emerald Article The effect of processing parameters on characteristics of

selective laser sintering dental glass-ceramic powder.

14. Prof. Deepa yagnik: Fused Deposition Modeling A Rapid Prototyping

technique for Product Cycle Time Reduction cost effectively in Aerospace

Applications.

15.

V. Scott Gordon James M. Bieman: Rapid Prototyping, Lessons Learned;

Department of Computer Science Colorado State University

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.61.8

2

0 2 4 6 8 10

Y-wear(g/hr)

Y-wear(g/hr)


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16. K.H. Ho, S.T. Newman:State of the art electrical discharge machining

(EDM).

Documents

Fabrication of EDM Tool Using Rapid Prototyping and Electroforming