“EXPERIMENTAL ANALYSIS AND OPTIMIZATION OF PROCESS PARAMETER IN WEDM FOR ALUMINUM-6082.”

GUIDED BY:- PROF. KRUNAL SHAH

DEPT. MECHANICAL

VICT , KALOL

PREPARED BY: ANUP B PATELENROLLMENT NO. : 130810750008ME (AMS) SEM III

OUTLINE

INTRODUCTION HOW WEDM WORKS? LITERATURE REVIEW METHODOLOGY SELECTION OF MATERIAL EXPERIMENTAL SETUP SPECIFICATION OF MACHINE INPUT-OUTPUT PARAMETERS REFERENCES

INTRODUCTION TO WIRE-EDM

Electro discharge machining (EDM) is an electro-thermal non-traditional machining process, where electrical energy is used to generate electrical spark and material removal mainly occurs due to thermal energy of the spark.

EDM is mainly used to machine difficult-to-machine materials and high strength temperature resistant alloys. EDM can be used to machine difficult geometries in small batches or even on job-shop basis. Work material to be machined by EDM has to be electrically conductive.

DIAGRAM OF BASIC WORKING PRINCIPLE OF WEDM PROCESS AND WEDM CUTTING GAP

Diagram for Basic principle of WEDM process Diagram for WEDM cutting gap

HOW WEDM WORKS?

WEDM uses a travelling electrode that passes through the work piece.

The wire is monitored precisely by a CNC system.

WEDM removes material by means of spark erosion, thus the material which is used must be electrically conductive.

Rapid pulses are generated between wire and work piece.

Between wire and work piece is a shield of dielectric water called dielectric.

MATERIALS THAT CAN BE MACHINED IN WEDM

All electrically conductive metals.

Metal alloys.

Graphite, diamond, Tungsten carbide

Steels such as Stainless steel, tool steel, high speed steed.

Super alloys.

Aerospace materials etc.

ADVANTAGES, DISADVANTAGES AND APPLICATIONS OF WEDM

Advantages:-

Continuously travelling wire is used as negative electrode, so electrode fabrication is not required as in EDM.

There is no contact between the work piece and the wire, eliminating the mechanical stresses during machining.

WEDM process applies to all electrically conductive metals and alloys irrespective of their melting point, hardness, toughness or brittleness.

Parts with complex shapes and close tolerances can be easily machined.

Disadvantages:- High capital cost is required for WEDM process.

WEDM process exhibits very slow cutting rates.

It is not applicable for very large work piece.

Applications:- Progressive, blanking, trim die and Extrusion die.

Narrow keyways, micro holes and slots.

Medical and dental instruments.

Aerospace, defense, electronic parts and Prototype parts.

Electrodes for vertical EDM.

LITERATURE REVIEWTITLE SPARK GAP OPTIMIZATION OF WEDM PROCESS ON

TI6AL4V.[1]

AUTHOR Kuriachen Basil, Dr. Josephkunju Paul, Dr. Jeoju M. Issac

ABSTRACT Effect of voltage, dielectric pressure, pulse on-time and pulse off-time on spark gap of Ti6AL4V alloy was investigated. The WEDM experiments were conducted in Electronic ultra cut S1 machine using 0.25 mm brass wire as the tool electrode. ‘Pulse on time’, ‘pulse off time’, ‘voltage’ and ‘dielectric pressure’ are the four WEDM parameters that were selected for investigations. In this experimental study two level full factorial experiment is adopted because this gives all possible combinations of machine parameters.

CONCLUSION It can be noticed that corresponding to minimum value of pulse off time the spark gap decreases with increase in dielectric pressure, whereas the spark gap increases with increase in dielectric pressure corresponding to maximum value of pulse off time.

TITLE WEDM: INFLUENCE OF MACHINE FEED RATE IN MACHINING TITANIUM Ti-6Al-4V USING BRASS WIRE AND CONSTANT CURRENT [2].

AUTHOR Aniza Alias, Bulan Abdullah, Norliana Mohd Abbas

ABSTRACT Investigated the influence of feed rate on the performance of WEDM on Titanium Ti-Al-4V. Brass wire was employed as the electrode for the investigation. The selection of parameters depends on the requirements based on a better surface roughness or a maximum material removal rate. Hence an appropriate combination of variables can be selected accordingly. Furthermore, this combination can contributes to increase production rates perceptibly by reducing machining time.

CONCLUSION The selection of parameters depends on the requirements based on a better surface roughness or a maximum material removal rate. Hence an appropriate combination of variables can be selected accordingly.

TITLE EFFECT OF WEDM CONDITIONS ON SURFACE ROUGHNESS : A PRAPMETRIC OPTIMISATION USING TAGUCHI METHOD.[3]

AUTHOR Pujari Srinivasa Rao, Koona Ramji, Beela Satyanarayana

ABSTRACT Studied Wire-cut electric discharge machining of Aluminum-24345. Experimentation has been done by using Taguchi’s L18 orthogonal array under different conditions of parameters. The response of surface roughness is considered for improving the machining efficiency. Multiple linear regression model have been developed relating the process parameters and machining performance and a high correlation coefficient (r2 = 0.97) indicates the suitability of the proposed model in predicting surface roughness.

CONCLUSION It is found that SR tends to decrease significantly with decrease in IP and TON.

TITLE EFFECT OF PROCESS PARAMETERS ON PERFORMANCE MEASURES OF WIRE EDM FOR AISI A2 TOOL STEEL [4]

AUTHOR S. B. Prajapati, N. S. Patel

ABSTRACT The effect of process parameter like Pulse ON time, Pulse OFF time, Voltage, Wire Feed and Wire Tension on MRR, SR, Kerf and Gap current is studied by conducting an experiment. Response surface methodology is used to analyze the data for optimization and performance. The AISI A2 tool steel is used as work piece material in the form of square bar.

CONCLUSION For cutting rate and surface roughness, the pulse ON and pulse OFF time is most significant. The spark gape set voltage is significant for kerf. The normal probability distribution for all measurement indicates high confidence.

METHODOLOGY

Selection of work piece material:-

Use of electrically conductive metal or alloy.

Use of standard materials widely used for application of WEDM.

Use of easily available material.

Materials generally used in WEDM: Brass, copper, graphite, tungsten carbide, tool steels, high speed steels, stainless steels, diamond, super alloys, aerospace materials.

Types of electrode material:-

Half hard and soft brass wire (Available wires are .006”, .008”, .010”, .012”)

Gamma on brass wire (Available wires is .010”)

Zinc coated wire (Available wires are .008”, .010”, .012”)

Tungsten wires (Available wires are .008”, .010”, .012”)

Electrode material to be used : -

NiCut ECONO (Soft Brass wire)

NiCut Race (Half Hard Zinc Coated wire)

NiCut COMBII (Half Hard Brass wire)

Use of Full Factorial 3 Level method for DOE.

Optimization to be done by Genetic Algorithm (GA).

FLOW CHART OF METHODOLOGYSpecimen Preparation

Design Plan

Three level L27 Orthogonal Full Factorial Design

Run experiment according to design plan

Measurement & Result Table Preparation

Perform analysis based on Genetic Algorithm using Matlab

Result analysis and discussion

Conclusion

End

SELECTING ALUMINUM-6082 AS WORK PIECE

Aluminum alloy 6082 is a medium strength alloy with excellent corrosion

resistance. It has the highest strength of the 6000 series alloys.

Alloy 6082 is known as a structural alloy. In plate form,  Aluminum alloy 6082  is

the alloy most commonly used for machining.

As a relatively new alloy, the higher strength of Aluminum alloy 6082  has seen it

replace 6061 in many applications.

The addition of a large amount of manganese controls the grain structure which in

turn results in a stronger alloy.

In the T6 and T651 temper, Aluminum alloy 6082  machines well and produces

tight coils of swarf when chip breakers are used.

COMPARISON BETWEEN AL 6082AND AL 6061

AL6082 AL 6061Component Amount (wt.%)

Aluminum Balance

Magnesium 0.8-1.2

Silicon 0.4 – 0.8

Iron Max. 0.7

Copper 0.15-0.40

Zinc Max. 0.25

Titanium Max. 0.15

Manganese Max. 0.15

Chromium 0.04-0.35

Others 0.05

Element % Present

Al Balance

Si 0.7-1.3

Fe 0.0-0.5

Cu 0.0-0.1

Mn 0.4-1.0

Mg 0.6-1.2

Zn 0.0-0.2

Ti 0.0-0.1

Cr 0.0-0.25

APPLICATIONS OF AL 6082

Highly stressed applications

Trusses

Bridges

Cranes

Transport applications

Ore skips

Beer barrels

Milk churns

EXPERIMENTAL SETUP

Material to be used :-AL6082

Electrodes (Wire) to be used :- Soft plain brass wire, Half hard plain brass

wire, Half hard coated wire all of 0.25 mm diameter.

Variable Parameters :-

Wire Speed (WS)

Wire Tension (WB)

Injection Pressure (INJ)

Wire material

27 different combination are possible for each wire to be used.

Experiment to be done on EZEECUT CNC Wire – EDM.

Full Factorial design used for DOE.

EXPERIMENTATION ON 5530 CNC WIRE - EDM.

Machine tool – EZEECUT NXG Parameter Model 4050H Work table size mm 410X710 XY Table traverse mm 400X500  Max Z height mm 300  Max work piece weight kg 450  Max taper cutting angle +_3 degree / 100mm  Higher degree optional 

Dielectric Unit  Dielectric capacity Tap water + coolant oil (40:1 lit) Tap water + Multipass paste (40:1kg)  Tank capacity 55 Litres  Filter Magnetic separator. 

Wire Diameter Type of Wire  0.2 to 0.25 Brass  0.12 to 0.25 Molybdenum

TECHNICAL SPECIFICATIONS- 

PARAMETERS AFFECTING WEDM

Fishbone cause and effect diagram

Process parameters and performance measures

Input Parameters Output Parameters

Wire Tension ( Kg) Material Removal Rate (mm/min)

Wire Speed (m/min) Surface Roughness (µm)

Injection Pressure (Bar) Kerf Width (mm)

Wire Material

Full Factorial method for DOE :-

A design in which every setting of every factor appears with every setting of every other factor is a full factorial design.

Three-level full factorial designs Three-level designs are useful for investigating quadratic effects. The three-level design is written as a 3^k factorial design. It means that k

factors are considered, each at 3 levels. These are (usually) referred to as low, intermediate and high levels.

The 3^3 Design The model and treatment runs for a 3 factor, 3-level design. This is a design that consists of three factors, each at three levels. It can be

expressed as a 3 x 3 x 3 = 27 designs.

Level 1 Level 2 Level 3

Wire Speed

(WS)

5 m/min 10 m/min 15 m/min

Wire Tension

(WB)

1 Kg 1.5 Kg 2 Kg

Injection

Pressure (INJ)

1 Bar 2 Bar 4 Bar

Wire Material Soft Brass ½ Hard Brass ½ Hard Coated

INPUT VARIABLE FACTORS WITH LEVEL VALUES

EXPECTED OUTCOME

The wire materials to be used include plain brass and coated wires. Thus it is likely that the coated wire will be more effective in terms of MRR and Surface roughness but with increased cost and high wear rate.

Thus we may use ½ hard plain brass wires which perform reasonably well for the required application with optimized input parameters.

Use of AL6082may increase the life of components that may wear out quickly by using AL6061.

Higher surface finish may be obtained by the use of coated wires.

Best utilization of machine can be done by operating it at optimum parameters.

REFERENCES

Papers:

1) Kuriachen Basil, Dr. Josephkunju Paul, Dr. Jeojum.Issac, “Spark Gap Optimization Of Wedm Process On Ti6al4v”.pp.364-368,(2013)

2) Aniza Aliasa , Bulan Abdullaha *, Norliana Mohd Abbasa . “Influence Of Machine Feed Rate In Machiningtitanium Ti-6al-4v Using Brass Wire And Constantcurrent” .pp.1812-1817,(2012)

3) Pujari Srinivasa Rao, Koona Ramji, Beela Satyanarayana, “Effect Of Wedm Conditions On Surface Roughness : A Prapmetric Optimisation Using Taguchi Method”.pp.41-48,(2011)

4) S. B. Prajapati , ,N. S. Patel “Effect Of Process Parameters On Performance Measures Of Wire Edm For Aisi A2 Tool Steel”.pp.274-278,(2013 )

Websites:a. Wire EDM “THE FUNDAMENTALS” by Donald B. Moulton.

b. http://www.wireedm.net/

c. Effect of process parameters on performance measures of WEDM by Rohit Garg.

d. Current Research Trends in Wire Electrical Discharge Machining: An Overview by Rajeev Kumar and Shankar Singh.

e. Wire EDM Fundamentals- www.reliableedm.com

THANK YOU