PROJECT  REPORTBy:

 Tarun Sharma (2007EME18)Nikhil Sharma (2007EME33)Ishan chib (2007EME30)Sumit khajuria (2007EME37)

PROJECT GUIDE:

Mr. ANKUSH ANAND

Aim of the project:

To study the effect of current &voltage on MRR of EN31 & D3 using electric discharge machining (EDM).

 

Materials considered for Analysis:-

• EN31• D3

EN31

• EN31 is a high carbon alloy steel which achieves a high degree of hardness with compressive strength and abrasion resistance

TYPICAL ANALYSIS  

C. Mn. Cr. Si.

1.00% 0.50% 1.40% 0.20%

D3

• D-3 steel is a steel that is vacuum heat treated i.e raised to a high temp and rapidly cooled by a vacuum process.

• It is a difficult material to machine and requires a special wheel for surface grinding after heat treatment.

• D-3 is a high-carbon high-chromium tool steel manufactured for high abrasive wear applications.

OBSERVATION TABLE OF EN31S.NO. VOLTAGE(V) CURRENT(I) MATERIAL  REMOVAL 

RATE(MRR)1

2

3

4

5

6

OBSERVATION TABLE OF D3S.NO. VOLTAGE(V) CURRENT(I) MATERIAL REMOVAL 

RATE(MRR)1

2

3

4

5

6

Process Used

• To meet the objective, ELECTRIC DISCHARGE MACHINING (EDM) Process is used.

ELECTRIC DISCHARGE MACHINING

• It is a controlled metal-removal process that is used to remove metal by means of electric spark erosion.

Principle of EDM • In this process an electric spark is used as the

cutting tool to cut (erode) the workpiece to produce the finished part to the desired shape

• The metal-removal process is performed by applying a pulsating (ON/OFF) electrical charge of high-frequency current through the electrode to the workpiece.

• This removes (erodes) very tiny pieces of metal from the workpiece at a controlled rate.

• With the EDM process both the workpiece material and the electrode,material must be conductors of electricity.

DESCRIPTION

• The electrode and the workpiece are both submerged in a dielectric fluid, which is generally light lubricating oil.

• A servomechanism maintains a space of about the thickness of a human hair between the electrode and the work, preventing them from contacting each other.

Dielectric Fluids

• During the EDM process the workpiece and the electrode are submerged in the dielectric oil.

• It is an electrical insulator that helps to control the arc discharge.

• The dielectric oil, that provides a means of flushing, is pumped through the arc gap.

• This removes suspended particles of workpiece material and electrode from the work cavity

Servo Mechanism

• It automatically maintains a constant gap of about the thickness of a human hair between the electrode and the workpiece.

• It is important for both machine types that there is no physical contact between the electrode and the workpiece, otherwise arcing could damage the workpiece and break the wire.

• maintain the proper arc gap which is essential to a successful machining operation.

ADVANTAGES OF EDM

• Complex shapes that would otherwise be difficult to produce with conventional cutting tools.

• Extremely hard material to very close tolerances.

• Very small work pieces where conventional cutting tools may damage the part from excess cutting tool pressure.

CONTINUED....

• There is no direct contact between tool and work piece. Therefore delicate sections and weak materials can be machined without any distortion.

• A good surface finish can be obtained.• Very fine holes can be easily drilled.

DISADVANTAGES OF EDM

• The slow rate of material removal.• Reproducing sharp corners on the workpiece

is difficult due to electrode wear.• Power consumption is high.• Excessive tool wear occurs during machining.

References

• Manufacturing engineering and techonology by Serope Kalpakjian

• Modern machining processes by Pandey and Sham

• From intrernet resources• Some research papers

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Thank You