08-08-2012, 01:35 PM
MICRO ELECTRICAL DISCHARGE MACHINING
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INTRODUCTION
MICRO EDM IS QUITE SIMILAR WITH THE PRINCIPLE OF EDM.
THERE IS A HUGE DEMAND IN THE PRODUCTION OF MICRO STRUCTURE BY A NON TRADITIONAL METHOD WHICH IS KNOWN AS MICRO EDM.
MICRO EDM PROCESS IS BASED ON THE THERMO ELECTRICAL ENERGY BETWEEN THE WORK PIECE AND AN ELECTRODE.
WORKING PRINCIPLE
WHEN TWO ELECTRODES IS SEPARATED BY A DIELECTRIC MEDIUM,COME CLOSER TO EACH OTHER,THE DIELECTRIC MEDIUM THAT IS INITIALLY NON CONDUCTIVE BREAKS DOWN AND BECOMES CONDUCTIVE. DURING THIS PERIOD SPARK WILL BE GENERATED BETWEEN THE ELECTRODES. THE THERMAL ENERGY RELEASED WILL BE USED FOR THE MATERIAL REMOVAL BY MELTING AND EVAPORATION.
DIELECTRIC FLUID
In MEDM the dielectric fluid acts as a cutting medium to improve surface roughness, corrosion resistance and wear resistance.
In most die-sinking process use kerosene as the dielectric fluid . However there are a lot of dielectric fluids that can be replace to replace kerosene such as pure water (distilled water) because pure water has a high thermal conductivity, a low viscosity coefficient, and a high flowing rate. Pure water temperature is not affected by long working time, and this will improve the material removal rate (MRR).
ELECTRODE MATERIAL
THE SELECTION OF THE ELECTRODE MATERIAL IS DEPEND UPON:-
1.MATERIAL REMOVAL RATE
2.WEAR RATIO
3.EASE OF SHAPING THE ELECTRODE
4.COST
THE MOST COMMONLY USED ELECTRODE MATERIAL ARE:
=>BRASS, COPPER, GRAPHITE, AL ALLOYS, COPPER TUNGSTEN ALLOYS, SILVER TUNGSTEN ALLOYS.
[attachment=30572]
INTRODUCTION
MICRO EDM IS QUITE SIMILAR WITH THE PRINCIPLE OF EDM.
THERE IS A HUGE DEMAND IN THE PRODUCTION OF MICRO STRUCTURE BY A NON TRADITIONAL METHOD WHICH IS KNOWN AS MICRO EDM.
MICRO EDM PROCESS IS BASED ON THE THERMO ELECTRICAL ENERGY BETWEEN THE WORK PIECE AND AN ELECTRODE.
WORKING PRINCIPLE
WHEN TWO ELECTRODES IS SEPARATED BY A DIELECTRIC MEDIUM,COME CLOSER TO EACH OTHER,THE DIELECTRIC MEDIUM THAT IS INITIALLY NON CONDUCTIVE BREAKS DOWN AND BECOMES CONDUCTIVE. DURING THIS PERIOD SPARK WILL BE GENERATED BETWEEN THE ELECTRODES. THE THERMAL ENERGY RELEASED WILL BE USED FOR THE MATERIAL REMOVAL BY MELTING AND EVAPORATION.
DIELECTRIC FLUID
In MEDM the dielectric fluid acts as a cutting medium to improve surface roughness, corrosion resistance and wear resistance.
In most die-sinking process use kerosene as the dielectric fluid . However there are a lot of dielectric fluids that can be replace to replace kerosene such as pure water (distilled water) because pure water has a high thermal conductivity, a low viscosity coefficient, and a high flowing rate. Pure water temperature is not affected by long working time, and this will improve the material removal rate (MRR).
ELECTRODE MATERIAL
THE SELECTION OF THE ELECTRODE MATERIAL IS DEPEND UPON:-
1.MATERIAL REMOVAL RATE
2.WEAR RATIO
3.EASE OF SHAPING THE ELECTRODE
4.COST
THE MOST COMMONLY USED ELECTRODE MATERIAL ARE:
=>BRASS, COPPER, GRAPHITE, AL ALLOYS, COPPER TUNGSTEN ALLOYS, SILVER TUNGSTEN ALLOYS.