COMPARISSION BETWEEN AJM ,USM AND EDM

SHUKLA SHIVAM SATYANARAYAN184

M. Tech. (Production Engineering)2015-2016

DEPARTMENT OF MECHANICAL ENGINEERING

MSU BARODA

Mechanism of Material Removal in EDM Process

The material removal process by a single spark is as follows:• An intense electric field develops in the gap between electrode and

workpiece.• There are some contaminants inside the dielectric fluid which build a

high conductivity bridge between the electrode and workpiece.• When the voltage increases, the bridge and dielectric fluid

between the electrode and workpiece heat up. • The dielectric is ionized to form a spark channel. • The temperature and pressure rapidly increase and a spark is

generated. • A small amount of material is evaporated on the electrode and

workpiece at the spark contact point.• Bubbles rapidly expand & explode during sparking until voltage is

turned off.• Next the heating channel collapses and the dielectric fluid enters

into the gap • in-order to flush away the molten metal particles.

USM MACHINE

The application of non traditional machining are influence by the workpiece shape and size to be produced like holes ,through cavities ,pocketing surfacing and special application

For comparison the following parameter are considered •Material removal rate •Power consumed •Accuracy•Surface finish

PROCESS AJM USM EDM

CharacteristicsSuitable for all material•Tapered surface generated•Effect of standoff distance

Brittle fracture•Abrasive embedding

Shaping and cutting complex parts made of hard materialsWhite layerExpensive tooling and equipment

Operating parameters V = 110, I = 1.5 A,Gap = 0.76

V=220,A=12ampAC ,Gap=0.25

V=50-380,A=0.1-500, Gap=0.01-0.50

Form of Energy Abrasive propelled at in high speed air

Small amplitude and high frequency

Series of sparks

TOOL MATERIAL ABRASIVE STEEL GIVEN ABOVE

POCESS AJM USM EDM

Variant processAbrasive Flow Machining (AFM)•Orbital Grinding (OG)•Abrasive Water Jet Machining (AWJM)

Ultrasonically Assisted Machining (UAM)•Rotary ultrasonically Assisted Machining(RUM)

Wire Electrical Discharge Machining (WEDM)Wire Electrical Discharge Grinding (WEDG)

MRR 0.0001 cm3/min 0.8 cm3/min 2 to 400 mm3/min

MEDIUM Gas like air, nitrogen Abrasive slurry Dielectric fluid

Surface roughness 0.3 - 2.3 µm 0.2 – 1.6 µm 0.05 – 12.5 µm

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