its helpfull for ntm

1. COMPARISSION BETWEEN
AJM ,USM AND EDM
SHUKLA SHIVAM SATYANARAYAN
184
M. Tech. (Production Engineering)
2015-2016
DEPARTMENT OF MECHANICAL
ENGINEERING
MSU BARODA

7. 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.

19. 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

22. PROCESS AJM USM EDM
Characteristics
Suitable for all
material
•Tapered surface
generated
•Effect of standoff
distance
Brittle fracture
•Abrasive embedding
Shaping and cutting
complex parts made
of hard materials
White layer
Expensive 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

23. POCESS AJM USM EDM
Variant process
Abrasive 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