non conventional machining process

1. Electrochemical grinding (ECG)
- Prof. SAVAN FEFAR
Electrochemical grinding (ECG)
Prof. SAVAN FEFAR

2. • The process is similar to
cathode is a specially constructed grinding
wheel instead of a cathodic shaped
• The insulating abrasive material (diamond or
aluminum oxide) of the grinding wheel is set
in a conductive bonding
• the wheel is a rotating cathodic tool with
abrasive particles on its periphery.
• Electrolyte flow, usually NaNO3, is provided
for ECD (Electro chemical dissolution).
similar to ECM except that the
cathode is a specially constructed grinding
of a cathodic shaped tool.
The insulating abrasive material (diamond or
the grinding wheel is set
in a conductive bonding material.
the wheel is a rotating cathodic tool with
abrasive particles on its periphery.
Electrolyte flow, usually NaNO3, is provided
for ECD (Electro chemical dissolution).

3. Working PrincipleWorking Principle

4. • The wheel rotates at a surface
m/s, while current ratings
• When a gap voltage of
between the cathodic
anodic workpiece, a current
to 240 A/cm2 is created.
• The current density depends on the material
being machined, the gap width, and the applied
voltage
surface speed of 20 to 35
ratings are from 50 to 300 A.
of 4 to 40 V is applied
grinding wheel and the
current density of about 120
.
The current density depends on the material
, the gap width, and the applied

5. ECG machining system components.ECG machining system components.

6. MRR
• Material is mainly removed by ECD, while the
MA of the abrasive grits accounts for an
additional 5 to 10 percent of the total material
removal.
• Removal rates by ECG are 4 times faster than
by conventional grinding, and
produces burr-free parts that are unstressed
• The volumetric removal rate (VRR) is typically
1600 mm3/min.
MRR
Material is mainly removed by ECD, while the
MA of the abrasive grits accounts for an
additional 5 to 10 percent of the total material
rates by ECG are 4 times faster than
grinding, and ECG always
free parts that are unstressed.
removal rate (VRR) is typically

7. The volumetric removal rate
(mm3/min) in ECG can be calculated
using the following equation:
The volumetric removal rate
(mm3/min) in ECG can be calculated
using the following equation:

9. • In the machining zone there is an area of
simultaneous ECD and MA of the
surface, where the gap width is less than the
height of the grain part projecting over the
binder.
• Another area of pure electrochemical removal
where the abrasive grains do not touch the
workpiece surface exists at the entry and exit
sides of the wheel.
In the machining zone there is an area of
simultaneous ECD and MA of the workpiece
surface, where the gap width is less than the
height of the grain part projecting over the
Another area of pure electrochemical removal
where the abrasive grains do not touch the
surface exists at the entry and exit

10. • Machining conditions at which the MA
disappears depend on the electrical
parameters, electrochemical
of the material in a given electrolyte, and
grinding wheel features especially grain
size and height.
• Generally slow feed rates produce larger
overcut, poor surface finish, and wider
tolerances, while excessive wheel wear
occurs as a result of a feed rate that is too
fast.
Machining conditions at which the MA
disappears depend on the electrical
parameters, electrochemical machinability
of the material in a given electrolyte, and
grinding wheel features especially grain
Generally slow feed rates produce larger
overcut, poor surface finish, and wider
tolerances, while excessive wheel wear
occurs as a result of a feed rate that is too

11. Accuracy and surface quality
• Traditional grinding removes metal by
abrasion, leaving tolerances of about
mm and creating heat and stresses that make
grinding thin stock very difficult. In ECG
however a production tolerance of
is easily obtainable
• The ability to hold closer tolerances depends
upon the current, electrolyte flow, feed rate,
and metallurgy of the workpiece
Accuracy and surface quality
Traditional grinding removes metal by
abrasion, leaving tolerances of about ±0.003
mm and creating heat and stresses that make
grinding thin stock very difficult. In ECG
however a production tolerance of ±0.025 mm
The ability to hold closer tolerances depends
upon the current, electrolyte flow, feed rate,
workpiece itself.

12. • ECG can grind thin material of 1.02 mm, which
normally warp by the heat and pressure of the
conventional grinding thus making closer
tolerances difficult to achieve.
• The main drawback of ECG is the loss of
accuracy when the inside corners are ground.
Because of the electric field effect, radii better
than 0.25 to 0.375 mm can seldom be
achieved
ECG can grind thin material of 1.02 mm, which
normally warp by the heat and pressure of the
conventional grinding thus making closer
tolerances difficult to achieve.
The main drawback of ECG is the loss of
accuracy when the inside corners are ground.
Because of the electric field effect, radii better
than 0.25 to 0.375 mm can seldom be

13. Applications
• Machining parts made from difficult
such as sintered
carbides, creep-resisting (Inconel
titanium alloys, and metallic composites.
• Applications similar to milling, grinding, cutting off,
sawing, and tool and cutter sharpening.
• Production of tungsten carbide cutting tools, fragile
parts, and thin walled
tubes.
• Producing specimens for metal fatigue and tensile tests.
• Machining of carbides and a variety of high
alloys.
Applications
Machining parts made from difficult-to-cut materials,
Inconel, Nimonic) alloys,
titanium alloys, and metallic composites.
Applications similar to milling, grinding, cutting off,
sawing, and tool and cutter sharpening.
Production of tungsten carbide cutting tools, fragile
Producing specimens for metal fatigue and tensile tests.
Machining of carbides and a variety of high-strength

14. Advantages
• Absence of work hardening
• Elimination of grinding burrs
• Absence of distortion of thin fragile or
thermosensitive parts
• Good surface quality
• Production of narrow tolerances
• Longer grinding wheel life
Advantages
Absence of work hardening
Elimination of grinding burrs
Absence of distortion of thin fragile or
Production of narrow tolerances
Longer grinding wheel life

15. Disadvantages
• Higher capital cost than conventional
machines
• Process limited to electrically conductive
materials
• Corrosive nature of electrolyte
• Requires disposal and filtering of
electrolyte
Disadvantages
Higher capital cost than conventional
Process limited to electrically conductive
Corrosive nature of electrolyte
Requires disposal and filtering of