Electrochemical
Grinding (ECG) Process Overview
Electrochemical
Grinding, or ECG, is a variation of ECM (Electrochemical
Machining) that combines electrolytic activity with
the physical removal of material by means of charged
grinding wheels. Electrochemical Grinding (ECG) can
produce burr free and stress free parts without heat
or other metallurgical damage caused by mechanical grinding,
eliminating the need for secondary machining operations.
Like ECM, Electrochemical Grinding (ECG) generates little
or no heat that can distort delicate components.
What are the criteria for selecting Electrochemical
Grinding (ECG) as a process?
Electrochemical Grinding (ECG) can process any conductive
material that is electrochemically
reactive. The most common reason customers choose
ELECTROCHEMICAL GRINDING (ECG) is for the burr free
quality of the cut. If a part is difficult or costly
to deburr, then ELECTROCHEMICAL GRINDING (ECG) is the
best option. Materials that are difficult to machine
by conventional methods, that work harden easily or
are subject to heat damage are also good candidates
for the stress free and no heat characteristics of ELECTROCHEMICAL
GRINDING (ECG). The stress free cutting capability of
the process also make it ideal for thin wall and delicate
parts.
The real value of Electrochemical Grinding (ECG) is
in metalworking applications that are too difficult
or time-consuming for traditional mechanical methods
(milling, turning, grinding, deburring etc.). It is
also effective when compared to non-traditional machining
processes such as wire and sinker EDM.
ELECTROCHEMICAL GRINDING (ECG) is almost always more
cost effective than EDM.
How
does ELECTROCHEMICAL GRINDING (ECG) differ from conventional
grinding?
Conventional
surface grinding typically uses shallow reciprocating
cuts that sweep across the work surface to create a
flat plane or groove. Another conventional surface grinding
process, creep feed grinding, typically uses slower
feeds than conventional surface grinding and removes
material in deep cuts. Because of the abrasive nature
of these processes, the equipment used must be rigid
and this is especially true of creep feed grinding.
Quality ELECTROCHEMICAL GRINDING (ECG) machines must
also be rigid for close tolerance results but since
very little of the material removed is done so abrasively
the machines do not have to be as massive as their conventional
counterparts. To a user familiar with creep feed grinding
ELECTROCHEMICAL GRINDING (ECG) will appear to be very
similar, that is, relatively slow feeds (as compared
to conventional surface grinding) and deep cuts as opposed
to shallow reciprocating cuts. ELECTROCHEMICAL GRINDING
(ECG) is a combination of electrochemical (Anodic) dissolution
of a material, according to Faradays Law, and
light abrasive action. The metal is decomposed to some
degree by the DC current flow between the conductive
grinding wheel (Cathode) and the work piece (Anode)
in the presence of an electrolyte solution.
Unlike conventional grinding techniques, ELECTROCHEMICAL
GRINDING (ECG) offers the ability to machine difficult
materials independent of their hardness or strength.
ELECTROCHEMICAL GRINDING (ECG) does not rely solely
on an abrasive process; the results are precise burr
free and stress free cuts with no heat and mechanical
distortions.
How
does ELECTROCHEMICAL GRINDING (ECG) compare to EDM,
laser, water-jet and other non-traditional technologies?
EDM
and laser both cut metal by vaporizing the material
at very high temperatures. This results in a re-cast
layer and a heat
affected zone on the material surface. ELECTROCHEMICAL
GRINDING (ECG) is a no heat process that never causes
metallurgical damage. ELECTROCHEMICAL GRINDING (ECG)
is usually much faster than EDM but typically is less
accurate. Laser cutting can be very fast and accurate
but it is normally limited to thin materials. Water-jet
cutting can be quite fast and usually leaves no metallurgical
damage but the consumable costs can be very high and
the cuts are limited to jigsaw type cuts much like Wire
EDM. In most cases, ELECTROCHEMICAL GRINDING (ECG) is
a more accurate process than water-jet. Another difference
between water jet and laser machining compared to ELECTROCHEMICAL
GRINDING (ECG) is laser and water jet can both process
materials that are not conductive. EDM and ELECTROCHEMICAL
GRINDING (ECG) processes can only work on materials
that are conductive.
What
tolerances can be achieved with ELECTROCHEMICAL GRINDING
(ECG)?
The
tolerances that can be achieved using ELECTROCHEMICAL
GRINDING (ECG) depend greatly on the material being
cut, the size and depth of cut and the ELECTROCHEMICAL
GRINDING (ECG) parameters being used. On small cuts,
tolerances of .0005 (.013mm) have been achieved
but generally tolerances of less than +/- .0005
(+/-.013mm) are not practical.
What
surface finishes can be achieved with ELECTROCHEMICAL
GRINDING (ECG)?
The
ELECTROCHEMICAL GRINDING (ECG) process does not leave
the typical shiny finish of abrasive grinding. This
is because there is no smearing of the metal as in conventional
grinding. A 16 micro inch finish or better can be achieved
but it will have a matte (dull) rather than a polished
look.
What
materials can be cut with ELECTROCHEMICAL GRINDING (ECG)?
Almost
any conductive metal can cut with ELECTROCHEMICAL GRINDING
(ECG). Steel, Aluminum, Copper , Stainless Steels, Inconel
and Hastelloy cut very freely with ELECTROCHEMICAL GRINDING
(ECG). Nickel/Titanium, Cobalt alloys, Amorphous metals,
Berilium, Berilium Copper, Iridium Neodymium Iron Boron,
Titanium, Nickel/Titanium, Nitinol, Powdered Metals,
Rene 41, Rhenium, Rhodium, Stelllite, Vitalium, Zirconium
and Tungsten can also be cut effectively.
What
are the ADVANTAGES OF ELECTROCHEMICAL GRINDING (ECG)?
- Improved wheel life
- Burr free
- No work hardening
- Stress free
- Better finish
- No cracking
- Less frequent wheel dressing
- No metallurgical damage from heat
- Faster for tough materials
- No wheel loading or glazing
- More precise tolerances
Samples
of HIGH VOLUME, PRECISION PRODUCTS manufactured with
Electrochemical Grinding.
Click on a picture for more details.
Industries
Served by Electrochemical Grinding (ECG) Processes
Everite
is serving a variety of industries and applications
that are utilizing Everite's complete line of burr free
and stress free cutting and grinding equipment.
Industries
served:
| Aerospace |
Medical Tools &
Devices |
Automotive |
| Power Tools |
Hardware Surgical Implants |
Military |
| Industrial Heaters |
Telecommunications |
Appliances |
|