Title of Invention

A SYNERGISTIC COMPOSITION USEFUL FOR ELECTROCHEMICALLY ASSISTED ARC MACHINING

Abstract This invention relates to a novel electrolyte composition useful for electrochemically assisted arc machining. The novel electrolyte essentially prevents wandering of arc in addition to providing electrochemical machining. Thus making it possible to combine arc cutting and electrochemical machining, which helps in fast cutting of difficult to cut hard metals of various sections. The novel electrolyte composition is based on sodium silicate and sodium nitrate with other additives that act as corrosion inhibitors.
Full Text The present invention relates to a novel electrolyte composition useful for electrochemically assisted arc machining such as cutting metals and alloys which are very difficult to cut by conventional methods. The mechanical engineering industry requires an operation for cutting billets, rods and sheets for further machining to specific components such as cutting operation proves to be difficult and time consuming in the case of difficult-to-machine materials like stainless steel, nimonics, tungsten carbide.
Conventionally for cutting stainless steel, flame cutting with iron powder feeding, has been used. This method results not only in a jaggered cut edge, but also in an edge with significantly altered chemical composition for an appreciable depth. As a result one has to machine-off several millimeters, thus adding to time and cost. Plasma arc or laser cutting also produce a cut edge with severe undulation. Plasma cutting produces the surface with oxides or nitrides of the metal being cut and bottom dross which has to be ground after cutting operation. Cutting of stainless steel with a power hack saw is quite slow and requires a special saw like diamond coated blades or slitting saw, which is expensive. This process is costly because of the consumption of expensive tool.
In the light of the above, one can see that there is a need for fast cutting of difficult-to-cut hard metals of various sections. To the best of our knowledge and
belief, the very concept of combined arc and electrochemical machining is novel and as such is not known in the art.
The principal object of the present invention is to provide a novel electrolyte compowtebn useful for electrochemically assisted arc machining (ECAAM).
Accordingly the present invention provides a novel electrolyte composition
useful for electrochemically assisted arc machining which comprises :
Sodium silicate - 5 to 35 W%
Sodium Nitrate - 1 to 15 W%
Boric acid - 1 to 5 W%
Sodium hydroxide - 1 to 5 W%
Distilled water - Balance
In an embodiment of the present invention the sodium silicate used may be of technical grade with specific gravity of liquid 1.60.
In another embodiment of the present invention the sodium nitrate used may be technical grade.
In still another embodiment of the present invention the boric acid used may be technical grade.
In yet another embodiment of the present invention the sodium hydroxide used may be LR grade.
In still yet another embodiment of the present invention the water used may be distilled water.
The novel electrolyte composition of the present invention is not a mere admixture, but is a synergistic mixture having properties which are not a mere aggregation of the individual properties of the ingredients and there is no chemical reactions.
Electrochemically Assisted Arc Machining (ECAAM) is a novel means which can be used for fast cutting of billets, rods and sheets of metallic materials, which are difficult-to-cut by conventional methods.
In the present invention, the novel electrolyte composition is useful for electrochemically assisted arc machining (ECAAM) which may be carried out by combining electrochemical dissolution and arcing processes. Arc is used for cutting which enhances the cutting rates along with electrolytic dissolution. The
cutting rates are fast because of arcing. The electrolyte prevents wild cutting by making the arcing periodic.
Arc has the ability to cut fast, but unfortunately it leads to wild cutting and hence cannot be used for practical application. If this drawback is removed, then it would be possible to achieve fast cutting with arc. This has been made possible by the novel electrolyte of the present invention which prevents wandering of arc.
During electrochemically assisted arc machining using the novel electrolyte of the present invention, the cut edge is straight and free from undulation. The novel electrolyte of the present invention is passivating electrolyte that prevents the arc from wandering by intermittently stopping it. Since the medium is an electrolyte conductor, one is able to arc at low voltages.
This novel electrolyte of the present invention functions in two ways:
a) It permits formation of spark / arc at low D.C Voltages (10 to 40V).
b) Makes the occurrence of spark / arc intermittent and thereby avoids the wild
cutting.
Thus by the combined action of spark / arc and electrolyte, fast cutting of difficult-to-cut metallic materials has been achieved.
The novel electrolyte of the present invention has been used in our copending patent application No: NF.250/02wherein we have described and claimed a machine for electrochemically assisted arc machining and copending patent application No: NF.251/02 wherein we have described and claimed a machine for electrochemically assisted arc machining for 2D-shape generation.
The mam advantages of the present invention are :
1. To provide a novel electrolyte composition useful for electrochemically
assisted arc machining.
2. A novel electrolyte composition can be used for cutting metals and alloys
which are very difficult to cut by conventional methods.
3. A novel electrolyte composition employed in this process is
environmentally friendly, non-hazardous, non polluting and safe-to-handle.
4. A novel electrolyte composition can be considered as versatile since it can
be used for cutting all the ferrous materials.





We claim:
1. A novel electrolyte composition useful for electrochemically assisted arc
machining which comprises :
Sodium silicate - 5 to 35 W%
Sodium nitrate - 1 to 15 W%
Boric acid - 1 to 5 W%
Sodium hydroxide - 1 to 5 W%
Distilled water - Balance
2. A novel electrolyte composition as claimed in claim 1, wherein the sodium
silicate used is of technical grade with specific gravity of liquid 1.60.
3. A novel electrolyte composition as claimed in claim 1,wherein the sodium
nitrate used is of technical grade.
4. A novel electrolyte composition as claimed in claim 1, wherein boric acid
used is of technical grade.
5. A novel electrolyte composition as claimed in claim 1, wherein sodium
hydroxide used is LR grade.
6. A novel electrolyte composition as claimed in claim 1, wherein water used
is distilled water.
7. A novel electrolyte composition useful for electrochemically assisted arc
machining substantially as herein described.

Documents:

477-del-2002-abstract.pdf

477-del-2002-claims.pdf

477-del-2002-correspondence-others.pdf

477-del-2002-correspondence-po.pdf

477-del-2002-description (complete).pdf

477-del-2002-form-1.pdf

477-del-2002-form-19.pdf

477-del-2002-form-2.pdf

477-del-2002-form-3.pdf


Patent Number 220689
Indian Patent Application Number 477/DEL/2002
PG Journal Number 30/2008
Publication Date 25-Jul-2008
Grant Date 02-Jun-2008
Date of Filing 22-Apr-2002
Name of Patentee COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH
Applicant Address
Inventors:
# Inventor's Name Inventor's Address
1 KUPPAM JAYARAM SANTOSH KUMAR
2 SUNDARAPANDIUM RAMA RAJAGOPALAN
3 INDIRA RAJAGOPAL
4 KARAIKUDI SANKARANARAYANA RAJAM
5 ANNAMALAI POURASSAMY
PCT International Classification Number H01M 6/18
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA