technical science
PhD in Technical sciences Khafizov Ildar Ilsurovich
Kazan federal
university
PROCESSING
METHODS WITH APPLICATION OF AN ELECTRIC FIELD AT LOW WASTE SEPARATION OF
MATERIALS
Electrochemical method was originally developed for the grinding tools
made of tungsten carbide[1]. The new process has shown clear advantages
compared to expensive conventional grinding. The progress made at the present
time, allow economical use of electrolytic method for machining of hardened
steel. The use of abrasive wheels at a coal bundle will also contribute to the
further development of the electrolytic polishing.
In the development of intractable materials designed electrochemical
method should be compared with the spark erosion. Where you can use tools and a
large area required to bring them current, electrochemical spark much more
productive work. But if for some reason you can only use tools with a small
footprint, the treatment will be the spark may be more economical, as the cost
of the equipment for it is only about half the cost of equipment for the
electrochemical treatment. Design tool to spark processing easier, but in
electrochemical machining, the tool does not wear out. Furthermore, the
electrochemical treatment does not damage the work surface provides a high
purity grade and, in addition, the highest surface quality is obtained when the
current density, and hence, the local metal removal rate maximum. This means
that the highest surface quality is obtained when the processing is done at the
maximum feed rate.
Combination treatments are aimed at intensification of the process of
anodic dissolution. [2] Metal removal rate and precision formation in
electrochemical processing depends on how fast the reaction is going transition
of the workpiece material in the sludge. The rate of anodic dissolution limited
by the presence of the film, passivating the surface and thickness of the
diffusion layer.
When electric polishers allowance is removed or anodic dissolution of
the metal and the pickup abrasive grain or just dissolved. In the first case,
the tool contains a linked or free abrasive powder in the second - as a tool to
use wooden or plastic blocks, located between the metal electrode-tool.
Areas of application processes with an electric field.
Comparing the technological characteristics of different ways, we can
determine the most efficient possible use in engineering.
Electrical discharge machining in the electro-mode occurs at a
relatively low energy pulses. Volume of metal removed during each pulse is
small, and the depth of the wells is negligible. This allows you to take a
surface with high precision and low surface roughness at low performance. In
addition, the process is very power-hungry.
When using electrochemical treatment must meet the following
requirements are common to all types of procurement and processing circuits.
1. Surface before electrochemical treatment must be free of scale and
other non-conductive materials.
2. In places where the metal removal plan to do with the use of
electrochemical treatment is not allowed local cleaning surfaces such as hard
to control.
3. electrochemical treatment should be carried out after the heat
treatment of workpieces. This avoids inaccurate due to distortion during heat
treatment, prevents layer in the finished part.
4. When designing pieces allowance shall not be less than a certain
limit, determined according to the possible dissolution in treated and adjacent
surfaces, where the metal can be dissolved by the currents of the scattering
and rapid removal at the edges of the details.
5. In the process does not involve surgery, and transitions to remove
burrs and rounded edges on the surfaces after electrochemical.
After studying drawing blanks, parts, technical design features of
electrochemical treatment process:
1. Choose a scheme of electrochemical treatment, given the shape of the
workpiece, depending on the availability of equipment and tools.
2. Evaluate the manufacturability of the details and make the necessary
changes to the drawings, applying electrochemical treatment.
3. Evaluate the technological characteristics of electrochemical
processing and compare them with those of machining.
4. The expediency of the use of electrochemical treatment. If the item
can not be made in another way, such a study is not required.
Series production of electrochemical treatment are useful in the
processing of complex-shaped piece of high-strength alloys and materials with
brittle, viscosity (superalloys, titanium and other alloys). Details of the
construction materials are manufactured using an electrochemical process, if
not easily accessible tool to the cutting area, or other ways to cause
deformation, such as processing tubes and non-circular holes, a length to
diameter ratio greater than 10.
Keep in mind also that the process of electrochemical machining can be
easily automated and can be used to produce parts of the toxic, flammable
materials, such as beryllium, magnesium.
The exception of the
subsequent operations on processing of places of division of details allows to
accelerate several times processing process, considerably to increase accuracy
and quality of details, to lower an expense of scarce materials.
The
list of the used sources
1. Khafizov
I.I. An intensification of the combined process of electrodiamond processing of
metals and alloys and improvement of quality of a workability of a surface of
metals//Technological support of quality of cars and devices: collection of
articles III of the International scientific and practical conference. Penza:
2006-Pages 64-66.
2. Khafizov
I.I. Avtoref. yew. PhD.Tech.Sci. Publishing house of Public Educational
Institution of Higher Professional Training VGTU, 2007, 18 c.
3.
Smolentsev V.P. Sukhorukov N. V. Physical bases and technological application
of electrocontact process. Voronezh 1998, 148ñ.