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PROFESSIONAL ADVICE PROFESSIONAL ADVICE

TECHNOLOGY OF OPERATION OF THE ● d2 = 200 × 20 × 51.
The minimum wear diameter of the
FLAT GRINDING BRH 20A II LATHE grinding wheel is 120 mm, the maximum
To help the technologist of the total width of individual twin wheels is 100

production site mm. The optimum peripheral speed (V

okr.) of these grinding wheels is 35 m / s.
Oil change in the grinding (spindle)

FOREWORD headstock should be carried out once every
3 months. The amount of oil refilled in the

The need to write this manual is due to the presence grinding headstock is 0.3 l. The viscosity
of two factors. The first, objective, is predetermined by of the oil is 3.9 ... 6.2 / 20° C. Russian I
5A oil is a replacing for Czech OL-OT oil.
the fact that of the whole series of grinding machines,
the most exploited at the machine-building enterprises of Coolant tank filling capacity - 63
Russia are surface grinding machines. At one time, at the l. Composition of coolant: water - 95%,
end of the 80s of the last century, in the framework of the emulsol - 2.5%, soda ash - 2.5%. During operation, the coolant must not fall
Coolant replacement – once every
economic integration of the Comecon countries into the by the grinding operator. six months (with cleaning the tank of on a non-rotating circle.
Soviet Union, machines from the GDR, Czechoslovakia, However, the problem is The magnetic (electromagnetic) plate
Romania, etc., including grinding, went in a wide flow. that the job responsibilities for dirt). When replacing the coolant, it is should be periodically grinded to exclude non-
Now, at many machine-building enterprises of the Russian operating a surface grinding mandatory to clean the magnetic dirt trap planar installation of the grinding part.
Federation, those foreign machines continue to work, machine for the grinding from mechanical impurities in the form of When cleaning the lathe from dust and dirt,
waiting for a change. A change they should come in the operator at many of our machine- silty deposits and check its serviceability. the use of compressed air is prohibited. Clean with
When installing a new grinding
form of more modern machines, but already Russian- building enterprises are not a vacuum cleaner and a lint free cloth.
made. So, at least, that’s how it is planned. But when will even mentioned. What makes it wheel, observe the following rules: Do not place the tool on the guides of the
this shift come? Therefore, the veterans of the machine impossible to organize the system ● check the circle for possible cracks table and bed of the grinding head of the lathe.
tool park of Russia should not be weakened, in the sense of preventive maintenance BRH (shells) by tapping it with a wooden
of their skilled operation. In a number of foreign grinding 20A II in the time indicated by hammer, when tapping, the sound should LATHE SETTING
be clean, without rattling;
machines in our country, the most widely represented is a its technical documentation. This
surface grinding machine type BRH 20A of Czechoslovak circumstance predetermines the ● when fixing the circle on the spindle, ADJUSTING OF DUMPING OF EXTREME
production. Unfortunately, this category of machines of second, already subjective, factor pay attention to the condition of the TABLE POSITIONS (Fig. 1)
the last century is now being operated on the residual - the technical incompetence of adapter flanges and nuts; uneven in size With a correctly selected table speed, the
principle, with the squeezing of the latest production the shop managers regarding the or bent adapter flanges when tightening damping value is regulated by a throttle valve (2).
the nuts create uneven pressure on the
resources from them. Moreover, the BRH 20A lathe are organization of routine maintenance, Turning the throttle valve control (1) clockwise
operated in the conditions of the complete absence of in particular surface grinding circle, which can lead to its destruction; softens the table damping process. When rotated
branded spare parts and consumables. machine, at the appropriate time, worn nuts must be replaced; counterclockwise, damping becomes harder.
Accordingly, in such critical conditions, these machines within the framework of the rules for ● between the transitional flanges and the
require a very careful attitude to observing the technology its operation. circle it is necessary to install elastic gaskets: Note: the control element (1) by the throttle
cardboard or leather, the diameter of the
of their operation and maintenance. Undoubtedly, the The proposed manual has the valve is located on the front panel of the machine
organization of their proper operation is completely and following objectives: specification gaskets must be at least 2 mm larger than - under the handwheel for manual movement of
completely the prerogative of shop-floor managers, of the specifics of operation of the the diameter of the transitional flanges; the table.
including production site technologists. These managers surface grinding machine BRH gasket thickness - 2 mm; gaskets before
are required to responsibly observe the operation 20A II at a conceptual level and installation should be oiled to protect SETTING AND CONTROL OF THE PRESSURE
against soaking under the influence of
technology of the machine in question by monitoring the assistance to the management OF THE WORKING LIQUID IN THE HYDRAULIC
implementation of the rules for its routine maintenance of the shop floor in organizing its coolant; SYSTEM (Fig. 2)
planned routine maintenance. ● assembly of the circle and adapter
The manual will also be useful for flanges is performed using a torque wrench; The pressure in the hydraulic operating circuit
the operator of a surface grinding first tighten the mounting screws to gently is regulated by the bypass valve (5). The pressure
machine of this type in terms tighten the circle, then alternately tighten in the hydraulic control circuit is controlled by a
of consolidating his theoretical the diametrically opposite screws of the bypass valve (7).
knowledge and practical skills. adapter flanges with a torque wrench;
● when installing a circle on a machine Note: adjustment of the indicated valves by
GENERAL INFORMATION spindle, it is forbidden to hit it with metal the required value is carried out only by a qualified
objects; in order to remove the circle mechanic-adjuster, if necessary.
For work on the BRH 20A from the spindle, you must first unscrew The pressure in the hydraulic circuits of
lathe it is recommended to use the screws and remove the outer adapter the machine should correspond to the following
grinding wheels of the following flange, which secures the circle; values: hydraulic working circuit – 1.2 MPa;
sizes: ● before starting work, you should hydraulic control circuit – 2 MPa.
● d1 = 250 × 20 × 76; test a new circle at idle for 5 to 10 minutes.

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