SU1313607A1 - Device for controlling process of abrasive and electric discharge machining - Google Patents

Abstract

The invention relates to electrophysical and electrochemical processing methods and, in particular, relates to devices for electroabrasive grinding. The purpose of the invention is to increase productivity in terms of reducing wear on the machining electrode. The multivibrator 13 periodically closes the switch 5 and loads the source 1 to the additional resistor 6. If the short circuit is present regardless of the switching on of the resistor 6, i.e. irrespective of the voltage of the pulses, the relays 8, 10 do not operate and the self-oscillations of the multivibrator 13 will continue. If, when the voltage decreases, when the resistor 6 is turned on, the short circuit disappears, then the multivibrator oscillations will continue until a situation occurs when the short circuit of the resistor 6 does not cause a short circuit. This causes the opening of contacts 5, 11, 12 before the new occurrence of a short circuit. neither The device automatically adjusts to a high performance mode and low wear. . f-ly, 2 ill. .hg //: -04F (L ha oo with O5 O VI MS - “J-JHZD-PG / 5 Fig. 7

Description

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The invention relates to electrophysical and electrochemical processing methods, in particular to electro-abrasive grinding.

The purpose of the invention is to increase the production and while reducing tool wear by eliminating accident modes, processing.

Fig. 1 is a schematic diagram of the device; in fig. 2-- device diagram for a version with an extended range of variation of the output voltage of a technological current source.

The device for controlling the process of abrasive-electroerosive processing contains a pulsed source 1 of technological current (connected to the interelectrode gap 2. and

3 constant voltage. Parallel to the variable first resistor 4, which regulates the amplitude of the pulses of the output voltage of the source 15, through the first normally open control, a floating switch (LRU) 5, a second resistor 6 is connected.

Source 3 is connected through a normally open contact (NDT) 7 of the first relay 8 of the unit 9, neither the second JO, nor short circuits, and through a normally closed contact (NZK) 11 of the relay 10, in parallel to which the second (NRUK) 12 is connected, a multivibrator 13 , the output of which is connected to the control inputs of the keys 5 and 12.

For versions with an extended range, the output voltage to the device described is additionally in the form of a divider with a resistor

4 through the first NRK 14 of the third relay 15, the third resistor 16 is connected, parallel to which the fourth resistor 19 is connected through the first NRK 17 of the fourth relay 18, in parallel to which the fifth resistor 22 is connected through the first NRK of the 20th fifth relay 21.

In addition, the source 3 is connected via a series-connected second NRK 23 relay 10 and a third normally closed control switch (NZUK) 24, shunted by a second NRK .25 relay 15, the first chain of series-connected sixth resistor 26, the first dynistor

27 and relay 15, where the seventh resistor is connected in parallel with the distributor and the relay

28 and the first capacitor 29 and later

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the second connected power supply assembly 30 relays; 18 and the first HRC 3 1 of the sixth relay 32. through the third NDK 33 connected in series, the relay 10 and the fourth IZUK 34, which are shunted by the third NDT 35, relays 10, the second chain of the first tiris in series 365, the control torus is connected to the output of the dynistor 27 , the eighth resistor 37, the second dynistor 38 and the relay 18, where the ninth resistor 39 and the second capacitor 40 and the second NZK 41 of the relay 21 and the NRK 42 of the relay 32 are connected in parallel with the dynistor and the relay, through the fourth connected NRK 43 of the relay 10 and p Ty NZ Criminal Code 44, shunted by the third NRK 45 relay 21, the third is a chain of sequentially connected second thyristor 46 control electrode, which is connected to the output of the dynistor 38, the tenth resistor 47, the third dynistor 48 and the relay 21, in parallel with the dynistor and the relay the eleventh resistor 49, the third capacitor 50 and the third NDT 51 32, and the fourth circuit from the series-connected 5 th NSC 52 relays 10, the sixth NZUK 53 and relays 32.

The control inputs of the keys 24, 34, 44 and 53 are connected to the output of the multivibrator 13,

The device works as follows.

The source 3 is switched on, from which, through the NZK 1.1, the voltage is applied to the multivibrator 13, the latter starts to work, and the circuit switches to self-oscillation mode with the frequency of the multivibrator.

Source 1 is switched on. Depending on the initial magnitude of the voltage pulse amplitude, which is increased when the resistor 6 is turned on via the key 5 in the control circuit of source 1, three cases can occur.

First case. This initial value is set so that during the processing of the part, even when a resistor 6 is connected, a technological short circuit takes place (TKZ), the relay 8 does not work, the NRK 7 is open, the relay 10 does not work, as a result of which the auto-oscillation mode continues.

The second case. The specified initial value is set so that when p0

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There are no key resistor 6 TKZ, but when it is off, it is. If source 1 is turned on, when a resistor 6 is connected, then relay 8 is activated and its NRK 7 is closed, relay 10 is activated and its NZK 11 is opened. Since the key 12 is closed, the multivibrator 13 is connected to the power supply. When it changes the state, the key 5 is disconnected and the resistor 6 is turned off, the amplitude of the pulses of the output voltage of the source 1 decreases and a TKZ begins to occur. As a result, the relay 8 is turned off and its contact 7 is opened, the relay 10 is turned off and its NZK 11 is closed, i.e. the circuit has a mode of self-oscillations. The time of the multivibrator jumps is chosen such that the connection time of the resistor 6 (6-7 s) is much longer than the time of its disconnection. (1-2 s). - the minimum time required for reliable operation of the relay 8. Thus, in this case, most of the time, processing occurs at an increased pulse amplitude of the output voltage of source 1 and the absence of a TKZ, and after certain periods of time the device returns to work at a lower value amplitudes that automatically determine the ability to work at reduced voltage with reduced tool wear. If this is not possible due to the occurrence of a TKZ, the device returns to operation at a lower amplitude to eliminate the TKZ. If the transition to a lower amplitude TKZ does not occur, then the keys 5 and 12 and contact 11 are open and the device does not return to work on the above amplitude, i.e. resistor 6 is disconnected and the circuit does not have a self-oscillation mode until TKZ occurs.

The third case. The keys 5 and 12 are open, the resistor 6 is disconnected from the source 1. The amplitude indicated is reduced, and since there is no TKZ; then relay 8 is not turned off and its HPK 7 is closed, relay 10 remains on, and its NZK 11 is open. Thus, the circuit is disconnected from source 3 until the appearance of the TCH.

 In a device with a performance with an extended voltage range, in this case the following occurs.

Pin 23 and key 24 are closed, and relay 10 is turned on, capacitor 29 starts charging from source 3 to the voltage of the dynistor 27. The latter opens, and relay 15 turns on, closes its NRK 25 and 14 Contact 25 blocks the relay 15 itself, and contact 14 connects a resistor 16 to the circuit, due to which the indicated amplitude of source 1 drops somewhat, and then when the resistor 6 is turned off, a TKZ appears, and the circuit shown in FIG. 1, comes into oscillatory mode again. The presence of resistor 28 is caused by the following: the absence of a TKZ with a disconnected resistor 6 may be temporary (10-40 s), then a TKZ again occurs, and the circuit increases the indicated amplitude this is repeated several times. Then the capacitor 29 during periods of no TKZ (pin 23 open) is energized on the resistor 28, relay 15 does not operate and the indicated amplitude does not decrease.

If, after connecting to source 1 of resistor 16 (with disconnected resistor 6), there is no TKZ, then the second stage is switched on (from elements 17-19, 33-42), which operates in the same way as described for the first stage (from elements 14-16, 23- 31). The second stage is switched on - after opening the dynistor 27 and applying a positive voltage to the control electrode of the thyristor 36.

After connecting to the resistor 19 circuit, the indicated amplitude is still reduced.

The third cascade (of elements 20-23 gZ-51) operates in a similar manner to the first and second. Thus, there are, as it were, four levels of coarse, automatic control of the specified amplitude, and at each level - two more limits (determined by connecting-resistor 6): upper and lower, i.e. the device automatically finds the minimum specified amplitude at which the treatment goes without TKZ. If a TKZ occurs at the upper limit of any of the last 3 adjustment steps, the following happens: since relay 10 is off and its NZK 52 is closed, and key 53 is also locked, relay 32 and its NPK 31 42 and 51 are activated in each stage . However, only the cascade is disabled.

corresponding to the stage within which TKZ emerged. If this is the third stage, then after closing the NRK 51, the capacitor 50 is discharged, the dynistor 48 is closed, the relay 21 is turned off, the contacts 45, 20 are opened, the resistor 22 is turned off, the indicated amplitude increases. However, relays 18 and 15 are not turned off, as of NZK 41 and 30 are open. Relay 32 due to the disappearance of the TKZ again de-energizes. If this is the second stage, then the closure of the NRK 51 of the third

the cascade does not affect anything, since

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20

relay 21 is off and its NZK 41 is closed.

Resistors 6, 16, 19 and 22 are selected so as to provide a stepped control of the specified amplitude.

The use of the device provides automatic adjustment of the voltage amplitude to a level corresponding to the maximum performance, while reducing wear on the processed 25 electrodes.

Claims (2)

1. Process control device abrasive electroerosive processing, which contains a technological current source with a variable first resistor that regulates the amplitude of its output voltage pulses, and a short circuit detection unit with the first relay, which is different. It is noted that, in order to increase processing performance, it is additionally equipped with two normally open controlled keys, a second resistor, a constant voltage source, a second relay and a multivibrator, while the second resistor is connected via a first key parallel to the first resistor, to a constant source the voltage is connected through a normally open contact of the first relay to the second relay, and through the normally closed contact of the second relay, in parallel to which the second switch is connected, a multivibrator, the output of which connected to the control inputs of both keys. 2. The device according to claim 1, characterized in that it is additionally equipped with four relays, three dynistors, nine resistors, three capacitors, two five . five 0 five 0 five 0 five 0 five thyristors and even 1) rm normally closed controlled keys, the control inputs of which are connected to the output of the multivibrator, according to the splitter circuit with the first resistor through a normally open first contact of the third relay the third resistor is connected, in parallel with which the fourth resistor is turned on through the normally open first contact of the fourth relay, pa- rstly which through a normally open first contact of the nth relay A fifth resistor is connected, a second voltage source is connected to a constant voltage source through a serially connected, normally open second contact of a second relay and a third switch, bounded by a normally open second contact of a third relay, the first string of sixth resistor connected in series, the first driver and the third the relay, where the parallel} and the relay are connected to the seventh resistor and the first capacitor and in series connected normally closed second and open first contacts, respectively, four the second and the sixth relays, through a serially connected normally open third contact of the second relay and a fourth key are shunted by a normally open third contact of the fourth relay; and the fourth relay where parallel to the dynistor and the relay are included the ninth resistor and the second capacitor and in series connected normally closed and open w These are the contacts of the fifth and sixth relays, respectively, through the fourth relay of the second relay and the fifth key sequentially connected, the fifth key shunted by the normally open third contact of the fifth relay, the third chain of the second thyristor connected in series, the control electrode of which is connected to the output of the second dynistor, the tenth resistor, the third dynistor and the fifth relay, where the eleventh resistor, the third capacitor and the normally open third contact are connected parallel to the dynistor and the relay estogo relay, and a fourth chain of 713136078 serially connected nor-second relvg of the sixth key and the neck circuit of the relay. 5 72 Editor A. Ogar y Compiled by R. Tehred M. Khodanich Proofreader S. Cherni Order 2163/13 Circulation 976 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Design, And .2