RU1776491C - Device for checking serviceability of machine - Google Patents

Abstract

The invention can be used in mechanical engineering when processing parts on CNC machines. The device comprises a machine control unit 1, a short-pulse shaper 2, a delay circuit 3, a second AND 4 circuit, a NOT 5 circuit, a trigger 6, and a vibration converter 7, a band-pass amplifier 8, a first band-pass filter 9, a first detector 10 with an integrated low-pass filter frequencies, the first comparator 11, the OR circuit 12, the first And 13 circuit, the second band-pass filter 14, the second detector 15 with an integrated low-pass filter, the second comparator 16, the third And 17 circuit, the setting unit 18, which contains the decoder, the first, second and third sensors. The master circuit includes electronic switches 25 and variable resistors. 3 ill. Yo XI VI O O

Description

The invention relates to the field of grooving machines and can be used to control the machining process on CNC machines.

A device for monitoring machines is known, comprising a vibration transducer and a band-pass amplifier in series, a band-pass filter, a detector with an integrated low-pass filter, a comparator, a two-input element And, a machine control unit, and also a second band-pass filter connected in series with the output of the band-pass amplifier, the second detector with an integrated low-pass filter, the second comparator, the element NOT, the second two-input element And, the output of which is connected to the control unit of the machine, are connected m through the setting unit with the second input of the second comparator and with the delay element, the second input of the delay element being connected to the machine control unit, the output connected to the second input of the second element And, and the second input of the first element And connected to the machine control unit,

The device provides for the detection of tool breakage, the absence of a workpiece, exceeding the maximum permissible dynamic loads on the machine, however, it has limited technological capabilities and low reliability, since it does not exclude false alarms during periods of short interruption of the cutting process, as well as blocking the operation of the machine with simultaneous rapid progress and a signal about the presence of the cutting process,

These disadvantages are partially eliminated by another machine monitoring device comprising a machine control unit, a first AND circuit and a vibration converter connected in series, a bandpass amplifier: a first bandpass filter, a first detector with an integrated low-pass filter, a first comparator, and also a second bandpass filter associated with the output of the strip amplifier, a second detector with an integrated low-pass filter, a second comparator, a NOT circuit, a second AND circuit, the output of which is connected to the first input the house of the machine control unit, connected by the first output through the setpoint setting unit to the second input of the second comparator and to the first input of the delay circuit, the output of which is connected to the second input of the second circuit And, and the first input and output of the first circuit And are connected respectively to the second output and second entrance

the control unit of the machine tool, a short-pulse generator, the first input of which is connected to the output of the circuit NOT, and the output is connected to the second input of the delay circuit, trigger

the input of which is connected to the third output of the machine control unit, and the output to the third input of the second AND circuit, as well as the third AND circuit connected in series and the OR circuit, the second input of which

connected to the output of the first comparator, and the output to the first input of the first circuit And, and the output of the second comparator is connected to the second input of the third circuit And, the fourth output of the machine control unit

connected to the second input of the short pulse generator and to the fourth input of the second circuit And, and the fifth output of the machine control unit to the first input of the third circuit I.

The device provides an increase

reliability by eliminating false alarms of the device during periods of interruption of the cutting process in overrun areas, blocking the operation of the machine in the presence of

at the same time a signal - High speed and a signal about the presence of the cutting process, the expansion of technological capabilities by controlling the device lock according to the program in areas with intermittent

forming, however, the technological capabilities of the device are still insufficient, because it is not possible to set several maximum permissible values of dynamic loads for various cutting tools of multi-tool setting and various technological modes and processing conditions.

So, for example, the device will provide

turning off the machine when one set value of the maximum permissible dynamic load is exceeded, while the threshold value of these loads for various processing conditions, i.e. different cutting tools is quite certain.

As a result, when machining on passes with a small allowance, the dynamic loads caused by critical wear of the tool will be insufficient to trigger the device and block the operation of the machine, which will inevitably lead to breakage of the corresponding cutter and marriage

the workpiece.

The aim of the invention is to expand the technological capabilities of the device for monitoring machine tools by setting a threshold value for the amplitude of vibrations for each cutting tool multi-tool setup.

On Fig, 1 shows a structural diagram of the proposed device; in FIG. 2 is a block diagram of a setting unit; in FIG. 3 - structural diagram of the setter.

The control device for CNC machines includes a machine control unit 1, a short pulse shaper 2, a delay circuit 3, a second AND circuit 4, a HE circuit 5, a trigger 6 and a vibration converter 7 connected in series, a band-pass amplifier 8, a first band-pass filter 9, the first detector 10 with an integrated low-pass filter, the first comparator 11, the OR circuit 12, the first AND circuit 13, the output of which is connected to the second input of the machine control unit 1, and the second input to the second output of the machine control unit 1, the third output of which oucher q is connected to trigger 6, a second band-pass filter 14 connected in series, a second detector 15 with an integrated low-pass filter, a second comparator 16, a third AND circuit 17, the output of which is connected to an OR circuit 12, and the first output to p to that output, the machine control unit 1, which is connected with its fourth output to the second input of the short pulse generator 2 and to the fourth input of the second AND 4 circuit, which, in turn, is connected to the output of the second comparator 16 by the first input through the NOT 5 circuit, about the second input - to the output of the delay circuit 3, in addition, the first input of the driver 2 short pulses is connected to the output of the circuit NOT 5, and the output is to the second input of the delay circuit 3, to the first output of the machine control unit 1 is connected to the setpoint setting unit 18, the first and the second outputs of which are connected to the second input of the second comparator 16 and to the first input of the delay circuit 3, respectively, the third output of the setpoint unit 18 is connected to the second input of the first comparator 11.

Block 13 (see FIG. 2) for setting the settings contains a decoder 19, a first 20, a second 21 and a third 22 switches, the input of a decoder 19 being the input of a block 18. The output of a decoder 19 is connected to the inputs of the first 20, second 21, and third 22 - sensors whose outputs are respectively the first, second and third outputs of block 18.

The setter circuit (see Fig. 3) includes the first 23, second 24, 25 electronic keys and 26.27, .... 28 variable resistors, the outputs of which are connected to the corresponding electronic keys, according to the second

the first electronic key inputs are the input of the master, and the outputs are the output of the master.

The machine control unit 1 is - 5 a numerical control system. The system uses: a block of technological commands (inputs 1.2; outputs 1.2, 3) a speed setting block (outputs 4.5). The H22-1M numerical control system is described in the technical description G61.700.040-02T01, as well as with. 18 Sergievsky L.V. Electronic devices of the CNC system. Moscow. Mechanical engineering, 1977. The master is a 10-day switch of the type ПП10.

The rest of the newly introduced blocks and their functions: a decoder, an electronic key are standard and are described in the reference manual Integrated circuits under

0 ed. B.V. Tarabrina, Moscow, Radio and communications. 1984 year

The device operates as follows. The signal from the vibration transducer 7 mounted on the spindle hem- v

5, nickel is fed through a band-pass amplifier 8 to the inputs of the band-pass filters 9 and 14. The band-pass filter 9 is tuned to the fundamental frequency of natural vibrations of the machine spindle. The amplitude of oscillations at this frequency reflects the dynamic load on the spindle, which can exceed the allowable for critical wear of the tool, improperly selected operating modes and various emergency situations.

5 The signal from the band-pass filter 9 is detected and smoothed by a detector 10 with an integrated low-pass filter and supplied to the comparator 11.

So for every cutting

0 of the tool, its threshold value of the amplitude of oscillation of the spindle assembly of the machine due to dynamic loads during cutting can be set. Those. for each rusting tool it is possible to admit its degree of critical contribution or the maximum allowable machining conditions for the part.

The first comparator 11 is configured with an adjustable threshold. When the voltage at the output of the first detector 10 exceeds the operating voltage of the comparator, the value of which is different for different instruments, from the third output of the setting unit 18 is fed to the second input, the first comparator 11, causing it to operate and appears at its output logical signal 1, which is supplied through the OR circuit 12 to the first input of the first circuit And 13. To the second input of the first cx, circuit And 13 from the machine control unit 1

a logical G signal is generated when the machine spindle rotates. That way, if during the rotation of the spindle the dynamic load in the AIDS system of the machine is exceeded, which is detected by the vibration transducer 7 and causes the first comparator 11. The logic 1, which is fed to the CNC system, will appear at the output of the first circuit And 13. turns off the feed and rotation of the spindle. The first circuit And 13 prevents false operation of the device during auxiliary operations on the machine.

A second channel, consisting of a second band-pass filter 14, a second detector 15 with an integrated low-pass filter, and a second comparator 16, serves to receive a signal about the presence of the cutting process. The second band-pass filter 14 is tuned to a frequency in the range of 10-30 kHz, at which the ratio of the signal from the cutting process to the noise of the rotating bearing is maximum.

To increase the sensitivity, the second comparator 16 is made with an adjustable threshold, the value of which is set from the first output by the setting unit 18, separately for each tool. The need to increase sensitivity is caused by the fact that the noise level of the spindle bearing substantially depends on its rotation speed,

The principle of operation of the second channel is based on the receipt of a signal from the vibration transducer 7 about the presence of cutting and at the same time a signal on the presence of the machine support in the Working feed mode. If the tool breaks, the workpiece is not supplied to the processing zone, there will be no signal about the presence of the cutting process at those moments when it should be in the program. In this case, the device turns off the feed and the spindle of the machine and turns on the call signal of the installer. A signal about the presence of the cutting process from the output of the second comparator 16 is fed through the NOT 5 circuit to the first input of the second And 4 circuit. The logical 1 from the machine control unit 1 to turn on the working feed is fed to the fourth input of the second And 4 circuit. To the second input of the second circuit And 4, zero pulsed signals are supplied to prevent false alarms of the device in the interval from switching on the working feed to touching the tool with the part (in the cutting area) and in the period from the moment the tool comes out of contact with the part to turning off the working feed ( in areas of run). On the third

the input of the second circuit And 4, a logical signal 1 - Blocking the control signal of the presence of the cutting process is turned off. By a positive differential signal, the working feed (on the leading edge) from the machine control unit 1 at the second input at the moment of turning on the working feed and a positive differential signal on the presence of the cutting process (on the falling edge) along

0 to the first input at the moment the tool comes out of contact with the part by the short pulse shaper 2, short pulses are generated, which are supplied to the second input of the delay circuit 3. At the output of the delay circuit 3, zero delay impulse signals are generated to prevent false alarms in the plunge and overrun sections, the duration of which is set by the variable resistors 29 ... 31 of the second setpoint unit 24 of the setpoint setting unit 18 from the second output separately for each tool. The setting unit 18 receives information from the machine control unit 1 (system

5) in binary decimal code, which, after being converted by the decoder 22, provides information to the inputs of the setters 23, 24, 25 about which tool is currently in operation. Consider

0 operation of this part of the circuit for the case when the cutting tool is broken. At the output of the second comparator 16, the logical 1 signal changes to O, since there is no signal from the cutting zone (the cutting tool5 does not touch the part, since it is broken. This logical O signal is inverted by the NOT 5 circuit and the first input of the second And 4 circuit comes logical signal G, at the fourth input of the second circuit And 4 there is a logical signal for the presence of the working feed, and at the third input of this circuit there is also a logical signal 1 - Blocking the control signal for the presence of the cutting process is turned off.

5, the second input of the second circuit And 4 after breaking the instrument and after the time set by the delay circuit 3 also receives a logical 1 signal. The arrival of four logical 1 to the inputs of the second circuit And 4 leads to the appearance of a logical 1 signal at its output , which enters the CNC system, stops the machine and turns on the call signal of the installer,

In the case when it is necessary to move on the working feed in the absence of the cutting process, to trigger 6 from the third output of the machine control unit 1 according to the technological command entered in the program (644) - Signal control block

the presence of the cutting process is included in

9

while the frame containing this command is being read, a logical O signal is issued, which sets trigger 6 to the zero state. The logical O signal is fed to the third input of the second circuit And 4 and prohibits the control of the signal from the presence of the cutting process. To cancel this command, the technology command G45 is entered into the program. The blocking of the monitoring signal of the presence of the cutting process is turned off. When reading the corresponding frame, a single signal from the third output of the machine control unit 1 sets the trigger 6 to a single state and enables control of the cutting process. This is necessary when machining surfaces with an intermittent generatrix having various grooves, grooves, grooves, or eccentric surfaces, including rough surfaces, during pretreatment of parts with uneven allowance. The operation of the device provides protection against breakage when the cutting tool is inserted at high speed into the workpiece as a result of malfunctions in the CNC system of the machine or in case of errors in the calculation of the control program. The signal from the vibration converter 7 causes the output of the second comparator 16 to generate a logical 1 signal (the presence of a cutting process) much faster than a logical 1 signal (exceeding the maximum dynamic load) at the output of the first comparator, since the frequency is 10-30 kHz, which controls the cutting process, is significantly larger than the natural frequency of the spindle. Logic signal 1 from the output of the second comparator 16 is supplied to the second input of the third circuit And 17. At the first input of the third circuit And 17, for certain malfunctions, a logical signal 1 - High speed is supplied. Logical signal 1, which appears at the output of the third AND circuit 17, is fed through the OR circuit 12 to the first input of the first And 13 circuit and stops the processing.

Based on the present invention, a control device for CNC machines is developed. The control blocking of the control signal of the presence of the cutting process is carried out using redundant technological commands:

G44 - lock control signal presence of the cutting process is on;

G45 - blocking the control signal of the presence of the cutting process is turned off.

Technological teams are included in the part management program. The main part of the device is installed

on a separate board that fits on

/

the backup location of the N22-Sh CNC system, and the control elements (variable resistors) are separately designed by the panel and installed on the operator’s console of the CNC system.

Using the present invention, it will be possible to use the device for monitoring on CNC multi-tool machines, setting for each cutting tool the corresponding value of the maximum allowable dynamic loads during critical wear of the tool, improperly selected machining modes or other emergency situations.

The device will also increase the productivity of machining parts by setting the optimal cutting conditions for each tool during multi-tool machining, protecting them from critical wear and breakage using the proposed design of the machine control device, which provides differentiated setting of threshold values of the vibration amplitude of the machine spindle assembly for each cutting tool.

Claims (1)

SUMMARY OF THE INVENTION A device for monitoring the health of a machine, comprising a machine control unit, a short pulse shaper, a delay circuit, a second AND circuit, a NOT circuit, a trigger and a vibration converter connected in series, a band-pass amplifier, a first band-pass filter, a first detector with an integrated low-pass filter, a first a comparator, an OR circuit, a first AND circuit, the output of which is connected to the second input of the machine control unit, and the second input - to the second output of the machine control unit, the third output of which in turn, it is connected to a trigger, a second band-pass filter, a second detector with an integrated low-pass filter, a second comparator, a third AND circuit, whose output is connected to the first input of the OR circuit, and the first input to the fifth output are connected to the output of the band amplifier the control unit of the machine, which is connected with its fourth output to the second input of the short pulse generator and to the fourth input of the second AND circuit, which, in turn, is not connected to the output of the second com a parator, the second input to the output of the delay circuit, in addition, the first input of the short-pulse generator is connected to the output of the circuit NOT, and the output - to the second input of the delay circuit, to the first output of the machine control unit a setpoint unit is connected, the first and second outputs of which are connected to the second input of the second comparator and to the first input of the delay circuit, respectively, characterized in that. in order to expand the technological capabilities of the device, the third output of the setting unit is connected to the second the input of the first comparator, while the setting unit is in the form of a decoder, first, second and third sensors, the input of the decoder is the input of the setting unit, the output of the decoder is connected to the inputs of the first, second and third sets, the outputs of which are respectively the first , second and third outputs of the setting unit. input / g: and 23 4 2b FIG. 2 25 Output