SU1371786A1 - Apparatus for monitoring the wear of cutting edge of tools - Google Patents

Abstract

The invention relates to a machine tool industry and can be used to automatically control the cutting process on metalworking machines. Objective 7 of the invention is to improve the accuracy of control by eliminating the influence of wear character measurements on the result of the control. The device contains a current source 1 and a voltmeter 2, each connected by the first clips through the respective current collectors 3 and 4 to the part 5. The current collector 3 of the current source 1 is located at the rear center 6 of the machine 7, isolated from the tailstock 8. The current collector 4 of the voltmeter 2 is mounted on spindle 9 machine 7 and electrically connected. The voltmeter 2 is connected to the cutting tool 10 by the second terminal. The device also contains the first and second resistors I and 12 in series. The first input of the resistor 11 is connected to the first terminal of the voltmeter 2. The first input (L with 00 O5: t v / 7y

Description

switch 13 is connected to the second terminal of the current source 1, the second input is connected to the second output of the second resistor 12, the third input is connected to the common point of the first and second resistors II and 12, and the output is connected to the cutting tool 10. The first output of the control unit 14 is connected to the input input of the switch 13. The first storage device 17, the divider 18 and the recorder 19 are connected in series, with the first input of the first storage device 15 and the second inputs of the multiplier 16 and the divider 18 connected to the output of the voltmeter 2, and the second inputs of the first The first and second memory devices 15 and 17 and the recorder 19 are connected to the second, third and fourth outputs of the control unit 14, respectively. The cutting tool 10 and the rear center 6 of the machine 7 are isolated respectively from the machine 7 and the rear beam 8 by insulating pads 20. 1 slug.

one

The invention relates to a machine tool industry and can be used to automatically control the cutting process on metalworking machines.

The purpose of the invention is to increase the monitoring depth by eliminating the influence of changes in the nature of wear on the control result.

The drawing shows a diagram of the device.

The device contains a current source 1 and a voltmeter 2, each connected by the first clamps through the respective current collectors 3 and 4 to part 5, the current collector 3 of the current source 1 is located at the rear center 6 of the machine 7, isolated from the tailstock 8, and the current collector 4 voltmeter 2 is installed on the spindle 9 of the machine 7 and electrically connected to it, the voltmeter 2 is connected to the cutting tool 10 by a second clamp, the first and second resistors 11 and 12 are connected in series, the first lead of the first resistor 11 is connected to the first clip of the voltmeter 2, switch 13, the first input of which is connected to the second terminal of the current source 1, the second input to the second output of the second resistor 12, the third input is connected to the common point of the first and second resistors 11 and 12, and the output is connected to the cutting tool 10, control unit 14, the first output of which is connected to the control input of the switch 13, the first storage device 15, the multiplier 16, the second storage device 17, the divider 18 and the recorder 19, and the first input of the first storage device 15 and the second inputs of the variable storage device are connected in series Residents 16 and divider 18 are connected to a voltmeter The yields house 2 and the second inputs of the first and second memory devices 15 and 17 and recorder 19 are connected respectively to the second, third and fourth outputs of the control unit 14. Cutting tool 10

and the rear center 6 of the machine 7 are isolated, respectively, from the machine 7 and the tailstock 8 with insulating spacers 20.

The device works as follows.

At the initial time, the signal from the control unit 14 controls the output of the switch 13 to switch with its third input.

During cutting, a natural thermocouple arises between the workpiece 5 and the tool 10 and a current flows through the circuit formed by the thermocouple, the current collector 4 of the voltmeter, the first resistor 11 and the switch 13. The resistance of the first resistor 11 is chosen so small (fractions of ohm) that the maximum current of the natural thermocouple flows through the circuit. The readings of the voltmeter 2, proportional to the maximum current, are recorded in the first memory 15, controlled by the control unit 14.

The transition from the current change to the measurement of the thermo-emf is carried out by the signal from the control unit 14, through which the output of the switch 13 is switched with its second input. The resistance of the second resistor 12 is of the order of a few kilo, so the readings of the voltmeter 2 are almost equal to the emf of a natural thermocouple. At the same time, a signal from the control unit 14 to the output of the first storage device 15 displays information on the maximum current of the natural thermocouple. Signals proportional to the maximum current and thermo-emf are fed to the first and second inputs of the multiplier 16, and the multiplication result is entered into the second memory device 17, the operation of which is controlled by the control unit 14.

After performing these operations, the signal from the control unit 14 controls the output of the switch 13 to switch to its first input, while the current of a certain amount from the current source 1 flows through the circuit formed by the switch 13, the detail-tool contact junction, the rear center 6 of the machine 7 and the current collector 3 I current. The resistance of the contact transition of a tool part depends on the area and state of contact of the part 5 and tool 10, i.e., on the wear surface of the tool I). Signal-i from the output of a voltmeter 2, which is a non-norioopal transition resistance, arrives at the second input of the divider 18, the first input of which receives a signal from the output of the second memory device 17, which is the result of the product of the current to the thermal emf. The result of de: 1 enters the registrar 19, in which the current wear deterioration, determined by the product of the current strength and the thermo-emf of the natural thermonar to the resistance of the contact-component-tool, with the specified critical value, is compared. The registrar 19 detects the indication of wear, and also issues a signal to stop cutting in the CNC rack of the machine 7 (when machining with an FG1U) when the wear value reaches the specified critical value. The operation of the recorder 19 is controlled by a control unit 14.

When changing cutting conditions or materials of part 5 and tool 10, the ratio of measured values changes significantly: current strength and thermo-emf, and the nature of wear may not change, for example |) with increasing cutting speed, thermo-emf increases. As a result of an increase in temperature with pezkachitel1 varying current, the product of the current by thermo-EMF with iTOM also increases, although the magnitude and nature of wear does not change.

When the wear pattern changes, even at monotons. The increasing product of the current strength on thermo-EMF, the steepness of the product curve changes significantly, which reduces the accuracy to () nt) ol with changing cutting conditions and materials of the part 5 and tool 10.

But when the cutting conditions change, the contact resistance of the part-tool contact transition also changes, and the resistance increases with the predominance of ado

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of the nature of wear and with increasing thermo-EMF (due to temperature increase of the materials of the part 5 and the tool 10), which allows using the quality resistance of the normalized parameter, i.e., the parameter, allows to change the cutting conditions .

In de; 1 telle 18 occurs de. 1 the product of the current and thermo-emf to resistance, at the expense of which the mind is carried out (the dependence of the results of the copter, 1 cutting modes, materials of the part and the tool.

Claims (1)

Invention Formula A device for monitoring the wear of the cutting edge of the tool during the cutting process, contains a current source and a voltmeter, each connected by first clamps through the respective current collectors to the part, the current source current collector located at the rear center of the machine and isolated from the tailstock of the voltmeter mounted on a machine pint and electrically connected to it, a voltmeter) with a second clamp connected to a cutting tool, characterized in that, in order to increase the control accuracy, the device is equipped with connected by nerve and second resistors, where the first terminal of the first resistor is connected to the nerve terminal of a voltmeter, the switch, the first input of which is connected to the second terminal of the current source, the second input to the second terminal of the second resistor, the third input, and the output should be dinne to the cutting tool, b. The control unit, whose first stroke is connected to the control input of the switch, is connected in series by the first storage device, multiplier, second storage device, divider and recorder, the first input of the first storage device and the second input are connected to the output in, , t-meters, and the second inputs of the first and BTopoi o storage devices and the recorder are connected respectively to the second, third and fourth outputs of the unrav unit: 1epi.