SU1415151A1 - Method of measuring wear of cutting tool - Google Patents

Abstract

The invention relates to metal cutting and can be used to determine tool wear on the back surface during cutting. The purpose of the invention is to improve the accuracy of measurement by creating a constant cutting temperature regardless of the type of processing (black, pure, asymmetric, etc.). During the cutting process, the electrical resistance of the tool-part- contact is recorded. Additionally, periodically short-term tool feed is periodically reduced, the temperature in the cutting zone is measured and kept constant by changing the cutting speed, and tool wear is determined by the ratio of the average per revolution spindle values of the electrical resistance of the contact tool - part at the working and reduced feed rates. 3 il. but "

Description

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The invention relates to metal working industry and can be used in systems that control the wear of a cutting tool during a durability period.

The purpose of the invention is to improve the accuracy of wear measurement by creating a constant cutting temperature regardless of the type of treatment (black-and-white, pure, asymmetrical, etc.). 1 FIG. Figure 1 shows the dependence of the average width of the wear chamfer along the back surface of the tool on the ratios of contact resistances at reduced 5 || and working feeds at a constant temperature in the cutting zone in FIG. 2 fo, experimentally obtained constant cutting speed | Fig. 3. is a block diagram of a device implementing the method; i The device contains a reference current source 1, the load of which is a circuit formed by a current collector 2, a spindle 3, processed by a retal 4 and a 1-meter dash with a tool in the cutter exit 5. Information inputs of the meter 6 electrical contact resistance tool - part and sampling - storage unit 7: connected to cutter 5 in the immediate vicinity of its tip and through measuring current collector 8 to workpiece 4, Generator output 9 of rectangular pulses It is connected to the control inputs of the source of the reference current 1, the electrical resistance meter 6 is a contact-: that tool is a component, and the sampling-storage unit 7. The output of the meter 6 is connected to the information input of the unit 10 for determining the average electrical contact resistance of the tool — a detail per spindle revolution, the input of which is connected to the output of the angle sensor 11 of the spindle gate and the output to the information input of the calculator 12. The control input of the calculator 12 is connected to the output of the schL-gram control device 13. The output of the sampling - storage unit 7 is connected to the first input of the comparator unit 14, the second input is connected to the output of the cut thermo-emf sensor 15. The output of the comparison unit f4 is connected to the input of the controller 16, the output of which is connected to the input of the spindle 17 drive. The output of the spindle drive 17 is connected to the spindle

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Lem 3 of the machine and the input of the sensor 17 of the angle of rotation of the spindle.

The method is implemented as follows.

During the cutting process, the contact resistance is recorded and, by changing its value, a tool wear is judged. Tool wear is determined by the ratio of the resistances that occur with reduced and normal feeds per revolution of the part. During the cutting process, the source 1 of the reference current, controlled by the square-pulse generator 9, generates square-wave pulses of constant frequency and reference amplitude. The voltage at the tool-part contact is also in the form of rectangular pulses, their amplitude being equal in magnitude to the thermo-emf of cutting B at zero current of source 1 of the reference current. In the instrument-electric contact resistance meter 6, periodic contact voltage is memorized at a current of the source 1 of the reference current equal to O and at the current of the reference amplitude.

Thus, at the output of the meter 6, a voltage is formed in proportion to the resistance of the contact. The voltage from the contact tool - part also enters the sampling block 7 - storage, controls the same generator 9. As a result, when the current source 1 of the reference current is 0, the block 7 is in the sampling mode and a signal is generated at its output Thermal cutting EMF E, With a current of source 1 of the reference current equal to I ,, unit 7 switches to storage mode and at its output a signal equal to the thermal EMF of the cutting before switching from source 1 of the reference current from the state IO to state

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at a high enough frequency

Oscillator 9, the minimum value of which must exceed the maximum possible frequency of depth of cut, the signal at the output of the meter 6 is proportional to the current value of the electrical resistance R contact tool - part, and the output of the sampling unit 7 is a signal equal to the current value - EMF cutting E,

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In block 14, a comparison is made between the current and set thermo-emf of the cutting, respectively, from the output of block 7 and the setting device 15. The feedback signal from the output of block 14 is fed to the controller 16, which generates a signal to the spindle drive 17 so that the thermo-emf is constant nnoy. The control unit 10 is produced by the sensor 11, the rotation of the spindle. Periodically. The device 13 generates signals for measuring wear. These signals in block 12 memorize and generate a signal to change the feed.

15151

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the invention

The method of measuring the wear of the cutting tool, which consists in recording the electrical resistance of the contact of the tool — the workpiece to be processed — and judging by the change in its size, the tool is judged to wear the tool, which means, in order to improve the measurement accuracy, maintain a constant temperature in the cutting zone by changing the parameters of the cutting mode.

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Claims (1)

Claim The method 'of measuring the wear of a cutting tool, which consists in the fact that during the cutting process, the electrical resistance of the contact between the tool and the workpiece is recorded, and tool wear is judged by changing its value, which means that, in order to increase the measurement accuracy, they are kept constant temperature in the cutting zone by changing the parameters of the cutting mode. Fig .1 '1415151