SU1471114A1 - Device for determining a moment of cutting tool dulling - Google Patents

Abstract

The invention relates to the automatic determination of the cutting properties of tools and can be used on automatic lines and program-controlled machines. The aim of the invention is to increase the reliability of determining the moment of blunting of the cutting tool by continuously determining the wear of the cutting tool and the moment of critical blunting of the cutting tool until auto-oscillations occur. The device consists of a vibration sensor 1, an amplifier 2, a command channel connected to the latter, and N high-frequency channels connected to the logic element AND 10. A nonlinearity unit 3 is input into the device, its input is connected to the output of amplifier 2, and the output is to the command inputs and high-frequency channels, and a computing unit 13 connected to the detector output of the first high-frequency channel. 1 il.

Description

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The invention relates to the automatic determination of the cutting properties of tools and can be used on automatic lines and program-controlled machines, in

particular in flexible automatic

production, and machine tools with program control, work in the mode of deserted technology.

The aim of the invention is to increase the reliability of determining the moment of blunting of the cutting tool by continuously determining the wear of the cutting tool and the moment of critical blunting of the cutting tool until the occurrence of self-oscillations in the elastic system of the machine.

The drawing shows a block diagram of the device.

The device consists of a vibration sensor 1, an amplifier 2 connected to it, a nonlinearity unit 3 connected to the amplifier 2, connected to the last n high-frequency channels, consisting of connected in series antenna 4, detector 5 and comparison circuit 6, a command channel consisting of ftpra 7, the detector 8 of the automatic tuning frequency block 9 of the filters according to the amplitude of the output signal of the AND 10 logic element, the inputs of which are connected to the outputs of each of the n high-frequency channels of the threshold value generator 11, the outputs of which connected to the second inputs of the comparison circuit 6 in each of the n channels, n-1 multiplication blocks 12, the inputs of which are connected to the output

block 9 automatic setting hour

filter taps, and outputs to the control inputs of the NARROWBAND tunable filters 4 (in the first channel the input of the filter 4 is connected directly to the output of block 9), the computing unit 13, whose input is connected to the input of the detector 5 of the first channel. - The device works as follows.

The signal from vibration sensor 1 (for example, a piezo accelerometer) mounted on an instrumental block or another machine node is fed to preamplifier 2. After amplification, the signal during normal operation of the tool passes without distortion through block 3 non-linearity due to the presence of a linear portion when approaching wear to critical ve

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The signal in block 3 is limited in amplitude. Using a filter with a constant bandwidth, a frequency band is allocated that contains the natural frequency of the instrument, the signal is detected by the detector 8 and fed to the input of block 9 for automatically adjusting the filter frequency according to the amplitude of the output signal, the output of block 9 is given the maximum amplitude per tuner of narrow-band tunable filters 4, one of which in the first channel is tuned to the frequency component of the maximum amplitude — the natural frequency of the instrument, and the other e with the help of blocks 12 multiplied by frequencies, by 2, 3 ... are large. The components allocated by the filters 4 are detected by the detectors 5. In the comparison circuits 6, the levels of each component are compared with the corresponding threshold value, above which the voltage is applied to the element. And 10. In the event that all the components exceed the respective threshold values, the And 10 element gives a blunt signal. The shelf in the characteristic of non-linearity block 3 is selected so that the signal is limited before the onset of self-oscillations in the machine tool system. When a signal in its spectrum is limited in terms of VTS harmonics at frequencies multiple to the natural frequency of the instrument, the I 30 element transmits to the numerical control unit (CNC) a signal that the wear value approaches the critical value according to the criterion of vibration resistance. The functions of the computing unit 13, which can be used, for example, a microcomputer, is included in either the CNC machine tool or the site diagnostics system (line, workshop), includes a programmatic determination of the amount of tool wear by the signal level in the first channel and outputting a signal about the amount of wear for the subsequent correction of the position of the executive body of the machine.

Claims (1)

Invention Formula Device for determining the time of blunting of a cutting tool on CNC machines containing a vibration sensor connected in series, an amplifier and a command channel, which is made in the form of a filter connected in series, a detector and an automatic filter frequency tuning unit by the amplitude of the input signal connected to the output of the amplifier n high-frequency channels each consisting of a second filter connected in series, the second input of which is connected to the output of an automatic frequency tuning unit filter in the second detector and a comparing circuit, an AND gate whose inputs are the compounds: the outputs of the comparison circuit, dial thresholds, the outputs of which are connected to the second inputs of the comparison circuits, and p-1 multiplication units, the inputs of which are connected to the output of the automatic filter frequency setting unit, and the outputs to the second inputs of the n-1 second filters, characterized in that, in order to increase the reliability of the cutting tool blunting moment, it is equipped with a nonlinearity unit, the input of which is connected to the output of the amplifier, and the output is connected to the inputs n of the high-frequency and command channels, and a computing unit whose input is connected to the output of the detector of the first high-frequency channel, and the output dnaznachen for connection to the machine control. Editor S.Pekar Compiled by R. Kanzafarov Tehred M. Hodannch Proofreader O. Kravtsova Order 1602/46 Circulation 788 VNIIPI State Committee for Inventions and Discoveries npvi SCST of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 The production and publishing plant Patent, Uzhgorod, vji. Mr. Garina, 101 Subscription