SU425100A1 - DEVICE FOR ACOUSTIC DIMENSIONAL QUALITY CONTROL OF PRODUCTS - Google Patents

Description

one

The invention relates to non-destructive testing methods and can be used for volumetric quality control of parts.

Devices for acoustic volumetric quality control of parts are known, comprising excitation and reception coils, a permanent magnet, a continuous oscillation generator for powering the excitation coil, and a recording unit.

However, such devices give insufficient accuracy of control, for example when monitoring parts of small dimensions, due to the fact that during continuous operation, the signal from the excitation coil to the receiving signal significantly exceeds the useful signal.

The proposed device is characterized in that it is equipped with a pulse packet generator, an electronic key connected between the continuous vibration generator and the excitation coil and controlled by the pulse packet generator, an amplitude discriminator of two levels and a time selector connected to the pulse packet generator and the amplitude discriminator whose input connected to the receiving coil, and the registration unit is designed as a pulse splitter connected in series, a pulse counter and a digital indicator pa and connected to an output of temporary

2

selector. In addition, the device is equipped with a compensation coil connected to the receive coil.

FIG. 1 is given a block diagram of the proposed device; in fig. 2 - waveform at the output of the device nodes, respectively:

a) generator of continuous oscillations

b) pulse packet generator

c) excitation coil d) receiving coil

e) amplitude discriminator

f) temporary selector.

The system consists of a continuous oscillator 1 with a tunable frequency, an electronic switch 2 controlled by a generator of 3 pulses, a power amplifier 4, an excitation coil 5, a reception coil 6, a compensation coil 7, a permanent magnet 8, an amplitude amplifier 9

discriminator 10, time selector I, pulse divider 12, pulse counter 13, digital indicator 14, detector 15, dial indicator 16. The device is based on electroless electrodynamic excitation and reception of the natural oscillations of the part and automatic reading of the average Q-factor of these oscillations. The power amplifier 4 powers the excitation coil 5 with a variable frequency current set by the generator

The torus 1. In the controlled part 17, eddy currents of the same frequency are induced, the interaction of which with the permanent magnet zero causes the appearance of electrodynamic forces causing elastic oscillations of the part. The signal from the receiving coil 6, induced by the eddy currents of the part, is amplified, detected and fed to the dial indicator 16. The continuous oscillation generator 1 is tuned to the resonant frequency of the part oscillation according to the maximum deviation of the indicator hand 16. The gain of the amplifier 4 is adjusted to set level Then, on a one-time command, a generator of 3 pulse packets is started, which generates n modulation pulses. The electronic key 2 modulates the continuous oscillations of the generator 1. The cessation of the exciting force in the pause between pulses causes the damping of the natural oscillations of the part 17. After amplification, these oscillations are fed to the input of the amplitude discriminator by two levels AI and A. corresponding fluctuations at the inlet between the AI and AZ levels. The time selector 11, triggered by the generator of 3 pulse packets, passes pulses to the divider G2 pulses, corresponding to the portion of the falling exponent (in the pause between the excitation pulses). This avoids any influence on the accuracy of measuring the quality of pickup with

excitation coil 5 on the receiving coil 6. Counter 13 outputs on a digital display the number of pulses corresponding to the average value of the quality factor of oscillations for n measurements. The compensating coil 7 reduces the pickup signal on the receiving coil 6 in the process of adjusting the frequency of the generator I continuous oscillations by, the own resonant frequency of the part 17.

Subject invention

Claims (2)

1. A device for acoustic volumetric quality control of products, comprising a permanent magnet, excitation coils and 5, an oscillator of non-continuous oscillations for powering the excitation coil and a recording unit, characterized in that, in order to improve the measurement accuracy, it is equipped with a pulse packet generator, an electronic key connected between the continuous oscillation generator and the excitation roller and the pulse generator controlled by the pulse amplitude discriminator on two levels and a temporary selector, connected to a generator of pulse packets and an amplitude discriminator whose input is connected to a receiving coil, and the registration unit is designed as a series of pulse splitters connected in series, a pulse counter and a digital indicator and connected to the output of the time selector. 2. A device according to claim 1, characterized in that it is provided with a compensation coil connected to the reception coil.  Umnt / flllC