SU1260781A1 - Device for checking quality of article and material surface - Google Patents

Abstract

A device for controlling the quality of the surface of products and materials relates to the field of non-destructive testing, and more specifically to devices for removing defects on the surface of products and materials. The purpose of the invention is to increase the reliability of quality control of the surface of products and materials by filtering electrical signals by a parameter corresponding to the sum of the signal durations at different levels. The device contains an illuminator 1, a phototransducer 3 connected in series, a bandpass amplifier 4, an electronic processing unit 5. Block 5 allows to increase the signal-to-noise ratio. Block 5 is made in the form of a rectifier 7, threshold elements 8, the number of which corresponds to the number of levels at which the duration of the signal is measured, digital-analog converter 9, control threshold element 11, integrator 12. At the output of the integrator 12, the corresponding S is formed ( L t Od o | 00

Description

step signal, in which the ratio of the useful signal / igum is higher than that of the original signals. In block 5, a pulse generator 10 is inserted, and digital-analog converter 9 is executed. gated with the output of the pulse generator 10 is connected to the upi

The invention relates to non-destructive testing, and specifically to devices for detecting defects on the surface of products and materials.

The purpose of the invention is to increase the reliability of monitoring by filtering electrical signals by a parameter corresponding to the sum of signal durations at different levels.

FIG. 1 shows a block diagram of the device; in fig. 2 - diagrams on the operation of the device.

The device contains an illuminator 1, an item 2 whose surface is monitored, a series-connected transducer 3, a band-pass amplifier A, an electronic processing unit 5, a recorder 6. The electronic processing unit 5 is made in the form of cut-outs 7, N threshold elements 8, the number of which corresponds to the number of levels , on which the duration of the signal, a digital-to-analog converter (DAC) 9, a pulse generator 10, adjustable in frequency, a control threshold element 11, an integrator 12, is measured, the integral output ora 12 is connected to the input of the recorder 6, the control input with the output of the control threshold element 11, the information input with the output of the DAC 9, the control input connected to the output of the pulse generator 10, and information inputs to the outputs of the corresponding threshold elements 8, the inputs of which are combined with the input of the control threshold element 11 and are connected to the output of the rectifier 7, the input connected to the output of the bandpass amplifier 4. FIG. 2 shows the noise signal 13 and the signals 14 and 15 generated from defects.

0781

By equalizing the input of the digital-to-tax converter 9. By adjusting the frequency of the pulse generator 10, a change in the sensitivity of the device to defects is achieved without changing the settings of the recorder 6. 1 s, p. 2, 2 sig.

The device works as follows.

Product 2 rotating at a constant angular velocity CJ is illuminated by illuminator 1 (Fig. 1). The radiation reflected from the product 2, modulated by the surface profile and a change in its reflection coefficient, is perceived by the phototransducer 3, which converts the optical signal into an electrical one. The signals from the photovoltaic converter 3 are often filtered and amplified in the bandwidth amplifier 4 and fed to the electronic processing unit 5.

In the bandpass amplifier 4, interference signals are filtered out, for example, signals generated from the beat of a rotating product 2, whose frequency corresponds to the angular speed of rotation of the product 2.

Thus, only the signals generated from the controlled surface come to the input of the electronic processing unit 5. It is a mixture of useful signals with noises.

In order to increase the reliability of detection of signals from defects (useful signals) against the background of noise in the electronic processing unit 5, the signals are subjected to transformations that allow an enhanced signal-to-noise ratio to be increased in the converted signal, in the proposed device as follows.

In the electronic processing unit 5, the input signals are sent to the transmitter 7, which performs a two-cycle signal rectification. As positive, that: k and the negative component of the input signal can contain information about the defect, so both components

signal needs to be analyzed. The introduction of rectifier 7 allows you to continue to work only with mono-polarized signals, for example, positive polarity.

At the output of the sensor 7, the signals 13 15 are formed from defects (Fig. 2). Signal 14 is characteristic of defects with sharp edges such as cracks, sprapin, and signal 15 is characteristic of defects with smooth outlines of vm-type edges. From the output of the rectifier 7, signals are fed to the inputs N. of the threshold elements 8 and to the input of the control threshold element 11.

The trigger levels of the threshold elements 8 are set respectively by a value equal to,, U,

, and

  porg

..D1 „

   and, and | org t, re --- por4 (fig. 2). When the amplitudes of the signals 13-15 are set above the set response levels, the output of the corresponding threshold elements 8 is formed by the normalized amplitude rectangular pulses with a duration equal to the signal duration at the corresponding level,

. The pulses from the outputs of the threshold elements 8 arrive at the information inputs of the gated DAC 9. The DAC gates with 9 pulses that receive the control input from a frequency-controlled pulse generator 10. The pulse generator 10 generates pulses U (Fig. 2) . Upon the arrival of the next pulse U. to the control input of the DAC 9, a current pulse with a duration equal to the pulse duration Uf. And an amplitude corresponding to the number of simultaneously triggered threshold elements 8 at the instant of the pulse Up is generated at its output.

The current pulses 1cap are fed to the informant input input of integrator 12, which summarizes them if there is a gate 1 pulse on its control input. A pulse gate 1 (Fig. 2) is formed at the output of the control threshold element 11 each time when the signals amplitude is 13-15 at its entrance exceeds the level of UUHB,

At the output of the integrator 12 from each signal 13–15, the corresponding step signal UBJ, X.,

The maximum amplitude of the signal U is proportional to

tshp about

N f

Z --- iTi. at

-

15

20

25

thirty

four

Where

onZ

sh

At

the sum of the amplitudes of the current pulses at the output of the DAC 9 during the pulse time of the strobe, the magnitude of the amplitude of the current pulse at the output of the DAC 9 with one threshold element 8 triggered, is the number of levels at which the signal duration is measured;

pulse period Uj. i

signal duration at the appropriate level

and"

Since they are, then I

 pore

Hut

and

values of constant n, respectively, and

 TsaPg OtJUlDCI.lDC.nraU Ug |, j

proportional to the total duration of the corresponding signal 13 - 15 at the levels,, ..., U ,,,,

In the stepped signals Ujj, which are the signals 13–15 converted by the total duration, the useful signal-to-noise ratio is Bbmie than the original signals (Fig. 2).

The signals Ug, proceed further to the recorder 6.

In the registrar 6, which can be made in the form of a comparator.

35 amplitude of the signal U,

out

corresponding to 5

0

The cumulative duration of a particular signal 13 through 15 at the levels Oqoj ,,, ..., Unop is compared with a predetermined voltage value. (Fig.2), corresponding to the total duration of the signal from the maximum permissible defect at the level x U (, pp,

   G7or N

When the amplitude of the Ugy signal exceeds this voltage, the impulse defect is formed at the output of the recorder 6, which can then be fed to the actuator, which removes the product into a reject container.

After reducing the amplitude of the signal at the output of the rectifier 7 below the value at the output of the control sub-element of the threshold element 11, the pulse 1 ends, the integrator 12 is reset to its original zero state. After that, the device is ready to measure and analyze the total, duration of the next signal.

51260781

The value of U., p is set from the condition O and, „(Uu ,, j is the amplitude of the noise from the defect-free over 5 s

nosti). The value of Uppp is chosen from the condition Ui ,,, p. The values U (, op, ..,, L (, op N of the response of the threshold elements 8 are set in such a way as to cover the entire expected range of variation of the amplitudes of signals from the monitored surface. Installation step tft, ap, ... uneven and is selected on the basis of the minimum signal-to-noise ratio of defects to be detected. If defects with a signal exceeding the noise amplitude of more than 2 times, it is necessary to reveal with a high degree of accuracy, then installations,, ..., and "pp can be uniform. If the main mass def As the signals to be detected are characterized by a signal-to-noise ratio less than 1 but not more than 2, then the installation step is 11, in the range from Uynp to, it is preferable to set to be smaller than the step

installations and

2 U

Pore

at level x more

UliM

in this example

implementations of the device and „op, and„ „p, U.

Porj uhe Uijij.

. but

UnopN more By adjusting the frequency of the pulse generator 10, a change in the sensitivity of the device to defects is achieved without changing the setting of the recorder 6.

The present invention allows detection of signals from defects by filtering signals according to the magnitude of the total duration determined for each signal by durations measured at levels both above and below the noise level, which allows an increase in the number of signals used. . Moreover, additional informative features are extracted from the noise location area. This reduces the loss of information

The max with amplitude is lower, the level of tumors increases the reliability of detection of defects with an amplitude of no more than 20% higher than the level of noise and, accordingly, the accuracy of quality control of the surfaces of products and materials increases.

Claims (2)

Invention Formula 1, A device for controlling the quality of the surface of products and MaTepHa--, containing an illuminator, along the rays of which a phototransducer is installed, to the output of which a band amplifier, a processing unit, whose input is an input of a rectifier and a recorder, are distinguished the fact that, in order to increase the reliability of control by filtering electrical signals by a parameter corresponding to the sum of the signal duration at different levels, block: the electronic processing is in the form of a set of threshold elements, the number of which corresponds to the number of levels on which the duration of the signal is measured, the digital-to-analog converter, the control threshold element and the integrator whose output is the output of the electronic processing unit, and the information input connected to the output of a digital-to-analog converter, the information inputs of which are connected to the outputs of the corresponding threshold elements, the inputs of which are connected to the output of the rectifier and with Odom control threshold element whose output is connected to a control input of the integrator. 2. Device by. Claim 1, characterized in that a pulse generator is inputted into the electronic processing unit, the output of which is connected to the control input of a digital-to-analog converter. 1zap Shyh. and then. L 15 lfnop3 uu f / a 2 Compiled by A. Churbakov. Editor I. Segl. N. Tehred M. Khodanich Proofreader V. But ha Order 5220/41 Edition 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Project St.,