RU2044270C1 - Device for inspection of surface finish - Google Patents

Abstract

FIELD: measuring equipment. SUBSTANCE: device comprises two light-guide collectors 1, 2 each having transmitting 3, 4 and receiving 5, 6 branches, optically conjugated with each other. Device also has two radiators 8, 9, two photodetectors 10, 11, synchrogenerator 12, two information discrimination channels comprising switching devices 13, 14, demodulators 15, 16, difference unit 17, adder 18, two rejection units 21, 22, measuring information processing circuit, and registration unit 27. Synchrogenerator 12 shapes time-shifted phase pulses of radiators 87,9 which illuminate the inspected flat article 28 whose larger side is positioned normally to the common optical axis of the light-guide collectors 1,2. The received signals in each channel are broken into the components which carry information on the magnitude of the reflected and passed radiation fluxes. The magnitude of the reflect ed radiation flux serves for assessing the surface finish while the magnitude of the passed radiation gives a notion of the flat article width. After rejection by the units 21,22 the result goes to the registration unit 27. EFFECT: wider functional capabilities. 2 dwg

Description

 The invention relates to measuring equipment, and in particular to surface quality control devices.

 A device for monitoring the quality of a cylindrical surface [1] containing a light source, a beam splitter plate, a light guide, a photodetector, a processing unit.

 The disadvantage of this device is the large measurement error, since the measurement result is affected not only by the surface quality, but also by the distance to it due to the monotonous decrease in the optical characteristic, in addition, the device has narrow functionality, since it does not allow you to control the diameter of the wire.

 A device for monitoring the quality of a cylindrical surface [2] containing a light source, a lens, a fiber optic fiber, supplying and removing radiation, alternating between each other, a radiation receiver, an information processing unit.

 The disadvantage of this device is the narrow functionality, since the device does not allow you to control the diameter of the wire.

 The problem solved by the proposed device is to expand the functionality by simultaneously monitoring the surface quality and width of the part.

 This is achieved by the fact that in a device for controlling the quality of a surface, comprising two light guide collectors with transmitting and receiving branches each, an orientation unit, first and second emitters optically coupled to the transmitting branch of the respective light guide collector, first and second photodetectors optically coupled to the receiving branch the corresponding light guide collector, a synchronizer, the first and second outputs of which are connected respectively to the first and second emitter, connected in series to the first commutator a torus, a first demodulator, a difference unit, a comparator, a first rejection unit and a registration unit, the outputs of the first and second photodetectors are connected respectively to the first and second inputs of the first switch, the third output of the clock generator to the third input of the first switch and the second input of the first demodulator, the output of the difference unit is connected also to the second input of the first block of sorting, the light guide tubes are aligned and optically connected to each other, and the device is equipped with a second switch connected in series ohm, a second demodulator, an adder, an averaging unit, an amplifier, the output of which is connected to the third input of the first block of rejection, and also connected by the first and second input to the outputs of the difference unit and the adder, by a differential amplifier connected to its output by the first input by an integrator connected to the output of the latter by a second block of rejection, the output of which is connected to the second input of the registration unit, connected to the output of the comparator by a gating pulse shaper, the output of which is connected to to the second inputs of the second block of sorting and the integrator, the output of the comparator is also connected to the third input of the integrator, the outputs of the second and first photodetectors are connected respectively to the first and second inputs of the second switch, the third input of which is connected to the third output of the sync generator, also connected to the second input of the second demodulator, the output the first demodulator is connected to the second input of the adder, and the output of the second demodulator is connected to the second input of the difference block.

 In FIG. 1 presents a structural diagram of the proposed device; figure 2 is a timing diagram of the operation of individual blocks of the device.

 The device contains (Fig. 1) mounted coaxially and optically interconnected first 1 and second 2 light guide collectors with 3, 4 and 5, 6 receiving branches, orientation unit 7, first 8 and second 9 emitters, first 10 and second 11 photodetectors , a clock 12, the first and second outputs of which are connected respectively to the first 8 and second 9 emitter.

 The device also contains the first 13 and second 14 switches, the first 15 and second 16 demodulators, each connected with the first input to the output of the corresponding switch 13, 14, the difference unit 17, the adder 18, connected to the outputs of the difference unit 17 and the adder 18, respectively, the first and second input a differential amplifier 19, an integrator 20 connected to its output by the first input. The device also includes the first 21 and second 22 rejection units, a comparator 23, a gate pulse generator 24, an averaging unit 25, an amplifier 26, a recording unit 27.

 The emitters 8, 9 are optically coupled to the transmitting branch 3, 4 of the corresponding light guide body 1, 2.

 The photodetectors 9, 10 are optically coupled to the receiving branches 5, 6 of the corresponding fiber 1, 2. The output of the first photodetector 10 is connected to the first input of the first switch 13, the output of the second photodetector 11 is connected to the second input of it. The output of the second photodetector 11 is connected to the first input of the second switch 14, to the second input of which the output of the first photodetector 10 is connected.

 The third output of the clock 12 is connected to the third input of the switch 14, 15 and the second inputs of the demodulators 15, 16. The output of the first demodulator is connected to the first input of the difference unit 17, the second input of which is connected to the output of the second demodulator 15. The output of the last is also connected to the first input of the adder 18 , to the second input of which the output of the first demodulator 15 is connected. The output of the difference unit 17 is connected to the input of the comparator 23, the output of which is connected to the first input of the first block 21 of rejection and the input of the gate generator 24 is. The output of the integrator 20 is connected to the first input of the second block 22 of rejection, the second input of which is connected to the output of the driver 24 of the strobe pulse, also connected to the second input of the integrator 20, to the third input of which the output of the comparator 23 is connected. The output of the difference unit 17 is connected to the second input of the first block 22 sorting, to the third input of which the output of the amplifier 26 is connected. The output of the adder 18 is connected to the input of the averaging unit 25, the output of which is connected to the input of the amplifier 26. The outputs of the first 21 and second 22 blocks and respectively connected to first and second inputs 27 of the recording unit.

 Fiber optic collectors 1, 2 are fiber-optic collectors with mixed fiber branches at the joint end. The size of the light guide tubes 1, 2 along the line for measuring the width of the part is larger than the maximum possible width of the measured part 28.

 The device operates as follows.

At first, part 28 is not in the control zone. The synchronizer 12 generates a continuous sequence of pulses of the clock signal U _t and synchronously with it two sequences of pulses signals of the phase U _f1 and U _f2 , the active levels of which do not coincide in time (see figure 2), for example, shifted by half the period. The signal U _{f1 is} supplied to the emitter 8, the signal U _f2 to the emitter 9, and the radiation pulses along the transmitting branches 3 and 4 of the corresponding light guide body 1 and 2 are alternately transmitted to the control zone.

In the absence of part 28 at the control position, part of the study flow is reflected from the elements of the orientation unit 7, the end face of the coaxial fiber guide 2 or 1, and is captured by the receiving branch 5 or 6 of the corresponding collector 1 and 2 and fed to the photodetector 10 or 11. In phase with the corresponding _Q-1 phase signals U and U _Q2 formed pulse signal U _P1, U with amplitude _n2 (see FIG. 2). Another part of the backlight radiation flux along the receiving branch 5 or 6 of the coaxial collector passes to the photodetector 10 or 11, and pulses U _p1 , U _{p2 with an} amplitude U _ρ in antiphase with the corresponding signals U _f1 and U _f2 are formed at their outputs. The channels are identical and the amplitudes of the corresponding pair of signals of the same name are equal to each other in each clock cycle, which is achieved by appropriate tuning of the channels.

Thus, at the output of each of the photodetectors 10 and 11, pulses of amplitude U _ρ and U _τ are present alternately with a clock frequency U _t . For their separation, switches 13, 14 controlled by a clock generator 12 are used. The input of the first demodulator 15 receives a sequence of pulses of amplitude U _ρ to the input of the second demodulator 16 with amplitude U _τ
Demodulators 15, 16 operate as sampling devices for storing analog signals with a storage time significantly longer than the sampling time.

The sampling is carried out by the clock signal U _{t of the} clock 12. At the output of block 15 there is a constant signal with an amplitude U _ρ and at the output of block 16 there is a signal with an amplitude U _τ (see figure 2 of the diagram U _ρ (t), U _τ (t) in interval 0 t ₁ ).

лностью
Соответственно, сигнал на выходе второго демодулятора 16 может быть записан в виде
U_τ (t, τ ( g)) U_τ Δ U_τ (t,τ (g)) ˙f(t), где τ (g) функция, определяющая зависимость интегральной пропускной способности системы из двух волоконно-оптических коллекторов от геометрических параметров контролируемой детали.Further, in block 17 of the difference, subtraction occurs, and in the adder 18, the summation of these signals, respectively, at their outputs, we have U _p U _ρ - U _τ and U _c U _ρ + U _τ . The signal U _c through the averaging unit 25, which is a low-pass filter, and the amplifier 26 with an adjustable gain already as a reference signal U _{op is} fed to the input of the first block 21 rejection. To the other input of block 21, the signal U _ρ arrives. Since in this mode the part 28 does not have an output signal from the comparator 23 U _к (see Fig. 2), it prohibits signal analysis in the first block 21 of rejection, as well as the operation of the gate generator 24 and the integrator 20. Block 19 of the differential amplifier provides the selection of the signal U ₁ proportional to the component of the backlight radiation flux passing from one channel to another. The input of the integrator 20 receives a signal
U ₁ U _c U _ρ 2U _τ
When block 7 feeds the orientation of the flat part 28 to the control position so that the plane of the larger face is normal to the optical axis of the light guide tubes 1, 2, the ratio between the reflected and transmitted components of the backlight radiation flux and, therefore, between the signals U _ρ and U _τ Signal U _ρ increases by Δ U _ρ , and the signal U _τ decreases by Δ U _τ In general, for one surface the signal at the output of the first demodulator 15 can be written as
U _ρ (t, R ((ρ g ')) = U _ρ + Δ U _ρ (t, R (ρ g')) ˙ f (t), where t is the time parameter;
R (ρg ') is a function that determines the dependence of the reflectivity of a part of a part on the reflection coefficient ρ and the geometric parameters g' of surface defects;
f (t) is a function that describes the response of the transmitter to the presentation of an ideal part and taking on values:
f (t)

personality
Accordingly, the signal at the output of the second demodulator 16 can be recorded as
U _τ (t, τ (g)) U _τ Δ U _τ (t, τ (g)) ˙f (t), where τ (g) is the function that determines the dependence of the integral throughput of a system of two fiber-optic collectors on geometric parameters of the controlled part.

The value Δ U _g (t, R (ρy ') decreases in the presence of a defect, and the value ΔU _τ (t, τ (g)) is directly proportional to the width of the part. The time parameter t indicates that the value Δ U _ρ or Δ U _τ changes only when scanning the surface area of a defective part Scanning a part with smooth, defect-free surfaces and with a constant width does not change the magnitude of these signals.

In FIG. 2 shows diagrams of the signals U _ρ and U _τ described above; the interval (0, t) corresponds to the absence of the part at the control position; the interval (t ₁ , t ₂ ) supplying the part to the control position; the interval (t ₂ , t ₃ ) overlapping part of the control zone; the interval (t ₃ , t ₄ ) the output of the part from the position of control; the interval (t ₄ , ∞) is similar to the interval (0, t ₁ ), i.e. the absence of the part in the control position after it has passed.

(t, R(ρ, g′))K+ ΔU_τ(t, τ(g))·(1+K)]·f(t)≥
где Δ

(t,R(ρg') функция, значения которой равны среднему арифметическому между значениями Δ U_ρ (t, R (ρg'), соответствующим состоянию каждой из контролируемых поверхностей. В отсутствиe дефекта на всех поверхностях

(t) ΔU_ρ(t)
К нормирующий коэффициент, устанавливающий уровень опорного сигнала.In accordance with the described algorithm, the condition for accepting the part as suitable is the fulfillment of the inequality

(t, R (ρ, g ′)) K + ΔU _τ (t, τ (g)) · (1 + K)] · f (t) ≥
where Δ

(t, R (ρg ') function whose values are equal to the arithmetic mean between the values Δ U _ρ (t, R (ρg'), corresponding to the state of each of the controlled surfaces. In the absence of a defect on all surfaces

(t) ΔU _ρ (t)
K normalizing coefficient, which sets the level of the reference signal.

Thus, when a part 28 with a surface defect arrives at the control position with the active signal level of the comparator 23 U _k , the analysis of the incoming measuring and reference signals in the first block 21 of the rejection is allowed. In fact, here at each instant of time t, condition (1) is checked and, if it is violated, a reject signal is issued, which is recorded in the registration unit 27. At the same time, a signal is input to the integrator 20
U ₁ (t, τ (g)) 2 U _τ 2 Δ U _τ (t, τ (g)) ˙f (t)
When the part 28 is fed to the monitoring position, the comparator 23 is activated and allows the signal to accumulate until the moment of arrival of the pulse from the gate pulse generator 24. The leading edge of the gating pulse is formed along the falling edge of the signal U _k . Detail 28 is considered accepted if the signal at the output of the integrator 20 is in a predetermined interval.

 Verification of this condition is carried out in the second block 22 of the rejection at the time of arrival of the strobe pulse from the driver 24 of the strobe pulse. The result is recorded in block 27 registration. The trailing edge of the gate pulse integrator 20 is set to its original state.

 Thus, the device has wider functionality than the prototype, because it allows you to control the width of the part along with the control of surface quality.

Claims (1)

 A QUALITY QUALITY CONTROL DEVICE, comprising two light guide collectors with transmitting and receiving branches each, an orientation unit, first and second emitters, optically coupled to the transmitting branch of the corresponding light guide collector, first and second photodetectors, optically coupled to the receiving branch of the corresponding light guide collector, a sync generator, the first and second outputs of which are connected respectively to the first and second emitters, connected in series to the first switch, the first demodulated , difference block, comparator, first block of rejection and registration block, outputs of the first and second photodetectors are connected respectively to the first and second inputs of the first switch, the third output of the clock is connected to the third input of the first switch and the second input of the first demodulator, the output of the difference block is also connected to the second the input of the first block of the rejection, characterized in that the fiber-optic collectors are coaxial and optically connected to each other, the device is equipped with series-connected second a mutator, a second demodulator, an adder, an averaging unit, an amplifier, the output of which is connected to the third input of the first block of rejection, as well as connected to the outputs of the difference unit and the adder, respectively, with a differential amplifier connected to its output by an integrator connected to the output by an integrator connected to the output of the latter by a second block of rejection, the output of which is connected to the second input of the registration unit, connected to the output of the comparator by a gating pulse shaper, the output of which is under it is connected to the second inputs of the second block of sorting and the integrator, the output of the comparator is also connected to the third input of the integrator, the outputs of the second and first photodetectors are connected respectively to the first and second inputs of the second switch, the third input of which is connected to the third output of the sync generator, also connected to the second input of the second demodulator , the output of the first demodulator is connected to the second input of the adder, and the output of the second demodulator is connected to the second input of the difference block.

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