JPH05169150A - Device for discriminating front surface and rear of blanked part - Google Patents

Abstract

PURPOSE:To discriminate the front surface and the rear of a blanked part by utilizing a difference of a reflection factor caused by a state of the broken surface of the blanked part, moving the blanked part in the thickness direction while irradiating the side face of the blanked part with a light beam spot, and comparing peak positions of a variation of reflected light intensity. CONSTITUTION:The subject device is provided with a photodetector 14 for holding a blanked, part 4 in a standing posture and moving it in the thickness direction, irradiating its side face with a light beam, condensing its irregularly reflected light, and outputting an electric signal in accordance with its condensing quantity. Also, this device is provided with a peak detecting block 20 for measuring a peak time tp of an output signal of the photodetector 14. Moreover, this device consists of a time measuring block 21 for comparing a set threshold and an output signal of the photodetector and measuring a time t1 when the output signal is above the threshold, and a time t2 when the signal is below the threshold and a deciding block 22 for calculating an intermediate time tc of the time t1 and t2, comparing whether tc is larger or smaller than the time tp and outputting the result as a front surface/rear deciding signal. In such a way, a stable processing for deciding the front surface and the rear of the blanked part at a high speed and without scarcely generating an error can be executed with high productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front / back surface discriminating apparatus for a punched product which is capable of discriminating between the front and back surfaces of a punched product by a contactless method.

[0002]

2. Description of the Related Art FIG. 7 (A) is a sectional view showing a state where a punched product is punched by press working, and the punched product is a washer. 1
Is a punch punch attached to a punch holder (not shown) of the press, 2 is a die attached to a bolster of the press (not shown), and 3 is a material plate fixed on the die 2. When the punch 1 is lowered as shown in the figure, a punched product (for example, a washer) 4 is punched. As shown in Fig. B, the punched product 4 has a side surface with a curved surface 4a on the front side 4a.
b, and there is a return 4d on the back side 4b.

FIG. 8 shows a conventional front / back discriminating means for a punched product. The punched product 4 has a center hole punched by a press in a later step, is held by the moving support 5 in an upright posture, and is moved in the arrow direction. The inspector 6 visually observed the punched product 4 directly or on a monitor screen via a television camera, and judged the front and back by the curved surface 4c and the return 4d.

[0004]

In the above-mentioned conventional front and back discriminating means for punched products, it is a visual judgment of the inspector 6, and it is necessary to process a large number of punched products 4 continuously, and There is a problem in that the rate of oversights and mistakes may increase due to carelessness, and mental fatigue increases due to continuous monotonous work. Further, there is a problem that the workability is low and the labor cost is large with respect to the quantity to be processed.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a punched product front / back discriminating apparatus which is high-speed, large-volume, and always has very few errors.

[0006]

SUMMARY OF THE INVENTION A front / back surface discrimination device for a punched product according to the present invention irradiates a side surface of the target punched product with a beam spot of light, moves the punched product in a thickness direction, and reflects it. It receives light and outputs an electrical signal. Claim 1
In the invention, the front and back directions of the punched product are discriminated from the peak position of the change in reflected light intensity.

According to the second aspect of the invention, the time integral value of the reflected light intensity is divided into the first half and the second half, and the sizes are compared to determine the front and back direction of the punched product. ..

Further, in the invention of claim 3, the front and back direction of the punched product is discriminated from the time when the predetermined threshold value of the reflected light intensity is crossed.

[0009]

In the present invention, the difference between the curved surface of the side surface fracture surface caused by the punching and the reflectance due to the return is detected by the amount of the received light of the reflected light due to the irradiation of the light beam spot, and the front and back are discriminated. High-speed, large-volume processing with almost no error, and can be applied to various punched products.

[0010]

【Example】

Example 1. FIG. 1 is a block diagram of a front / back surface discrimination device for punched products according to an embodiment of the present invention. In the figure, 4 is a punched product such as a washer, which is supported by the moving support 5 and is moved in the direction of the arrow. Reference numeral 10 denotes a light source such as a laser, which is a light source drive circuit 11
Pulsed light emission. Reference numeral 12 denotes a light projecting lens for converging the light emitted from the light source 10 on the side surface of the punched product 4, and 13 denotes the punched product 4.
A light receiving lens for collecting light diffusedly reflected from the side surface of the light receiving element 14 such as a photodiode, 15 an amplifier, 16
Is a sample and hold circuit that samples and holds the light reception signal in synchronization with the light emission pulse of the light source drive circuit 11 to obtain a difference signal between light emission and non-light emission, 17 is an A / D converter, 18 is a microcomputer, and Reference numerals 19 to 22 are blocks showing each processing performed in the microcomputer.

Next, the operation will be described. The light source drive circuit 11 drives the light source 10 so as to repeat light emission and non-light emission with time. The output light of the light source 10 is condensed by the light projecting lens 12 on the side surface of the punched product 4 such that the beam diameter is smaller than the thickness of the punched product 4. Since the side surface of the punched product 4 is a fractured surface by punching, it has small irregularities and has a property of irregularly reflecting light. Therefore, the incident light is diffusely reflected to the surroundings, a part of which is collected on the light receiving element 14 by the light receiving lens 13, converted into an electric signal proportional to the amount of light, and further amplified by the amplifier 15.

The sample and hold circuit 16 samples and holds the light receiving signal at the time of light emission and at the time of non-light emission based on the drive pulse of the light source drive circuit 11, and the difference between the two, that is, the light source 10
The reflected light component generated by the light is output. This signal is A
The signal is converted into a digital signal by the / D converter 17 and input to the microcomputer 18.

In the microcomputer 18, the following signal processing is performed as software processing. First, the moving average processing block 19 performs moving average processing to reduce noise components. This result will be referred to as a light amount signal L. As shown in FIG. 2 (A), as the irradiation beam spot P relatively moves on the side surface of the punched product 4 from the back side 4b to the front side 4a, the light quantity signal L changes as shown in FIG. 2 (B). Change dramatically. When punched with a press, it shifts while sticking at first, so the side surface (the one closer to the front side 4a) that occurs at that time exhibits a glittering phenomenon, and the latter half breaks at once, resulting in a low reflectance surface with large irregularities. .. Therefore, when the light quantity is measured while the beam spot is relatively moved from the back side 4b to the front side 4a, it is always shown in FIG.
As described above, a peak of the amount of light occurs near the front side 4a.

The peak detection block 20 detects and outputs tp at which a light amount peak has occurred from the temporal change of the light amount signal L. At the same time, the peak value Lp is obtained, and a value obtained by dividing it by an appropriate value is output as the threshold value Lth. The time measurement block 21 compares the light amount signal L with a threshold value Lth, which is given as an input, and compares the threshold value Lth with the time point t when L exceeds Lth.
₁ and the time t _{2 at} which L falls below Lth are measured and output. The threshold value Lth given to the time measurement block 21 may be given a constant value from the outside, but by using the value calculated based on the peak value obtained from the peak detection block 20, Is less affected by the difference in reflectance.

The decision block 22 determines the times t ₁ , t ₂ , tp.
(See FIG. 2B) is input, and the direction of the front and back is determined depending on which side tp is with respect to the time tc intermediate between t ₁ and t ₂ . Specifically, (t ₁ + t ₂ ) / 2 is compared with tp, and if tp> (t ₁ + t ₂ ) / 2, the later in time is the front side 4a, tp <(t ₁ + t ₂ ) / If it is 2, the front side in time is judged to be the front side 4a.

In the above embodiment, the case where the microcomputer 18 is used as the signal processing front / back determination means has been described, but the processing performed by the microcomputer (19
22) may be partially or entirely realized by an electric circuit.

Embodiment 2. FIG. 3 is a block diagram of a front / back surface discrimination device for punched products according to a second embodiment of the present invention.
17 to 19 are the same as those in FIG. Reference numeral 25 is a microcomputer, and internal reference numerals 19 and 26 to 28 are blocks showing respective processes performed in the microcomputer.

Next, the operation will be described. Similar to Example 1,
A side surface of the punched product 4 to be moved is irradiated with a light beam spot, and a part of the reflected light is collected by the light receiving lens 13 in the light receiving element 14 and converted into an electric signal proportional to the amount of light. After passing through the hold circuit 16, it is converted into a digital signal by the A / D converter 17 and input to the microcomputer 25.

In the microcomputer 25, the following signal processing is performed as software processing. The input signal is
First, the moving average processing block 19 performs moving average processing to reduce noise components, and outputs the light amount signal L. Figure 4
As shown in (A), the irradiation beam spot p has a punched product 4
As the side surface relatively moves from the back side 4b to the front side 4a, the light amount signal L changes with time as shown in FIG. 4 (B). As a result of the press punching, the side surface of the punched product 4 exhibits a glittering phenomenon closer to the front side 4a, and a low reflectance surface having large irregularities near the back side 4b. Therefore, when the amount of reflected light is measured while the beam spot is relatively moved from the back side 4b to the front side 4a,
As shown in FIG. 4B, the amount of light becomes larger toward the front side 4a.

The time measuring block 26 receives the light amount signal L as an input and compares it with a given threshold value Lth, and L is Lth.
The time t _{1 at} which L exceeds Lth and the time t _{2 at} which L falls below Lth are measured, and the intermediate time tc between t ₁ and t ₂ is tc = (t ₁ + t ₂ ) /
2 is calculated, and the values of these times t ₁ , t ₂ , and tc and the input light amount L are output.

The integration block 27 determines the times t ₁ , t ₂ and tc.
And the light amount L are input, the light amount L is integrated over time, and time t ₁
And an integrated value S ₂ is calculated between the integration value S _1, and time Tc～t ₂ between to Tc, and outputs it to the decision block 28. This is shown in Equation 1.

[0022]

[Equation 1]

The decision block 28 receives the integrated values S ₁ and S ₂ as inputs and compares the magnitudes of S ₁ and S ₂ to decide the front and back directions. Specifically, if S ₁ <S ₂ , it is determined that the temporally rear side is the front side 4 a, and if S ₁ > S ₂ , the temporally front side is the front side 4 a.

In the second embodiment, the case where the microcomputer 25 is used as the signal processing front / back determination means has been described. However, some or all of the processing blocks 19, 26 to 28 performed by the microcomputer are electrically operated. You may make it a circuit.

Example 3. FIG. 5 is a block diagram of a front and back discriminating apparatus for punched products according to a third embodiment of the present invention.
17 to 19 are the same as those in FIG. Reference numeral 30 is a microcomputer, and internal reference numerals 19 and 31 to 33 are blocks showing respective processes performed in the microcomputer.

Next, the operation will be described. Similar to Example 1,
The side surface of the punched product 4 to be moved is irradiated with a light beam spot, and a part of the reflected light is collected by the light receiving lens 13 in the light receiving element and converted into an electric signal proportional to the amount of light.
A / D converter 17 via sample and hold circuit 16
Is converted into a digital signal by the microcomputer 3
Input to 0.

In the microcomputer 30, the following signal processing is performed as software processing. The input signal is
First, the moving average processing block 19 performs moving average processing to reduce noise components, and outputs the light amount signal L. Figure 6
As shown in (A), the irradiation beam spot p has a punched product 4
The light amount signal L changes with time as shown in FIG. 6B as the side surface relatively moves from the back side 4b to the front side 4a. By press punching, the side surface of the punched product 4 exhibits a glittering phenomenon near the front side 4a, and a low reflectance surface with large irregularities near the back side 4b. Therefore, when the light amount is measured while the beam spot is relatively moved from the back side 4b to the front side 4a, the light amount is always larger on the front side 4a as shown in FIG. 6B.

The peak detection block 31 detects the peak value Lp of the temporal change of the light quantity signal L, multiplies it by predetermined coefficients K ₁ and K ₂ , and calculates and outputs two threshold values Lth ₁ and Lth ₂ . To do. The coefficients K ₁ and K ₂ are set in advance so that the threshold value Lth ₁ crosses a portion where the light amount is small and the threshold value Lth ₂ crosses a sharp portion that occurs in the latter half of the light amount change. Therefore, Lth ₁ <Lth _2, that is, 0 <K ₁
<K ₂ <1.

The time measuring block 32 receives the light amount signal L as an input and compares it with two given threshold values Lth ₁ and Lth _2, and at time t ₁ when L exceeds Lth ₁ and when L exceeds Lth ₂ . time t ₂ has the time t ₃ when L is below the Lth ₂ after time t _2, L after time t ₁ is operative to output by measuring the time t ₄ when below the Lth _1, respectively. Although the threshold values Lth ₁ and Lth ₂ given to the time measurement block 32 may be given constant values from the outside, measurement is performed by using a value calculated based on the peak value obtained from the peak detection block 31. It is less likely to be affected by the difference in reflectance of each punched product 4.

The decision block 33 determines at times t ₁ , t ₂ ,
Using t ₃ and t ₄ as inputs, the time difference between t ₁ and t ₂ and t ₃ and t ₄
The direction of the front and back is determined by which of the time differences is larger. Specifically, if t ₂ −t ₁ > t ₄ −t ₃ , the temporally rear side is the front side 4a, and if t ₂ −t ₁ <t ₄ −t ₃ , the temporally front side is the front side 4a. To determine.

In the third embodiment, the microcomputer 30 is used as the signal processing front / back determination means, but the processing block 1 executed by the microcomputer 1 is used.
A part or all of 9, 31 to 33 may be performed by an electric circuit.

[0032]

As described above, according to the present invention, the state of the side surface fracture surface generated during punching of the punched product has a high reflectance on the side closer to the front and a lower reflectance on the side closer to the back. By utilizing the difference in reflectance, the side surface of the punched product is irradiated with a light beam spot and relatively moved in the thickness direction, and the reflected light is received to output an electric signal according to the light amount. In the first embodiment, the front-back direction is discriminated by detecting the position where the peak value of the reflected light amount occurs, and in the second embodiment, the integrated value of the reflected light amount is divided into the first half and the second half, and the magnitudes are compared. The front-back direction is determined, and in the third embodiment, the front-back direction is determined by comparing the time difference when the amount of reflected light crosses two threshold values in the first half and the second half. As a result, high-speed, stable processing with few errors can be performed with high productivity for determining the front and back of punched products. Further, since the state of the fracture surface generated during pressing is used, it can be applied to punched products in general.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a front / back surface discrimination device for a punched product according to an embodiment of the present invention.

2A is a plan view showing a state in which a beam spot is relatively moved and irradiated on a side surface of the punched product of FIG.
(B) is a curve diagram showing the movement of the beam spot and the change in the amount of received light in (A).

FIG. 3 is a configuration diagram of a front / back surface discrimination device for punched products according to a second embodiment of the present invention.

FIG. 4A is a plan view showing a state in which a beam spot is relatively moved and irradiated on the side surface of the punched product of FIG. 3;
(B) is a curve diagram showing the movement of the beam spot and the change in the amount of received light in (A).

FIG. 5 is a configuration diagram of a punched product front / back discriminating apparatus according to a third embodiment of the present invention.

6A is a plan view showing a state where a beam spot is relatively moved and irradiated on a side surface of the punched product of FIG.
(B) is a curve diagram showing the movement of the beam spot and the change in the amount of received light in (A).

7A is an explanatory view showing a punched state of a punched product by a press, and FIG. 7B is a cross-sectional view of the punched product punched by (A).

FIG. 8 is an explanatory view showing a conventional front / back discriminating means for a punched product.

[Explanation of symbols]

4 Punched product 4a Front side 4b Back side 5 Moving holder 10 Light source 12 Light emitting lens 13 Light receiving lens 14 Light receiving element 18, 25, 30 Signal processing front / back judgment means (microcomputer) 20, 31 Peak detection block 21, 26, 32 Time Measurement block 22, 28, 33 Judgment block 27 Integration block

Claims (3)

[Claims] 1. A movable holder for holding a punched product by a press in an upright position and moving it in a thickness direction, a light source for generating a light beam, and irradiating the light beam by condensing the side face of the punched product. Then, a light projecting lens for moving the light beam spot relative to the side surface temporally, a light receiving lens for collecting diffused reflected light from the light beam spot formed on the side surface, and a light receiving lens for collecting light. A light receiving element that outputs an electric signal according to the received light intensity, a peak detection block that measures the peak time tp of the output signal of the light receiving element, and a threshold value that is compared with the output signal of the light receiving element and time measuring block the output signal after time t _1, and time t ₁ signal exceeds the threshold value to measure a time t ₂ to below the threshold value, the intermediate time of the time t ₁ and t ₂ t _c to calculate a, t _c and the time t _p Front and back discrimination device of the punching 抜品 having a signal processing front and back determining means comprising a decision block for outputting the results by comparing the magnitude as front and back determination signal. 2. A movable holder for holding a punched product by a press in an upright posture and moving it in the thickness direction, a light source for generating a light beam, and irradiating the light beam by condensing the side face of the punched product. Then, a light projecting lens for moving the light beam spot relative to the side surface temporally, a light receiving lens for collecting diffused reflected light from the light beam spot formed on the side surface, and a light receiving lens for collecting light. receiving element for outputting an electric signal corresponding to the quantity of light is compared with the given threshold and an output signal of the light receiving element, time t ₁ and time t ₁ in which the output signal exceeds the threshold
After that, the time t _{2 at} which the output signal falls below the threshold value is measured, and the time measurement block for calculating an intermediate time t _c between the times t ₁ and t ₂ and the output signal of the light receiving element from the time t ₁ to t to _c, and each integrated from time t _c to t _2, and integration block to obtain each of the integrated values S ₁ and S _2, integrated values S ₁
And a front and back discriminating apparatus for a punched product provided with a signal processing front and back discriminating means which comprises a comparison block for comparing the magnitude of S ₂ and outputting the result as a front and back discrimination signal. 3. A movable holder that holds a punched product by a press in an upright position and moves in a thickness direction, a light source that generates a light beam, and irradiates the light beam by condensing the side face of the punched product. Then, a light projecting lens for moving the light beam spot relative to the side surface temporally, a light receiving lens for collecting diffused reflected light from the light beam spot formed on the side surface, and a light receiving lens for collecting light. The light receiving element that outputs an electric signal according to the received light amount, compares the threshold value Lth ₁ having a large value and the threshold value Lth ₂ having a small value with the output signal of the above light receiving element, and the output signal is the threshold value Lth _1. the time t ₁ exceeds the time t ₂ exceeds the threshold value Lth _2, the output signal after time t ₂ is the time t ₃ when below the threshold Lth _2, the output signal is after time t ₁ Threshold L
a time measurement block for measuring time t ₄ when it is less than th ₁ ,
Calculating a time t ₁ and the time difference t ₂ t ₂ -t ₁ and time t ₃ and the time difference t ₄ -t ₃ of t _4, the by comparing the magnitudes of these t ₂ -t ₁ and t ₄ -t ₃ A front and back discriminating apparatus for a punched product, comprising a signal processing front and back discriminating means, which comprises a judgment block for outputting a result as a front and rear judgment signal.