JP2817831B2 - Scrap up detection method and scrap up detection apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting a rise of a scrap generated in press working.

[0002]

2. Description of the Related Art As a conventional method for detecting a sludge rising, as disclosed in Japanese Patent Application Laid-Open No. 61-9933, a stripper collides with a lower die or a workpiece (plate material). There is a process including a process of obtaining a dead center and a process of comparing the bottom dead center position with a set position. Explaining with a graph showing the displacement of the stripper in FIG. 6, in the case where the scrap rises, the bottom dead center position of the first bounce when the stripper collides with the plate material is set to the set position (the stripper displacement a− during normal punching). The displacement from the bottom dead center c) on the line b to the bottom dead center c ′ can be detected, and by detecting this displacement, it is possible to judge that a dreg has risen.

[0003]

However, in the conventional method of detecting the rise of the scum, when the scum is small enough to be crushed by the collision of the stripper, the bottom dead center in the normal state and the bottom dead center when the scum rises are generated. There was a risk that a clear displacement difference could not be obtained, and no dregs could be detected. Also, even if the waste is of a size that does not collapse due to the collision of the stripper,
The vibration generated when the stripper collides (displacement a in FIG. 6)
Bottom dead center c under normal conditions
And the bottom dead center c 'at the time of the occurrence of the ascending may hardly occur, so that there is also a problem that the accuracy of detecting the ascending is not sufficient.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an object to improve the accuracy of detecting a dregs rise.
A step of detecting a displacement before and after the stripper collides with the workpiece and calculating a displacement gradient (d / Δt) immediately before the bottom dead center position from the displacement of the stripper in order to reliably detect even a small residue; And comparing it with a predetermined reference value.

In the above detection method, a displacement gradient immediately before the bottom dead center may be calculated based on a point which is a predetermined value D from the bottom dead center position. The above detection method may use a step of calculating the displacement gradient in two sections immediately before the bottom dead center position from the displacement of the stripper, and a step of comparing the two displacement gradients with each other.

[0006] On the other hand, the present invention relates to a scrap rising detecting device provided in a press device for pressing a metal plate material sandwiched between a stripper and a die plate by a punch, wherein the displacement of the stripper during the pressing is detected. Detecting means for detecting, and calculating means for calculating a displacement gradient immediately before bottom dead center from the stripper displacement detected by the detecting means,
It is an object of the present invention to provide a dregs rising detecting device comprising a comparing means for comparing the displacement gradient with a predetermined reference value and outputting a stop signal to a press device based on the comparison result.

The above-described detecting device may calculate the displacement gradient immediately before the bottom dead center with reference to a point which is a predetermined value D from the bottom dead center position. The above-mentioned detecting device comprises a calculating means for calculating a displacement gradient in two sections immediately before the bottom dead center from the stripper displacement detected by the detecting means;
A comparison means for comparing two displacement gradients with each other and outputting a stop signal to the press device based on the comparison result may be used.

[0008]

1 and 2 show an embodiment of a scrap rising detecting device according to the present invention, in which a displacement sensor 11 attached to detect displacement of a stripper 7 and a target fixed to a stripper backing plate 6 are shown. An A / D converter 13 for converting a displacement (distance x) signal of the target 12 measured by the displacement sensor 11 into a digital value;
A bottom dead center position detector 14 for obtaining the position (displacement) of the first bound bottom dead center based on the digitized signal, and a gradient for inputting the displacement signal and the bottom dead center position signal and calculating a gradient value by a predetermined arithmetic expression An arithmetic circuit 15, a gradient comparison circuit 16 for comparing the gradient value with a gradient value (reference value) obtained in the previous stripper shot, a reference value input circuit 19 for inputting a reference value, and a gradient value exceeding the reference value When the gradient comparison circuit 16
And a stop circuit 17 for inputting a signal from and sending a stop signal to the press 18.

The bottom dead center position detector 14 is indispensable when the first bound bottom dead center is regarded as an optimum reference position. In addition, the bottom dead center position detector 14 is obtained by obtaining a reference position. In some embodiments, 14 may be omitted. On the other hand, in FIG. 1, the plate material 9 is first clamped between the stripper 7 and the die 8, and the plate pressing force at this time is given by the spring 2 arranged above the stripper backing plate 6, and from this state, the entire upper die is removed. Descend, punch 1
And die 8 are punched. Scrap generated by punching usually falls from the scrap hole 10. However, rarely after punching, it may adhere to the tip of the punch 1 and be caught between the plate material 9 and the stripper 7 or between the die 8. In addition, in addition to the above-mentioned scum, burrs generated on the product by punching may fall off. If these foreign substances are caught above or below the plate material 9, the product will be damaged, and a large number of defective products will be generated.

[0010] A method for detecting a dust rise using these dust rise detection devices will be described below.

[0011]

[Detection Method 1] The first scum up detection method is to calculate the displacement gradient (d / Δt) immediately before the bottom dead center. That is, the curve b in FIG. 3 is the displacement of the stripper backing plate 6 when the scum is hit, but if the scum is present before coming into contact with the plate material 9, it becomes a cushion and it is compared with the curve a when there is no scum. The gradient becomes gentle. Therefore, the presence or absence of scum can be determined by comparing this gradient with the reference value.

FIG. 2 shows a detection circuit of the descent detector, in which a signal from the displacement sensor 11 is converted into a digital value by an A / D converter 13, and the signal is converted to a first bound by a bottom dead center position detector 14. Find the bottom dead center position. Next, the displacement gradient is calculated by the calculation circuit 15 from these values. The calculated gradient value is compared with the gradient value in the previous shot (the reference value input to the reference value input circuit 19) by the comparison circuit 16, and when the calculated value exceeds the set reference value, the stop circuit 17 stops the press 18 from the stop circuit. A signal is sent to press 1
8 stops.

[0013]

[Detection method 2] In the second method for detecting a dregs ascending, the displacement immediately before the bottom dead center is divided into two fixed sections and the gradient of each section is compared. That is, in FIG. 3, when the scum is not hit, in the sections I and II, the gradients are almost the same as shown by the curves ab. However, when the scum is hit, the scum becomes a buffer material, and the gradient b ′ in the section II becomes smaller than the gradient a in the section I. Therefore, by comparing the gradient between the section I and the section II, it is possible to determine the presence / absence of scum.

The detection circuit used in the second detection method is shown in FIG.
The signal is converted into a digital value by a converter 13 and a first bound bottom dead center position is obtained from the signal by a bottom dead center position detector 14. The comparison circuit 16 compares the gradient values in both sections. If the gradient value exceeds the reference value, a stop signal is sent from the stop circuit 17 to the press 18 so that the press 1
8 may be stopped.

In this detection method, the gradients in the constant sections I and II are calculated based on the value of the bottom dead center. However, as shown in FIG. It is preferable that the calculation is performed with reference to the time at which Δt has elapsed. This is because, generally, the displacement near the bottom dead center of the first wave is a rounded curve, and the slope becomes apparently a straight line b (FIG. 4) based on the bottom dead center. That is, based on the time (Δt) slightly rising from the position of the first wave bottom dead center, the interval II
By performing the gradient calculation, the gradient as shown by the straight line b ″ can be obtained, and a more accurate gradient value can be obtained.

[0016]

[Detection method 3] In the third method for detecting a dreg, the displacement gradient (d / d
Δt). That is, FIG. 5 shows the behavior of the stripper backing plate 6,
Calculate the displacement gradient (d / Δt) between two points, a point that is up a fixed value D from the bottom dead center position of the stripper displacement and a point that is down a fixed displacement d therefrom. By performing the comparison, it is possible to determine the presence or absence of the waste.

Here, D is desirably the thickness of the waste, ie, the thickness of the plate material, and d is desirably １ ／ to ３ of D. D is the thickness of the plate material because that point is the point at which the gradient of the stripper displacement starts to change due to the scum, and d is made smaller than D because the value before the stripper comes into contact with the plate material is This is for use.

The detection circuit used in the third detection method is shown in FIG.
The signal is converted into a digital value by a converter 13, a first bound bottom dead center position is obtained from this signal by a bottom dead center position detector 14, and then a displacement gradient is calculated from these values by a calculation circuit 15, If the value exceeds the reference value in the reference value input device 19 in comparison with the value in the shot, the stop circuit 1
A stop signal is sent from 7 to the press 18, and the press 18 may be stopped.

In the above embodiment, the displacement gradient (d
/ Δt) may be determined by the least square method. Δt
If a point in the section is sampled and a straight line approximation is performed by the least squares method, a slight variation in displacement is absorbed, and a stable velocity value can be obtained. According to this calculation method, variation in the speed value when there is no scum can be reduced, and a smaller speed change, that is, a small scum can be detected.

On the other hand, the average value in the Δt section may be used for the speed calculation instead of the least square method. By doing so, the amount of calculation is reduced and the load on the microcomputer is reduced, so that even when the press speed is increased, it is possible to detect the dregs rising which can sufficiently follow the press speed.

[0021]

As described above in detail, according to the scrap rising detection method of the present invention, the displacement before and after the stripper collides with the workpiece is detected, and the displacement gradient (the displacement gradient immediately before the bottom dead center position) is detected from the displacement of the stripper. (d / Δt) and a step of comparing the displacement gradient with a predetermined reference value, so that the detection accuracy of the ascending up can be improved and even small asperity can be reliably detected.

Similarly, according to the present invention, there is provided a scrap rising detecting apparatus provided in a press apparatus for performing a pressing process by a punch on a metal plate sandwiched between a stripper and a die plate. Detecting means for detecting the displacement of the stripper during machining, calculating means for calculating a displacement gradient immediately before bottom dead center from the stripper displacement detected by the detecting means, and comparing the displacement gradient with a predetermined reference value. And a comparing means for outputting a stop signal to the press device based on the comparison result.
It is possible to increase the accuracy of detecting the dregs rising, and to reliably detect small dregs.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment in which a part of a scrap rising detection device of the present invention is disposed in a press device.

FIG. 2 is an explanatory diagram showing an embodiment of a detection circuit of the dust rise detection device of the present invention.

FIG. 3 is an explanatory diagram showing an embodiment of a scrap rising detection method according to the present invention.

FIG. 4 is an explanatory diagram showing an embodiment of a scrap rising detection method according to the present invention.

FIG. 5 is an explanatory diagram showing another embodiment of the scrap rising detection method of the present invention.

FIG. 6 is a graph showing the displacement of the stripper at the time of normal operation and at the time of ascending of the waste.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Punch 2 Spring 3 Stud 4 Sub guide post 5 Main post 6 Stripper backing plate 7 Stripper 8 Die 9 Plate material 10 Casing hole 11 Displacement sensor 12 Target 13 A / D converter 14 First bound bottom dead center position detector 15 Gradient calculation Circuit 16 Gradient comparison circuit 17 Stop circuit 18 Press 19 Reference value input circuit

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Ryuji Yonemoto 3550 Kida Yomachi, Tsuchiura-shi, Ibaraki Hitachi Systems, Ltd. System Materials Research Laboratory (58) Field surveyed (Int. Cl. ⁶ , DB name) B21D 28/00 B21D 37/00

Claims (7)

(57) [Claims] A step of detecting a displacement before and after the stripper collides with a workpiece and calculating a displacement gradient (d / Δt) immediately before a bottom dead center position from the displacement of the stripper; Comparing with a value and outputting a control signal according to the comparison result. 2. A step of detecting a displacement before and after the stripper collides with the workpiece and obtaining a first bound bottom dead center at the time of the collision, and a displacement gradient (d) immediately before the bottom dead center position from the displacement of the stripper. /
Δt), and a step of comparing the displacement gradient with a predetermined reference value and outputting a control signal based on the comparison result. 3. A step of detecting a displacement before and after the stripper collides with the workpiece, and obtaining an initial bound bottom dead center at the time of the collision, and using a point ascending a predetermined value D from the bottom dead center position as a reference. A step of calculating a displacement gradient immediately before the bottom dead center position from the displacement of the stripper, and a step of comparing the displacement gradient with a predetermined reference value and outputting a control signal based on the comparison result. , Scrap rising detection method. 4. A step of detecting a displacement before and after the stripper collides with the workpiece and obtaining an initial bound bottom dead center at the time of the collision, and two sections immediately before the bottom dead center position from the displacement of the stripper. A step of calculating a displacement gradient; and a step of comparing the two displacement gradients with each other and outputting a control signal based on the comparison result. 5. A scrap rising detecting device provided in a press device for pressing a metal plate material held between a stripper and a die plate by a punch, wherein a detecting means for detecting a displacement of the stripper during the pressing. Calculating means for calculating a displacement gradient immediately before bottom dead center from the stripper displacement detected by the detecting means; comparing the displacement gradient with a predetermined reference value; and, based on the comparison result, a stop signal to the press device. And a comparing means for outputting a signal. 6. A scrap-up detecting device provided in a press device for performing a press working by a punch on a metal plate material sandwiched between a stripper and a die plate, wherein a detecting means for detecting a displacement of the stripper during the press working. And a point that is a fixed value D from the bottom dead center position as a reference,
Calculating means for calculating a displacement gradient immediately before bottom dead center from the stripper displacement detected by the detecting means; comparing the displacement gradient with a predetermined reference value; and outputting a stop signal to the press device based on the comparison result. And a comparing means for performing the detection. 7. A scrap rising detecting device provided in a press device for performing a press working by a punch on a metal plate material sandwiched between a stripper and a die plate, wherein a detecting means for detecting a displacement of the stripper during the press working. Calculating means for calculating a displacement gradient in two sections immediately before the bottom dead center from the stripper displacement detected by the detecting means; comparing the two displacement gradients with each other; and stopping the press device based on the comparison result. And a comparing means for outputting a signal.