JPS63165030A - Method and device for detecting scum riser on press work - Google Patents

Abstract

PURPOSE:To prevent generating an off-specification product or a damage of a punch by detecting the generation of a scum riser based on the difference between outputs of ultrasonic sensors at the times of non-generating the scum riser and generating the scum riser. CONSTITUTION:The ultrasonic sensor 1 is disposed on a press machine or a stripper. The ultrasonic signals are outputted from the ultrasonic sensor 1 and these output signals are added to a comparator circuit 3 after amplified by an amplifier 2. Because the comparator circuit 3 outputs a signal of a logic level (1) when it is higher than a prescribed shreshold value, at the time of outputting the ultrasonic signal of non-generating the scum riser from the amplifier 2, the number of (m) of pulse signals are outputted from the comparator circuit 3. Furthermore, when the ultrasonic signals at the time of generating the scum riser is outputted from the amplifier 2, the number of (n) of pulse signals are outputted. The pulse signals are counted by the counter 4, the counted value at the counter 4 is compared with a preset value by the comparator circuit 5. When the counted value at the counter 4 is over the preset value, the comparator circuit 5 outputs the scum riser signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for detecting scrap build-up during press working.

[Prior art] IC lead frames and electric motor iron core components
When a press machine is used to punch and form a material such as the like, so-called punching waste is pushed into the die by the punch.

After pushing the above punching waste (hereinafter referred to as waste),
When the punch performs an upward movement, a vacuum state is created between the tip of the punch and the scraps, so that the scraps that have been pushed up may rise and fly out of the die, that is, so-called scrap lifting may occur.

When this scrap build-up occurs, the scrap adheres to the die or the stripper, resulting in continuous dents on the processed material, resulting in a large number of defective products. This residue also causes breakage or chipping of the punch.

By the way, if the above-mentioned scum buildup occurs and the scum adheres to the surface of the processed material, the stripper will be separated from the die by the thickness of the scum during punching.

Therefore, conventionally, a method has been proposed in which the above-mentioned scrap rising is detected based on the height of the stripper when the punch is positioned at the bottom dead center.

[Problem that the invention seeks to solve]

However, the above conventional method has the following drawbacks.

a) If the shape of the debris is small, it is not possible to accurately detect the debris. Incidentally, scum build-up mainly occurs when fine processing is required, such as in the case of the lead frame, and the shape of the scum is also small in such processing.

b) Scrap build-up cannot be detected when the hardness of the processed material is low. This is because the scraps are crushed by the stripper and pushed into the material, so that changes in the height of the stripper due to the lifting of the scraps will no longer occur.

The object of the present invention is to solve such conventional problems.

[Means for solving problems]

When an object is broken or crushed, an ultrasonic wave called an intracorporeal TAE (ACUSTICE formerly TlON) wave is emitted. In the present invention, this AE wave is used to detect debris rise. That is,
In the scrap lifting detection method according to the present invention, an ultrasonic sensor for detecting AE waves is installed at a suitable location of a press machine, and based on the difference in the output signal of the ultrasonic sensor when scrap lifting is not occurring and when scrap lifting is occurring, The occurrence of the above-mentioned waste is detected.

Further, in the detection device according to the present invention for carrying out the above method, an ultrasonic sensor for detecting AE waves provided at an appropriate location of the press machine, and a signal of a predetermined value or more output from the ultrasonic sensor are converted into pulse signals. A waveform conversion means for converting the pulse signal into a pulse signal, a means for counting the pulse signal, and a comparison means for comparing the count value of the counting means with a preset value are provided.

Further, the detection device of the present invention includes means for extracting a non-punching operation period of the press machine, and means for detecting that a signal of a predetermined value or more is output from the ultrasonic sensor within the period. ing.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

As mentioned above, so-called scrap lifting occurs when punching scraps fly out from the die.

When the above-mentioned scrap lifting does not occur, an AE wave as illustrated in FIG. 3(a) is generated every time a material is punched out by a press machine. That is, AE waves having substantially the same waveform are generated during each punching operation period T centered at the bottom dead center.

On the other hand, when scraps rise, the material is crushed by the scraps immediately before the above period T, and the scraps themselves are also crushed, so that the scraps are crushed just before the above period (C). Based on the upstream <AE wave appears.

In this way, the AE wave when debris rises occurs is different from that when debris does not occur.

Therefore, in the embodiment of the scrap rising detection method according to the present invention,
The AE wave is detected by an ultrasonic sensor, and debris build-up is detected based on the difference in the output signal of this sensor when no debris is generated.

FIG. 1 shows an example of a device for carrying out such a detection method, and an ultrasonic sensor 1 shown in the figure is disposed in a die or a stripper of a press machine (not shown).

This ultrasonic sensor 1 outputs a signal corresponding to the AE wave, and this output signal is amplified by an amplifier 2 and then applied to a comparison circuit 3.

When the input AE signal is larger than the threshold value Vr shown in FIG.
Since the signal of circuit 3
is output from.

In addition, the AE from the amplifier 2 when the waste rises as shown in the same figure (C).
When the signal is output, n
l! A pulse signal of l (>m1ll> is output.

The counter 4 counts the pulse signal output from the comparison circuit 3, and the comparison circuit 5 compares the count value of the counter 4 with a preset value.

The counter 4 is reset by a signal from a rotary cam switch (not shown), for example, when the press machine is located at the top dead center.

The comparison circuit 5 is configured to output a waste signal when the count value of the counter 4 is greater than or equal to a preset value. In this embodiment, the preset value is set to m+1, so that the comparator circuit 5 outputs a scrap rising detection signal only when scrap rising occurs.

Note that the above-mentioned scrap rising detection signal is used as a stop signal of the press machine and a scrap rising display signal.

FIG. 2 shows another embodiment of the residue detection device according to the present invention.

This embodiment includes a one-shot circuit 6, an inverter circuit 7 that inverts the output signal of the one-shot circuit 6, and an AND circuit 8 that performs the logical product of the output signal of the inverter circuit 7 and the output signal of the comparator circuit 3. It is equipped with

The one-shot circuit 6 receives, as a trigger signal, a timing signal shown in FIG. 3(e) given from a rotary cam switch or the like, that is, a timing signal indicating the start point of the punching operation period (■), and then inputs the timing signal shown in FIG. 3(f) as a trigger signal. Like the above period■
Outputs a signal with the same time width as . This signal is inverted by the inverter circuit 7 as shown in (9) in the same figure.
The logic level at the output terminal of this inverter circuit 7 becomes "1" during the non-punching operation period of the press machine. In this way, the one-shot circuit 6 and the inverter circuit 7 have the function of extracting the non-punching operation period.

Note that the one-shot circuit 6 indicating the above-mentioned punching operation period T
The monostable time varies depending on the operating speed of the press machine, the thickness of the material, etc., so it is set appropriately according to these factors.

From the comparator circuit 3, as mentioned above, the third
The pulse signal shown in Figure (b) and the pulse signal shown in Figure (d) at the time of scrap rising are output, respectively.

The pulse signal based on the rise of scraps, which is shown by hatching in FIG. 2D, is output during the non-punching operation period, that is, during the period when the logic level of the output signal of the inverter circuit 7 is 1''. Therefore, in this embodiment, only the pulse signal based on this rising waste is outputted from the AND circuit 8 as the rising waste detection signal.

In the above embodiment, the ultrasonic sensor 1 is arranged on the die or the stripper of the press machine, but one or more sensors 1 are arranged on both of them, and each output signal of these sensors 1 is individually transmitted. It is also possible to detect the above-mentioned waste by processing.

In addition, the comparison circuits 3, 5, . counter 4
．． One-shot circuit 6. Of course, it is also possible to have a microcomputer perform the functions of the AND circuit 8 and the like.

〔Effect of the invention〕

In the present invention, an ultrasonic sensor for detecting AE wave nuclei is installed at a suitable location of a press machine, and the generation of the above-mentioned scrap is detected based on the difference in the output signal of the ultrasonic sensor when no scrap is generated and when scrap is generated. Detected.

Therefore, even when the shape of the punched waste is small, such as during lead frame molding, or when the hardness of the material is low,
Scrap build-up can be detected reliably and quickly, thereby minimizing the occurrence of dents caused by scrap build-up, and also reliably preventing breakage, chipping, etc. of the punch.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a scrap rising detection device according to the present invention, FIG. 2 is a block diagram showing another embodiment of the same device, and FIG. 3 is a block diagram showing another embodiment of the device. 3 is a timing chart showing the operation of the embodiment shown in FIG. 1... Ultrasonic sensor, 3, 5... Comparison circuit, 4...
・Counter, 6...one-shot circuit, 8...AND circuit.

Claims (4)

[Claims] (1) An ultrasonic sensor for detecting AE waves is installed at an appropriate location on the press machine, and the occurrence of the above scrap lifting is detected based on the difference in the output signal of the ultrasonic sensor when no scrap lifting occurs and when scrap lifting occurs. A method for detecting scrap build-up in press processing, characterized by: (2) The method for detecting scrap build-up in press processing according to claim (1), wherein the ultrasonic sensor is installed in one or both of a stripper and a die of the press machine. (3) An ultrasonic sensor for detecting AE waves provided at a suitable location on the press machine; a waveform conversion means for converting a signal of a predetermined value or more outputted from the ultrasonic sensor into a pulse signal; and a means for counting the pulse signal. What is claimed is: 1. A detection device for scrap build-up in press working, comprising: means; and comparison means for comparing the count value of the counting means with a preset value. (4) an ultrasonic sensor for detecting AE waves installed at a suitable location on a press machine; means for extracting a non-punching operation period of the press machine; and a signal of a predetermined value or more is output from the ultrasonic sensor within the period; What is claimed is: 1. A device for detecting scrap build-up in press working, comprising: means for detecting that the scrap has been removed.