JPH029892B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an automatic control method for a press machine.

[Background of the invention]

Generally, when a workpiece material is punched using an upper die and a lower die, as the upper die rises after punching, the punching residue remaining in the lower die is piled up on the lower die or the workpiece material, and is used for the next punching operation. It often has negative effects.

When the punching scraps are placed on the lower mold or the workpiece material in this way, this is called scrap lifting.

Figure 1 shows a conventional press device, where 1 is an upper die;
2 is a lower die, 3 is a workpiece material, and 5 is a stripper connected to the lower surface of the upper die 1 via a spring 4. The workpiece material 3 on the lower die 2 is first pushed by the stripper 5, and then The upper mold 1 descends and punches out the workpiece material 3. Conventionally, a common method for detecting scrap lifting as described above is to detect the bottom dead center of the movement of the stripper 5 during one stroke of press work, and to compare this bottom dead center position with a set value. , to detect scrap removal.

In this method, when scraps rise, the stripper 5 is lifted up by the punching scraps placed on the lower die 2 and the workpiece material 3 placed on the punching scraps, and the stripper 5 is lifted up to its usual bottom dead center position. It detects that the target cannot be reached and detects the removal of waste. In this way, the conventional method of simply determining the bottom dead center position of the stripper 5 and detecting scrap lifting in one-stroke press work is a simple and effective method, but in the following cases, that is, scrap lifting If the stripper is small, the material is soft, the stripper is large, the spring pressure of the stripper is high, the stripper has a liner, and the stripper is completely pushed in, etc., most of the scum will be crushed, resulting in a change in the bottom dead center. It was difficult to detect the residue and it was very difficult to detect it.

[Object of the Invention] An object of the present invention is to provide an automatic control method for a press machine that can detect scrap lifting that could not be detected by conventional methods.

[Summary of the invention]

The automatic control method for a press machine of the present invention includes a step of determining the bottom dead center of the first bounce caused by the stripper colliding with the lower die or workpiece material in the first punching process of the press machine, and a step of setting the bottom dead center position obtained as a set value, and a step of determining the bottom dead center of the first bounce caused by the stripper colliding with the lower die or workpiece material in the next punching step.
The method is characterized by comprising a step of comparing the bottom dead center position obtained in this step with the set value, and a step of controlling the press machine based on the value obtained in this comparison step.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention was made by focusing on the fact that bounce occurs when the stripper 5 descends and hits the lower die 2 or the workpiece material 3. This bounce is repeated stably in each press operation, but when scrap lifting occurs, the stripper 5 first comes into contact with the scrap, the waveform of the bounce changes, and the position of the bottom dead center of the first bounce changes. also changes significantly.

In the present invention, in a one-stroke press operation, point a in FIG. 2, which is the bottom dead center of the first bounce of the stripper 5, is detected by the circuit shown in FIG. 3.

In this circuit, the movement of the stripper 5 is detected by a sensor 6 that detects the position of the stripper 5,
The output information of this sensor 6 is converted into an electric signal by a conversion circuit 7, and the output information is sent to the stripper 5 by a detector 8.
It is detected that has passed a predetermined point, and the differentiation circuit 9
Then, the point at which the stripper 5 stops descending, that is, the bottom dead center of the first bounce is detected, this position is held by the hold circuit 10, and the bottom dead center position is transmitted to the microcontroller via the A/D conversion circuit 11. In addition to the processor 12, the bottom dead center position is read, compared with the setting value set by the setting circuit 13, and judged. If it is judged that scrap lifting has occurred, the stop output circuit 14 is activated, and the press This will cause machine 15 to stop.

Note that the first punching process of the press is performed without scraping up, so the above setting circuit 1 is used.
Of course, the setting value to be set to 3 may be simply the above-mentioned bottom dead center position at this time.

〔Effect of the invention〕

Since the present invention is as described above, it has the great advantage of being able to detect scrap removal with high probability even under conditions where conventional methods cannot detect it.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional press apparatus, FIG. 2 is a graph showing the relationship between stripper position and elapsed time, and FIG. 3 is a block diagram of the apparatus used to carry out the method of the present invention. 1... Upper die, 2... Lower die, 3... Work material,
4... Spring, 5... Stripper, 6... Sensor, 7... Conversion circuit, 8... Detector, 9... Differential circuit, 10... Hold circuit, 11... A/D
Conversion circuit, 12...Microprocessor, 13
... Setting circuit, 14 ... Stop output circuit, 15 ...
press machine.

Claims (1)

[Claims] 1 The process of determining the bottom dead center of the first bounce caused by the stripper colliding with the lower die or workpiece material in the first punching process of the press machine, and the bottom dead center position obtained by this process as a set value. A process of determining the bottom dead center of the first bounce caused by the stripper colliding with the lower die or workpiece material in the next punching process, and a process of determining the bottom dead center position obtained by this process as described above. An automatic control method for a press machine, comprising a step of comparing it with a set value, and a step of controlling the press machine based on the value obtained in the comparison step.