JPH0767572B2 - Method for detecting defective aluminum cap molding - Google Patents

Description

The present invention relates to an aluminum cap molding defect detection method.

(Prior Art) Conventionally, an electromagnetic sensor is brought close to a blank punching hole after a product is punched by a press, and the output of the electromagnetic sensor changes depending on whether or not the punching hole periphery electrically forms a closed loop. Japanese Patent Laid-Open Publication Nos. 57-179739 and 58-42902 disclose a method for detecting a punching defect of a press that determines the quality of a product punched by the press from the level.

(Problems to be Solved by the Invention) The above-mentioned conventional method is a method of determining whether or not there is a peripheral break with an electromagnetic sensor for a blank after a product is punched, It does not simultaneously identify defects during molding.

Generally, when stamping and forming an aluminum cap, after fixing the aluminum film with a film retainer, punching with a male blade,
Next, extrusion molding is performed by a former.
As shown in the figure, the film (a) fixed to the cap holder (1) includes a former (3) and a piston (4).
And are extruded in the punched hole (2).

The aluminum wrapping material used for such molding is, for example, as shown in FIG. 2, in which a polyethylene layer (6) and a hot melt layer (7) are formed on an aluminum material (5) of 30 to 40 μm, Although it is adhered to the container by heat sealing, the defective products that occur during punching and molding are the blank top surface as shown in Fig. 3 (a) and the skirt as shown in Fig. 3 (b). 3), a cutout as shown in FIG. 3 (c), a wrinkle as shown in FIG. 3 (d), and double punching as shown in FIG. 3 (e).

Heretofore, there has been no method of simultaneously discriminating a defective product of the aluminum cap as described above, that is, a defect at the time of punching and a defect at the time of molding.

If an optical sensor is used to detect all defective patterns, the number of sensors will be large and the structure will be complicated. In addition, if an image sensor is used to detect the defect, not only will it not be possible to detect it as a defect by simply seeing through the top surface, but the device is expensive.

(Means for Solving the Problems) Therefore, the technical problem of the present invention is to provide a molding defect detection method of an aluminum cap capable of detecting the presence or absence of defects for all expected defect patterns. The technical means of the present invention for solving this technical problem are:
After fixing an aluminum film with a film retainer, punch it out with a male blade, and extrude with a former to form a cap, measure the peak value at the time of overshoot of the cap extrusion piston supported by the spring corresponding to that former. Is a method for detecting defective aluminum cap molding, which is characterized by determining whether the cap is good or bad.

(Advantages of the Invention) According to this technical means, it is possible to detect the presence or absence of defects in all of the expected defect patterns when forming the aluminum cap.

And the device for measuring the peak position of the extrusion piston is μ
If it can be measured with m accuracy, it can be used, for example,
There are electromagnetic sensors and optical sensors.

(Example) An example shown in the drawings will be described below.

In the present invention, when the cap pushing piston (4) supported by the spring (8) is moved by being pushed by the former (3) as shown in FIG. 1, inertia is maintained even after the former (3) is stopped. It is separated from the cap surface by force, and after overshooting about 600 μm, it returns to the front surface of the former (3) and stops.

When the peak value of the piston (4) at the time of overshoot was continuously measured, it was found that the peak value greatly changed at the time of defective molding.

This change in peak value changes the frictional force of the aluminum cap sliding between the former (3) and the cap holder (1),
This is because the speed of the former (3) changes.

Therefore, the defect can be detected by continuously measuring the peak value and detecting the displacement amount from the average value.

Fig. 4 shows the displacement of the extrusion piston.
It shows a state for 1 second.

The figure shows the movement distance on the vertical axis and the time on the horizontal axis.
The state where the piston overshoots and then returns to the front of the former and stops is clearly shown.

FIG. 5 is a continuous recording of the peak value of the piston (100 seconds), and shows an example of the occurrence of cutting defects when the film is meandering.

The vertical axis shows the piston peak value and the horizontal axis shows the time.

FIG. 6 shows a punching and molding machine for aluminum packaging materials.
The same parts as those in the figure are denoted by the same reference numerals.

Aluminum packaging material (a) is from the upper feed roll (18)
The slider (12) and the former (3) move integrally while moving toward the lower feed roll (17), and the film retainer (9) which is elastically pressed by the spring (10). ) Fixes the film (a), then punches the cap with the cutter male blade (11) and the cutter female blade (14), and then extrudes the former (3) to open the hole in the cap holder (1). In (2),
Molded with the help of the piston (4).

The piston (4) is supported by a cap pushing spring (8), and the cap push-back rod (15) is retracted by the piston (4) against the force of the spring (8).

Next, as shown in FIG. 6, when the cap push-back rod (15) is retracted from the piston holder (16), the sensor (1
9) works and operates the amplifier (20) to activate the recorder (21)
The peak value of the spring will be recorded at.

FIG. 9 shows a heat-sealing machine. When the container (b) is supplied to the turret board (22) by the roll conveyor (26), the aluminum cap (c) is transferred from the shooter (23) to the container (b). The aluminum cap (c) is heat-sealed to the container (b) by the heater (24). The container (b) with the aluminum cap (c) heat-sealed is discharged from the turret board (25) toward the conveyor (27).

As described above, the aluminum cap is heat-sealed in the container, but defective products are discharged before the aluminum cap is supplied to the shooter (23).

FIG. 8 shows the defective product discharge port. At the entrance of the product shooter (23), there is an open / close valve (28) controlled by the sensor. In the case of defective product, this opens and the discharge port (29). ) Is discharged to the outside. (30) is an air nozzle which allows the product to be ejected toward the shooter (23).

By the way, 1 shot during normal operation is measured as shown in FIG. 10 (a), the cap pressing piston is supported by a spring, and during punching, it stops after overshooting about 600 μm.

As described above, the continuous data are shown in FIG. 10B, and all the data hold the peak value at the time of overshoot.

Note that FIG. 10 (a) is the same as FIG. 4, and the continuous values are shown in FIG. 10 (b).

During normal operation, the peak value varied by about ± 30 μm. The aluminum thickness at this time was 35 μm.

Next, the case where the driving air pressure is reduced will be explained. When the driving air pressure of the punching molding machine is reduced to about 4.5 kg / cm ² , the skirt portion spreads and molding defects frequently occur. This is shown in FIG. The peak value changes by about -800 μm, and defect detection is possible.

Next, explaining the case of wrinkling of the film,
It looks like this:

That is, if the aluminum sheet has deep wrinkles, defects such as the top surface being cut off and the skirt being deformed may occur.

In this case, the peak value is ± 30 μm if the wrinkles are within the range that does not cause any problems as a product, and the variation range under normal conditions (No.
(Fig. 12), but if it is a deep wrinkle where defective products appear, ±
It is about 135 μm, and defect detection is possible (see Fig. 13).

Next, the case of double punching will be described. In this case, the peak value changes by −250 μm or more, and defect detection is possible (see FIG. 14).

Next, description will be made on the case of a defect due to film meandering. If a defect occurs in the cap, a negative displacement (about −250 μm at the maximum) proportional to the area of the defective portion is output, and the defect can be detected (15th). See figure).

Next, the maximum peak value when chips are mixed is +225 μm.
It is possible to detect defects (see Fig. 16).

The peak value of the piston shifts greatly when defective,
Drift due to changes in environmental conditions (temperature), aluminum thickness, drive air pressure, etc.

Normally, the upper and lower limit alarms from the set value are sufficient for detecting defects, but in order to improve the detection accuracy, the average value is given at several points of each peak value, and it is judged by the tolerance from the average value (see Fig. 17). .

In any case, the present invention can determine the quality of the cap by measuring the peak value of the piston corresponding to the former at the time of overshoot.

By utilizing the fact that the frictional force generated between the former and the cap changes according to the cap shape, the overshoot peak value during molding of the extrusion piston as described above is measured, and the peak stress of the former occurs. The value may be measured to detect the defect.

In order to measure the stress of the former, for example, the strain gauge (32) is attached to the former drive shaft (31) shown in FIG. 6 for measurement.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention. FIG. 2 is a cross-sectional view of an aluminum packaging material. FIG. 3 is a diagram showing types of defective products in (a) to (e). FIG. 4 is a displacement diagram of an extrusion piston. Continuous recording of peak value of piston Fig. 6, Fig. 7 and Fig. 8 are explanatory views of the apparatus used for carrying out the method of the present invention, partial view of the molding machine and explanatory view of defective product discharge chute. Fig. 9 is a heat sealing machine. FIG. 10 to FIG. 16 are recording diagrams for defect detection. FIG. 17 is a determination diagram of good / defective peak value. (1) …… Cap holder (3) …… Former (4) …… Extrusion piston (8) …… Spring (9) …… Film retainer (10) …… Film retainer spring (11) …… Cutter male blade ( 12) …… Slider (13) …… Film retainer mounting bar (14) …… Cutter male blade (15) …… Cap push back rod (16) …… Piston holder (17) …… Lower fiddler (18) …… Upper feed roll (19) …… Sensor (20) …… Amplifier (21) …… Recorder

Claims (1)

[Claims] 1. A peak value at the time of overshooting of an extrusion piston supported by a spring corresponding to the former when the aluminum film is fixed by a film retainer, punched by a male blade, and extrusion-molded by a former to form a cap. A method for detecting a defective aluminum cap molding, which comprises determining whether the cap is good or bad by measuring.