JPH0435705B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a coating film inspection device for the inner surface of a can lid.

Prior Art A coating film of a certain thickness is formed on the inner surface of a can lid to prevent corrosion due to contact with the contents.

If this coating film has even minute pores, the can lid will corrode through the pores over a long period of time, so it is required that a complete coating layer be formed.

Conventionally, as an inspection device for the inner surface coating of can lids, the can lid is set between opposing electrodes, the outer surface of the can lid is grounded as one electrode, and a predetermined voltage is applied between the can lid and the opposing electrode to measure the discharge current. There is a known method that detects coating defects based on the presence or absence of . In addition, with the outer surface of the can lid grounded as one electrode and the back surface of the can lid in contact with the liquid surface, which is the current-carrying medium, a voltage is applied between the outer surface of the can lid and the liquid, and the detection is performed based on the presence or absence of current. Devices are also provided.

Problems to be Solved by the Invention However, in the conventional method, which is installed between electrodes and detects coating film defects using discharge current, a voltage smaller than the dielectric strength of the coating film is applied between the electrodes to ensure proper discharge. It is difficult to test, and the reliability of the test is also poor. In addition, a method that applies a voltage between the outside surface of the can lid and the liquid by bringing the inside surface of the can lid into contact with the liquid surface is more reliable than the above method, but inspection is complicated because it is performed manually one by one. It takes a long time and is inefficient, so there is a need for automation.

The present invention was devised in view of the above circumstances, and provides a coating film inspection device for the inner surface of can lids that has high inspection reliability, can inspect multiple items at once, and can be automated. The purpose is to provide

Means for Solving the Problems Technical means of the present invention adopted to solve the above problems will be explained based on drawings of embodiments.

That is, the apparatus for inspecting a coating film on the inner surface of a can lid according to the present invention has an inspection tank 1 divided into a plurality of liquid tanks 3 by a partition wall 2 in which test liquid passage holes 6 and air passage holes 7 are formed. It is pivotably attached to the machine frame 15 so as to be able to be turned upside down, and a can lid engaging portion 8 is provided at the opening of the liquid tank, and by suctioning the inside of the liquid tank, the can lid is held by suction in the can lid engaging portion 8. One electrode 12 is provided in the internal space near the opening of the liquid tank 3, and the other electrode 21 is attached to the surface of the can lid 10 that is held in the opening when the liquid tank is turned over. It is characterized in that it is provided so that it can be contacted.

Operation When the opening of the liquid tank 3 is located upward, the liquid tank 3
Supply test liquid inside. The test liquid supplied to one liquid tank is uniformly supplied into all liquid tanks through the liquid passage hole 6. Thereafter, the can lid is placed on the can lid engaging portion and held by a vacuum. From this state, the test tank 1 is turned over, the opening holding the can lid is positioned downward, and the back surface of the can lid is connected to the electrode 1 through the test liquid.
2 and bring the can lid surface into contact with another electrode 21. In this state, a voltage is applied between the electrodes 12 and 21.

If there is a hole or other missing part in the paint film, a current flows between the two electrodes via the test liquid and the can lid, and by detecting this current, a paint film defect is detected.

The above-mentioned inspection can be automated by placing and discharging the can lid into the above-mentioned inspection tank by a robot and by performing the above-mentioned operations by sequence control.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 and 2 are side views of an embodiment of the apparatus for inspecting a coating film on the inner surface of a can lid according to the present invention. FIG. 1 shows the state at the can lid set position, and FIG. 2 shows the state at the inspection position. Each state is shown.

In the figure, reference numeral 1 denotes an inspection tank, which is divided into a plurality of liquid tanks 3 by a partition wall 2 . Each partition wall 2 is provided with a test liquid passage hole 6 and an air passage hole 7. At the can lid set position (Fig. 1), the test liquid passage hole 6 allows the test liquid 5 such as water supplied to the liquid tank 3 at the end to flow into each liquid tank 3 and supply each tank to the same water level. The test liquid 5 in each liquid tank 3 communicates with each other through the through hole 6 so that the test liquid 5 in each liquid tank 3 is liquid, but in the test position (FIG. 2), the test liquid 5 in each liquid tank It is located at a position as shown in FIG. 4 so that it is isolated.

In addition, the air passage hole 7 is provided with a fourth hole so that the test liquid 5 in the liquid tank does not come into contact with the can lid set position, while the test tank 1 is being inverted, and at the test position after the inversion is completed.
As shown in the figure, it is provided at a position slightly offset from the center 4 of the liquid tank 3 in the width direction in the counter-rotational direction.
This prevents the test liquid from being sucked by the vacuum during rotation, and prevents the test liquid from being sucked into the liquid tank 3.
The amount of can be increased. A can lid butt 8 is a can lid engaging portion provided at the opening of each liquid tank 3, and is formed in a donut shape so as to engage with a shoulder portion of the can lid 10. The can lid 10 will be described later. It is designed to become watertight when adsorbed. In this embodiment, the test tank 1 is made of a plastic material to provide electrical insulation between the test tank and the can lid 10 and an electrode rod, which will be described later.

The electrode rod 11 is provided so that it penetrates the bottom of each liquid tank 3 and the electrode at the top is located near the opening, and in the test position, the electrode is immersed in the surface of the test liquid and is electrically conductive with the test liquid. , the power supply side terminal 12 is connected to the electrode of the power supply.

The inspection tank 1 configured as described above has the machine frame 15
It is rotatably supported by a shaft, and is driven by a motor or air means 16 via gears 17 and 18 to reverse the rotation. Reference numeral 20 is a support shaft of the test tank 1 and also serves as a liquid supply pipe to the test tank 1. 21
are electrodes provided on the electrode terminal support base 22 of the base frame 15, and are arranged so that the shoulder portion of the can lid contacts each corresponding electrode at the inspection position, as shown in FIG. 24 is a vacuum pipe attached to one side wall of the inspection tank 1, and is connected to a vacuum pump 25.

30 is a test liquid tank whose liquid level is kept constant by a float valve or the like. 31 is a solenoid valve provided in the middle of the liquid supply pipe 32 to the test tank, and 34 is a pipe joint rotatably connecting the pipes 32 and 20.

With the coating film inspection apparatus for the inner surface of a can lid configured as described above, a defective coating film on the inner surface of the can lid is detected as follows.

The can lids 10 conveyed by the sampling conveyor 40 are sucked one by one by the robot device 43 from the stacking position 41 at the end thereof and placed one by one on the can lid pads 8 at the openings of each liquid tank 3. (See Figure 3).

On the other hand, pipes 32 and 20 from the test liquid tank 30
A test liquid 5 is supplied to the test tank 1 through the test tank 1 . 1st
The liquid supplied to the leftmost liquid tank in the figure is supplied to each liquid tank 3 through the liquid passage hole 6 of the partition wall 2, and each liquid tank is maintained at a constant water level. The water level in each liquid tank is determined by the water level in the test liquid tank 30, but in order to prevent the liquid from coming into contact with the air passage hole 7 during rotation of each test tank 1, the water level is set at about 1/3 of the liquid tank 3. Supplied.

When the liquid supply to the inspection tank 1 is completed, the solenoid valve 31 closes to cut off communication of the liquid. When the supply of the can lid 10 and the test liquid 5 to the test tank 1 is completed, the vacuum pump 25 is activated to suction and hold the can lid 10 to complete the setting.

Thereafter, the motor 16 is driven, and the test tank 1 is rotated 180 degrees from the state shown in FIG. 1, and set at the test position shown in FIG.

During half rotation of the test tank 1, the test liquid in the liquid tank 3 does not reach the air passage hole 7 as shown in FIG. The vacuum state is maintained without moving. In addition, at the test position after the inversion is completed, the liquid conduction hole 6 is also located above the liquid level, and the test liquid 5 in each liquid tank 3 is completely isolated from the test liquid in other liquid tanks.
Electrical insulation is provided.

If there is a pinhole or the like in the coating on the back of the can lid, the electrical insulation will be broken and the electrode 11 - test liquid 5 - can lid 10
- A current flows through the circuit of the terminal 21, and a detection switch (not shown) is activated, making it possible to detect a coating film defect.

The test data is automatically processed by a data processing device. When the inspection is completed, the motor 16 is driven again, and the inspection tank 1 returns to the state shown in FIG. 1 again. In this state, the vacuum is released and the inspected can lid 10 is removed from the inspection tank 1 by the robot 43.

Effects As described above, the present invention detects paint film defects by sensing the insulation condition of the inner surface of the can lid through the test liquid, so even small holes in the paint film can be reliably detected and are highly reliable. . In addition, since the can lid is simply placed on the opening of the inspection tank, the inspection can be performed easily, and multiple can lids can be inspected at the same time, making it possible to perform the inspection quickly and efficiently. I can do it.

Furthermore, since a robot can be easily applied to setting and discharging can lids, inspection can be automated.

[Brief explanation of drawings]

The drawings show an embodiment of the apparatus for inspecting a coating film on the inner surface of a can lid according to the present invention, and FIG. 1 is a side view at the can lid set position, FIG. 2 is a side view at the inspection position, and FIG. 3 is a side view at the inspection position. 4 is a plan view, and FIGS. 4A to 4E are front sectional views showing the rotating state of the liquid tank. 1: Inspection tank, 2: Partition wall, 3: Liquid tank, 5: Test liquid, 6: Liquid conduction hole, 7: Air conduction hole, 8: Pad, 10: Can lid, 11: Electrode rod, 12: Electrode,
15: Machine frame, 16: Motor, 21: Electrode, 2
5: Vacuum pump, 30: Test liquid tank, 3
1: Solenoid valve.

Claims (1)

[Claims] 1. A test tank divided into a plurality of liquid tanks by a partition wall having a test liquid passage hole and an air passage hole is rotatably supported on the machine frame so that it can be turned upside down, and a can is inserted into the opening of the liquid tank. A lid engaging portion is provided, and the can lid is suctioned and held in the can lid engaging portion by suctioning the inside of the liquid tank, and one electrode is provided in an internal space near the opening of the liquid tank. An apparatus for inspecting a coating film on the inner surface of a can lid, characterized in that the other electrode is provided so as to be able to come into contact with the surface of the can lid held in the opening when the liquid tank is turned over.