JPS6047524B2 - Paint film thickness measuring device for painted steel plates - Google Patents

Description

[Detailed description of the invention] The present invention relates to an apparatus for measuring the coating film thickness of a painted steel plate.

In recent years, painted steel sheets have been widely used for various purposes, and are also manufactured in large quantities.

Furthermore, high quality is required, and to achieve this, it is necessary to measure the coating film thickness with high precision and feed back the measured value to control the coating thickness and obtain a uniform thickness. I'm getting old. Conventional methods for measuring paint film thickness include using a comb gauge, a lens gauge, and a rotary gauge, but all of these methods use gauges, which have low accuracy and are artificial. There were disadvantages such as errors, fragmentary detection, and inability to perform automatic control. The present invention measures the paint film thickness by spraying air at a predetermined pressure onto the paint film surface in spots and detecting the size of the depression image formed by the air using an optical detection device. Then, the coating film thickness can be measured in units of P, and the measured value is fed back and used as a control signal for the coating thickness.

The following will explain the embodiments shown in the drawings. FIG. 1 is a diagram explaining the principle of the present invention.

Reference numeral 1 denotes a coated steel plate, the surface of which is coated at a front stage (not shown), and which is manufactured continuously while moving in the direction of the arrow.

2 is an air generator, 3 is an air jet nozzle, and 4 is an anemometer, and the air device including these components is installed facing the painted surface.

Then, by jetting air toward the painted surface, a dimpled image 5 is formed on the painted film. Reference numeral b denotes a light emitter, which is installed so as to illuminate the depression image 5 on the coating film.

Reference numeral 1 denotes an optical sensor that detects the recessed image 5.

8 is a focusing lens, which together with the light emitter 6 and sensor 7 constitutes an optical detection device. Reference numeral 9 denotes a signal processing device which receives the signal from the optical sensor 7, compares it with predetermined values and various conditions, and calculates the coating film thickness.

Then, a control signal is issued to the coating thickness adjusting device 10 in the coating station (not shown). The structure of the present invention is as described above, and its operation will be explained next.

First, when air is ejected from the air nozzle 3 toward the surface of the painted steel plate 1, a dimple image 5 is formed on the surface of the painted film.

As shown in FIGS. 2A, B, and C, this depression image is formed small when the coating film is thick, and large when the coating film is thin. The sensor 7 detects the size of the hollow image 5 illuminated by the light emitter 6 in terms of area, and sends the detected value at each time to the signal processing device. The flow velocity of the air nozzle 3 is a factor that changes the formation of the concave image, so the air nozzle 3
The air flow velocity inside the tank is measured by an anemometer 4, and the value is sent to a signal processing device 9.

The signal processing device 9 compares the signal input from the sensor 7 with a predetermined setting value that has been input in advance and the air flow rate sent from the anemometer 4, calculates it, and calculates the coating film thickness at that time. It will be calculated.

The signal from the anemometer 4 is input to the processing device 9, where it is compared with a pre-input flow velocity reference value, and the air generator 1 is controlled to determine the amount of air to be ejected. It may also be a signal that controls the flow velocity to always be constant. In addition to the flow rate, the nozzle diameter, the distance between the nozzle and the steel plate surface,
The nozzle installation angle and the like are also factors that change the recessed image, but these can be fixed for each device.

Furthermore, even if a dimple image is formed on the painted steel plate surface, once the paint is removed from the air spraying position, the paint will return to its original state and no dimples will remain.

Further, the formation of the recessed image may be performed by jetting air all the time, or may be performed by jetting air at every predetermined cycle.

In addition, when the above-mentioned air is constantly ejected to form a concave image, the shape becomes a trailing shape along the moving direction of the steel plate, so the sensor 7 is configured to detect the width of the image at a predetermined position. You can.

As described above, according to the present invention, a concave image is formed by blowing air at a predetermined pressure on the surface of the coating film, the size of this image is detected by an optical system detection device, and the detection signal is used to paint the coating film. Since the film thickness is measured, it is non-contact and highly accurate.
The film thickness can be measured continuously, and the coating thickness can be accurately controlled based on the measured values.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention, and FIGS. 2A, B, and C are diagrams showing the state of formation of a recessed image. 1... Painted steel plate, 2... Air generator,
3...Air jet nozzle, 4...Anemometer, 5
...Indented image, 6...Light emitter, 7...
...Sensor, 9...Signal processing device, 10.
...Paint thickness adjustment device.

Claims (1)

[Claims] 1. An air device consisting of an air generator, an air nozzle, and an anemometer and capable of ejecting air at a constant flow rate or a predetermined pressure toward the painted surface to form a concave image on the painted film, a light emitter, a sensor, and an air device. A painted steel board characterized by having an optical system detection device configured with an optical lens and capable of detecting the size of the dented image, and a signal processing device inputting a signal from the sensor and processing the signal. Paint film thickness measuring device.