JPS63169513A - Coating film thickness measuring instrument - Google Patents

Abstract

PURPOSE:To measure the thickness of a coating film in a wet state without contacting by providing a main body successively with a distance sensor which measures the distance to the surface of the coating film formed on the surface of a coated body and a distance sensor which measures the distance to the surface of the coated body. CONSTITUTION:The distance 3 is an optical trigonometric type sensor and measures the distance A to the surface of the coating film (a) from the sensor 3 by reflecting projection light from a light emitting element by the surface of the coating film (a), receiving its reflected light as spot light on a position detecting element, and utilizing the position on the detecting element. The distance sensor 4, on the other hand, is an electromagnetic type sensor and measures the distance B from the sensor 4 to the coated body (b) by setting a coil which has an iron core internally opposite the coated body (b) made of a magnetic material and utilizing variation in the inductance of the coil with their opposition distance. Then detecting circuits 5 and 6 obtain the measured values A and B as electric signals and an arithmetic circuit 9 performs arithmetic by subtracting the measured value A from the measured value B, so that the result is displayed 10 as the thickness of the coating film (a). Thus no trace of the measurement is left.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for measuring the thickness of a wet coating film formed on the surface of an object to be coated before drying.

Problems to be solved by conventional techniques and inventions, for example,
In an automatic coating line that continuously applies coating to objects transported by a conveyor, knowing the thickness of the wet coating before drying is useful in controlling the amount of paint discharged and performing correction coating. It is important that when measuring the thickness of this wet film, as when measuring the dry film thickness,
for example.

A contact-type film thickness meter such as an electromagnetic film thickness meter is used, which measures the film thickness by placing a coil with an iron core in contact with the coating and measuring the distance to the surface of the object to be coated based on changes in the coil's inductance. Conventionally, wet gauges such as a rotary type using an eccentric shaft or a comb type wet gauge that measures by the increments of the tooth profile were used exclusively for wet coating. Because it is a structure that is pushed into the film, there was a problem that large measurement marks remained on the coating film.

Means for Solving the Problems As a means for solving the above-mentioned problems, the coating film thickness measuring device of the present invention has a method for measuring the distance to the surface of the coating film formed on the surface of the object to be coated. A first distance sensor and a second distance sensor for measuring the distance to the surface of the object to be coated are arranged in parallel on the main body.

The present invention is configured to include a calculation display device that calculates and displays the difference between the measured values of the first and second distance sensors.

Functions and Effects of the Invention The present invention has the above configuration, and when the main body is brought into contact with an object to be coated on which a wet paint film is formed on the surface, the first distance sensor installed in parallel on the main body detects the paint film. The distance to the surface of the object to be coated is measured, the second distance sensor measures the distance to the surface of the object to be coated, and the calculation display device calculates the difference between the measured values of the first and second distance sensors. The calculated value is displayed as the coating film thickness, and since the structure does not allow any contact with the coating film, it is possible to measure the thickness of the wet coating film without leaving any traces of measurement. Moreover, since the coating film thickness is displayed, there is an effect that the coating film thickness can be easily and reliably recognized.

Example An embodiment of the present invention will be described below with reference to FIG.

In the figure, ■ is the main body of the measuring device, which is installed in front of the object to be coated, which is made of a magnetic material such as iron and has a wet coating film a formed on its surface. A first distance sensor 3 for measuring the distance to the surface of the coating film a and a second distance sensor 4 for measuring the distance to the surface of the object to be coated are attached to the main body 1 side by side. 1st
The distance sensor 3 is an optical triangulation type distance sensor, which reflects the projected light from the light emitting element on the surface of the coating film a, and uses the reflected light to detect the position provided on the side of the light emitting element. A spot light is received on the element, and the distance from the distance sensor 3 to the surface of the coating film a is measured based on the position of the spot light on the position detection element. is an electromagnetic distance sensor that uses a coil with an iron core to correspond to the object to be coated made of magnetic material, and the inductance of the coil changes according to the corresponding distance. 4 to the surface of the object to be coated, and the first and second distance sensors 3 and 4 each have a detection circuit 5 that extracts each measured distance as an electrical measurement value. , 6 are connected, and each detection circuit 5.6 is connected to a sample hold circuit 7.8 that extracts and holds each measured value. An arithmetic circuit 9 is connected to the arithmetic circuit 9, and a display circuit 10 is connected to the arithmetic circuit 9 to display the arithmetic results.

This embodiment has such a structure, and the first distance sensor 3
The distance A to the surface of the coating film a is measured at , and the distance B to the surface of the object to be coated is measured by the second distance sensor 4.The arithmetic circuit 9 calculates the measured value A from the measured value B. A subtraction operation is performed.

The calculation result is displayed on the display circuit 10 as the thickness of the coating film a.

Note that the second distance sensor 4 that measures the distance WaB to the surface of the object to be coated is used when the object to be coated is a metal material other than a magnetic material such as aluminum, aluminum alloy, copper, or non-magnetic stainless steel. For this purpose, it is sufficient to use an eddy current type distance sensor that measures distance based on the magnitude of eddy current induced on the metal surface by a high frequency electric field, and for non-metallic materials such as plastic, an ultrasonic type distance sensor can be used. Just use it.

FIG. 2 shows another embodiment of the present invention. In the embodiment of FIG. 1, the measurement positions of the first and second distance sensors 3.4 do not match and are shifted, so for example, When the object to be coated is in a tilted position.

This will cause an error in the measured value of the coating film thickness, so in this embodiment, two first distance sensors 3 for measuring the distance to the surface of the coating film a are installed at intervals, and the center A second distance sensor 4 for measuring the distance to the surface of the object to be coated is attached, and an arithmetic circuit calculates the average value of the measured values A1 and A2 of the two first distance sensors 3, 3. Subtract the average value from the measured value B of the second distance sensor 4,
This allows the thickness of the coating film a to be measured, and even if the object to be coated is tilted, the coating thickness can be measured with the error kept small.

In addition, contrary to the above, it is also possible to have a structure in which two second distance sensors 4 are arranged and the first distance sensor 3 is arranged in the center. The larger the number of sensors, the smaller the coating thickness measurement error can be.

[Brief explanation of the drawing]

FIG. 1 is a front view and block diagram of one embodiment of the present invention, and FIG. 2 is a front view of another embodiment. a: Paint film b: Object to be coated 1: Main body 3: First distance sensor 4: Second distance sensor 9: Arithmetic circuit 10: Display circuit

Claims (1)

[Claims] 1. A first distance sensor that measures the distance to the surface of the coating film formed on the surface of the object to be coated, and a second distance sensor that measures the distance to the surface of the object to be coated. Coating film thickness measuring device 2, characterized in that it has a calculation display device that calculates and displays the difference between the measured values of the first and second distance sensors. A plurality of one of the two distance sensors is disposed at a position where the other distance sensor is approximately at the center, and the calculation display device calculates the average value of the measured values of the one distance sensor. The coating thickness measuring device according to claim 1, wherein the device calculates the difference between the measured value of the other distance sensor and the measured value of the other distance sensor.