JPH06300509A - Device for measuring thickness of insulating coating film or insulating member and measuring method - Google Patents

Abstract

PURPOSE:To provide a device and a measuring method for measuring thickness of an insulating coating film formed on a metal plate or an insulating member, in which the number of times of zero-adjustment conducted at a measuring start is few and accurate thickness measurement can be conducted even in a state where the metal plate is deviated up and down. CONSTITUTION:In a sensor part 11, an electrostatic capacity electrode 12 and an eddy current electrode 13, being as a set, are arranged in the same height. A correction value setting part measures displacement between a surface of a metal plate 15 and the sensor part 11 by means of the eddy current electrode 13 in the sensor part 11. An electrostatic capacity detecting part measures electrostatic capacity between the surface of the metal plate 15 and the sensor part 11. A thickness computing part computes thickness of an insulating coating film 16 on the metal plate 15 based on a value obtained from the electrostatic capacity detecting part and a correction value obtained from the correction value setting part. In the case of only an insulating member 16', thickness can be measured similarly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the thickness of an insulating film or an insulating member formed on a metal plate by a hybrid structure of an electrostatic capacity method and an eddy current method, and a measuring method thereof. It is about. In recent years, there has been a demand for highly accurate thickness control of insulators such as the thickness of the adhesive applied to the metal plate, the thickness of the ink applied to the metal plate, and the thickness of the coating that insulates the metal plate. The ink, coating, etc. applied to the metal plate is processed while the metal plate moves at high speed. When manufacturing an insulating film or the like, it has become necessary to control the thickness during manufacturing. Therefore, the present invention provides a measuring device and a measuring method capable of measuring the thickness of an insulating film or an insulating member formed on a metal plate which is moving at a high speed as described above with high accuracy.

[0002]

2. Description of the Related Art FIG. 3 is a diagram for explaining the principle of measuring the distance between a sensor section and a metal plate by utilizing an eddy current. In FIG. 3, the distance measuring device is composed of a coil 32 arranged to face the metal plate 31 and a measuring unit 33. Then, the measuring unit 33 generates an eddy current in the metal plate 31 by causing the oscillating circuit 331 for flowing a high frequency current in the coil 32 and the high frequency current to flow in the coil 32, and changes by the eddy current. Coil 32
Circuit 332 that detects the impedance of the metal plate 31 and the calculation circuit 3 that calculates the distance h between the metal plate 31 and the coil 32 in consideration of the type of the object to be measured, the size of the coil 32, and the like
33, and a power supply circuit 334 that supplies current to each circuit.

The distance measuring device shown in FIG.
An electric current is passed from 1 to the coil 32 arranged so as to face the metal plate 31. The current flowing through the coil 32 generates an electric field and an eddy current on the surface of the metal plate 31 by electromagnetic induction. The eddy current causes an induction current in the coil 32. The detection circuit 332 in the measurement unit 33 detects the impedance viewed from the detection circuit 332 of the coil 32. The impedance of the coil 32 viewed from the detection circuit 332 changes depending on the distance between the coil 32 and the metal plate 31. Therefore, when the arithmetic circuit 333 corrects in consideration of the conductivity, magnetic permeability, thickness, temperature, coil size, etc. of the metal plate 31, the output voltage 34 of the arithmetic circuit 333 causes the metal plate 31 and the coil 32 to be separated. The distance between them can be measured in μm.

FIG. 4 is a diagram for explaining the principle of a thickness gauge in the capacitance type. In FIG. 4, the thickness gauge is
In order to measure the capacitance, it is composed of a main electrode 41 and a counter electrode 42. The insulating coating 43 formed on the metal plate 43 ′ is arranged between the main electrode 41 and the counter electrode 42. The counter electrode 42 is placed or attached on a base 44 or the like. The sliding rod 45 provided on the base 44 has a support rod 46 slidably movable in the vertical direction.
Is attached. An external holder 47 that holds the main electrode 41 in an insulated state is provided on the support rod 46.
Is fixed. The measuring device 48 includes a power supply circuit (not shown) that applies a voltage to the main electrode 41 and the counter electrode 42, an oscillation circuit, a detection circuit that detects electrostatic capacitance, and an arithmetic circuit that calculates thickness.

In such a thickness gauge, for example, the metal plate 43 'on which the insulating coating 43 is formed is the main electrode 4
1 and the counter electrode 42. In this case, the capacitance changes as compared with that before the metal plate 43 'having the insulating coating 43 formed thereon is inserted. Therefore, the capacitance of the insulating coating film 43 whose thickness is known is measured in advance, and based on this capacitance, the measuring device 48 uses the capacitance value detected from the insulating coating film 43. The arithmetic circuit therein calculates the thickness of the insulating film 43 by performing a comparison operation.

Further, in recent years, it has become necessary to measure the thickness of the coating film such as the insulating coating film 43 formed on the moving metal plate. FIG. 5 is an explanatory diagram for measuring the thickness of the insulating coating formed on the moving metal plate by the conventional measuring method. In FIG. 5, the metal roller 52 is rotated by the rotating shaft 53. Further, the metal roller 52 rotates while coating the surface thereof with the insulating coating 54. Then, the thickness of the insulating coating 54 formed on the rotating metal roller 52 is determined by the capacitance measured by applying a voltage to the capacitance electrode 51 and the metal roller 52.

FIG. 6 is an explanatory view for measuring the thickness of a wide insulating coating formed on a metal plate by a conventional measuring method. In FIG. 6, for example, the capacitance electrodes 62 to 65 are installed flush with the capacitance electrode support member 61 with the sensor section facing downward. Metal plate 6
The thickness of the insulating coating 67 formed on the surface of 6 is measured at various points of the insulating coating 67, and this value is sent to a controller for controlling the thickness, for example. Further, the thickness of only the insulating member is the capacitance electrode 6 in which the insulating member is inserted.
The capacitance between 2 and the base 68 is measured, and this value and the capacitance value when an insulating member whose thickness is known in advance are inserted are calculated.

[0008]

The distance measuring device shown in FIG. 3 measures the distance, but cannot measure the thickness of the insulating coating formed on the metal plate 31. Also,
The capacitance meter shown in FIG. 4 can measure the thickness of the insulating film 43 formed on the metal plate 43 'as long as the vertical deviation of the metal plate 43' does not occur. However, when the insulating coating 43 is formed on the metal plate 43 ', the height is not always constant during the movement. Therefore, the insulating coating 43 formed on the metal plate 43 '
Had a problem in that it was impossible to accurately measure the thickness because the reference electrostatic capacitance changed when moving in a vertically shaken state. In particular, the metal roller 5 as shown in FIG.
The insulating film 54 formed on the surface of the metal roller 5 is
If the second rotating shaft 53 vibrates in the direction of the arrow 55, for example, there is a problem in that the thickness measured by the capacitance electrode 51 may have an error for the same reason as above.

Further, the thickness of the insulating coating 67 formed on the metal plate 66 is determined by the plurality of capacitance electrodes 62 shown in FIG.
Through 65, accurate measurement can be made at various points in the width direction. However, the insulating coating 67 formed on the metal plate 66 may be vertically displaced from the base 68 during movement. In this case, the metal plate 66 and the base 6
It is difficult to measure the distance 71 between the insulating film 67 and 8 and correct the thickness of the insulating coating 67 accurately from this value. Therefore, the measuring device shown in FIG. 6 calculates the thickness 70 of the insulating coating 67 from the distance 69 ignoring the distance 71 and the measured capacitance.

When the thickness of the insulating coating 67 formed on the metal plate 66 is measured by the capacitance in the conventional example shown in FIG. 6, the capacitance electrodes 62 to 65 and the base 68 are separated. The interval changes depending on the temperature change such as time and date. Therefore, in such a thickness meter, the correct distance is constantly adjusted (0 adjustment) to perform highly accurate measurement. However, in recent years, measurement with higher accuracy has been demanded, and an error due to a temperature difference in one day becomes a problem. In this case, it is necessary to stop the production line several times a day and perform zero adjustment, which causes a problem of reducing productivity.

Further, the thickness of only the insulating member is accurately measured without being affected even if the insulating member moves vertically between the capacitance electrode 62 and the base 68. However, the height of the capacitance electrodes 62 to 65 may change, and the thickness of the insulating member must be calculated in consideration of this height at all times. Therefore, the distance between the capacitance electrode 62 and the base 68 should be zero so that the distance is always constant.
It has the problem that adjustments must be made frequently.

In order to solve the above problems, the present invention requires a small number of zero adjustments at the start of measurement, and provides a metal plate on which a precise thickness can be measured even when the metal plate is vertically shaken. An object of the present invention is to provide an apparatus and a method for measuring the thickness of the formed insulating film. Another object of the present invention is to provide an apparatus and a method for measuring the thickness of an insulating member that does not require zero adjustment even if the sensor unit moves in the vertical direction.

[0013]

[Means for Solving the Problems]

(First invention) In order to achieve the above-mentioned object, an apparatus for measuring the thickness of an insulating coating formed on a metal plate according to the present invention comprises a capacitance electrode (12) and an eddy current electrode (13). And a sensor unit (11) including a set of
The displacement between the surface of the metal plate (15) and the sensor unit (11) is measured by the eddy current electrode (13) in FIG.
5) A correction value setting unit for obtaining a correction distance between the surface and the sensor unit (11), and the surface of the metal plate (15) and the sensor unit (11) by the capacitance electrode (12) in the sensor unit (11). The capacitance on the metal plate (15) based on the capacitance detection unit for measuring the capacitance between the capacitance detection unit and the correction value obtained from the correction value setting unit. And a thickness calculator for calculating the thickness of the coating film (16).

(Second Invention) An apparatus for measuring the thickness of an insulating member according to the present invention comprises a sensor section (11) having a pair of a capacitance electrode (12) and an eddy current electrode (13), The displacement between the surface of the metal base (14 ') and the sensor section (11) is measured by the eddy current electrode (13) in the sensor section (11), and the surface of the metal base (14') and the sensor section (11) are measured.
A metal base (1) is provided by a distance setting unit for obtaining a distance between the metal base (1) and a capacitance electrode (12) in the sensor unit (11).
4 ') An electrostatic capacitance detection unit that measures the electrostatic capacitance between the surface and the sensor unit (11), and a value obtained from the electrostatic capacitance detection unit is calculated according to the value obtained from the distance setting unit. It is composed of a metal base (14 ') and a thickness calculator for calculating the thickness of the insulating member existing between the sensor part (11).

(Third invention) A method of measuring the thickness of an insulating coating formed on a metal plate according to the present invention is performed by an eddy current meter between the sensor part (11) and the metal plate (15) in the measured part. After measuring the displacement with the surface and the capacitance between the sensor unit (11) and the surface of the metal plate (15) by the capacitance meter, the sensor unit (1 measured by the eddy ammeter
The capacitance is corrected based on the displacement between 1) and the surface of the metal plate (15).

(Fourth Invention) The method for measuring the thickness of the insulating member according to the present invention is based on an eddy current meter and a sensor unit (1
1) and the surface of the metal base (14 '), and the sensor unit (11) and the metal base (1) by the capacitance meter.
4 ') After measuring the electrostatic capacitance between the surface and the surface, the sensor section (11) measured by an eddy current meter and the metal base (1
4 ') The electrostatic capacity is corrected based on the displacement with respect to the surface.

[0017]

[Operation] The present invention focuses on an eddy ammeter capable of accurately measuring the displacement between the metal plate and the electrode even when the measured object moving at high speed vertically shakes. Is combined with a capacitance meter for measuring the thickness of the. That is, when measuring the thickness of the insulating coating formed on the metal plate, the correction value setting unit measures the displacement between the metal plate and the sensor unit by the eddy current electrode in the sensor unit. After that, the capacitance detecting unit measures the capacitance when an insulating coating formed on the metal plate is interposed between the capacitance electrode and the surface of the metal plate. Further, the thickness calculation unit corrects the electrostatic capacitance detected by the electrostatic capacitance detection unit based on the correction value obtained by the correction value setting unit to obtain the insulating film formed on the metal plate. Calculate the thickness. As described above, the present invention is formed on a metal plate by a measurement system in which a capacitance electrode and an eddy current electrode are paired, for example, even when the metal plate is vertically shaken during movement. The thickness of the insulating coating can be accurately measured.

The thickness of the insulating member inserted between the sensor section and the metal base is measured as follows.
That is, the eddy current electrode in the sensor unit measures the displacement between the sensor unit and the metal base. Next, the electrostatic capacitance electrode in the sensor unit, in the state where the insulating member is inserted,
The capacitance between the sensor unit and the metal base is measured. Then, the thickness of the insulating member is obtained by correcting the capacitance based on the displacement between the sensor unit and the metal base. Since the present invention measures the displacement between the sensor unit and the metal base by the eddy current electrode in the sensor unit when measuring the insulating member, the thickness of the insulating member can be accurately measured even if the sensor unit moves in the vertical direction. Can be measured. Further, according to the present invention, since the capacitance is corrected and the accurate thickness is calculated while measuring the displacement between the sensor unit and the metal base, the displacement between the sensor unit and the metal base is 0. No need to make adjustments.

[0019]

EXAMPLE FIG. 1 (a) is an example of the present invention, and is a principle explanatory view for measuring the thickness of an insulating film formed on a moving metal plate. The sensor unit 11 is composed of a pair of a capacitance electrode 12 and an eddy current electrode 13. Further, the capacitance electrode 12 and the eddy current electrode 13 are
For example, it is integrally embedded in an insulating member, or detachably attached by a well-known fixing means.
Further, the capacitance electrode 12 and the eddy current electrode 13 can be slidable so that their mounting positions can be changed. Then, the capacitance electrode 12 and the eddy current electrode 1
The lower surfaces of 3 and 3 are formed so as to be flush with each other. The capacitance electrode 12 and the eddy current electrode 13 are connected via an output 17 thereof to a measuring device (not shown).

On the base 14, the metal plate 15 on which the insulating coating 16 is formed moves. The metal plate 15 on which the insulating coating 16 is formed may float by a displacement a while moving, as shown in FIG. 1, for example. However, the measuring device calculates the thickness of the insulating coating 16 as the capacitance at the preset distance a + b. Therefore, the thickness calculated by the measuring device and the actual insulating film 1
There is an error with the thickness of 6. Therefore, in this embodiment, first, the displacement c between the lower portion of the sensor unit 11 and the surface of the metal plate 15 is measured by the eddy current electrode 13. A correction value setting unit (not shown) of the measuring device sets a correction value based on the displacement c. That is, the correct displacement c between the metal plate 15 and the sensor unit 11 can be obtained by measuring the displacement of the eddy current electrode 13. After that, the electrostatic capacity detection unit (not shown) detects the electrostatic capacity electrode 12 and the metal plate 15 by the electrostatic capacity detection unit.
The capacitance b between and is measured. The thickness calculator of the measuring device (not shown) calculates an accurate thickness d of the insulating film 16 based on the capacitance b at the reference displacement c.

FIG. 1 (B) is another embodiment of the present invention, and is an explanatory view of the principle for measuring the thickness of the insulating member on the metal base. What is different from FIG. 1A is that the object to be measured is only an insulating member, and the base is made of metal. Similarly to the above, the eddy current electrode 13 measures the displacement c ′ between the metal base 14 ′ and the sensor unit 11. Next, the capacitance electrode 12 is used to set the capacitance electrode 1
The capacitance is measured when the insulating member 16 'is inserted between 2 and the metal base 14'. Therefore, even if the distance between the sensor unit 11 and the metal base 14 ′ varies, the capacitance can be corrected based on the correct displacement obtained by the eddy current electrode 13, so that the sensor unit 11 and the metal base 14 ′ can be corrected. The exact thickness d'of the insulating member 16 'inserted between the base 14' and the base 14 'is measured.

FIG. 2 is a diagram for explaining the sensor section in one embodiment of the present invention. In FIG. 2, holders 21 and 22 of the capacitance electrode 12 and the eddy current electrode 13 are supported by a measurement electrode support member 23. Each of the electrodes 12 and 13 is connected to a metal displacement detector, a capacitance detector, and a power source (not shown) via a cable 24. The capacitance electrode 12 and the eddy current electrode 13 are formed integrally with the measurement electrode support member 23, or are configured such that the holders 21 and 22 can be slid in the height direction and adjusted. You can also

As described above, the measuring device provided with the sensor portion consisting of the pair of the capacitance electrode and the eddy current electrode is provided with the metal plate even if the metal plate is vertically displaced from the base during movement. And the displacement of the distance between the electrostatic capacitance electrode and
Since the correction is performed by the arithmetic circuit, the thickness of the insulating film formed on the metal plate can be accurately measured. The measurement results using the measuring device of the present invention are as follows. Measurement conditions Fix the object to be measured formed on the metal plate and move the capacitance electrode and the eddy current electrode up and down. Object to be measured Acrylic resin film thickness 300 μm Distance between the electrode and object to be measured 4 .2 mm Moving amount of the measured object (vertical direction) 0.4 mm Thickness of the metal plate on which the measured object is formed 10 mm While moving the measured object in the vertical direction by 0.4 mm, the measured object As a result of measuring the thickness, the error is 1
To 5 μm or less.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. And
Various design changes can be made without departing from the invention as set forth in the claims. For example, the shapes of the capacitance electrode and the eddy current electrode, or the means for attaching these to the measurement electrode support member,
It can be modified in various ways. Further, by providing a plurality of pairs of capacitance electrodes and eddy current electrodes and arranging them in the width direction of the metal plate, it is possible to accurately measure the thickness of the insulating film formed on the wide metal plate. Further, by doing so, it is not necessary to scan the capacitance electrode and the eddy current electrode in the width direction of the metal plate. Furthermore, in the present embodiment, the measurement of the thickness is described, but the physical quantity including the weight and the like in addition to the thickness can be measured. That is, if a table of changes in physical quantity and capacitance value is prepared, the physical quantity can be calculated from capacitance. further,
Infrared rays or radiation can be used as the measuring means of the sensor unit. In addition, the sensor units can also be used as one set to perform measurement while moving in the width direction of the measured object.

[0025]

According to the present invention, even if the moving metal plate is vertically shaken on the base, it is possible to combine the thickness meter based on the capacitance and the distance meter based on the eddy current on the metal plate. It is possible to accurately measure the thickness of the insulating coating formed on the substrate. Further, according to the present invention, even if the sensor unit moves in the vertical direction, the electrostatic capacitance is measured by this value while measuring the distance between the sensor unit and the metal base every time the thickness of the insulating member is measured. Since the capacitance is corrected, the thickness of the insulating member can be accurately measured.

[Brief description of drawings]

FIG. 1A is an explanatory view of the principle for measuring the thickness of an insulating coating formed on a moving metal plate in one embodiment of the present invention. (B) is another example of the present invention, and is a principle explanatory view for measuring the thickness of the insulating member on the metal base.

FIG. 2 is a diagram illustrating a sensor unit according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a principle of measuring a distance between a sensor unit and a metal plate by using an eddy current.

FIG. 4 is a diagram for explaining the principle of a capacitance-type thickness gauge.

FIG. 5 is an explanatory diagram for measuring the thickness of an insulating film formed on a moving metal plate by a conventional measuring method.

FIG. 6 is an explanatory diagram for measuring the thickness of a wide insulating coating formed on a metal plate by a measuring method in a conventional example.

[Explanation of symbols]

 11 ... Sensor part 12 ... Capacitance electrode 13 ... Eddy current electrode 14 ... Base 14 '... Metal base 15 ... Metal plate 16 ... Insulating film 16 ′ ... Insulating member 17 ... Output 21, 22 ... Holder 23 ... Measuring electrode support member 24 ... Cable

Claims (4)

[Claims] 1. A device for measuring the thickness of an insulating coating formed on a metal plate, comprising: a sensor section having a pair of a capacitance electrode and an eddy current electrode; and an eddy current electrode in the sensor section. A correction value setting unit that measures the displacement between the surface of the metal plate and the sensor unit to obtain a correction distance between the surface of the metal plate and the sensor unit, and the surface of the metal plate and the sensor unit by the capacitance electrode in the sensor unit. The capacitance detection unit that measures the capacitance between the two, and the value obtained from the capacitance detection unit is used to adjust the thickness of the insulating coating on the metal plate by the correction value obtained from the correction value setting unit. An apparatus for measuring the thickness of an insulating coating formed on a metal plate, comprising: a thickness calculator for calculating the thickness. 2. An apparatus for measuring the thickness of an insulating member, comprising: a sensor section having a set of a capacitance electrode and an eddy current electrode; and a metal base surface and a sensor section by the eddy current electrode in the sensor section. And a distance setting unit that obtains the distance between the metal base surface and the sensor unit, and the capacitance between the metal base surface and the sensor unit by the capacitance electrode in the sensor unit. The thickness of the insulating member existing between the metal base and the sensor unit is calculated by measuring the capacitance detecting unit and the value obtained from the capacitance detecting unit from the value obtained from the distance setting unit. An apparatus for measuring the thickness of an insulating member, comprising: 3. A method for measuring the thickness of an insulating coating formed on a metal plate, comprising: a displacement between a sensor part and a surface of the metal plate at a measured part by an eddy current meter; and a sensor by a capacitance meter. After measuring the electrostatic capacitance between the surface and the surface of the metal plate, the electrostatic capacitance is corrected based on the displacement between the sensor unit and the surface of the metal plate measured by the eddy current meter. A method for measuring the thickness of an insulating coating formed on the above. 4. A method for measuring the thickness of an insulating member, comprising: displacing a sensor section and a surface of a metal base with an eddy current meter; and between the sensor section and a metal base surface with a capacitance meter. After measuring the capacitance, the capacitance is corrected by the displacement of the sensor part and the surface of the metal base by an eddy current meter, and the thickness of the insulating member is measured.