JPH06160071A - Apparatus for measuring thickness of wet paint film - Google Patents

Abstract

PURPOSE:To measure the thickness of a paint film accurately without destruction based on the dynamic smoothing characteristic of the roughness of the painted surface by operating the roughness of the painted surface immediately after the painting of paint by using the amount of the time change in measured value and the component information of the paint. CONSTITUTION:At the time t1 immediately after paint is applied, light is emitted from a light source on a substance to be painted 1. The reflected light from the painted surface is received with a surface-roughness gage (head) 4. The image information of the surface roughness of the substance to be painted 1 at the time t1 is obtained and stored in a memory. Then, the measurement is repeated at the time t2 after the time DELTAt. The image information stored in the memory is supplied into an image processing device 5, and the formation of the coordinates and the coordinate conversion are performed. Then, the result is supplied into a paint-film, roughness/smoothness operating device 6. Here, the peak-to-peak values of the irregularities and the wavelengths of the surface at the times t1 and t2 are computed based on the surface toughness information of the substance to be painted 1. The computed values are inputted into a film-thickness operating device 7 together with the painting conditions such as the components of the paint inputted from an input device 8, and the thickness of the paint film is computed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet coating film thickness measuring device for measuring a coating film thickness from dynamic roughness information of a undried coating surface immediately after coating a coating material.

[0002]

2. Description of the Related Art There are various conventional wet coating film thickness measuring devices of this type, for example, a contact type using a needle gauge, a non-contact type using an electromagnetic type or an eddy current type. . FIG. 20 is an explanatory view showing a non-contact type wet coating film thickness measuring device utilizing the non-magnetic property of the coating material among such conventional wet coating film thickness measuring devices. In this conventional wet coating film thickness measuring device, a non-contact film thickness sensor 82 is preliminarily positioned at a short distance h _{o so as} to face the coating surface of a coating object 81 made of a steel plate as shown in FIG. After that, the object 81 to be coated and the non-contact film thickness sensor 82 are connected to each other by the transmitting / receiving coil provided in the non-contact film thickness sensor 82.
Generates a magnetic field between and. Then, as shown in FIG. 2B, when the wet paint 83 is applied onto the surface of the object 81 to be coated, the object 81 to be coated and the non-contact film thickness sensor 82 are applied.
The magnetic field between and is attenuated by the electromagnetic resistance due to the coating film thickness and is sensed by the receiving coil. Therefore, the coating film thickness can be measured by detecting the change in the magnetic flux that is inversely proportional to the film thickness.

[0003]

Among the above-mentioned wet coating film thickness measuring devices, the contact gauge type such as the needle gauge type has a problem that the flaws on the coated surface affect the coating quality.

Among the non-contact type ones, the non-contact type wet coating film thickness measuring device as shown in FIG. 20 has a predetermined distance between the object to be coated and the non-contact film thickness sensor before coating. It is necessary to set the distance, but there is a problem that the coating film thickness cannot be measured after coating the object to be coated, or that the measurement itself needs to be performed twice before and after coating. There is a problem that the measurement accuracy is poor.

The present invention has been made in view of the above,
The point is to provide a wet coating film thickness measuring device capable of accurately measuring the coating film thickness without contact from the dynamic smoothing characteristic of the roughness of the coating surface immediately after coating the coating film. Especially.

[0006]

In order to achieve the above object, the wet coating film thickness measuring apparatus of the present invention comprises a roughness measuring means for measuring the roughness of the undried coating surface immediately after coating the coating material, Time change amount calculating means for calculating the time change amount of the surface roughness information measured by the roughness measuring means, input means for inputting the component information of the paint, and the component information of the paint and the surface roughness information The gist is to have a coating film thickness calculating means for calculating the coating film thickness based on the amount of change over time.

Further, the wet coating film thickness measuring device of the present invention comprises a roughness measuring means for measuring the roughness of the undried coating surface immediately after coating the coating material, and the surface roughness measured by the roughness measuring means. Inputting the calculating means for calculating the peak-to-peak value and wavelength of the surface unevenness from the information, the time change amount calculating means for calculating the time-dependent change amount of the peak-to-peak value of the surface unevenness, and the component information of the paint. It is characterized in that it has an input means and a coating film thickness calculation means for calculating a coating film thickness based on the component information of the coating material, the time variation of the peak-to-peak value of the surface unevenness and the wavelength of the surface unevenness. .

Further, the wet coating film thickness measuring device of the present invention comprises a roughness measuring means for measuring the roughness of the undried coating surface immediately after coating the coating material, and the surface roughness measured by the roughness measuring means. Arithmetic means for calculating the surface roughness and wavelength from information, time change amount calculating means for calculating the time change amount of the surface roughness, input means for inputting the component information of the paint, and the paint And a coating film thickness calculating means for calculating a coating film thickness based on the time variation of the surface roughness and the wavelength of the surface roughness.

Furthermore, the wet coating film thickness measuring device of the present invention comprises a roughness measuring means for measuring the roughness of the undried coated surface immediately after coating the coating material, and the surface roughness measured by the roughness measuring means. Calculation means for calculating the roughness and wavelength of the surface or the peak-to-peak value and wavelength of the surface irregularities from input information, the input means for inputting the component information of the paint and the coating conditions, the component information of the paint and the coating Estimating means for estimating a smoothing initial value based on conditions, the surface roughness and wavelength or the peak-to-peak value and wavelength of the surface irregularities, and the surface roughness and wavelength or the peak-to-peak of the surface irregularities. The gist is to have a coating film thickness calculating means for calculating the coating film thickness based on the peak value and the wavelength, and the smoothing initial value.

The wet coating film thickness measuring device of the present invention comprises an image pickup means for picking up an image of the roughness of the undried coating surface immediately after the paint is applied, and a power spectrum analysis of the surface roughness information picked up by the image pickup means. Power spectrum analysis means for outputting as power spectrum data, calculation means for calculating a power spectrum integral value and wavelength corresponding to surface roughness from the power spectrum data from the power spectrum analysis means, component information of the paint and coating conditions Input means for inputting, using a smoothing theoretical formula using the power spectrum analysis value, a coating film thickness calculating means for calculating the coating film thickness from the power spectrum integral value, the wavelength, the coating component information and coating conditions. Having it is the gist.

[0011]

With the wet coating film thickness measuring device of the present invention, the roughness of the undried coating surface immediately after coating is measured, the time change amount of this surface roughness information is calculated, and the component information and the surface roughness information of the coating material are calculated. The coating film thickness is calculated based on the amount of change over time.

In the wet coating film thickness measuring device of the present invention, the roughness of the undried coating surface immediately after coating is measured, and the peak-to-peak value and the wavelength of the unevenness of the surface are calculated from the surface roughness information, The amount of change in peak-to-peak value of surface unevenness is calculated, and the coating film thickness is calculated based on the component information of the coating, the amount of change in peak-to-peak value of surface unevenness and the wavelength of surface unevenness.

Further, in the wet coating film thickness measuring apparatus of the present invention, the roughness of the undried coating surface immediately after coating is measured, the surface roughness degree and the wavelength are calculated from the surface roughness information, and the surface roughness is calculated. The amount of change over time of the degree of saturation is calculated, and the coating film thickness is calculated based on the component information of the paint, the amount of change over time of the degree of surface roughness and the wavelength of surface roughness.

Furthermore, in the wet coating film thickness measuring device of the present invention, the roughness of the undried coating surface immediately after coating is measured, and from this surface roughness information, the surface roughness and the wavelength or the peak of the surface irregularity is measured. Calculate the two peak value and wavelength, estimate the smoothing initial value based on the paint component information and coating conditions, surface roughness and wavelength or the peak to peak value and wavelength of surface irregularities, and calculate the surface roughness and The coating film thickness is calculated based on the wavelength or the peak-to-peak value and wavelength of the surface irregularities, and the initial smoothing value.

In the wet coating film thickness measuring apparatus of the present invention, the surface roughness information obtained by imaging the roughness of the undried coating surface immediately after coating is subjected to power spectrum analysis, and a power spectrum integration corresponding to the surface roughness is obtained from the power spectrum data. The value and the wavelength are calculated, and the coating film thickness is calculated from the power spectrum integral value, the wavelength, the paint component information and the coating conditions by using the smoothing theoretical formula using the power spectrum analysis value.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the structure of a wet coating film thickness measuring apparatus according to the first embodiment of the present invention.
The wet coating film thickness measuring device shown in the figure measures the coating film thickness by paying attention to the flattening phenomenon of the coating surface in the undried state immediately after coating the coating material, that is, in the wet state. Specifically, as shown in FIG. 2 (a), the wet coating surface immediately after coating is in a concavo-convex state, and initial eddy flow exists. The unevenness in such a state is flattened with time due to the leveling force as shown in FIG. 7B, and finally becomes a flattened state as shown in FIG. The wet coating film thickness measuring device pays attention to such a flattening phenomenon and accurately calculates the coating film thickness after the wet coating surface is dried by non-contact by measuring the unevenness of the coating surface. In addition to the above, it is possible to calculate by measuring only after coating the coating material.

The structure of the wet coating film thickness measuring device shown in FIG. 1 will be described. In FIG. 1, an object to be coated 1 to be coated
Is provided with a non-contact light interference type surface roughness meter 4 facing each other and constituting a roughness measuring means. In the present embodiment, the top coating material is applied to the article to be coated 1.

In the surface roughness meter 4, as shown in FIG. 3, the light emitted from the light source 13 passes through the pinhole and the opening,
The objective lens 1 is hit by a half mirror and reflected downward.
5 through the reference surface 16 and the beam splitter, the object to be coated 1
Of the beam splitter,
After passing through the reference surface 16 and the objective lens 15, the light passes through the half mirror upward, passes through the filter, and is received by the CCD sensor 12, whereby the roughness information of the surface of the article 1 to be coated is obtained. There is.

The surface roughness information of the object to be coated 1 from the surface roughness meter 4 is supplied to the image processing device 5 which constitutes the controller 9, where it is coordinated and coordinate-converted, and then the coating film roughness is obtained. The smoothness arithmetic processing unit 6 is supplied.

The coating surface roughness smoothness arithmetic processing device 6 calculates the surface roughness smoothness information from the surface roughness image information supplied from the image processing device 5, that is, the peak-to-peak (p-
p) The value a and the wavelength λ of the unevenness are calculated and supplied to the film thickness calculation processing device 7. Further, the film thickness calculation processing device 7 is inputted with the component information of the paint including the content of volatile components etc. from the input device 8, whereby the film thickness calculation processing device 7 is applied to the wet coating film thickness measuring method described later. The coating film thickness is calculated based on this, and the calculated coating film thickness is output to the display 10 and the plotter 11. The image processing device 5, coating film roughness smoothness arithmetic processing device 6 and film thickness arithmetic processing device 7 constitute a controller 9.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to the flow chart shown in FIG.

In FIG. 4, first, at time t ₁ immediately after the coating material is applied by the surface roughness meter 4, the object 1
The surface roughness of the surface of the article 1 to be coated is obtained by irradiating the surface of the object with light and receiving the reflected light.
At step 110, light is generated from the light source 13,
The light is dispersed by the spectroscopic unit (step 120), the coating surface of the object to be coated 1 is irradiated (step 130), and the reflected light from the coating surface is measured by the photometric portion (step 140), whereby the image at time t ₁ is obtained. Information, that is, surface roughness information of the article to be coated 1 is obtained (step 150), and this image information is stored in the memory (step 160).

FIG. 5A is a diagram showing an example of optical interference fringe data showing the surface roughness of the article to be coated 1 measured by the surface roughness meter 4. Further, FIG. 5B shows an example of analysis of three-dimensional surface roughness.

The availability of this surface roughness information, following the time t _1, performed also repeated at time t ₂ after the time _{Δt (= t 1 + Δt)} , thereby to be coated at time t _1, t ₂ The surface roughness information of the object 1 is measured and stored in the memory as image information. This image information is the image processing device 5.
And the image processing device 5 performs coordinate conversion and coordinate conversion (step 170).

Next, the surface roughness information of the object to be coated 1 which is the image information coordinated and coordinate-converted by the image processing device 5 is supplied to the coating film roughness smoothness arithmetic processing device 6 where it is processed. From the surface roughness information of the coated object 1, the times t ₁ and t ₂
The peak-to-peak value a and the wavelength λ of the surface irregularities are calculated (step 180). Then, the peak-to-peak value a and the wavelength λ of the surface irregularities at the calculated times t ₁ and t ₂ are calculated along with the coating conditions such as the components of the coating material input from the input device 8 (step 190) and the film thickness calculation. The coating film thickness h is input to the processing unit 7 (step 200), and the calculated coating film thickness h is displayed on the display 10 and printed by the plotter 11 (step 210).

Next, the processing for calculating the peak-to-peak value a and the wavelength λ of the irregularities on the surface of the object to be coated 6 by the coating surface roughness smoothness processing device 6 in step 180 and the film thickness processing device in step 200. The calculation process of the coating film thickness h by 7 will be described with reference to FIG.

As described with reference to FIG. 2, the coated surface in a wet state immediately after the coating material is applied to the surface of the object to be coated 1 has unevenness with a large roughness. This surface state is shown in FIG.
As shown in (b), it can be expressed by surface irregularities a and wavelength λ.

The surface irregularities in the wet state immediately after coating shown in FIG. 6A are smoothed with time as described above. The dynamic characteristics of this surface smoothing are as shown in FIG. 6A. Further, when the average value of the coating film thickness in this wet state is h, the viscosity of the coating material is η, the surface tension of the coating film is γ, and the initial value of surface irregularities is a _o , it is generally expressed by the following equation.

[0030]

## EQU1 ## da / dt = (− h ³ γ) / (3η) × (2π / λ) ⁴ a (1) a = a _o · exp −t / τ (2) τ = 3ηλ ⁴ / ( 16π ⁴ × γh ³ ) (3) Actually, the coating film viscosity after coating is shown as an example as shown in FIG. 7 under the condition that atomizing air pressure, solvent, viscosity before coating, temperature, etc. are constant. To be done. In FIG. 7, the horizontal axis represents the elapsed time after coating the coating material, the vertical axis represents the coating film viscosity η, and η ₀
And η ₁ represent the viscosity value before coating and the initial viscosity value immediately after coating with the coating material, respectively.

Therefore, as shown in FIG. 7, since the viscosity immediately after coating the coating changes with time, the above equations (1) to (3) are used.
It is necessary to use a correction value such as the following formula for the viscosity η of.

Η = η ₁ + Kt (4) Note that η ₁ > η ₀ , and K is a coefficient far smaller than 1.0 (K << 1.0).

As shown in the smoothing dynamic characteristics of the wet film thickness in FIG. 8, the peak-to-peak values of the unevenness of the coated surface at the times t ₁ and t ₂ immediately after coating the coating material are a ₁ and a ₂ , respectively. If the wavelength of is λ ₁₂ , then:

[0034]

A ₁ = a ₀ exp (−t ₁ / τ ₁ ) ... (5) τ ₁ = {3 × η (t ₁ ) × λ ₁₂ ⁴ } / (16π ⁴ × γ × h ³ ) ... ( 6) a ₂ = a ₀ exp (−t ₂ / τ ₂ ) ... (7) τ ₂ = {3 × η (t ₂ ) × λ ₁₂ ⁴ } / (16π ⁴ × γ × h ³ ) ... (8) When the coating film thickness h is calculated from the above equations (5) to (8), (5)
Dividing the equation by the equation (7) gives the following.

[0035]

A ₁ / a ₂ = exp (−t ₁ / τ ₁ + t ₂ / τ ₂ ) ... (9) 1na ₁ / a ₂ = (− t ₁ / τ ₁ + t ₂ / τ ₂ ) ... (10) ) Then, the coating film thickness h is obtained from the equations (6), (8) and (10) as the following equation.

[0036]

H = {(1na ₁ / a ₂ ) / (-t ₁ / τ ₁ '+ t ₂ / τ ₂ ')} ^1/3 (11) τ ₁ '= (3η ₁ × λ ₁₂ ⁴ ) / (16π ⁴ γ) (12) τ ₂ ′ = (3η ₂ × λ ₁₂ ⁴ ) / (16π ⁴ γ) (13) From these formulas (11) to (13), the time t immediately after coating the coating material _The coating film thickness h can be calculated by measuring the coating surface roughnesses a ₁ and a ₂ at ₁ and t ₂ and the wavelength λ ₀ .

Similarly, the equation (1) is changed to da / dt = (a ₂ −
a ₁₎ and _{/ (t 2 -t 1),} (4) by the addition type, it is possible to calculate the paint film thickness h.

[0038]

[Equation 5] In addition, it is necessary to select which of the equation (11) or the equation (14) is used depending on the measurement system.

FIG. 9 is a graph comparing the measured value of the top coating material with the theoretical value. The theoretical value and the measured value of the smoothing dynamic characteristics in 60 to 100 seconds after application are very close to each other, and the film thickness value is about 38 to 40 μ when calculated from the equation (11).
Which is close to the measured value.

Next, a second embodiment of the present invention will be described with reference to FIG.

The wet coating film thickness measuring device according to the second embodiment shown in FIG. 10 is an alternative to the coating film roughness smoothness arithmetic processing device 6 constituting the controller 9 in the first embodiment shown in FIG. The difference is that the surface roughness degree arithmetic processing unit 17 is used, and the other configurations and operations are the same. The wet coating film thickness measuring device of the second embodiment uses the surface roughness degree arithmetic processing device 17 in place of the peak-to-peak value a and the wavelength λ of the surface unevenness in the first embodiment. By calculating the surface roughness and the surface roughness wavelength, and by using this surface roughness and the wavelength, it is possible to calculate the average coating film thickness in a relatively short measuring time, and to select specific irregularities. It has the advantage that it becomes unnecessary. The surface roughness and the wavelength are the average roughness _Ra and the average wavelength λ.
_a , or root mean square R _q and root mean square wavelength λ _q .

FIG. 11 is a flowchart showing the operation of the second embodiment, which is shown in FIG.
The difference from the flowchart of the first embodiment shown in FIG. 8 is that instead of calculating the peak-to-peak value and the wavelength in step 180, the surface roughness degree and the surface roughness wavelength are calculated in step 182. Only.

In the wet coating film thickness measuring apparatus of the second embodiment shown in FIGS. 10 and 11, the surface roughness degree arithmetic processing unit 17 determines time t ₁ and time t from the surface roughness image information supplied from the image processing unit 5. The roughness and wavelength of the surface at t ₂ , ie the average roughness R _a and its average wavelength λ _a
Alternatively, the root mean square R _q and the root mean square λ _q are calculated (step 182 in FIG. 11) and supplied to the film thickness calculation processing device 7.

The film thickness calculation processing device 7 determines the roughness and wavelength of the surface, that is, the average roughness R _a and its average wavelength λ.
_a or root mean square R _q and root mean square λ _q
Is supplied, the coating film thickness h is calculated from these information and the paint condition supplied from the input device 8 according to the following equations (15) to (20) corresponding to the above equation (11) (step 200).

That is, the above equation (11) is applied to the surface roughness and its wavelength, that is, the average roughness R _a and its average wavelength λ _a or the root mean square R _q and the root mean square wavelength λ _q. However, it holds as shown below.

[0046]

H = {(1nR _a1 / R _a2 ) / (-t ₁ / τ ₁ '+ t ₂ / τ ₂ ')} ^1/3 (15) τ ₁ '= (3η ₁ × λ _a ) / (16π ⁴ γ) (16) τ ₂ ′ = (3η ₂ × λ _a ) / (16π ⁴ γ) (17) h = {(1nR _q1 / R _q2 ) / (− t ₁ / τ ₁ ′ + t ₂ / τ ₂ ')} ^1/3 (18) τ ₁ ' = (3η ₁ × λ _q ) / (16π ⁴ γ) (19) τ ₂ '= (3η ₂ × λ _q ) / (16π ⁴ γ) (20) FIG. 12 is a graph showing the smoothing dynamic characteristics of the surface roughness, where the abscissa indicates the elapsed time after coating and the ordinate indicates the surface roughness R _a , R _q. Is shown. From the figure, 6 after application
It can be seen that the smoothed dynamic characteristic in 0 to 100 seconds is almost the same as the theoretical value with respect to the roughness (R _a , R _q ) as in the case shown in FIG. Further, the coating film thickness value h also substantially matches h _a = 40 μm and h _q = 39 μm.

Also in the second embodiment, the optical interference fringe data showing the surface roughness of the article to be coated 1 shown in FIG. 5A is measured by the surface roughness meter 4. In this case, the average roughness R _a and the root mean square R _q are expressed by the following equations, and the average roughness R _a = 0.861 μm, the root mean square R _q = 0.959 μm, and the wavelength λ = 4. It is 0.6 μm.

[0048]

[Equation 7] Next, a third embodiment of the present invention will be described with reference to FIG.

The wet coating film thickness measuring apparatus according to the third embodiment shown in FIG. 13 includes a surface roughness degree arithmetic processing unit 17 and a film thickness arithmetic processing unit 7 in the second embodiment shown in FIG. A smoothing initial value estimating device 18 is provided between them, and the paint condition information from the input device 8 is input to the smoothing initial value estimating device 18 only. Is the same. The wet coating film thickness measuring apparatus according to the third embodiment estimates and calculates the smoothing initial value by the smoothing initial value estimating device 18, so that only one time t seconds after the application of the coating material is shortened. The coating film thickness h can be calculated only by measuring the roughness information of the above, which improves the adaptability of the present wet coating film thickness measuring device to the line.

FIG. 11 is a flow chart showing the operation of the third embodiment, which is shown in FIG.
In the flow chart of the second embodiment shown in FIG. ₁ , instead of calculating the surface roughness degree and the wavelength twice at times t ₁ and t ₂ at step 182, as step 184, one surface roughness only at time t _1. The only difference is that the degree and wavelength are calculated, and step 186 is subsequently added to estimate the smoothing initial value in this step.

In the wet coating film thickness measuring apparatus of the second embodiment shown in FIGS. 13 and 14, the surface roughness calculation processing unit 17 uses the surface roughness R _a and the wavelength λ at time t ₁ .
_a is measured (step 184) and the surface roughness R _a and the wavelength λ _a are supplied to the smoothing initial value estimation device 18.
The smoothing initial value estimation device 18 estimates the smoothing initial value a _o from the paint condition including the paint component input from the input device 8 in addition to the surface roughness R _a and the wavelength λ _a (step 186).

The estimation of the smoothed initial value a _o will be described.

From the above equation (5), the peak-to-peak peak-to-peak value a _o immediately after coating is given by the following equation.

A _o = a ₁ exp (t ₁ / τ ₁ ) ... (21) Note that τ ₁ and η ₁ (t ₁ ) in this equation are those shown in the above equations (4) and (6), respectively. Is the same as.

The peak-to-peak peak-to-peak value a _o immediately after coating (t = 0) can be obtained from the above equation (21) from the measured data of the smoothed dynamic characteristics of the coated surface (provided that the gun characteristics are constant).

Further, for example, when the coating film thickness h = 60 μm and the wavelength λ = 6 mm, the uneven peak-to-peak value a _o = 8.
5 to 8.7 μm (t = t _{1 to} t ₃ ), coating film thickness h
= 40 μm and wavelength λ = 4.3 mm, the peak-to-peak peak-to-peak value a _o = 8.4 to 8.6 μm (t = t ₁ to
It can be seen that the initial value is approximately constant with respect to the coating film thickness h and the wavelength λ, such as t ₃ ). That is,
It can be said that there is a relationship shown in the following equation. This relationship is shown in Figure 1.
It is also clear from the comparison between the theoretical value of the smoothing dynamic characteristics and the measured value shown in the graph of the peak-to-peak (pp) peak-to-peak (pp) value of the coating film surface unevenness with respect to the time immediately after coating shown in FIG.

Λ ⁴ / h ³ = K _o (constant) (22) Therefore, if the coating composition is known in advance, the peak-to-peak peak-to-peak value a and the wavelength λ at a certain time t are measured to obtain the unevenness. The initial value a _o of the peak-to-peak value can be obtained in advance by using the above equations (21), (6), (4) and (22). Also, the initial value a _o may be measured in advance.

When the smoothing initial value a _o is calculated as described above, this smoothing initial value is supplied to the film thickness calculation processing device 7 to calculate the coating film thickness h (step 200).

The calculation of the coating film thickness h will be described.

If the coating composition is known in the calculation of the smoothing initial value and the coating conditions (gun characteristics) are constant, the uneven peak-to-peak value a _o immediately after coating can be estimated as described above. Therefore, the coating film thickness h is t ₁ = 0, t ₂ = t _{1 in the} above equations (11) to (13).
Then, it can be obtained by the following equation.

[0061]

H = {(1na ₀ / a ₁ ) / (− 0 / τ ₀ + t ₁ / τ ₁ '} ^1/3 = {(1na _o / a ₁ ) / (t ₁ / τ ₁ ')} ^1/3 (23) τ ₁ '= (3η ₁ × λ ⁴ ) / (16π ⁴ γ) (12) η ₁ = η ₀ + Kt ₁ (4) Above (23), (12), ( From the equation 4), the coating film thickness h can be calculated by measuring the time t ₁ , the wavelength λ, and the uneven peak-to-peak value a ₁ at the time t ₁ .

In the third embodiment described above, the case where the surface peak-to-peak value is used has been described, but instead of this, the surface roughness and its wavelength, that is, the average roughness _Ra and the average wavelength λ. _{Using a} or the root mean square R _q and the root mean square wavelength λ _q also holds as shown in the following equation.

[0063]

H = (1nR _a0 / R _a1 ) / (t ₁ / τ ₁ ')} ^1/3 (24) τ ₁ ' = (3η ₁ × λ _a ⁴ ) / (16π ⁴ γ) ( 25) h = (1nR _q0 / R _q1 ) / (t ₁ / τ ₁ ′)} ^1/3 (26) τ ₁ ′ = (3η ₁ × λ _q ⁴ ) / (16π ⁴ γ) (27) Next, a fourth embodiment of the present invention will be described with reference to FIG.

A wet coating film thickness measuring apparatus according to a fourth embodiment shown in FIG. 16 is provided so as to face a coated object 1 to be coated, and an image of the coated surface of the object 1 to be coated is imaged. It has an image pickup unit 2 for obtaining surface roughness information. In the present embodiment, the top coating material is applied to the article to be coated 1.

As shown in detail in FIG. 17, the image pickup section 2 comprises a light source 31, a light / dark pattern plate 32, a reflecting mirror 33, a lens 34, and a CCD camera 35, and the coating object picked up by the image pickup section 2 is coated. The surface roughness information of the object 1 is obtained by the image processing unit 3.
Is supplied to.

The image processing section 3 is composed of various image processing programs, an image analysis sequence program, a waveform analysis program, a film thickness calculation program, etc., and performs image processing on the surface roughness information supplied from the image pickup section 2 to obtain a power spectrum. Frequency analysis (FFT) and long-wave waveform separation are performed, and the surface roughness information is supplied to the power spectrum integral value calculation unit 21 as power spectrum data P.

The power spectrum integral value calculator 21 calculates the power spectrum integral value P _i and the long wavelength λ corresponding to the roughness from the power spectrum data from the image processor 3 and supplies it to the film thickness calculator 22. In addition to the power spectrum integral value i and the long wavelength λ, the film thickness calculation unit 22 uses a smoothing theoretical formula using a power spectrum P, which will be described later, on the basis of the coating condition input from the input device 8. Calculate the thickness h. Then, the calculated coating film thickness h
Is displayed on the display 10 and printed by the plotter 11.

Next, the derivation of the smoothing theoretical formula using the power spectrum P will be described.

[0069] First, explaining the smoothing characteristics of the power spectrum P, a surface roughness R _a and the power spectrum integral value P _i, is in the relationship as shown in FIG. 18, has the following relationship.

P _i = P _o + k × R _a ^1/2 (28) R _a = {(P _i −P _o ) / k} ² (29) In the derivation of the smoothing theoretical formula by the power spectrum analysis value, First, as a wet coating smoothing theoretical formula (approximate formula),
The surface roughness _Ra is represented by the following equation.

R _a = R _ao · exp (−t / τ) (30) When the equation (29) is substituted into the equation (30),

## EQU10 ## {(P _i −P _o ) / k} ² = {(P _io −P _oo ) / k} ² exp (−t / τ) (31) Here, P _io is P _i Is the initial value of, and P _oo is P _o
Is the initial value of.

Therefore, P = P _o · exp (−t / 2τ) (32) where P = P _i −P _o , τ = 3ηλ ⁴ / 16π ⁴ γh.

From the above, the coating film thickness h based on the power spectrum analysis value is given by the following equation.

[0074]

[Equation 11] However, τ ′ _i = 3ηiλ ⁴ / 16π ⁴ γ.

Next, the operation of the fourth embodiment shown in FIG. 16 will be described.

When the surface of the coating film of the article to be coated 1 is imaged by the image pickup section 2 and the surface roughness information at the times t ₁ and t ₂ after the coating of the coating material is measured, this information is input to the image processing section 3. Image processing is performed, and frequency analysis (FFT) processing and power spectrum data for each spatial frequency are supplied to the power spectrum integral value calculator 21. The power spectrum integral value calculator 21 uses the power spectrum data from the image processor 3 to perform waveform separation of the power spectrum and calculation of the long-wave power spectrum integral P _i and the long wavelength λ, which corresponds to the roughness degree. Information, and the film thickness calculation unit 22
Is supplied to. The coating conditions are input to the film thickness calculation unit 22 from the input device 8. From this information, the power spectrum integral value P _i from the power spectrum integral value calculation unit 21 and the long wavelength λ, the coating film thickness h is calculated as described above. Is calculated,
It is displayed on the display unit 10 and printed by the plotter 11.

In FIG. 19, the horizontal axis represents time and the vertical axis represents the power spectrum integral value P _i , and the wet smoothing dynamic characteristic (the smoothing theoretical value using equation (32) and the measured value are compared ( It is a graph which shows a power spectrum value. For the measurement, an image immediately after coating was taken by the imaging unit 2 and power spectrum analysis was performed. It can be seen from FIG. 19 that the measured value has a smoothing characteristic that is almost the same as the theoretical value.

Table 1 below shows film thicknesses of 60 μm and 54 μm.
The result of measuring the film thickness h using the estimation formula of the above-mentioned formula (33) is shown for the sample. Several μm from the table
It can be seen that measurement can be performed with the accuracy of.

[0079]

[Table 1]

[0080]

As described above, according to the present invention,
The peak-to-peak value and wavelength of surface irregularities or the surface roughness and wavelength are calculated from the roughness information of the undried coating surface immediately after coating, and the component information of the coating and the peak-to-peak value or roughness degree of surface irregularities are calculated. Calculate the coating film thickness based on the time change amount and the wavelength of surface irregularities or surface roughness,
Or, calculate the surface roughness and wavelength from the surface roughness information or the peak-to-peak value and wavelength of the surface irregularities,
Estimate the initial smoothing value based on the component information of the paint and coating conditions, surface roughness and wavelength or peak-to-peak value of surface irregularities, and wavelength, and peak-to-peak value of surface roughness and wavelength or surface irregularities. Since the coating film thickness is calculated based on the wavelength and the initial value of smoothing, the undried coating film thickness immediately after coating can be accurately measured without contact.

According to the present invention, the power spectrum information of the surface roughness is analyzed, the power spectrum integral value and the wavelength corresponding to the surface roughness are calculated from the power spectrum data, and the smoothing is performed using the power spectrum analysis value. Since the theoretical formula is used to calculate the coating film thickness from the power spectrum integral value, wavelength, paint component information and coating conditions,
It is possible to accurately measure the thickness of the undried coating immediately after coating without contact, reduce the cost of the device including the imaging means, increase the distance from the coating surface and reduce the risk of contact. The image pickup means can be simplified and reduced in weight, vibration resistance can be improved, and the like, which is most suitable for application to, for example, a painting line of an automobile.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wet coating film thickness measuring device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a flattening phenomenon of unevenness of a coating surface in a wet state immediately after coating.

FIG. 3 is a diagram showing a configuration of a surface roughness meter used in the wet coating film thickness measuring device of FIG.

FIG. 4 is a flowchart showing the operation of the wet coating film thickness measuring device of FIG.

5 is a diagram showing an example of optical interference fringe data showing the surface roughness of the object to be coated measured by the surface roughness meter in the wet coating film thickness measuring device of FIG.

FIG. 6 is a diagram showing a concavo-convex state of a coating surface in a wet state immediately after coating.

FIG. 7 is a graph showing the relationship between coating film viscosity and setting time.

FIG. 8 is a graph showing smoothing dynamic characteristics of wet film thickness.

FIG. 9 is a graph comparing measured values of a top-coat paint with theoretical values.

FIG. 10 is a block diagram showing a configuration of a wet coating film thickness measuring device according to a second embodiment of the present invention.

11 is a flowchart showing the operation of the wet coating film thickness measuring device of FIG.

FIG. 12 is a graph showing smoothing dynamic characteristics of surface roughness.

FIG. 13 is a block diagram showing a configuration of a wet coating film thickness measuring device according to a third embodiment of the present invention.

FIG. 14 is a flowchart showing the operation of the wet coating film thickness measuring device of FIG.

FIG. 15 is a comparison between the theoretical value of smoothed dynamic characteristics and the measured value.
-P) is a graph indicated by a value.

FIG. 16 is a block diagram showing the configuration of a wet coating film thickness measuring device according to a fourth embodiment of the present invention.

FIG. 17 is a diagram showing a configuration of an imaging unit used in the wet coating film thickness measuring device of FIG. 16.

FIG. 18: Surface roughness _Ra and power spectrum integral value P _i
It is a graph which shows the relationship of.

FIG. 19 is a graph showing a wet smoothing dynamic characteristic (power spectrum value) in which a horizontal axis represents time and a vertical axis represents a power spectrum integral value P _i , and a smoothing theoretical value and a measured value are compared.

FIG. 20 is an explanatory view showing a conventional coating film thickness measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coating object 2 Imaging part 3 Image processing part 4 Surface roughness meter 5 Image processing device 6 Coating film roughness smoothness arithmetic processing device 7 Film thickness arithmetic processing device 8 Input device 9, 19, 29 Controller 10 Display 11 Plotter 17 Surface Roughness Calculation Processing Device 18 Smoothing Initial Value Estimating Device 21 Power Spectrum Integral Value Calculation Unit 22 Film Thickness Calculation Unit

Claims (5)

[Claims] 1. Roughness measuring means for measuring the roughness of the undried coating surface immediately after coating with paint, and time change amount for calculating the time change amount of the surface roughness information measured by the roughness measuring means. A calculating means, an input means for inputting the component information of the paint, and a coating film thickness calculating means for calculating the coating film thickness based on the time change amount of the component information of the paint and the surface roughness information. Characteristic wet coating thickness measuring device. 2. Roughness measuring means for measuring the roughness of the undried coating surface immediately after the coating of the coating material, and peak-to-peak value of unevenness of the surface from the surface roughness information measured by the roughness measuring means and A calculation means for calculating a wavelength, a time change amount calculation means for calculating the time change amount of the peak-to-peak value of the surface irregularities, an input means for inputting the component information of the paint, the component information of the paint, A wet coating film thickness measuring device, comprising: a coating film thickness calculating means for calculating a coating film thickness based on a time change amount of peak-to-peak value of surface irregularities and a wavelength of the surface irregularities. 3. A surface roughness degree and a wavelength are calculated from roughness measuring means for measuring the roughness of the undried coating surface immediately after coating the coating material and the surface roughness information measured by the roughness measuring means. Calculating means, a time change amount calculating means for calculating a time change amount of the surface roughness, an input means for inputting component information of the paint, a component information of the paint, a time of the surface roughness A wet coating film thickness measuring device, comprising: a coating film thickness calculating means for calculating a coating film thickness based on the amount of change and the wavelength of the surface roughness. 4. Roughness measuring means for measuring the roughness of the undried coating surface immediately after coating with paint, and surface roughness and wavelength or surface based on the surface roughness information measured by the roughness measuring means. Calculating means for calculating peak-to-peak value and wavelength of unevenness of the coating material, input means for inputting component information and coating conditions of the coating material, component information and coating conditions of the coating material, the surface roughness and wavelength or the surface Estimating means for estimating a smoothing initial value based on the peak-to-peak value and wavelength of the unevenness of the surface roughness and wavelength or the peak-to-peak value and wavelength of the unevenness of the surface, and the smoothing initial value. And a coating film thickness calculating means for calculating the coating film thickness based on the coating film thickness measuring device. 5. An image pickup means for picking up an image of the surface roughness of the undried coating surface immediately after the paint is applied, and a power spectrum analysis for outputting power spectrum data of the surface roughness information picked up by the image pickup means. Means, calculating means for calculating the power spectrum integral value and wavelength corresponding to the surface roughness from the power spectrum data from the power spectrum analyzing means, input means for inputting the component information of the paint and coating conditions, and the power spectrum analysis Wet coating film having a coating film thickness calculating means for calculating a coating film thickness from the power spectrum integral value, the wavelength, the paint component information and coating conditions by using a smoothing theoretical formula using values. Thickness measuring device.