JP3358434B2 - Paint quality analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating quality analyzing apparatus for determining a coating quality, that is, a non-volatile component in a coating film immediately after coating or after a predetermined time (for example, several minutes) after coating.

[0002]

2. Description of the Related Art The evaluation of coating quality, for example, the evaluation of coating quality in car body coating, includes drying for a long time after coating, and after drying, sharpness of the coating, that is, smoothness, solid feeling and glossiness. Are inspected and evaluated. If the evaluation value of the sharpness varies when the coating quality is evaluated as described above, the cause is as follows.
The type and thickness of the paint at the time of spraying, the non-volatile components after coating (hereinafter abbreviated as coating NV), the coating viscosity, the spray pressure of the coating gun, and the like are considered. Among these factors, typical factors include a coating NV and a film thickness.
It is necessary to quantitatively grasp these factors as soon as possible immediately after coating, and to use them for improving the coating conditions thereafter. Conventionally,
To measure the coating NV on the coating film immediately after coating, apply aluminum foil to the body to be coated such as a car body, apply the paint with a coating gun, peel off the aluminum foil, The aluminum weight method is used to measure the weight of the aluminum foil and the weight of the dried aluminum foil.

[0003]

In the case of successive paintings on a painting automation line, such as the painting of a car body, the next painting condition is improved by feeding back the quality of the painting as soon as possible. It is necessary to always keep the best paint condition. However, in the conventional aluminum gravimetric method, as described above, since an aluminum foil attachment and peeling step, a drying step and a weight measuring step are required, many steps and time are required for measurement, and after drying, Since the coating NV immediately after the application is found only after the weight of the aluminum foil is measured, it is not possible to obtain the coating NV immediately after the coating or at any time after the coating (for example, several minutes later) in real time. I could not do it. For this reason, there has been a problem that it is not possible to meet the requirements of the above-mentioned automatic painting line.

[0004] In order to solve the above problems, the present applicant has
Applying the coating surface immediately after application based on the non-volatile component information of the coating material before coating, the degree of atomization of the coating material on the coating film surface, and the thinner evaporation amount of the coating material (evaporation amount per unit area) N.V., and based on the calculated coating N.V. immediately after the coating and the type information of the coating, the coating density of the coating film immediately after the coating is calculated, and the calculated coating density and Based on the measurement time (elapsed time from the time of application to an arbitrary measurement time), the film thickness, and the evaporation amount of the thinner, the coating NV of the coating film surface at an arbitrary set measurement time is calculated. A coating quality analyzer has been invented and has already been filed (Japanese Patent Application No. 6-258073, published late). In the above-mentioned prior invention of the present applicant, a non-volatile component in a coating film immediately after coating or at a predetermined time after the coating time, in a non-contact manner, can be measured in a short time, an excellent effect. can get. However, in the above-mentioned prior invention, the following problem remains.

[0005] (1) In order to improve the finish quality in an automatic coating line, there is a line in which the top coat is sprayed twice (set time after spraying once: several tens of seconds to several minutes). In such a case, Since the coating NV after the second blowing is a composite of the first blowing and the second blowing, the coating NV (non-volatile component) immediately after the second blowing is measured. It is difficult.

(2) Since the paint thinner evaporation rate greatly depends on the initial paint concentration (N.V), the coating conditions (rotational speed, discharge amount, coating distance, etc.) of an automatic coating machine such as a bell-type rotary machine are used. Is changed between the first blow and the second blow,
Since the value of the initial NV changes, it is difficult to secure measurement accuracy in the above-mentioned prior application.

As described above, even in the prior invention of the present applicant, in the case of a two-time spray coating line, particularly in a case where the present invention is applied to an automated line in which the coating conditions of an automatic coating machine are changed between a first time and a second time. Has room for further improvement.

The present invention has been made to solve the problems of the prior art as described above, and has been made to further improve the above-mentioned prior invention of the present applicant. An object of the present invention is to provide a coating quality analysis device capable of measuring NV immediately after wearing. The second purpose is that even if the coating conditions of the automatic coating machine are changed between the first and second times,
An object of the present invention is to provide a coating quality analyzing apparatus capable of ensuring the measurement accuracy of the coating NV after spraying.

[0009]

Means for Solving the Problems In order to achieve the above object, the present invention is configured as described in the claims. That is, the invention described in claim 1 is:
As shown in the figure, at least the non-volatile component information (N.V. of the paint) of the paint before painting, the kind information of the paint (including the kind of paint and the thinner kind), the temperature information in the painting booth, and the like. A coating condition input means 100 for inputting coating conditions including one-time and two-time coating conditions (for example, respective discharge amounts); and a fine-graining degree input for inputting a fine-graining degree of the paint on the coating film surface. Means 101, thinner evaporation amount input means 102 for inputting the thinner evaporation amount per unit area of the paint (evaporation speed × time), non-volatile components of the paint,
1 based on the atomization degree and the thinner evaporation amount.
The first applied non-volatile component calculating means 103 for calculating the applied non-volatile component of the coating surface immediately after the spray coating, and the immediately applied non-volatile component calculated by the first applied non-volatile component calculating means. First paint density calculating means 104 for calculating the paint density on the coating surface immediately after the first spray application based on the coating non-volatile component and the paint type information input from the coating condition input means.
A measuring time input means 105 for inputting a time from a paint application time to an arbitrary measuring time, a film thickness input means 106 for inputting a film thickness of a coating film surface, and a paint from the first paint density calculating means. Based on the density, the measurement time, the film thickness, the thinner evaporation amount, and the coating condition, the non-volatile component applied to the once-sprayed coating surface at the time of the second-spray coating is calculated. Second coating non-volatile component calculating means 107
And a non-volatile component applied to the coating surface immediately after the first spray application from the first applied non-volatile component calculating means, and a second non-volatile component applied from the second applied non-volatile component calculating means. Based on the non-volatile component applied to the once-sprayed coating surface at the time of the spraying application and the coating conditions in the one-time spraying and the two-time spraying, the coating non-volatile property of the coating surface immediately after the two-time spray coating is applied. The third to calculate the sex component
The non-volatile component calculating means 108, the non-volatile component applied immediately after the second spray application calculated by the third non-volatile component calculating means, and the paint input from the coating condition input means. Paint density calculating means 10 for calculating the paint density on the coating surface immediately after the second spray application based on the type information of
9, the applied non-volatile component immediately after the second spray application calculated by the third applied non-volatile component calculating means, the coating density from the second coating density calculating means, and the measurement time input. Based on the time input from the means, the film thickness, and the thinner evaporation amount, the value of 2
And a fourth coating non-volatile component calculating means 110 for calculating the coating non-volatile component on the surface of the blown coating film.

[0010] As described above, according to the first aspect of the present invention, the non-volatile component applied to the coating surface immediately after the one-time spray coating obtained by the first non-volatile component application calculating means, The non-volatile component applied to the once-sprayed coating film surface at the time of the second-spray coating obtained by the non-volatile component application calculating means of No. 2
Since the configuration is such that the non-volatile component applied to the coating film surface immediately after the second spray application is calculated (estimated) based on the paint conditions in the second spray application, two times that have not been obtained so far are obtained. It has become possible to determine the applied non-volatile components on the coating surface immediately after spray coating.

The thinner evaporation amount input means 102
Is used, for example, by correcting the reference thinner evaporation amount calculated by the configuration of claim 2 as described in claim 3. The paths indicated by broken lines in FIG. 1 indicate the paths of information for thinner evaporation amount correction when the thinner evaporation amount input means 102 has a correction function. In the embodiment described later, a portion for inputting a basic thinner evaporation amount (thinner evaporation amount input section 13) and a portion for correcting the same (thinner evaporation amount correction section 12) are described separately. . As described above,
The paint conditions (for example, the respective discharge amounts) in the first and second blows are incorporated into the calculation, and the initial coating N.
By correcting the thinner evaporation rate (evaporation rate × time = evaporation amount) of the coating film using the estimated value of V,
The measurement accuracy can be kept good even when changing between the first and second blows.

[0012] According to a fourth aspect of the present invention, the first type
The applied non-volatile component calculating means 103 immediately after application is performed based on the relationship between the input non-volatile component of the paint and the thinner evaporation amount and the surface area of the paint particles obtained from the input degree of atomization. This is for calculating the applied non-volatile component on the coating film surface. The atomization degree input means 101 has, for example, a configuration as described in claim 5.
The wavelength calculation means and the atomization calculation means described in claim 5 have, for example, a configuration as described in claim 6.

According to a seventh aspect of the present invention, the imaging means takes an image of a plurality of locations on the painting surface, and the subsequent means perform processing at each location, and the wavelength calculation means takes a picture at each location. A wavelength averaging means for sequentially calculating wavelength values and averaging the plurality of wavelength values, wherein the atomization calculating means calculates a degree of atomization based on a calculation result of the wavelength averaging means; Things. In general, in the case of a large object to be coated such as an automobile body, the spraying area is large, so that the coating conditions may not always be uniform depending on the coating site. Therefore, in order to perform accurate measurement, it is desirable to take an image of a plurality of locations on the painted surface and perform the atomization degree calculation using the average value of each of those locations.
The configuration is as described above.

The invention described in claim 8 is the same as the invention described in claim 7.
In the invention according to the invention, a plurality of image pickup means for picking up an image of the undried coating surface immediately after the application of the paint is provided for each of different portions of the coating surface, and the image information of the plurality of points picked up by the image pickup means is sequentially processed. It is what was constituted. As described above, if a plurality of imaging units are provided and the parallel processing is performed, the measurement calculation speed can be improved. Further, the film thickness input means 106 in the first aspect has, for example, a configuration as described in the ninth aspect.

As described above, the degree of atomization and the film thickness are as follows:
As described in claims 5 to 9, the image obtained by capturing the painted surface can be calculated by image processing. Therefore, it is possible to easily measure the coating NV immediately after the coating or a predetermined time after the coating in a very short time without contact. In addition, the coating NV is indicated by, for example, the content of the nonvolatile component, but the content may be used.

[0016]

According to the present invention, it is possible to measure the coating NV immediately after coating and after a predetermined time even on a two-time spray coating line. In addition, even when the coating conditions (rotational speed, discharge amount, coating distance, etc.) of the automatic coating machine are changed, the thinner evaporation rate of the coating film is corrected by using the estimated value of the initial coating NV immediately after the coating. , It is possible to ensure the measurement accuracy of the coating NV. Therefore, the coating NV can be accurately measured in a very short time immediately after coating or after a predetermined time from the time of coating in a non-contact manner during coating. Therefore, since the coating conditions can be immediately feedback-controlled, the coating quality can be maintained and improved, and the number of steps of the coating NV measurement can be greatly reduced.

[0017]

FIG. 2 is a view showing a first embodiment of the present invention, and is a block diagram in a case where the present invention is applied to an automatic coating line. First, an outline of the entire configuration will be described with reference to FIG. Reference numeral 1 denotes a body to be coated (for example, a body of an automobile), which is painted while moving on a painting line at a predetermined speed. Reference numeral 2 denotes an imaging unit for imaging a wet coating surface immediately after coating. The time of imaging is a predetermined time (for example, 1 to 2) after the paint is sprayed.
Minutes). Therefore, the imaging unit 2 is installed at a position where the vehicle body reaches after, for example, 1 to 2 minutes in accordance with the moving speed of the painting line.

In the case of a double spray coating line to which the present invention is applied, for example, two coating guns (only one coating gun 28 in FIG. Described), and spray coating is performed twice at intervals of about several tens of seconds to several minutes. Thereafter, the imaging unit 2 is installed at a position where the vehicle body reaches after 1 to 2 minutes. Note that it is difficult to install an imaging unit in a region between the first-time spray coating gun and the second-time spray coating gun because paint particles are scattered. Therefore, the painted surface imaged by the imaging unit 2 is the painted surface after the second spray painting. Therefore, it is not possible to image the painted surface immediately after the first blowing, but if the coating conditions are the same, the state of the attached particles on the painted surface after the first blowing and after the second blowing is the same, so the imaging screen after the second blowing , The degree of atomization of a single blow can be calculated. In the case where the coating conditions change, correction may be made according to the coating conditions (for example, the ratio of the discharge amount) (details will be described later). Further, since the coating NV after the second blowing is a combination of the first blowing and the second blowing, it is calculated by a method described later in detail.

The image of the painted surface (details will be described later) captured by the image capturing unit 2 is subjected to image processing such as binarization by the image processing unit 3. The image processing unit is composed of an image memory for storing image information and an arithmetic device such as a computer. The image processing data processed by the image processing unit 3 is sent to the wavelength calculation unit 4. In the wavelength calculation unit 4, power spectrum frequency analysis (for example, fast Fourier transform processing: FF
T) is performed to calculate a power spectrum PS (particularly, a peak wavelength λp and an integral value P in a long wavelength region thereof) of an uneven waveform of the coating surface from the input image processing data.

The operation result of the wavelength operation unit 5 is sent to the averaging unit 7. The averaging unit 7 calculates the average of the peak wavelength λp and the integral value P at a plurality of locations on the coating surface. In general, in the case of a large object to be coated such as an automobile body, the spraying area is large, so that the coating conditions may not always be uniform depending on the coating site. Therefore, in order to perform accurate measurement, it is desirable to image a plurality of locations on the painted surface and perform the atomization degree calculation using the average value at each of those locations. In the case of a small object to be coated, the above-described averaging process may be omitted and a value at one location may be used. The value of the power spectrum PS is sent to the atomization calculation unit 6.

The coating condition input unit 5 is an input means such as a keyboard, for example. The coating condition input unit 5 includes at least a non-volatile component (content or content) of the paint before painting and paint type information (paint thinner type information). ), Temperature information in the coating booth, and a difference in the coating conditions between the first and second blows (for example, a ratio of the discharge amount) is input. In addition, the coating conditions include the number of times of spraying (first time or second time), type of paint, spraying distance, and the like, and are input from the coating condition input unit 5 as necessary. Note that the thinner species is prepared by changing the boiling point of the thinner according to the season. For example, by changing the mixing ratio of the low boiling thinner and the high boiling thinner, it can be used for summer (high boiling) and winter (Low boiling point), for spring and autumn (middle)
It is adjusted to the boiling point according to the season. Therefore, the thinner type input from the coating condition input unit 5 can be represented by, for example, a mixture ratio of two types of thinner.

The atomization calculating section 6 atomizes the paint based on the coating condition from the coating condition input section 5 and the wavelength value obtained by the wavelength calculating section 4 and averaged by the averaging section 7. The degree is calculated (details will be described later).

The thinner evaporation amount input unit 13 inputs the thinner evaporation amount (evaporation speed × time: detailed later) of the paint measured in advance in an experiment. The thinner evaporation amount per unit area is calculated based on the relationship between the non-volatile component content of the paint before coating and the applied non-volatile component immediately after coating and the degree of atomization of the paint, which are measured in advance by experiments. You can do it. Although the thinner evaporation input unit 13 and the coating condition input unit 5 are described separately, they may be common.

Next, the thinner evaporation correction section 12 calculates the temperature in the coating booth input from the coating condition input section 5, the type of thinner of the coating, the coating film thickness input from the film thickness calculating section 15 described later, and the first The calculation result of the coating NV calculation unit 10 and the third
The thinner evaporation amount input from the thinner evaporation amount input unit 13 is corrected in accordance with the calculation result of the coating NV calculation unit 23. For example, a first correction value obtained by correcting the reference thinner evaporation amount according to the temperature in the coating booth and the type of paint thinner, and the reference thinner evaporation amount to the temperature in the coating booth and the paint thinner The second correction value corrected according to the seed, the film thickness, and the calculation result of the first coating NV calculation unit 10, the reference thinner evaporation amount, the temperature in the coating booth,
A third correction value corrected according to the paint thinner type, the film thickness, and the calculation result of the third coating NV calculation unit 23;
Is calculated, the first coating NV calculating unit 10 performs the calculation using the first correction value, and the second coating NV calculating unit 22 performs the calculation using the second correction value. Done, 4th coating NV
The calculation unit 25 performs a calculation using the third correction value. (Details described later).

Next, the first coating NV calculating section 10 calculates the degree of atomization of the paint input from the atomizing calculating section 6 and the non-painting degree of the unpainted paint input from the coating condition input section 5. Based on the volatile component and the corrected thinner evaporation amount (the first correction value) input from the thinner evaporation amount correction unit 12, the coating NV. Eye value) (details will be described later). However, the unit of the coating NV is, for example, the weight per unit area or%.

As described above, since it is difficult to install an imaging unit in the area between the one-time spray coating gun and the two-time spray coating gun, the coating surface to be imaged by the imaging unit 2 is difficult. This is the painted surface after the second spray painting. Therefore, it is not possible to image the painted surface immediately after the first blowing, but if the coating conditions are the same, the state of the attached particles on the painted surface after the first blowing and after the second blowing is the same, so the imaging screen after the second blowing , The degree of atomization of one-time blowing can be calculated. That is, the degree of atomization of the paint used for the calculation in the first coating NV calculating section 10 (the input value from the atomizing calculating section 6) is a value immediately after the second spray application.

Next, the first paint density calculating section 20 executes the first
The paint density immediately after the coating is calculated based on the paint NV immediately after the coating obtained by the coating NV calculating unit 10 and the coating condition (type of the paint) from the coating condition input unit 5 ( Details will be described later).

On the other hand, the surface roughness calculating section 14 calculates the roughness of the painted surface based on the image processing information obtained by the image processing section 3, and the film thickness calculating section 15 calculates the surface roughness and its value. The coating film thickness is calculated based on the time change amount and the wavelength (the peak wavelength λp in the long wavelength region of the power spectrum PS and the integrated value P of the power spectrum) obtained by the wavelength calculating unit 4 (described later in detail).

The measuring time input section 21 is provided for measuring at any time from the time when the paint is applied (at the time when a desired time has elapsed after coating, for example, at the time of double blowing or at any time after double blowing: 2 minutes). (To about 9 minutes) (hereinafter referred to as measurement time). Then, the second coating NV calculating unit 22
Are corrected by the thinner evaporation amount correction unit 12 and the film thickness obtained by the film thickness calculation unit 15, the paint density obtained by the first paint density calculation unit 20, the measurement time input from the measurement time input unit 21. On the basis of the thinner evaporation amount (the second correction value) and the coating conditions (such as the discharge amount of the first blow and the second blow) input from the coating condition input unit 5, the coating N at the time of the second spray coating is applied. .V2 is calculated (details will be described later). This coating NV2
Is the applied NV of the once-blown coating film at the time of the second-blown time.

Next, the third coating NV calculating section 23 calculates the coating NV 1 obtained by the first coating NV calculating section 10 and the second coating NV.
The coating NV2 obtained by the coating NV calculating unit 22 and the coating conditions of the first and second blowings input from the coating condition input unit 5 (for example, the first blowing and the second blowing). The application NV3 immediately after the second spray application is calculated from the ratio of the ejection amount of the second application (the details will be described later).

Next, the second paint density calculator 24 calculates the third paint density.
The coating density immediately after coating is determined based on the coating NV 3 immediately after the second spray coating obtained by the coating NV calculation unit 23 and the coating condition (type of coating) from the coating condition input unit 5. Calculate (details described later).

Next, the fourth coating NV calculating unit 25 calculates the coating NV3 obtained by the third coating NV calculating unit 24 and the second coating NV3.
The paint density calculated by the paint density calculation unit 24, the film thickness calculated by the film thickness calculation unit 15, the measurement time input from the measurement time input unit 21, and the thinner evaporation amount corrected by the thinner evaporation amount correction unit 12 ( Based on the third correction value), a coating NV4 (an entire value after the second blowing) after an arbitrary time from the coating time set by the measurement time input unit 21 is calculated (details). See below).

The coating NV1 determined as described above
The coated NV 4 is displayed on a display device 8 such as a liquid crystal display device or a CRT display device, is presented to an operator, and is taken out as a hard copy by the printer 11. In addition,
In the case of the double spraying, the coating NV3 and the coating NV4 are usually used as the coating conditions for actually controlling the coating gun. Therefore, only the coating NV3 and the coating NV4 may be displayed. Each of the calculation units and the correction unit is configured by a calculation device such as a computer.

Next, the detailed structure and operation of each part will be described. First, the imaging unit 2 will be described. FIG. 3 is a cross-sectional view illustrating an example of the imaging unit 2. As shown in FIG. 3, the basic configuration of the imaging unit includes a light source 31, a light / dark pattern plate 32, a reflecting mirror 33, a lens 34, and a CCD camera 35. The light / dark pattern plate 32 is an opaque plate provided with linear slits at a predetermined interval (for example, 1 mm interval) (or an opaque stripe pattern printed at a predetermined interval on a transparent plate). Then, a parallel light beam from the light source 31 is emitted from the oblique direction of the coating surface via the light / dark pattern plate 32, the reflecting mirror 33, and the lens 34 to form a stripe pattern corresponding to the slit on the object to be coated. This striped pattern
Waveforms distorted in accordance with irregularities on the object to be coated (for example, FIG.
1 waveform). The reflected light is transferred to the CCD camera 3
The image is picked up at 5 and the above-mentioned distorted stripe pattern, that is, information on the surface roughness is input.

The above-mentioned striped image information is subjected to image processing, and power spectrum frequency analysis (for example, fast Fourier transform processing: FFT) is performed to obtain a power spectrum PS. FIG. 4 is a frequency characteristic diagram of the power spectrum PS. The vertical axis represents the power spectrum PS, and the horizontal axis represents the frequency f (the reciprocal of the wavelength λ, f = 1 / λ). In FIG. 4, a first peak waveform is a power spectrum of a basic waveform by a basic fringe corresponding to the slit, and a second peak waveform is a long wavelength region (10 to l) of the uneven surface waveform of the coating surface.
The third peak waveform is a power spectrum corresponding to a medium wavelength region (approximately 1 to 0.1 mm) of the uneven waveform, and the fourth peak waveform is a short wavelength region (approximately 1 to 0.1 mm) of the uneven waveform. (Less than 0.1 mm).

In the above power spectrum waveform, the peak wavelength in the long wavelength region of the concavo-convex waveform, that is, the wavelength λp corresponding to the peak value of the second peak waveform, is obtained. Of the peak waveform (the area of the hatched portion) is determined as the power spectrum integrated value P. The wavelength λp and the power spectrum integral value P have a relationship with the film thickness as described below, and based on these values, the film thickness can be calculated using the theoretical formula of smoothing described later. Further, the wavelength λp has a correlation with the degree of atomization as described later, and the degree of atomization can be measured thereby. Further, the film thickness can be calculated only from this wavelength λp. In the embodiment shown in FIG. 2, the image processing and the power spectrum calculation as described above are performed by the image processing unit 3, the wavelength calculation unit 4, and the surface roughness calculation unit 14. The output of the wavelength calculator 4 is
The data is averaged by the averaging unit 7 and used.

Next, the NV of paint before painting, the kind of paint, the temperature in the paint booth, and other paint and paint information are input from the paint condition input unit 5. The atomization calculating section 6 calculates the degree of atomization according to the NV of the paint before coating and the information of the kind of the paint and the value of the peak wavelength λp from the wavelength calculating section 4.

Next, the principle of the measurement of the degree of atomization in the atomization calculating section 6 will be described. First, based on FIG. 5, a description will be given of the adhesion of paint particles to the painted surface and the process of forming the painted film surface during painting. As shown in FIG. 5A, atomized paint particles are sprayed from a paint gun toward a paint surface. At this time, the average particle diameter of the paint particles is basically
It is determined by the coating conditions, ie, the paint speed (described below), the air speed (described below), and the paint properties (described below). However, the above is as follows. Discharge volume of coating gun Bell rotation speed of coating gun Applied voltage Air pressure Physical properties of paint (viscosity, surface tension, density) The bell rotation speed is the rotation speed of the rotating body that atomizes the paint, and the applied voltage is the paint It is a static voltage (approximately 50 kV) applied to apply static electricity to the particles, and the air pressure is a pressure for creating an airflow wall around the paint particles so that the paint particles do not fly around. The paint particles sprayed as described above collide with the painted surface and adhere in a crushed form.

Next, as shown in FIG. 5B, in the early stage of the coating film formation, the small paint particles adhered are combined with the large paint particles to form larger particles. Then, the bonding of the particles further proceeds, and the initial coating surface is formed by the surface tension and the boundary tension. As described above, the coating film is formed by the attachment and bonding of the particles, and thus the initial coating film surface condition is such that the large coating particles have a particle diameter r, a particle collision velocity vx,
It depends on the paint properties (surface tension γ, viscosity η) and the like. For example, in the case of a top coat, the height of the unevenness on the surface of the initial coating film is about several to several tens of μm, and the wavelength distribution of the unevenness is 3 to 6 μm.
It was confirmed that a long wavelength region of about mm was dominant. Experiments have confirmed that there is a correlation between the peak wavelength λp in the long wavelength region and the particle diameter r of the large paint particles.

Next, as shown in FIG. 5C, the surface of the coating film after the formation of the initial coating film has a leveling force (surface tension γ).
And the gravity g).
The leveling speed is determined by the leveling force and the paint properties (surface tension γ, viscosity η) and the film thickness h. For example, in the case of a top coat, it has been confirmed that the flattening speed is a time constant of several tens of seconds to several hundreds of seconds.

Next, the relationship between the coating particle diameter and the unevenness of the coating film surface will be described in detail with reference to FIGS. As shown in FIG. 6, the particle diameter of the paint particles sprayed from the paint gun is represented by r, the width of the adhered particles adhered thereto is λ / 2,
Assuming that the thickness (peak value) is h, a coating film surface having irregularities of wavelength λ is formed. Note that the relationship between the width λ / 2 of the attached particles and the wavelength λ was determined experimentally, and it has been confirmed that the value is approximately this value. The paint particle diameter r in the above case is represented by the following (Equation 1).

[0042]

(Equation 1)

When the above theoretical formula is shown in a graph, it becomes a curve as shown by a broken line in FIG. However, in actuality, since the attached particles are bonded, the characteristics are as shown by the solid line in FIG. When the characteristics obtained in this experiment are shown by mathematical expressions, they are as shown in the following (Equation 2).

[0044]

(Equation 2)

Where, ks: correction coefficient λp: peak wavelength of the unevenness on the coating film surface (corresponding to the peak wavelength in the long wavelength region) a, β: constant The peak wavelength λp of the unevenness and the paint particle diameter obtained in the above experiment. The relationship with r is analyzed in consideration of the binding of the attached particles. First, as shown in FIG. 8, the attached particle diameter R sequentially increases as the coating time increases. This relationship is expressed by the following equation (Formula 3).

[0046]

(Equation 3)

Here, R ₀ : initial particle diameter b, c: constant In FIG. 8, the application time is the duration of application at one location, the initial particle diameter is the paint particle diameter before adhesion, The particle diameter is the particle diameter when the particles first adhere. The attached particle diameter R becomes gradually larger as the coating time becomes longer, since the particles to be applied sequentially bond.

FIG. 9 is a characteristic diagram comparing the relationship between the coating time and the uneven wavelength of the coating film surface with the measured value (broken line) and the result obtained from the power spectrum by frequency analysis. As can be seen from FIG. 9, the value obtained from the power spectrum agrees well with the actually measured value. Therefore, the attached particle diameter R can be determined using the uneven wavelength (peak wavelength λp of the long wavelength) determined from the power spectrum.
Further, in the automatic coating machine, since the application time is constant, the coating particle diameter r can also be determined by the following equation (4). 2r (t) = λp (t) (Equation 4) From the above considerations, basically, using the peak wavelength λp in the long wavelength region of the concavities and convexities obtained from the power spectrum by the above (Equation 2), The paint particle diameter r can be determined. More specifically, if the characteristics shown in FIG. 7 are obtained through experiments, and the respective coefficients ks, a, and β of Expression (2) are obtained in advance, the paint particle diameter can be obtained using the peak wavelength λp obtained from the captured image. r can be obtained. Since the particle diameter r of the paint particles corresponds to the degree of atomization of the paint, the degree of atomization may be expressed using the particle diameter r of the paint particles as they are, or the reciprocal of r, or the reference value. The degree of atomization can also be represented using the percentage of

Next, the principle of calculating the coating NV on the coating surface in the first coating NV calculating unit 10 shown in FIG. 2, the thinner evaporation input unit 13 and the thinner evaporation correcting unit 12
Will be described. FIG.
FIG. 3 is a view showing a situation until paint particles sprayed from a paint gun adhere to a surface to be coated. As shown in FIG.
The solvent (volatile component) evaporates from the paint particles during flight and after adhesion, and only the non-volatile component remains when the coating film is completely dried. The time from when the paint is sprayed from the coating gun until it adheres to the object to be coated is
Although it depends on the distance between the coating gun and the object to be coated, it is generally about 0.1 second to 0.5 second.

In the above situation, if the coating NV immediately after the deposition is X ₁ , X ₁ is given by the following equation (5). X ₁ = M ₁ × X ₀ / (M ₁ −V × S ₁ × t) (Equation 5) where M ₁ : mass of paint particles in flight X ₀ : NV of paint before application (paint Concentration) V: Thinner evaporation speed (value per unit area) S ₁ : Surface area of paint particles in flight t: Elapsed time from paint injection time (flight time of paint particles) Further, the above thinner evaporation speed V is as follows: It is given by the equation (6). V = V (C, T, X ₀ ) (Equation 6) where C: Thinner type mixing ratio T: Temperature (paint temperature or coating booth ambient temperature) Note that the thinner type mixing ratio C is the temperature depending on the season In order to cope with the change, it means a mixing ratio in a case where the mixing ratio between the low boiling thinner and the high boiling thinner is changed to adjust the boiling point according to the season.

The mass M _{1 of the} paint particles is given by
Given by the formula. M ₁ = (1/6) × πR ³ × ρ ₀ (Equation 7) where R: Paint particle diameter ρ ₀ : Paint density The paint particle surface area S ₁ is given by the following (Equation 8). S ₁ = πR ² (Equation 8) Therefore, the above-mentioned equations (7) and (8) are replaced by (5)
By substituting into the equation, the following (Equation 9) is obtained as an equation representing the coating NV = X ₁ (%).

[0052]

(Equation 9)

The thinner evaporation amount per unit area is represented by evaporation speed V × time t. Therefore, when the thinner evaporation amount at the reference temperature is obtained from the above equations (5) and (9), the following equation (10) is obtained. Vc × tc = (1/6) × R × ρ ₀ (Xc−X ₀ ) / Xc (Equation 10) where Vc: evaporation rate at the reference temperature tc: particle flight time (time from injection time to adhesion time) Xc: coating NV immediately after adhesion at the reference temperature Therefore, the particle flight time tc under the reference coating conditions is represented by the following equation (11).

Tc = (1/6) × R × ρ ₀ (Xc−X ₀ ) / Xc · Vc (Equation 11) Further, the thinner evaporation rate at an arbitrary temperature T, film thickness h, and thinner type mixing ratio C V is represented by the secondary characteristic of the value X ₀ of the coating NV immediately after coating, as shown in FIG. 18, and is expressed by the following (Equation 12).

[0055]

(Equation 12)

Where, Vc: evaporation rate at reference temperature T: temperature at measurement T ₀ : reference temperature C: paint thinner species mixture ratio at measurement C ₀ : paint thinner species mixture ratio X ₀ : before coating NV (paint concentration) of paint X ₀₀ : reference value of NV of paint before coating k ₁ , k ₂ , k ₃ , α, τ: constant The above-mentioned C and C ₀ paint thinner type mixing ratio Is
When the boiling point of the thinner is changed according to the season, by changing the mixing ratio of the low-boiling thinner and the high-boiling thinner, summer (high boiling), winter (low boiling), spring and autumn (middle)
Means the mixing ratio when the boiling point is adjusted according to the season. Therefore, the thinner type is for summer, winter,
It means the type of thinner due to the difference in boiling point like spring and autumn.

As shown in the above formulas (11) and (12), the particle flight time tc and the thinner evaporation speed V are
Coating conditions for coating machine R, Xc, it is calibrated by X ₀ and the like.
Further, as shown in the above equation (9), if the coating conditions are constant, the coating NV after adhesion is determined by the thinner evaporation amount (evaporation speed V × time t), the coating particle diameter R, and the coating density. It can be obtained by calculation from ρ ₀ . The thinner evaporation rate Vc at the reference temperature T ₀ can be obtained by an experiment in advance based on the above equation (Equation 10), and the thinner evaporation rate V at an arbitrary temperature T, the film thickness h, and the thinner type C is calculated by the above (Equation 1).
It can be obtained by equation (2).

In the embodiment of FIG. 2, the thinner evaporation speed Vc or the thinner evaporation amount (Vc × tc) at the reference temperature T ₀ obtained in advance as described above is input from the thinner evaporation amount input unit 13. Then, the thinner evaporation amount correction unit 12 uses the temperature (actually measured value: equivalent to the above T) and the type of thinner (corresponding to the above C) input from the coating condition input unit 5 (equation 12). )
The reference thinner evaporation amount is corrected by the equation, the thinner evaporation amount (first correction value) under the coating conditions is calculated, and the coating NV immediately after adhesion is calculated using the value. The paint particle diameter R uses the value obtained by the atomization calculation unit 6, and the paint density ρ ₀ uses the value input from the coating condition input unit 5.

Next, the calculation in the second coating NV calculating section 22 shown in FIG. 2 will be described. Second coating N.
In the V calculation unit 22, the point at which the spraying is performed twice after the spraying once (so-called set time: for example, 30 seconds to
(After one minute) to calculate the applied NV of the once-blown coating film. In addition, the first operation required to perform the above operation is performed.
The paint density calculation unit 20, measurement time input unit 21, and film thickness calculation unit 15 will also be described.

First, the first paint density calculating section 20 performs the first
The paint density is calculated from the paint NV calculated by the paint NV calculating unit 10 (described later in detail). The measurement time input unit 21
Is a time from the time when the paint is applied to an arbitrary measurement time (in this case, the time from the time of the first blow to the time of the second blow) is input. Further, the film thickness calculating section 15 calculates the coating film thickness in accordance with the peak wavelength λp obtained by the wavelength calculating section 4 and the roughness (and its time change amount) obtained by the surface roughness calculating section 14 (details). See below). In addition, the thinner evaporation amount correction unit 12 also calculates a correction value (second correction value) used for the calculation of the second coating NV calculation unit 22 (details will be described later). Then, the second coating NV calculating section 22 calculates the film thickness obtained by the film thickness calculating section 15, the paint density obtained by the first paint density calculating section 20, and the measurement time inputted from the measurement time input section 21. Based on the corrected thinner evaporation amount and the coating conditions, the application NV of the once-sprayed coating film at the time when the two-time spray coating is performed is calculated.

Hereinafter, the coating NV calculation performed by the second coating NV calculating section 22 at an arbitrary time after the coating time will be described. If the coating NV immediately after adhesion (after the paint particle flight time t _{1 has} elapsed since the time of paint spraying) is X ₁ , and the coating NV when the time t ₂ has elapsed after attachment is X ₂ , X ₁ below (number 13), X ₂ is given by the following equation (14) or (expression 15) below. X ₁ = M ₁ × X ₀ / (M ₁ −S ₁ × V × t ₁ ) (Expression 13) X ₂ = M ₁ × X ₀ / (M ₁ −S ₁ × V × t ₁ −S ₂ × V ′ × t ₂ ) (Equation 14) or X ₂ : M ₂ × X ₁ / (M ₂ −S ₂ × V ′ × t ₂ ) (Equation 15) where M ₁ : Paint particles in flight Mass M ₂ : Mass of paint particles after adhesion X ₀ : NV (paint concentration) of paint before application S ₁ : Surface area of paint particles in flight S ₂ : Surface area of paint particles after adhesion V: Unit in flight Thinner evaporation rate per unit area V ′: Thinner evaporation rate per unit area after adhesion “S ₁ × V × t ₁ ” in equation (13) corresponds to the thinner evaporation amount during flight of the coating particles, “S ₂ × V ′ × t ₂ ” in the equation (14) corresponds to the thinner evaporation amount after the adhesion.

The mass M ₂ of the paint particles after the adhesion is given by the following equation (Formula 16) based on the surface area S _{2 of} the coating film, the thickness h ′ of the single blow, and the paint density ρ ₂ immediately after the adhesion. M ₂ = S ₂ × h ′ × ρ ₂ (Equation 16) Here, the film thickness h ′ of the single blow is n, the discharge amount of the paint once blown is n, and the discharge amount of the double blow is m, twice. Assuming that the film thickness measured after blowing is h, it is given by h ′ = n × h / (n + m).

Further, the surface area S ₂ of the paint particles after the above-mentioned adhesion is obtained.
Is given by the following (Equation 17). S ₂ = k ₅ × S ₁ (Equation 17) where k ₅ = f (h), and k ₅ is a function of the film thickness h. Equations (16) and (17) are replaced by (1)
Substituting into the equations 4) and (Equation 15) gives the time t ₂ after the adhesion.
X ₂ indicating the coating NV at the time when the time elapses (at the time of second blowing)
(Equation 18) and (Equation 19)
An expression is obtained.

[0064]

(Equation 18)

An arbitrary temperature T, film thickness h, thinner type mixing ratio C, and thinner evaporation rate V ′ at time t ₂ after deposition are given by the following (Equation 20).

[0066]

(Equation 20)

Where X ₁ : N.V. Coating immediately after adhesion N.sub.X ₁₀ : Reference value of N.V. coating immediately after adhesion n: Discharge amount of one-time blowing m: Discharge amount of two-time blowing h: 2 degree Thickness at the time of blowing h ₀ : Reference film thickness at the time of blowing twice The meanings of the other symbols are the same as those of the above (Equation 12).

In the case where the above equation (19) is used, X ₁ indicating the coating NV immediately after the adhesion and the coating density ρ after the adhesion
_2, and the thickness h of the coating film, (input from paint condition input unit 5) n and m for calculating h ', the measurement time t ₂ to the measuring point from the coating point, thinner evaporation rate of the corrected V '(second
There is a need for correction values) but, X ₁ is as described above (Equation 1
The film thickness h is obtained by using the expression 3), and the film thickness
Can be calculated. The measurement time t ₂ may be input from the measurement time input unit 21. As the paint density ρ ₂ after application (ρ ₂ = ρ ₁ ), a value obtained by the first paint density calculator 20 is used. Also, the thinner evaporation rate V ′
Is obtained by the above equation (20). The thinner evaporation speed V ′ (second correction value) after the above correction is obtained by the thinner evaporation amount correction unit 12.

Next, the paint density calculation performed by the first paint density calculator 20 will be described. Coating NV immediately after adhesion
(X ₁ ) and the paint density ρ have a relationship as shown in FIG. Therefore, the first paint density calculating unit 20 stores the characteristics of FIG. 11 in advance, and according to the coating NV immediately after adhesion obtained by the first coating NV calculating unit 10, The current paint density ρ is read and output. The relationship in FIG. 11 is based on the type of paint (overcoat,
Therefore, the characteristic corresponding to each paint is stored, and the corresponding characteristic is used according to the information of the type of the paint input from the coating condition input unit 5. As described above, the value of 1 at the time of performing
The application NV of the blown coating film is calculated.

Next, the calculation of the surface roughness and the film thickness in the surface roughness calculator 14 and the film thickness calculator 15 shown in FIG. 2 will be described. FIG. 12 is a cross-sectional view of the coating film after painting.
Immediately after coating, as shown in (a), the coated surface is in an uneven state due to the initial bonding of the adhered particles. Then, as time passes, as shown in (b), smoothing is gradually performed by the leveling force, and finally, as shown in (c), a smoothed state is obtained. In the present embodiment,
Focusing on such a smoothing phenomenon, measuring the unevenness of the coating surface in a wet state, and after smoothing it,
Alternatively, the coating thickness after drying is calculated.

In order to measure the unevenness state in the wet state as described above, various methods such as an optical interference type surface roughness meter (for example, “Mechanical Engineering Service Section, Japan Society of Mechanical Engineers, September 30, 1989, issue of new edition 3rd edition, B2 edition) 207 pages to 208
Page), but here, the imaging means (for example, CC
A method of imaging the painted surface with a D camera) and image processing the information will be described.

[0072] First, explaining the smoothing characteristics of the power spectrum integral value P, and the surface of the uneven surface mean corresponding surface roughness value R _a and the power spectrum integral value P (peak-to-peak value), There is a relationship as shown in FIG. 13, and there is a relationship as shown in the following equations (21) and (22). P = Q tens k × √R _a ... (number _{21) R a = {(P} -Q) / k} 2 ... ( Equation 22) However, in the above formula, Q is the roughness correction value, k is Roughness conversion It is a coefficient.

In deriving the theoretical equation for smoothing based on the power spectrum analysis value, first, the surface roughness _Ra is expressed by the following equation (Equation 23) as the theoretical equation for wet coating film smoothing (approximate equation). R _a = R _a0 · exp (−t / τ) ...
( _Equation 23) Here, _Ra0 is the initial value of _Ra (time 0, that is, the value immediately after painting), and t is the elapsed time after painting. Τ is a time constant derived from the basic formula of a viscous fluid, and
8) This is as shown in the equation.

When the above equation (22) is substituted into the equation (23), the following equation (24) is obtained. {(P−Q) / k} ² = {(P ₀ −Q ₀ ) / k} ² exp (−t / τ) (Equation 24) where P ₀ is the initial value of P (the value at time 0) And Q ₀ is the initial value of Q. In the above equation (24), if P and P ₀ are values including the respective correction values Q and Q _{0 and} are expressed as (P ₀ −Q ₀ ) → P ₀ , (P−Q) → P,
The expression (24) can be expressed as the following expression (25). P = P ₀ · exp (−t / 2τ) (Equation 25) The time constant τ is expressed by the following (Equation 26). τ = 3ηλ ⁴ / 16π ⁴ γh ³ (Equation 26) where η is the viscosity of the paint, λ is the peak wavelength in the long wavelength region, γ is the surface tension of the coating film, and h is the film thickness in a wet state (imaging) (Average value of parts). From the above, the coating film thickness h based on the power spectrum analysis value is as follows (Equation 27).
It becomes as shown by the formula.

[0075]

[Equation 27]

Here, P ₁ is the value of the power spectrum integral value P at the time point t ₁ , and P ₂ is the time point t ₂ (where −t ₁ <
This is the value of P at t ₂ ). Note that τ ′ _i is as follows (Equation 2)
8) It is shown by the equation. τ ′ _i = 3η (t _i ) · λ ⁴ / 16π ⁴ γ (28) where i = 1,2, and η (t _i ) is a function of the viscosity of the paint and the elapsed time after painting. Indicates that That is, what is input from the coating condition input unit 5 is the viscosity η of the coating before the coating, but the coating viscosity after the coating is a value η (t _i ) that changes according to the elapsed time after the coating. . This value is determined by the paint composition (such as the proportion of volatile components in the paint) and the wind speed. As can be seen from the above equation (27),
From the values of the viscosity η of the paint, the surface tension γ of the paint film, the peak wavelength λ in the long wavelength region of the uneven waveform, and the integrated value P of the power spectrum at _two time points t ₁ and t ₂ after coating, the film thickness h in the wet state is obtained. Can be requested. Among the above values, the viscosity η of the paint and the surface tension γ of the paint film are values determined by the properties of the paint, so input a known value, and input the peak wavelength λ in the long wavelength region and the power spectrum integration. As the value P, a value obtained by processing the above-described image information is used.

FIG. 14 is a characteristic diagram showing a wet smoothing dynamic characteristic (power spectrum integral value P) obtained by comparing a measured value with a theoretical value of smoothing using the above equation (27). FIG.
In the graph, the horizontal axis represents the elapsed time after painting, and the vertical axis represents the power spectrum integrated value P. In the above measurement, an image immediately after application is taken by the imaging unit 2 and power spectrum analysis is performed. From FIG. 14, it can be seen that the measured value has a smoothing characteristic almost coincident with the theoretical value.

Table 1 is a table showing the results of measuring the film thickness h of the two samples having a film thickness of 60 μm and 54 μm by using the above-mentioned equation (27). As shown in Table 1, it can be seen that measurement is possible with an accuracy of several μm.

[0079]

[Table 1]

In the embodiment shown in FIG. 2, the image pickup unit 2,
The above processing is performed in the image processing unit 3, the wavelength calculation unit 4, the surface roughness calculation unit 14, and the film thickness calculation unit 15 to obtain the film thickness h at the imaging location.

In equation (27), the two values P ₁ and P ₂ at the _two time points t ₁ and t ₂ after painting are used to calculate using the time change amount of the roughness information. I have. Therefore, it is necessary to image the same place at two points after painting. For this purpose, it is necessary to move the imaging unit 2 in accordance with the movement of the vehicle body on the painting line, so that the apparatus becomes complicated. To avoid this, there are the following methods. That is, a test piece is prepared in addition to the vehicle body to be coated, and the coating is performed under the same conditions as the coated object, and the value P at time t ₁ (for example, t ₁ = 10 seconds, t ₁ <t ₂ )
₁ uses a value obtained by processing the image information of the test piece. In this way, the imaging unit 2 moves to the time point t.
₂ (for example, 1 to 2 minutes after painting), only one imaging need be performed.

In the present embodiment, the basic measurement is performed by imaging and image processing of the painted surface, and the power spectrum integral value P and the peak wavelength λ in the long wavelength region are used as information on the roughness of the painted surface. The case where the calculation is performed using the above is exemplified. However, as the roughness information of the painted surface, for example, a prior application (Japanese Patent Application No. 4-306966) of the present applicant is used.
As described in the above, using a light interference type surface roughness meter, a method of calculating based on the peak-to-peak of the unevenness and the wavelength λ of the unevenness, or the surface of the surface from the measurement results of the light interference type surface roughness meter There is a method of calculation using the mean wavelength of the roughness degree of R _a and irregularities lambda _a, it may be either.

Further, the film thickness can be calculated using only the unevenness wavelength of the coating film surface (peak wavelength λp in the long wavelength region). This will be described in detail below. In the power spectrum waveform (FIG. 4) obtained by the wavelength calculation unit 4, the peak wavelength in the long wavelength region of the concavo-convex waveform, that is, the wavelength λp corresponding to the peak value of the second peak waveform, is as described below. Since there is a correlation with the thickness, the coating film thickness can be measured by obtaining the wavelength λp.

A basic experiment on the adhesion mechanism of paint particles as described in FIG. 5, specifically, by controlling the spray time of the paint to change the film thickness and measuring the wavelength distribution of the paint film surface at that time. According to the results of the experiment, it was confirmed that the particles adhered to the surface to be coated grew as shown in FIG. Then, as described with reference to FIGS. 5 to 9, the paint particle diameter r can be obtained using the peak wavelength λp in the long wavelength region of the unevenness obtained from the power spectrum. Specifically, the characteristic of FIG. 7 is obtained by an experiment, and then each coefficient k
If s and a are determined in advance, the paint particle diameter r can be determined using the peak wavelength λp determined from the captured image.

Then, as shown in FIG.
Gradually increase as the coating time, that is, the film thickness increases. By analyzing the relationship between the film thickness and the attached particle diameter, that is, the relationship between the film thickness and the wavelength of the unevenness of the coating film surface, while actually measuring the film thickness value instead of the coating time, the relationship is obtained. The relationship with the peak wavelength λp) is as shown in FIG. That is, as the film thickness increases, the peak wavelength λp also increases.
The relationship as shown in the equation was obtained experimentally.

[0086]

(Equation 29)

H = k ′ × λ−k ″ (Equation 30), where k, k ′, k ″, α: constants determined according to the paint, as can be seen from the above formulas and the characteristics in the figures, the diameter of the adhered particles (I.e., the wavelength of the irregularities on the painted surface) increases as the film thickness increases, because the number of bonded particles increases. That is, it is shown that the growth of the coating film surface depends on the film thickness value which is a coating condition.
It is possible to calculate the film thickness value from the wavelength of the unevenness of the coating film surface by using the expression 9) or the expression (30). Therefore, the peak wavelength λp in the long wavelength region of the uneven waveform of the coating film surface
Is obtained, the film thickness h in a wet state can be calculated.

In the case of application to the embodiment of FIG. 2, the wavelength calculator 4 calculates the power spectrum PS of the uneven waveform of the coating surface from the input image processing data, and calculates the peak wavelength λp in the long wavelength region. calculate. And the film thickness calculating section 1
In step 5, the film thickness value of the coating is calculated from the peak wavelength λp using the characteristic (Equation 29 or Eq. 30) of FIG. In this case, the surface roughness calculator 14 can be omitted. In the above calculation, the characteristics in FIG. 15 are different depending on the type of the paint, to be exact. Therefore, according to the type of the paint such as the middle coat, the top coat base, and the clear top coat inputted from the coating condition input unit 5 ( The coefficient values of the equations (29) and (30) are changed.

Next, the calculation in the third coating NV calculating section 23 and the fourth coating NV calculating section 25 shown in FIG. 2 will be described. The third coating NV calculator 23 calculates the coating NV3 immediately after the second spray coating, and calculates the fourth coating NV.
In the calculation unit 25, after the elapse of an arbitrary time, the coating NV
4 is calculated.

FIG. 16 shows the elapsed time after coating and the coating NV.
FIG. 6 is a characteristic diagram showing an example of the relationship. In FIG.
The numerical value (about 38%) at the left end of the broken line indicates the NV of the paint,
An example is shown in which spray coating is performed once at 0 minutes, and then twice. Coating NV1 just after blowing once
(X ₁ ) is about 50%, and coating NV2 after 1 minute
(X ₂ ) has increased to about 53%. When the spraying is performed twice, paint particles having a large amount of volatile components are added, so that the coating NV3 (X ₃ ) has a slightly reduced value, and thereafter gradually increases with time (coating). NV4:
X _4). As described above, the coating NV immediately after the first spraying is applied.
1 (X ₁ ) is actually replaced with the value X ₁ ′ immediately after blowing twice. Further, the coating N.V3 (X ₃₎ can be estimated as the average of the X ₁ and X _2. The characteristic shown in FIG. 16 is a characteristic when the ejection amount of the first and second blows is the same, and when the ejection amount is different, a correction corresponding to the difference is necessary. FIG. 17 is a schematic diagram showing the cross section of the coating film in the above relationship, and the discharge amount of the first blow and the second blow is the same (the film thickness h is h / 2).
).

Hereafter, the coating NV3 =
Will be described operation of X ₃ and the coating film formed after t ₄ the coating after lapse N.V4 = X _4. X ₃ and X ₄ when once blown and discharge amount of blowing twice are the same, the following equation (31) and (Equation 3
It is shown by the equation 2). X ₃ = (X ₁ + X ₂ ) / 2 (Equation 31) X ₄ = X ₃ / [1− (V ″ × t ₄ / h × ρ ₃ )] (Equation 32) where V ″: after adhesion Thinning evaporation rate at time t ₄ ρ ₃ : paint density on the coating surface immediately after the second blow and X ₃ when the discharge amount of the first blow and the second blow is different
Is expressed by the following (Equation 33). Note that X ₄ is the same as the above (Equation 32). X ₃ = (nX ₁ + mX ₂ ) / (n + m) (Expression 33), where n: discharge amount of the first blow m: discharge amount of the second blow As described above, coating immediately after the second blow NV is X ₁ and X ₂
Is approximated as the average value of

Further, the coating NV4 after a lapse of t ₄ after the formation of the coating film
= X ₄ is performed in the same manner as the calculation in the second coating NV calculating unit 22. That is, the paint mass M ₄ is
Coating the surface area S _4, film thickness h, following the paint density [rho ₃ (Number 3
X ₄ is expressed by the following equation (Expression 35). M ₄ = S ₄ × h × ρ ₃ (Expression 34) X ₄ = M ₄ × X ₁ / (M ₂ −S ₂ ′ × V × t ₂ ) (Expression 35) by substituting the number 35), the coating N.V4 = X ₄ after t ₄ has elapsed after the film formation, the following equation (36)
The thinner evaporation rate V ″ at the time t ₄ after the adhesion is calculated by the following equation (Formula 37).

[0093]

[Equation 36]

Where h: the film thickness when blown twice and h ₀ : the reference film thickness when blown twice. The above-mentioned paint density ρ ₃ is calculated by the first paint density calculation unit 20.
, The second paint density calculator 2 in FIG.
In 4, the calculation is performed according to the result of the third coating NV calculating section and the coating conditions. As described above, in the embodiment of FIG. 2, even in the case of the double spray coating, the coating NV of the coating film immediately after the double spray or after an arbitrary time has elapsed can be accurately calculated.

Next, FIG. 19 is a block diagram showing a second embodiment of the present invention. This embodiment shows a case where the present invention is applied to an automatic painting line (for example, painting an automobile body).

In FIG. 19, the object 1 to be coated is the body of an automobile, and the object 1 is painted while sequentially moving on a painting line. Then, the first coating NV calculation unit 10, the second coating NV calculation unit 22, the third coating NV calculation unit 23, and the fourth coating NV calculation unit 25 determine the value. The various coating NV (particularly the third and fourth important) are sent to the coating condition control system 9. In the coating condition control system 9, the operating condition of the coating gun 28, that is, the discharge amount of the paint, so as to maintain the optimum condition for achieving the desired coating NV by promptly feeding back the quality of the coating condition. Controls bell speed, air pressure, etc. Thereby, a desired coating state can be realized.

Next, FIG. 20 is a block diagram showing a third embodiment of the present invention. This embodiment has a function of performing a curved surface correction of the object 1 to be coated. In the present invention, the surface roughness wavelength is determined from the image of the painted surface, and the degree of atomization and the film thickness are calculated based on the wavelength. However, if the painted surface has a curved surface such as a car body, the captured image is curved according to the curved surface.
In some cases, it may be difficult to accurately measure the surface unevenness wavelength. Therefore, in the present embodiment, the curved surface calculation unit 19 and the wavelength correction calculation unit 27 are provided, and the subsequent calculation is performed using the wavelength obtained by performing the curved surface correction.

Hereinafter, the curved surface calculation unit 19 and the wavelength correction calculation unit 2
7 will be described. Also, a curved surface calculation unit 1
In step 9, curved surface information of the painted surface is obtained based on at least one of the input image processing data and the calculation result of the wavelength calculation unit 4 (details will be described later). Also, in the curved surface correction calculation unit 27,
The calculation result of the wavelength calculation unit 4 is subjected to a curved surface correction process according to the result obtained by the curved surface calculation unit 19 (details will be described later).

FIGS. 21A and 21B are diagrams showing an example of an image picked up by the image pickup section 2. FIG. 21A shows an image when the painted surface is flat, and FIG. 21B shows an image when the painted surface is curved (curved in the x-axis direction). Is shown. When the painted surface is flat, the outer shape of the image becomes the same circle as the image projected from the image pickup unit 2 in FIG. 3 as shown in FIG. 3A, and the stripe pattern of the light / dark pattern plate 32 becomes uneven on the painted surface. Appears distorted accordingly. For curved surfaces, on the other hand,
As shown in (b), the curved surface direction is reduced to an elliptical shape. In FIG. 21, the intermittent direction of the stripe pattern is x
The axis, and the direction perpendicular thereto is the y-axis.

The curved surface calculation unit 19 derives the curvature r of the painted surface using the image data as described above in the following procedure.
First, as shown in FIG. 21B, the maximum length (bright area) x, y in the x-axis and y-axis directions of an image area having an elliptical shape is derived on the image. In the derivation method, the maximum length is calculated by searching the binarized initial bright spot position on each axis from the left and right. Next, since the coating surface having a convex curvature generally acts like a concave lens, the optical system of the imaging unit 2 and the coating surface of the convex surface in FIG. 3 is as shown in FIG. From the distance constant of such an optical system, the curvature r in the x direction of the coating film surface is given by the following equation (38). The y direction can be calculated in the same manner.

R = (L ₁ + L ₂ ) · (x ₀ −x) / 2L ₁ L ₂ · x (Expression 38) where x: measured maximum length of x axis x ₀ : when the painted surface is flat L ₁ : distance between the CCD camera 35 and the coating surface L ₂ : distance between the light source 31 and the coating surface Next, the curvature r and the correction coefficient K shown in FIG. From the relationship, a correction coefficient K for the wavelength λ based on the curvature r is obtained. FIG. 23 is a relational expression obtained by an experiment, in which the vertical axis represents the correction coefficient K, and the horizontal axis represents the reciprocal of the curvature r (1 / r = R: curved surface). The peak wavelength λ in the long wavelength region in the above-described film thickness calculation is obtained by the correction coefficient K obtained as described above.
Correct the value of p. That is, when the measured wavelength at the curved surface portion is λp, the corrected actual wavelength λp ′ corresponding to the plane is expressed by the following equation (39).

Λp ′ = K × λp = (R + a) × λp / R (Equation 39) where: a: constant R = 1 / r As described above, using the actual wavelength λp ′ calculated as described above. By performing atomization calculation or the like, accurate measurement can be performed even on a curved surface. In the embodiment of FIG. 20, the curved surface calculation unit 19 performs the calculation for obtaining the correction coefficient K, and the curved surface correction calculation unit 27 performs the calculation for obtaining the actual wavelength λp ′.

In the above description, the correction is performed by obtaining the curvature r only in the x-axis direction. This is because the intermittent direction of the striped pattern is set to the x-axis as shown in FIG. 21.
The correction coefficient K may be obtained by using the larger value of the curvature.

Next, another method of curved surface correction will be described. As shown in FIG. 4, in the frequency characteristic of the power spectrum PS, the first peak waveform
The power spectrum and the peak waveform of the basic waveform due to the basic stripe corresponding to the slit are power spectra corresponding to the long wavelength region (about 10 to 1 mm) of the uneven waveform on the coating surface. Although the peak values of these power spectra change according to the curvature of the painted surface, according to experiments performed by the present inventors, the peak frequency f of the basic fringe and the peak frequency f ′ (= 1 / λp) in the long wavelength region. Has a certain relationship regardless of the curvature of the painted surface. FIG. 24 is a characteristic diagram illustrating the curved surface dependence of the frequency characteristic of the power spectrum PS. In FIG. 24, the vertical axis is the power spectrum PS,
The horizontal axis indicates the frequency f (1 / λ), the solid line (A) indicates the characteristic of the painted surface being flat, the dotted line (B) indicates the characteristic when the painted surface has the curvature r ₁ , and the broken line (C) indicates that the painted surface has the curvature This shows the characteristics when r ₂ (r ₁ <r ₂ ).

As can be seen from FIG. 24, the peak frequency increases (the peak wavelength λp decreases) as the curvature increases, but it has been found that the following equation (Equation 40) holds regardless of the curvature.

[0106] _{f 0 / f 0 '= f} r / f r' = C ( constant) ... (number 40), where f _0: fundamental fringe peak frequency f ₀ at the time of the plane ': the long wavelength peak frequency f _r at the time of plane : Basic fringe peak frequency at the time of curvature r _fr ': Long wavelength peak frequency at the time of curvature r From the above (Equation 40), the long wavelength peak frequency f at the time of a plane is obtained.
₀ ′ is obtained by the following equation (41).

F ₀ ′ = (f ₀ / f _r ) × f _r ′ (Equation 41) In equation (41), the basic fringe peak frequency f in the plane is
A value of ₀ is a known value that can be measured in advance. Further, the basic fringe peak frequency _fr and the long wavelength peak frequency _fr 'at the curvature r are obtained as actual measured values by the above-described image processing. Therefore, the long wavelength peak frequency f at the time of the curvature r
_{In order} to convert _r ′ into a value f ₀ ′ in the plane, it is sufficient to multiply f _r ′ by f ₀ / f _r . In the case where the wavelength is expressed as λ as described in the above-described film thickness calculation, the correction may be performed as in the following (Equation 42).

Λ ₀ ′ = (λ ₀ / λ _r ) × λ _r ′ (Equation 42) where λ _{0 is a} peak wavelength of a basic fringe in a plane λ ₀ ′ is a peak wavelength of a long wavelength in a plane λ _{r is a} curvature r basic fringe peak wavelength lambda _r when ': According to the long wavelength peak wavelength this method when the curvature r, the basic pattern peak wavelength lambda _r and long wavelength peak wavelength lambda _r' to perform simply by a curved surface correction seeking and Can be done. When the above method is applied to the embodiment of FIG. 20, the surface calculation unit 19 performs an operation to obtain λ _r and λ _r ′ from the image processing data of the image processing unit 3, and the surface correction operation unit 27 performs it may be configured to perform a calculation for obtaining the lambda ₀ 'from the value of lambda ₀ which has been previously stored their values.

As described above, in the embodiment shown in FIG. 20, since the curved surface is corrected in accordance with the curvature of the surface to be painted, the painted surface is curved as in the case of a car body. However, the coating NV can be measured quickly and precisely without contact during coating.

FIG. 25 is a block diagram showing a fourth embodiment of the present invention. In this embodiment, a coating NV determining unit 26 is provided, and a first coating NV calculating unit 10 is provided.
Second coating NV calculation unit 22, third coating NV calculation unit 2
The various coating NVs (especially the third and fourth important ones) obtained by the third and fourth coating NV calculating units 25 are converted into predetermined NV management values (standards for each coating line). Values), a determination is made as to whether or not to continue the current coating conditions according to the deviation from the NV management value, and the coating condition control system 9 is controlled according to the result. is there.
With this configuration, the value of the coating NV becomes NV
In the case of a large deviation from the control value, the coating conditions (paint thinner mixture ratio, etc.) can be changed quickly, so that products with poor coating will not be continued, and the cause of the abnormality will be immediately investigated and resolved. You can do it.

In general, in the case of a large object to be coated such as the body of an automobile, the spraying area is large, so that the coating conditions may not always be uniform depending on the coating site. Therefore, in order to perform accurate measurement, it is desirable to take an image of a plurality of locations on the paint surface and perform the atomization degree calculation using the average value of the peak wavelength λp at each of those locations. Therefore, the image pickup unit 2 picks up an image of a plurality of places on the painted surface, sequentially processes the image information, and averages the plurality of peak wavelengths λp obtained by the wavelength calculation unit 4 by the averaging unit 7. The atomization calculating section 6 is configured to calculate the degree of atomization according to the averaged peak wavelength λp ′.

[0112] In addition, when a plurality of locations are sequentially imaged using one imaging unit 2, the measurement time may be long and the measurement procedure may be complicated. Therefore, by providing a plurality of imaging units and simultaneously inputting image information at a plurality of locations, the measurement time can be reduced and the measurement procedure can be simplified. The number of imaging units may be appropriately set according to the size of the surface to be coated.

[Brief description of the drawings]

FIG. 1 is a diagram showing functional blocks of the present invention.

FIG. 2 is a block diagram showing a first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating an example of an imaging unit 2.

FIG. 4 is a frequency characteristic diagram of a power spectrum PS.

FIG. 5 is a diagram showing a process of depositing paint particles on a paint surface and forming a paint film surface during painting.

FIG. 6 is a diagram showing the relationship between paint particles and adhered particles during flight.

FIG. 7 is a characteristic diagram showing a relationship between an average diameter of paint particles and a wavelength.

FIG. 8 is a characteristic diagram showing a relationship between a particle size of a paint and an application time.

FIG. 9 is a characteristic diagram showing a relationship between a wavelength λ and a coating time.

FIG. 10 is a diagram showing a situation of solvent evaporation from paint particles during coating.

FIG. 11 is a characteristic diagram showing a relationship between coating density and coating NV.

FIG. 12 is a sectional view showing a state of a coating film after painting.

FIG. 13 is a characteristic diagram showing a relationship between _a surface roughness Ra corresponding to an area average value of surface irregularities and a power spectrum integrated value P.

FIG. 14 is a characteristic diagram showing a wet smoothing dynamic characteristic obtained by comparing a smoothing theoretical value and a measured value.

FIG. 15 is a characteristic diagram showing a relationship between a wavelength and a wet film thickness.

FIG. 16 is a characteristic diagram showing an example of a relationship between elapsed time after coating and coating NV.

FIG. 17 is a schematic view showing a cross section of a coating film in the relationship of FIG. 16;

FIG. 18 is a characteristic diagram showing a relationship between a coating NV and a thinner evaporation rate.

FIG. 19 is a block diagram showing a second embodiment of the present invention.

FIG. 20 is a block diagram showing a third embodiment of the present invention.

FIG. 21 is an example of an image captured by the imaging unit 2.
(A) is a diagram showing an image when the painted surface is flat, and (b) is a diagram showing an image when the painted surface is curved (curved in the x-axis direction).

FIG. 22 is a diagram showing an optical system of the imaging unit 2 and the coating surface of the convex curved surface in FIG.

FIG. 23 is a characteristic diagram showing a relationship between a curvature r and a correction coefficient K.

FIG. 24 is a characteristic diagram showing the curved surface dependence of the frequency characteristic of the power spectrum PS.

FIG. 25 is a block diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Coated body (body) 6 ... Atomization calculation part 2 ... Imaging part 7 ... Average processing part 3 ... Image processing part 8 ... Display 4 ... Wavelength calculation part 9 ... Coating condition control system 5 ... Coating condition input part 10 ... First coating NV calculating unit 11 ... Printer 14 ... Surface roughness calculating unit 12 ... Thinner evaporation amount correcting unit 15 ... Thickness calculating unit 13 ... Thinner evaporation amount input unit 19 ... Curved surface calculating unit 20 ... First Paint density calculating section 25: fourth coating NV calculating section 21: measuring time input section 26: coating NV
Judgment unit 22: second coating NV calculation unit 27: wavelength correction calculation unit 23: third coating NV calculation unit 28: coating gun 24: second coating density calculation unit 100: coating condition input Means 106: Film thickness input means 101: Atomization degree input means 107: Second coating NV calculating means 102: Thinner evaporation amount input means 108: Third coating NV calculating means 103: First Coating NV calculating means 109 ... second paint density calculating means 104 ... first paint density calculating means 110 ... fourth coating NV calculating means 105 ... measurement time input time

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI G01N 21/88 G01B 11/24 M (56) References JP-A-56-51270 (JP, A) JP-A-6-142565 (JP, A JP-A-8-117656 (JP, A) JP-A-60-12696 (JP, A) JP-A-6-277574 (JP, A) JP-A-6-148090 (JP, A) JP-A-7-107 306016 (JP, A) JP-A-7-306156 (JP, A) JP-A-9-105612 (JP, A) JP-A-9-113462 (JP, A) JP-A-62-294946 (JP, A) JP-A-7-96228 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B05C 21/00 B05B 12/10 G01B 11/06 G01B 11/255 G01B 11/30 G01N 21 / 88

Claims (9)

(57) [Claims] A coating condition including at least non-volatile component information of a coating material before coating, type information of a coating material, temperature information in a coating booth, and coating conditions in a single blow and a double blow. Input means for inputting coating condition; input means for inputting the degree of atomization of the paint on the coating film surface; input means for inputting the amount of thinner evaporation per unit area of the coating; A first coating non-volatile component calculating means for calculating a coating non-volatile component on the coating surface immediately after the first spray coating based on the volatile component, the degree of atomization, and the thinner evaporation amount; One-time spray coating based on the applied non-volatile component immediately after application calculated by the first applied non-volatile component calculating means and the type of paint input from the coating condition input means. The first paint density to calculate the paint density on the coating surface immediately after Degree calculation means, measurement time input means for inputting a time from a paint application time to an arbitrary measurement time point, film thickness input means for inputting a film thickness of a coating film surface, and the first paint density calculation means Based on the paint density, the measurement time, the film thickness, the thinner evaporation amount, and the coating conditions, the non-volatile component applied to the once-sprayed coating surface at the time of the second-spray coating is calculated. A second applied non-volatile component calculating means, and a non-volatile applied component on the coating film surface immediately after the first spray application from the first applied non-volatile component calculating means; Based on the non-volatile component applied to the once-sprayed coating film surface at the time of the second-spray coating from the non-volatile component calculating means, and the coating conditions in the one-time and two-time spraying, two times A third applied non-volatile component operator for calculating the applied non-volatile component on the coating surface immediately after the spray application. Based on the coating non-volatile component immediately after the second spray application calculated by the third coating non-volatile component calculating means, and the paint type information input from the coating condition input means, A second paint density calculating means for calculating the paint density on the coating film surface immediately after the second spray coating, and a coating nonvolatile immediately after the second spray coating calculated by the third coating non-volatile component calculating means. A component, a paint density from the second paint density calculation means, a time input from the measurement time input means, the film thickness, the thinner evaporation amount,
A coating non-volatile component calculating means for calculating the non-volatile component applied to the twice-blown coating film surface at the set measurement time point based on the above. 2. The thinner evaporation amount input means includes: a non-volatile component of a paint before coating at a reference temperature measured in advance by an experiment; a non-volatile component of a coating film immediately after coating;
The coating quality analysis according to claim 1, wherein a thinner evaporation amount per unit area of the coating particles in flight at a reference temperature is calculated based on the degree of atomization of the coating and input. apparatus. 3. The thinner evaporation amount input means includes: first correction means for correcting the reference thinner evaporation amount according to the temperature in the coating booth and the type of paint thinner; The temperature in the painting booth,
Second correcting means for correcting according to the thinner type of the paint, the film thickness, and the calculation result of the first coating non-volatile component calculating means, and the reference thinner evaporation amount in the coating booth. Temperature and
A third correction unit that corrects according to a thinner type of the paint, a film thickness, and a calculation result of the third coating non-volatile component calculation unit; The sex component calculating means performs the calculation using the output of the first correction means as the thinner evaporation amount, and the second coating non-volatile component calculation means calculates the output of the second correction means as the thinning evaporation amount. 2. The coating according to claim 1, wherein the fourth coating non-volatile component calculating unit performs the calculation using the output of the third correction unit as the thinner evaporation amount. 3. Quality analysis device. 4. The first coating nonvolatile component calculating means,
Based on the relationship between the input non-volatile component of the paint, the thinner evaporation amount, and the surface area of the paint particles determined from the degree of atomization, the applied non-volatile component on the coating surface immediately after application is calculated. The coating quality analysis apparatus according to claim 1, wherein the calculation is performed. 5. The image forming apparatus according to claim 1, wherein said atomization degree input means includes: an image pickup means for picking up an image of an undried painted surface immediately after coating with a paint; an image processing means for image processing image information from said image pickup means; Based on the image processing data processed in, the wavelength calculation means for calculating the wavelength distribution of the uneven waveform of the coating surface, and atomization calculation means for calculating the degree of atomization based on the wavelength distribution obtained by the wavelength calculation means, The coating quality analysis apparatus according to claim 1, further comprising: inputting the calculated degree of atomization. 6. A wavelength calculating means for determining a peak wavelength in a long wavelength region in a power spectrum of an uneven waveform on a coating surface, wherein said atomization calculating means determines a peak wavelength in said long wavelength region in advance. The coating quality analysis apparatus according to claim 5, wherein a paint particle diameter is calculated from a relationship with the paint particle diameter obtained in an experiment, and the calculated paint particle diameter is used as a degree of atomization. 7. The image pickup means picks up an image of a plurality of places on the surface of the coating, the subsequent means perform processing for each point, the wavelength calculation means sequentially calculates the wavelength value at each point, and 7. The coating quality analysis apparatus according to claim 5, further comprising wavelength averaging means for averaging the plurality of wavelength values, wherein a calculation result of the wavelength averaging means is used as a wavelength value. . 8. The undried coating surface immediately after the coating is applied,
8. The coating quality analyzing apparatus according to claim 7, further comprising a plurality of image pickup means for picking up images of different places on the painted surface, and sequentially processing image information of the plurality of places picked up by the image pickup means. 9. An image pickup means for picking up an image of an undried coating surface immediately after a paint is applied, an image processing means for performing image processing of image information from the image pickup means, Wavelength calculating means for calculating the wavelength distribution of the uneven waveform of the coating surface based on the processed image processing data; and a surface calculating the roughness of the coating surface based on the image processing data processed by the image processing means. Roughness calculating means, coating condition input means for inputting coating conditions including at least the viscosity of the paint, roughness calculated by the surface roughness calculating means, time variation of the roughness, and the wavelength A film thickness calculating means for calculating a coating film thickness based on the wavelength distribution calculated by the distribution calculating means and the coating condition input from the coating condition input means; and inputting the calculated film thickness. What is this The coating quality analysis apparatus according to claim 1, wherein: