JP2022107869A - Film thickness estimation system for electrodeposition facility - Google Patents

Abstract

To provide a film thickness estimation system for an electrodeposition facility, capable of controlling the thickness of a coating film formed on the surface of a car body within an intended thickness range and of reducing the loss of electrodeposition paint, by adjusting factors relating to the thickness of the coating film without delay.SOLUTION: A film thickness estimation system 1 according to the present invention is a system of estimating the thickness of a film of electrodeposition paint P1 present on each area of a car body W1, in an electrodeposition facility 10. The film thickness estimation system 1 comprises a learning unit 55, a storage unit 54 and an estimation unit 56. The learning unit 55 performs learning by associating data relating to the composition condition factor of the electrodeposition paint P1, data relating to the film thickness, and data relating to the adjustment factor of the electrodeposition facility 10 with each other. The storage unit 54 stores the data associated by the learning unit 55 as learnt data. The estimation unit 56 estimates the thickness of the film present on each area of the car body W1 according to the learnt data.SELECTED DRAWING: Figure 1

Description

The present invention relates to a film thickness estimation system for estimating the film thickness of an electrodeposition paint for each part of a vehicle body in an electrodeposition coating facility.

Conventionally, the electrodeposition coating equipment performs electrodeposition coating on the vehicle body by applying current from a plurality of electrodes arranged in the electrodeposition tank to the vehicle body immersed in the electrodeposition paint in the electrodeposition tank. is known (see, for example, Patent Document 1). Electrodeposition coating by such an electrodeposition coating facility is widely used in the undercoating process of car body coating for the purpose of imparting antirust performance. However, in the electrodeposition coating, an excessive voltage is applied to secure the film thickness of the inner plate portion of the vehicle body, resulting in loss of energy and paint, resulting in excessive film thickness. For this reason, various methods have been devised to control the thickness of the coating film formed on the surface of the vehicle body to a desired range.

Factors relating to the thickness of the coating film include, for example, conditions for energizing the electrodes, composition of the electrodeposition paint (bath liquid), and the like. Data on these factors are usually acquired through the work shown in FIG. 6, recorded on a form 100 (paper), and managed. Specifically, first, each factor (for example, the acid concentration of the electrodeposition paint 102 in the electrodeposition tank 101, the current value of the current applied to the vehicle body 104 from the electrode 103 arranged in the electrodeposition tank 101, etc. ) are individually monitored. Next, the film thickness of the vehicle body 104 dried in a drying oven (not shown) after being transported out of the electrodeposition tank 101 is measured using a film thickness meter 105, and the measured film thickness is compared with each factor. perform comparison work. Data that associates each factor with the film thickness is recorded in the form 100 as past data. After that, each factor is adjusted by trial and error based on the past data while repeating the monitoring work and the comparison work many times. In this way, the coating film can be made close to the target thickness range.

Japanese Patent Application Laid-Open No. 2020-132903 (Figs. 1, 4, etc.)

By the way, the data of the film thickness and each factor are managed by being recorded in the form 100 as past data, as described above. However, the interval for acquiring data is not constant because it is every day or every few days. Moreover, since there are many kinds of factors, it is necessary to determine the factors to be adjusted by trial and error, and it takes time to determine the factors.

It should be noted that the composition of the electrodeposition paint 102 changes moment by moment with the lapse of time even when the equipment is operated under optimum conditions. Therefore, even if the factor to be adjusted is determined and the determined factor is adjusted based on the past data, there is a problem that the thickness range of the coating film cannot be approximated. In addition, in actual equipment, in anticipation of a change in the composition of the electrodeposition paint 102, for example, the electrodeposition tank 101 is operated with a large amount of the electrodeposition paint 102, so the amount of the electrodeposition paint 102 used is There is also a possibility that loss may occur.

The present invention has been made in view of the above problems, and an object of the present invention is to adjust the factors related to the thickness of the coating film without delay, so that the thickness of the coating film formed on the surface of the vehicle body can be adjusted. To provide a film thickness estimating system in electrodeposition coating equipment capable of reducing the loss of electrodeposition coating while reducing the loss of electrodeposition coating.

In order to solve the above problems, the invention according to claim 1 provides an electrodeposition tank that stores an electrodeposition paint and is transported in a state in which a vehicle body is immersed in the electrodeposition paint; A system for estimating the film thickness of the electrodeposition paint for each part of the vehicle body in an electrodeposition coating facility comprising a plurality of electrodes arranged and a transport means for transporting the vehicle body, the system comprising: a learning unit that associates and learns data on composition condition factors, data on the film thickness, and data on adjustment factors of the electrodeposition coating equipment; and a storage unit that stores the data associated by the learning unit as learned data. and an estimating unit for estimating the film thickness for each part of the vehicle body based on the learned data.

In the first aspect of the invention, the learning unit learns by associating the data regarding the composition condition factor of the electrodeposition paint, the data regarding the film thickness, and the data regarding the adjustment factor of the electrodeposition coating equipment, and the estimation unit learns Based on the data (learned data) associated with each part, the film thickness is estimated for each part of the vehicle body. In this case, since the film thickness can be estimated with almost no time delay after the data is associated, it is possible to prevent the composition of the electrodeposition paint from changing significantly before estimating the film thickness. As a result, even if the composition of the electrodeposition paint changes with the passage of time, the paint film formed on the surface of the car body can be formed within the desired thickness range, improving the paint quality of the car body. do. Moreover, since it is not necessary to add a large amount of the electrodeposition paint to the electrodeposition tank in anticipation of changes in the composition of the electrodeposition paint, the loss of the electrodeposition paint can be reduced.

Examples of the electrodeposition paint include cationic electrodeposition paint and anionic electrodeposition paint, but from the viewpoint of rust prevention, it is preferable to use the cationic electrodeposition paint.

In addition, the composition condition factor of the electrodeposition paint is preferably at least one selected from acid concentration (MEQ), NV (nonvolatile content), ash content, paint conductivity and coulombic efficiency (claim 2), Acid concentration is particularly preferred. This is because, as a result of intensive research by the inventors of the present application, it was confirmed that, among the compositional factors of the electrodeposition paint, the acid concentration in particular has a high correlation with the thickness of the coating film. However, since the acid concentration cannot be measured in real time, the inventors of the present application searched for a parameter linked to the acid concentration that can be measured in real time. Confirmed to be linked. From this fact, by measuring the fluctuation of the current value, it is possible to estimate the acid concentration of the electrodeposition paint, and thus the thickness of the coating film.

Furthermore, the adjustment factor of the electrodeposition coating equipment is preferably at least one selected from the current value of the current applied to the vehicle body, the liquid temperature of the electrodeposition paint, and the energization time of the electrodes (Claim 3).

As described in detail above, according to the invention of claims 1 to 3, by adjusting the factors related to the thickness of the coating film without delay, the thickness of the coating film formed on the surface of the vehicle body is achieved. It is possible to make it within the range and to reduce the loss of the electrodeposition paint.

1 is a schematic cross-sectional view showing an electrodeposition coating facility in this embodiment; FIG. Explanatory drawing which shows the adjustment method of a film thickness. Graph showing changes in acid concentration (MEQ) and current value. A table showing administrative data. Graph showing how missing values are interpolated. Explanatory drawing which shows the adjustment method of the film thickness in a prior art.

An embodiment embodying the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, the film thickness estimating system 1 of the present embodiment uses the electrodeposition coating equipment 10 to calculate the electrodeposition paint P1 for each part (for example, the door outer plate portion, the door inner plate portion, etc.) of the vehicle body W1. It is a system for estimating the film thickness of The electrodeposition coating facility 10 includes an electrodeposition bath 11 that stores an electrodeposition paint P1. In the electrodeposition tank 11, the vehicle body W1 is transported while being immersed in the electrodeposition paint P1. The electrodeposition bath 11 is composed of a bath top portion 12 forming a ceiling portion of the electrodeposition bath 11 , a bath bottom portion 13 forming a floor portion of the electrodeposition bath 11 , and two side walls 14 . The electrodeposition bath 11 is also provided with a loading port 15 for loading the vehicle body W1 into the electrodeposition bath 11 and a loading port 16 for transporting the vehicle body W1 out of the electrodeposition bath 11. . The electrodeposition paint P1 of the present embodiment is a paint using, for example, a cationic electrolytic resin as a main component of the vehicle.

The electrodeposition coating facility 10 also includes a conveyor 21 (conveying means) for conveying the vehicle body W1 in the conveying direction (the right direction in FIG. 1). The conveyor 21 carries the vehicle body W1 into the electrodeposition tank 11 through the inlet 15 while lowering it, and carries it out of the electrodeposition tank 11 through the outlet 16 while raising the vehicle body W1. there is The conveyor 21 includes a rail 22 extending in the transport direction and a plurality of hanger rails 23 provided on the rail 22 for suspending and transporting the vehicle body W1. Furthermore, each hanger rail 23 is provided with a pulse transmitter 24 that periodically transmits a pulse signal.

As shown in FIG. 1, a plurality of electrodes 31 are arranged in the electrodeposition bath 11 . Each electrode 31 consists of side electrodes 32 and 33 installed on the side walls 14 of the electrodeposition tank 11 and a bottom electrode 34 installed on the tank bottom 13 of the electrodeposition tank 11 . The side electrodes 32 are shaped like strip plates extending in the vertical direction, and are arranged at intervals along the transport direction of the vehicle body W1. Further, the side electrode 33 and the bottom electrode 34 are shaped like strip plates extending in the transport direction, and are spaced apart along the transport direction. A cable 35 (see FIG. 2) is connected to each electrode 31 . Each cable 35 is pulled out of the electrodeposition tank 11 .

As shown in FIG. 2, the electrodeposition coating facility 10 further comprises additive adding means 41 and liquid component reducing means 44 . The additive adding means 41 is for adding an additive 42 to the electrodeposition paint P1. In addition, the additive 42 of this embodiment is an organic acid such as citric acid, ascorbic acid, or tartaric acid. The additive adding means 41 includes a tank (not shown), an additive supply valve (not shown), and an additive supply nozzle 43 on an additive supply pipe (not shown) communicating with the electrodeposition tank 11 . become. The tank is adapted to deliver additive 42 . An additive supply valve is located downstream of the tank to switch the additive supply line to an open or closed state. The additive supply valve can supply the additive 42 sent out from the tank into the electrodeposition bath 11 when switched to the open state. Further, the additive supply nozzle 43 is arranged above the electrodeposition tank 11 so as to supply the additive 42 into the electrodeposition tank 11 .

As shown in FIG. 2, the liquid component reducing means 44 is for reducing the liquid component of the electrodeposition paint P1. The liquid component reducing means 44 includes an electrodeposition paint discharge port 46, an electrodeposition paint discharge valve 47, a filtering device 48, and an electrodeposition paint supply port 49 on a circulation pipe 45 that communicates with the electrodeposition tank 11 at both ends. become. The electrodeposition paint discharge port 46 is arranged in the tank bottom 13 of the electrodeposition tank 11 so as to discharge the electrodeposition paint P1 to the outside of the electrodeposition tank 11 . The electrodeposition paint discharge valve 47 is arranged downstream of the electrodeposition paint discharge port 46 and switches the circulation pipe 45 between an open state and a closed state. The electrodeposition paint discharge valve 47 can discharge the electrodeposition paint P1 to the outside of the electrodeposition tank 11 when switched to the open state. The filtering device 48 is arranged downstream of the electrodeposition paint discharge valve 47 and comprises a filter for separating the filtrate from the electrodeposition paint P1. In addition, the filter of this embodiment is a UF (ultrafiltration membrane) membrane. Further, the separation of the filtrate reduces the liquid component of the electrodeposition paint P1, and the filtrate separated from the electrodeposition paint P1 is discarded. The electrodeposition paint supply port 49 is arranged downstream of the filtering device 48 so as to supply the electrodeposition paint P1 from which the filtrate has been separated into the electrodeposition bath 11 .

Next, the electrical configuration of the electrodeposition coating equipment 10 will be described.

As shown in FIG. 1, the electrodeposition coating facility 10 is provided with a personal computer 50, and the personal computer 50 is provided with a control device 51 for centrally controlling the entire facility. The control device 51 is composed of a CPU 52, a ROM 53, a RAM 54, an input/output circuit, and the like. Note that the CPU 52 has functions as a learning section 55 and an estimation section 56 . A keyboard 57 of the personal computer 50 and a display 58 of the personal computer 50 are electrically connected to the CPU 52 . Further, the CPU 52 is electrically connected to the conveyor 21, each pulse transmitter 24, the additive supply valve and the electrodeposition paint discharge valve 47, and controls them by various drive signals. In this embodiment, each electrode 31 is electrically connected to the CPU 52 by connecting each electrode 31 to the control device 51 via the cable 35 . Further, the pulse signal output from each pulse transmitter 24 is periodically input to the CPU 52 . Further, the ROM 53 is preset (stored) with production tact time information indicating the work time for electrodeposition coating of each vehicle body W1. Further, the ROM 53 stores electrode distance information indicating the distance from the reference position S1 near the entrance 15 of the electrodeposition bath 11 to the side electrodes 32 for each of the plurality of side electrodes 32 .

Next, the electrodeposition coating method by the electrodeposition coating equipment 10 will be described.

First, the CPU 52 outputs a drive signal to the conveyor 21 to continuously carry the vehicle bodies W1 (the hanger rails 23) into the electrodeposition tank 11 through the carry-in opening 15 and the electrodeposition tank through the carry-out opening 16. 11 The vehicle body W1 is continuously carried out to the outside. Then, when the vehicle body W1 carried into the electrodeposition bath 11 is immersed in the electrodeposition paint P1, current is applied to the vehicle body W1 from each electrode 31 arranged in the electrodeposition bath 11, and the vehicle body W1 is electrodeposited. painting is done. As a result, a coating film is formed on the surface of the vehicle body W1.

If the thickness of the coating film is within the targeted range, the electrodeposition coating is continued without any particular adjustment work. However, since the composition of the electrodeposition paint P1 changes with the passage of time, if the electrodeposition coating is continued, the thickness of the coating film may fluctuate and deviate from the intended thickness range. Therefore, the CPU 52 performs processing for estimating the film thickness of the electrodeposition paint P1 for each portion of the vehicle body W1. Note that the estimation of the film thickness is performed periodically (every day in this embodiment).

Specifically, first, the CPU 52 calculates the current positions of a plurality of (here, six) vehicle bodies W1 immersed in the electrodeposition paint P1. Specifically, the CPU 52 acquires production tact time information stored in the ROM 53 . In addition, the CPU 52 determines the number of pulse signals (pulse number) output from the corresponding pulse transmitter 24 until the vehicle body W1 (hanger rail 23) moves from the reference position S1 (see FIG. 1) to the current position. to count. The number of pulses is counted for all vehicle bodies W1 immersed in the electrodeposition paint P1. Then, the CPU 52 calculates the moving distance of each vehicle body W1 from the reference position S1, that is, the current position of each vehicle body W1, based on the counted number of pulses. Further, the CPU 52 calculates the residence time (the time during which each vehicle body W1 is immersed in the electrodeposition paint P1) in the electrodeposition tank 11 based on the current position of each vehicle body W1.

Next, the CPU 52 measures (monitors) the current value of the current applied from the electrode 31 (side electrode 32) to each vehicle body W1 (see FIG. 2). Specifically, the CPU 52 selects one vehicle body W1 from a plurality of vehicle bodies W1 immersed in the electrodeposition paint P1. Next, the CPU 52 selects the electrode distance information in which the distance from the reference position S1 to the side electrode 32 is the closest distance to the movement distance of the selected vehicle body W1 among the plurality of electrode distance information stored in the ROM 53. select. Then, the CPU 52 outputs a drive signal to an ammeter (not shown) to measure the current value of the current applied to the vehicle body W1 from the side electrode 32 corresponding to the selected electrode distance information. After that, the measurement of the current value is similarly performed on the other vehicle body W1 immersed in the electrodeposition paint P1. Incidentally, the data regarding the current value is stored in the RAM 54 for each vehicle body W1.

In addition, the CPU 52 estimates (monitors) the acid concentration (MEQ) of the electrodeposition paint P1 based on the variation in the measured current value (see FIG. 2). The inventors of the present application have newly confirmed that the fluctuation of the current value and the fluctuation of the acid concentration are synchronized (see FIG. 3). Therefore, the CPU 52 can estimate the acid concentration of the electrodeposition paint P1 if the variation in the current value is known. Data on the acid concentration is stored in the RAM 54 for each vehicle body W1.

Then, the vehicle body W1 whose acid concentration has been estimated and whose electrodeposition coating has been completed is carried out of the electrodeposition tank 11 and then dried in a drying oven (not shown). After that, the film thickness of the electrodeposition paint P1 for each part of the vehicle body W1 is measured (monitored) by the film thickness meter 61 (see FIG. 2). Since the number of vehicles (vehicle bodies W1) produced in the electrodeposition coating facility 10 of this embodiment reaches several hundred thousand per year, it is difficult to measure the film thickness for each part of all the vehicle bodies W1. . Therefore, in this embodiment, the leading vehicle body W1 (the vehicle body W1 to be painted first) is selected from among the plurality of vehicle bodies W1 to be painted on the film thickness measurement day, and the film thickness of each part of the selected vehicle body W1 is calculated. to measure. That is, the measurement of the film thickness is performed at the same timing (for example, at the Nth unit after the start of coating, or after N minutes after the start of coating) on all measurement days. The film thickness meter 61 is not particularly limited, but may be, for example, an electromagnetic film thickness meter, an overcurrent film thickness meter, an infrared film thickness meter, an ultrasonic film thickness meter, a spectral interferometric film thickness meter, or the like. can be appropriately selected from among and used. Also, the film thickness gauge 61 is connected to the personal computer 50 via a cable (not shown). Therefore, data on the measured film thickness is transmitted to the personal computer 50 via a cable and stored in the RAM 54 for each portion of the vehicle body W1.

Then, the learning unit 55 of the CPU 52 stores data on the acid concentration (acid concentration data), data on the film thickness (film thickness data), which are the composition condition factors of the electrodeposition paint P1, and adjustment factors of the electrodeposition coating equipment 10. Data related to a certain current value (current value data) is associated and learned. Specifically, first, the learning unit 55 integrates the film thickness data stored in the RAM 54 with the current value data and the acid concentration data also stored in the RAM 54 .

FIG. 4 is a table showing management data. This table has columns of "ID", "production date and time", and "objective variable". The "ID" column displays the manufacturing number given to each vehicle body W1, and the "production date and time" column indicates the date and time when the electrodeposition coating for each vehicle body W1 was completed (specifically, when the vehicle body W1 was The date and time when it was taken out of the electrodeposition tank 11) is displayed. The "ID" and "production date and time" columns are associated with data (current value data and acid concentration data) of about 10,000 vehicle bodies W1 produced in one week. Further, film thickness data is recorded in part of the column of "objective variable". For example, when the film thickness data for March 5, 2020 is obtained, the film thickness data (objective variable A0) is recorded in the "objective variable" column at the beginning of the date (ID is "1"). be done. Thereby, the film thickness data is integrated with the current value data and the acid concentration data.

Although the current value data and the acid concentration data exist for the same number as the number of vehicles W1 produced, the film thickness data is for about 7 vehicles out of about 10,000. , the learning by the learning unit 55 cannot be performed with high accuracy. Therefore, the learning unit 55 performs a process of interpolating missing values for the input film thickness data. Specifically, each time new film thickness data (for example, objective variable A1 shown in FIG. 4) is obtained, the learning unit 55 adds new film thickness data (objective variable A1 ) and the film thickness data (objective variable A0) input one day before the objective variable A1 is drawn. As a result, the missing value (specifically, the film thickness data of the vehicle body W1 whose ID is 2 to 1429) between the objective variable A0 and the objective variable A1 is interpolated. If there is a clear correlation between the film thickness data and the observed data (current value data and acid concentration data), missing values are interpolated using a conventionally known regression equation based on a statistical method.

After that, by comparing the film thickness data and the observed data, the learning unit 55 obtains data about "to what extent the current value and the acid concentration should be set to achieve the desired film thickness." new can be obtained. Then, the learning unit 55 stores the obtained data in the RAM 54 as learned data (past data). That is, the RAM 54 functions as a "storage section".

Further, after the learned data is stored in the RAM 54, if there is a current value included in the observation data (current value data) that is outside a certain range (for example, see E1 in FIG. 3), the CPU 52 Remove current values as outliers. Accompanying this, the learned data including abnormal values are also removed. In the present embodiment, when the conveyor 21 stops, the current is applied to the vehicle body W1 for a longer time than usual, the hanger rail 23 is an empty hanger on which the vehicle body W1 is not suspended, or the current is applied to the vehicle body W1. If the integrated amount of the current value is 40% or less of the average due to malfunction of the electrodeposition coating equipment 10, the current value included in the data is removed as an abnormal value. That is, the CPU 52 also functions as a current abnormal value determination removing means.

On the other hand, if there is no abnormal value in the current value, the CPU 52 controls the display 58 to display the estimation results of the film thickness and acid concentration based on the learned model preset in the ROM 53 . Note that in the present embodiment, not only the current values (estimated values) of the film thickness and acid concentration, but also the past changes are displayed. The display of the estimation result is updated in real time each time the learned data is stored in the RAM 54 .

Next, the estimating section 56 of the CPU 52 estimates the film thickness for each part of the vehicle body W1 based on the learned data stored in the RAM 54 . Specifically, first, the estimator 56 estimates an appropriate voltage value to be applied from the side electrode 32 to the vehicle body W1. An appropriate voltage value is determined from learned data stored in the RAM 54 (specifically, current value data and film thickness data included in the learned data). The estimation unit 56 also estimates an appropriate acid concentration of the electrodeposition paint P1. An appropriate acid concentration is determined from learned data stored in the RAM 54 (specifically, acid concentration data and film thickness data included in the learned data).

After that, the CPU 52 controls the display 58 to display recommended setting conditions for the side electrode 32 and the electrodeposition paint P1 in order to set the thickness of the coating film within the target range. Specifically, the display 58 displays the predicted value of the film thickness for each part of the vehicle body W1. The display 58 also displays a recommended voltage value applied from the side electrode 32 to the vehicle body W1, a recommended acid concentration value, a recommended input amount of the additive 42, and a recommended discarded filtrate amount. be.

After that, the CPU 52 causes the side electrode 32 to apply a voltage to the vehicle body W1 based on the determined appropriate voltage value. As a result, the coating film formed on the surface of the vehicle body W1 is adjusted so as to approach the target thickness range. It is generally known that the film thickness tends to increase as the voltage value increases. Therefore, it can be said that there is a positive correlation between the voltage value and the film thickness.

In addition, the CPU 52 adjusts the electrodeposition paint P1 to the determined appropriate acid concentration. For example, when the acid concentration is lowered and the acid is reduced, the repulsion between the paint particles contained in the electrodeposition paint P1 is weakened, and the particles tend to aggregate. As a result, the coulombic efficiency (amount of deposition per coulomb) is higher than when the acid concentration is high, so that the electrodeposition paint P1 is easily deposited on the surface of the vehicle body W1 with a small amount of electricity. Therefore, under the same energization conditions, an excessive film thickness is generated. Therefore, it can be said that there is a negative correlation between the acid concentration and the film thickness.

Therefore, when the acid concentration is low, the CPU 52 adjusts so that the acid concentration is high. Specifically, the CPU 52 operates the additive adding means 41 to adjust the acid concentration. Specifically, first, the CPU 52 outputs a drive signal to the additive supply valve. As a result, the additive supply valve is switched to an open state, and the additive 42 in the tank passes through the additive supply pipe and is filled from the additive supply nozzle 43 into the electrodeposition bath 11 . That is, the adjustment work for increasing the acid concentration is the work of automatically adding (throwing) the additive 42 to the electrodeposition paint P1 in the electrodeposition tank 11 .

On the other hand, when the acid concentration increases and the acid increases, a large amount of current is required for deposition. As a result, electrolysis increases and more gas is generated. In addition, since a large amount of current is required to deposit the electrodeposition paint P1, the coulombic efficiency is lowered. In this case, deposition takes a long time, making it difficult to secure a film thickness.

Therefore, when the acid concentration is estimated to be high, the CPU 52 adjusts the acid concentration to be low. Specifically, the CPU 52 reduces the acid concentration by operating the liquid component reducing means 44 to reduce the liquid component of the electrodeposition paint P1. Specifically, first, the CPU 52 outputs a drive signal to the electrodeposition paint discharge valve 47 . As a result, the electrodeposition paint discharge valve 47 is switched to an open state, and the electrodeposition paint P1 is discharged from the electrodeposition paint discharge port 46 to the outside of the electrodeposition tank 11, passes through the circulation pipe 45, and is led to the filtering device 48. be killed. The filtering device 48 separates the filtrate from the electrodeposition paint P1. The separation of the filtrate reduces the liquid component of the electrodeposition paint P1, and the filtrate separated from the electrodeposition paint P1 is discarded. After that, the electrodeposition paint P1 from which the filtrate has been separated is supplied from the electrodeposition paint supply port 49 into the electrodeposition bath 11 . That is, the adjustment work for lowering the acid concentration is the work for automatically reducing the liquid component of the electrodeposition paint P1.

Therefore, according to this embodiment, the following effects can be obtained.

(1) In the present embodiment, the learning unit 55 acquires data on the acid concentration, data on the film thickness, which are the composition condition factors of the electrodeposition paint P1, and data on the current value, which is the adjustment factor of the electrodeposition coating equipment 10. Based on the data associated by the learning unit 55 (learned data), the estimating unit 56 estimates the film thickness for each part of the vehicle body W1. In this case, since the film thickness can be estimated with almost no time delay after the data is associated, the composition of the electrodeposition paint P1 is prevented from greatly changing before estimating the film thickness. As a result, even if the composition of the electrodeposition paint P1 changes with the passage of time, the thickness of the coating film formed on the surface of the vehicle body W1 can be within the target range. Improve quality. Moreover, if the learning section 55 has many chances to learn, the film thickness of each part of the vehicle body W1 is optimized, so that the coating quality is further stabilized. Further, since it is not necessary to add a large amount of the electrodeposition paint P1 into the electrodeposition tank 11 in anticipation of changes in the composition of the electrodeposition paint P1, the loss of the electrodeposition paint P1 can be reduced.

(2) In the present embodiment, when the acid concentration of the electrodeposition paint P1 is high, the CPU 52 performs control to reduce the liquid component of the electrodeposition paint P1 based on the learned data, thereby lowering the acid concentration. are adjusted so that As a result, the acid concentration is lowered and the amount of acid is reduced, so that the amount of current required for depositing the electrodeposition coating material P1 is reduced, and electrolysis is reduced. As a result, the generation of gas is reduced, so that the generation of gas pins (gas pinholes) in the coating film can be prevented, and the coating quality is improved.

(3) The electrodeposition coating is applied to a large number of vehicle bodies W1 (for example, approximately 10,000 vehicles per week). Therefore, measuring the film thickness of each portion of the vehicle body W1 is not realistic because it requires a lot of labor. Therefore, in the present embodiment, the film thickness is measured only for the vehicle body W1 to be painted first on the film thickness measurement day, and each time a new film thickness is measured, a new film thickness (for example, the objective variable A1 ) and the previously measured film thickness (eg objective variable A0) are automatically interpolated (see FIGS. 4 and 5). In other words, even if the vehicle body W1 is not measured for the film thickness, the film thickness data is automatically given. Thickness can be easily estimated.

(4) In the present embodiment, when the current value measured by the ammeter (not shown) is outside a certain range (see E1 in FIG. 3), the CPU 52 (learning unit 55) , are removed as abnormal values that are far from being possible, and the remaining current values (current value data) are obtained. As a result, the estimation unit 56 can accurately estimate the film thickness for each part of the vehicle body W1 based on the learned data including the current value data.

In addition, you may change the said embodiment as follows.

- In the above embodiment, the composition condition factor of the electrodeposition paint P1 included in the learned data was the acid concentration (MEQ). However, compositional parameters may be other such as NV (nonvolatile content), ash, paint conductivity and coulombic efficiency. In general, it is known that as the NV becomes higher, the film thickness tends to increase because the amount of the resin component remaining in the coating film after drying increases. Therefore, it can be said that there is a positive correlation between NV and film thickness. It is also known that as the ash content increases, the pigment content of the electrodeposition paint P1 increases, the film resistance increases, and the throwing power improves, so that the film thickness tends to increase. . Therefore, it can be said that there is also a positive correlation between the ash content and the film thickness. Furthermore, it is known that as the electrical conductivity of the coating material increases, the coating film tends to be formed more easily, so that the film thickness tends to increase. Therefore, it can be said that there is also a positive correlation between the paint conductivity and the film thickness. It is also known that as the coulombic efficiency increases, it becomes easier to deposit the electrodeposition paint P1 on the surface of the vehicle body W1 with a smaller amount of electricity, so that the film thickness tends to increase. Therefore, it can be said that there is also a positive correlation between the coulombic efficiency and the film thickness. Two or more of acid concentration, NV, ash content, paint conductivity, and coulombic efficiency may be selected and used as composition condition factors.

However, NV, ash content, paint conductivity, and coulombic efficiency among the above composition condition factors are obtained by collecting a sample of the electrodeposition paint P1 from the electrodeposition tank 11 and performing a component analysis of the collected sample at an external institution. It takes time to get the results because it is the first to be obtained. The conductivity of paint can be measured by using a conductivity meter. However, if the conductivity meter is permanently installed in the electrodeposition coating equipment 10, a stable measurement value cannot be obtained due to contamination of the sensor or the like. Therefore, the compositional condition factor is preferably the acid concentration.

- In the above embodiment, the adjustment factor of the electrodeposition coating equipment 10 included in the learned data was the current value of the current applied to the vehicle body W1. However, other adjustment factors such as the liquid temperature of the electrodeposition paint P1 and the energization time of the side electrode 32 may be used. It is generally known that the film thickness tends to increase as the liquid temperature increases. Therefore, it can be said that there is a positive correlation between the liquid temperature and the film thickness. Also, it is known that the film thickness tends to increase as the energization time increases. Therefore, it can be said that there is also a positive correlation between the ash content and the film thickness. As the adjustment factor, two or more of the current value, the liquid temperature, and the energization time may be selected and used.

In the above embodiment, the current value data is obtained by measuring the current applied to the vehicle body W1 with an ammeter (stored in the RAM 54), and the acid concentration data is obtained by estimating from the fluctuation of the current value. The film thickness data was obtained by measuring the film thickness of the electrodeposition paint P1 using a film thickness meter 61. FIG. However, these data may be recorded and managed on a form (paper) and stored in the RAM 54 by manual input by the operator using the keyboard 57 .

- In the above-described embodiment, the current value data, the acid concentration data, and the film thickness data are obtained every day, but these data may be obtained every few days. In addition, the film thickness data was obtained by measuring the film thickness of the vehicle body W1 that was painted first on the film thickness measurement day, but the film thickness data of the vehicle body W1 that was painted second or later on the measurement day was It may be obtained by measuring the thickness. Furthermore, although the film thickness data was obtained only once a day, it may be obtained two or more times a day.

- In the above embodiment, the liquid component of the electrodeposition paint P1 is reduced by separating the filtrate from the electrodeposition paint P1 using the filtering device 48, but the liquid component may be reduced by other methods. . For example, the liquid component may be reduced by evaporating the liquid component of the electrodeposition paint P1, or the liquid component may be reduced by separating the filtrate from the electrodeposition paint P1 using a centrifuge. good. In the above embodiment, the acid concentration is adjusted to be low by reducing the liquid component of the electrodeposition paint P1. can be adjusted to lower

Next, in addition to the technical ideas described in the claims, technical ideas grasped by the above-described embodiments are listed below.

(1) In any one of claims 1 to 3, the data on the film thickness is obtained by selecting a specific vehicle body from among a plurality of the vehicle bodies to be painted on the day when the film thickness is measured, and selecting the selected vehicle body. A film thickness estimating system for electrodeposition coating equipment characterized by being obtained by measuring the film thickness of a vehicle body.

(2) In any one of claims 1 to 3, each time the data on the film thickness is newly obtained, the learning unit adds the data on the film thickness obtained this time and the data on the film thickness obtained last time. A film thickness estimation system for electrodeposition coating equipment, characterized by performing a process of interpolating a missing value between data relating to thickness.

(3) In claim 3, the adjustment factor for the electrodeposition coating equipment is a current value of the current applied to the vehicle body, and the current value included in the data on the adjustment factor for the electrodeposition coating equipment is within a certain range. A film thickness estimation system for an electrodeposition coating facility, comprising a current abnormal value determination and removal means for removing a current value outside the predetermined range as being an abnormal value when there is an outside value.

(4) In any one of claims 1 to 3, the conveying means includes rails and a plurality of hanger rails provided on the rails for suspending and conveying the vehicle body, and each of the hanger rails A pulse transmitter for periodically transmitting a pulse signal is provided, and based on the number of the pulse signals transmitted from the pulse transmitter, the moving distance of the vehicle body suspended on the hanger rail from a reference position is calculated. A film thickness estimation system in an electrodeposition coating facility, characterized by:

(5) In any one of claims 1 to 3, the compositional condition factor of the electrodeposition paint is acid concentration, and an additive adding means for adding an additive to the electrodeposition paint; a liquid component reducing means for reducing the liquid component of the paint, wherein the adjustment work for increasing the acid concentration is the work for adding the additive to the electrodeposition paint, and the adjustment work for reducing the acid concentration. A system for estimating film thickness in an electrodeposition coating facility, characterized in that the operation is to reduce the liquid component of the electrodeposition coating. In this case, the additive adding means and the liquid component reducing means are operated to automatically perform the work of adding the additive to the electrodeposition paint and the work of reducing the liquid component of the electrodeposition paint. Therefore, the operator does not have to perform the work of adding the additive or the work of reducing the liquid component, thereby reducing the work load on the worker.

Reference Signs List 1 Film thickness estimation system 10 Electrodeposition coating equipment 11 Electrodeposition tank 21 Conveyor 31 as transport means Electrode 54 RAM as storage unit
55... Learning part 56... Estimating part P1... Electrodeposition paint W1... Vehicle body

Claims (3)

An electrodeposition bath that stores an electrodeposition paint and transports a vehicle body in a state of being immersed in the electrodeposition paint; a plurality of electrodes arranged in the electrodeposition bath; and a transport means that transports the vehicle body. A system for estimating the film thickness of the electrodeposition paint for each part of the vehicle body in an electrodeposition coating facility comprising:
a learning unit that learns by associating data on the compositional condition factors of the electrodeposition paint, data on the film thickness, and data on adjustment factors of the electrodeposition coating equipment;
a storage unit that stores the data associated by the learning unit as learned data;
and an estimating unit for estimating the film thickness for each part of the vehicle body based on the learned data. 2. The compositional factor of the electrodeposition paint is at least one selected from acid concentration (MEQ), nonvolatile content (NV), ash content, paint conductivity and coulombic efficiency. film thickness estimation system for electrodeposition coating equipment. 3. The adjusting factor of the electrodeposition coating equipment is at least one selected from a current value of the current applied to the vehicle body, a liquid temperature of the electrodeposition paint, and an energization time of the electrodes. 3. A film thickness estimation system in the electrodeposition coating facility according to 1 or 2.

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