JPH059795A - Electrodeposition coating method and device - Google Patents

Abstract

(57) [Summary] [Purpose] A uniform film thickness can be obtained even when coating objects having different coating areas at the same time, and a uniform film thickness can be obtained even in a portion having low throwing power. When the article to be coated 4 is conveyed by the conveyor 21, the recognition means 5 recognizes the type of the article to be coated 4, and the control means 22
Output to. The inside of the electrodeposition tank is divided into first, second and third coating regions 6, 7 and 8 along the transport direction, and the control means 22 controls the coating voltage according to the type of the article 4 to be transported. The voltage is applied so that it increases as it goes downstream.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition coating method and apparatus for performing electrodeposition coating by immersing a plurality of objects to be coated having different coating areas in an electrodeposition tank containing an electrodeposition coating material.

[0002]

2. Description of the Related Art Normally, when an object to be coated such as an automobile body is immersed in an electrodeposition tank containing an electrodeposition coating material for electrodeposition coating, a power source is installed in parallel along the electrodeposition tank. An electrodeposition coating film is formed on the surface of the article to be coated by applying a voltage between the article and the article to be coated.

[0003]

In the electrodeposition coating of automobile bodies as described above, it is required to control the thickness of the electrodeposition coating film within a certain range (for example, 20 μm to 30 μm).

However, in a coating line for automobiles, large and small automobile bodies such as large and small automobiles are mixed and conveyed. Therefore, for example, a large automobile with a large area can be energized if the electricity is applied according to the film thickness of the small automobile with a small coating area. Is too thin. In other words, the size of the article to be dipped in the electrodeposition tank varies depending on the type of the article to be coated, and if the coating areas are not uniform, the film thickness cannot be accurately controlled. .

Therefore, conventionally, when coating objects of different sizes, each of the objects having the same size is conveyed as a lot unit to the electrodeposition tank, and the voltage is changed for each lot unit. A method of coating by coating, or a method of alternately transporting objects to be coated having different sizes and coating under the same electrodeposition conditions has been considered. However, each method has a problem that productivity is reduced or economic efficiency is reduced.

The object of the present invention is to solve the above-mentioned problems,
An electrodeposition coating method that can always obtain a uniform film thickness even if the coating materials with uneven coating areas are alternately transported and subjected to electrodeposition coating, and a uniform film thickness can be obtained even in a portion with low throwing power. And to provide a device.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides an electrodeposition coating method for carrying out electrodeposition coating while transporting an object to be coated into a electrodeposition vessel containing an electrodeposition coating material by a transport means. Is
A plurality of electrodeposition coating areas are provided along the transportation route of the coating material by the transporting means, and when the coating material passes through each electrodeposition coating area, the coating material passing through the areas is sequentially subjected to each area. The electrodeposition coating method is characterized in that a relatively high voltage is applied.

Further, according to the present invention, an electrodeposition tank containing an electrodeposition coating material, a conveying means for conveying an article to be coated while immersing it in the electrodeposition tank, and a conveyance route for the article to be coated by the conveying means are provided. A plurality of electrodes to which a voltage is applied between the plurality of electrodes for forming a plurality of electrodeposition coating areas to be arranged, a recognition means for recognizing the type of the object to be coated, the object to be coated and the electrodeposition coating In response to the power supply for individually applying a voltage between the electrodes for each area and the output of the recognition means, the voltage in the electrodeposition coating area through which the article is passing corresponds to the type of the article. And a control means for controlling the output voltage of the power source so that the voltage becomes higher toward the downstream side in each region.

[0009]

According to the present invention, a plurality of electrodeposition coating regions are provided in the electrodeposition coating method for performing electrodeposition coating while the object to be coated is conveyed by the conveying means into the electrodeposition tank containing the electrodeposition coating material. , Provided in the electrodeposition tank along the transportation route of the article to be coated means, and when the article to be coated passes through each electrodeposition coating area, each area with respect to the article to be coated passing therethrough A high voltage is sequentially applied every time.

According to the invention, the electrodeposition coating apparatus includes an electrodeposition tank containing an electrodeposition coating material, a transfer means for transferring an object to be coated while being immersed in the electrodeposition tank, and a transfer means for transferring the object. A plurality of electrodes to which a voltage is applied between an object to be coated and a plurality of electrodes for forming a plurality of electrodeposition coating regions arranged along the conveyance path of the object to be coated, and a recognition means for recognizing the type of the object to be coated , A power source for individually applying a voltage between the object to be coated and the electrode for each electrodeposition coating area, and the voltage in the electrodeposition coating area through which the object to be coated responds to the output of the recognition means. A control means for controlling the output voltage of the power source so that the voltage becomes higher as it goes to the downstream side for each region corresponding to the type of object to be coated,
A voltage corresponding to the type of the object to be recognized recognized by the recognition means is applied to the object to be coated.

[0011]

FIG. 1 is a view showing an electrodeposition coating apparatus 1 which is an embodiment of the present invention, and FIG. 2 is a suspending member 14 for a coating object 4 and a pair of current collecting bars shown in FIG. It is a figure which shows 11a, 11b. The current collecting bars 11a and 11b may be collectively denoted by reference numeral 11. The electrodeposition tank 2 is filled with the electrodeposition coating material 3 so that the coating object 4 can be conveyed on the electrodeposition tank 2 via the hanging member 14 so that the electrodeposition coating material 3 can be immersed in the electrodeposition coating material 3. A conveyor 21, which is a simple transport means, is installed.

Before the article 4 to be coated on the conveyor 21 is dipped in the electrodeposition coating material 3, the recognition means 5 for the article 4 to be coated is installed. The recognition means 5 recognizes the type and the number of the objects to be coated 4 in response to the video signal from the camera.

A first coating region 6, a second coating region 7 and a third coating region 8 which are electrodeposition coating regions are formed in the electrodeposition tank 2. Three electrodes 9 are suspended in the first coating area 6, and a pair of collector bars 11 are installed above the electrodes 9.

The electrode 9 and the pair of collector bars 11 are connected to an AC power supply 10a, which is a power supply, via a power supply circuit 10b including a rectifier and a power supply adjusting circuit 10c so that the electrode 9 serves as an anode.

The AC power supplied from the AC power supply 10a is rectified and smoothed by the power supply circuit 10b, adjusted by the power supply adjustment circuit 10c to a current and voltage according to the control of the control means 22 described later, and collected. A voltage is applied between the electric bar 11 and the electrode 9.

The pair of current collecting bars 11 is composed of two current collecting bars 11a and 11b as shown in FIG. Supporting pieces 12a and 12b are formed at positions corresponding to the current collecting bars 11a and 11b of the hanging member 14, and the supporting pieces 12a and 12b are formed.
Current collecting terminals 23a and 23b are provided at the ends of b.

The collector terminals 23a and 23b are the collector bars 11.
The lengths of the support pieces 12a and 12b are selected so as to come into contact with the rollers 13a and 1b.
A voltage is applied between the object 4 to be coated and the electrode 9 which are being conveyed by the 3b via the suspending member 14 when the current collecting terminals 23a and 23b contact the current collecting bars 11a and 11b.

An insulating plate 24 made of Teflon or the like is provided between the rollers 13a and 13b of the suspension member 14 and the support pieces 12a and 12b to prevent a voltage from being applied to the conveyor 21.

Also in the second coating area 7, the first coating area 6
Similarly, the three electrodes 15 and the pair of collector bars 16 are connected to the AC power supply 17a, which is a power supply, through the power supply circuit 17b including the rectifier and the power supply adjustment circuit 17c, and also in the third coating area 8. Similar to the first coating area 6, the AC power source 2 in which the three electrodes 18 and the pair of collector bars 19 are power sources
0a is connected via a power supply circuit 20b including a rectifier and a power supply adjustment circuit 20c, and the hanging member 14 that suspends the article 4 is connected to the current collecting bars 16 and 19 with a support piece (not shown). Thus, a voltage is applied between the electrodes 15 and 18 and the corresponding collector bars 16 and 19.

The arrangement of the electrodes 9, 15, 18 and the like is set so that the distance between the electrodes 9, 15, 18 and the article 4 to be coated is a constant value in each of the coating areas 6, 7, 8. The recognition means 5 and the power supply adjustment circuits 10c, 17c, 20c are connected to the control means 22.

The type of the article to be coated 4 as shown in Table 1 and the applied voltage for each of the coating areas 6, 7 and 8 corresponding thereto are inputted to the recognition means 5 in advance.

[0022]

[Table 1]

The recognition means 5 outputs the recognition result of the article to be coated 4 to the control means 22. The control means 22 reads the control voltage according to the recognized type of the article to be coated 4, and the power supply adjusting circuit 10
The applied voltage is adjusted by controlling c, 17c and 20c.

FIG. 3 is a graph showing the relationship between voltage and film thickness and throwing power. The relationship between voltage and film thickness is L1
The relationship between voltage and throwing power is indicated by L2. It has been shown that as the voltage increases, the film thickness increases and the throwing power also improves.

FIG. 4 is a graph showing the relationship between the electrodeposition time and the film thickness and throwing power. The relationship between the electrodeposition time and the film thickness is shown by L3, and the relationship between the electrodeposition time and the throwing power is shown by L4. It has been shown that the longer the electrodeposition time, the thicker the film thickness and the better throwing power.

FIG. 5 is a diagram showing the relationship between time and applied voltage according to an embodiment of the present invention. In the first coating area 6, a voltage of a value is applied, and in the second coating area a
The voltage of b value larger than the value is applied, and the third coating area 8
In, the voltage of c value larger than b value is applied.

FIG. 6 is an example of a flowchart showing an embodiment of the present invention. In step s1, the recognition means 5 recognizes the type of the article 4 to be coated, and the recognition result is output to the control means 22. In step s2, the voltage corresponding to the type of the article 4 recognized by the control means 22 is read.

In step s3, the article to be coated 4 is painted on the coating area 6,
It is judged whether or not it has come to 7, 8 and if it has not come, it returns to step s3, and if it has come to the coating areas 6, 7, 8 the voltage read in step s4 is applied and the process ends.

As described above, according to this embodiment, the article to be coated 4
Since a voltage according to the type can be applied, accurate film thickness control can be performed even when a plurality of types of objects 4 to be coated are simultaneously electrodeposited.

Further, according to the present embodiment, three coating areas 6, 7, 8 are provided in the electrodeposition tank, and a higher voltage is applied as it goes downstream in the transport direction. A relatively low voltage is applied to the first coating area 6 to prevent defective finishes such as tank marks and gas pin holes, and a slightly higher voltage is applied to the second coating area 7 than the first coating area 6. By doing so, the film thickness of the outer plate portion is formed, and by applying a high voltage in the third coating region 8, the film thickness of the portion having low throwing power such as the inner plate portion and the bag structure portion is formed. .

When a high voltage is applied from the beginning, the film thickness becomes thicker and the electrodeposition paint is wasted. However, as described above, after forming the film thickness of the outer plate part, the inner plate part and the bag structure having a low turning property are formed. Since the film thickness will be formed under the coating condition with high throwing power to the inner part, it is possible to form the film thickness on the inner plate part and the bag structure part where it is difficult to apply a constant film thickness. Improves reliability.

In the present embodiment, three electrodes in each coating area are set as one set, but the number of electrodes is not limited to this, and may be one or two or more. Alternatively, the electrodeposition tank may be made of metal and electrically insulated for each electrodeposition coating area, and the metal part of the tank may be used as an electrode.

In addition, even if the voltage changes with the passage of time during the conveyance of a certain electrodeposition coating region during the period in which the object to be coated is conveyed and passes through each electrodeposition coating region. Good.

Similar effects can be obtained in the above-described modified examples.

[0035]

As described above, according to the present invention, in a plurality of electrodeposition coating areas provided on the conveying path of the object to be coated, the voltage for applying the electrodeposition coating to the object to be coated is at the downstream side in the conveying direction. The higher the voltage, the higher the voltage. Therefore, a constant film thickness can be obtained even in a portion having low throwing power, and the reliability of coating is improved.

Further, since the recognition device is provided to recognize the type of the object to be coated and the control means controls to apply the voltage corresponding to the type, even if the objects to be coated having different sizes are simultaneously coated. A constant film thickness can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an electrodeposition apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a diagram showing a set of collector bars 11 shown in FIG.

FIG. 3 is a graph showing the relationship between voltage and film thickness and throwing power.

FIG. 4 is a graph showing the relationship between electrodeposition time and film thickness and throwing power.

FIG. 5 is a diagram showing a relationship between time and applied voltage according to an embodiment of the present invention.

FIG. 6 is an example of a flowchart of an embodiment of the present invention.

[Explanation of symbols]

1 Electro-deposition coating device 2 electrodeposition tank 3 electrodeposition paint 4 coated objects 5 Recognition means 6 First coating area 7 Second painting area 8 third painting area 9,15,18 electrodes 10a, 17a, 20a AC power supply 10b, 17b, 20b power supply circuit 10c, 17c, 20c Power supply adjustment circuit 21 conveyor 22 Control means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuo Kurami             6-1073 God, Minamitsukaguchi-cho, Amagasaki-shi, Hyogo             Inside the East Paint Co., Ltd.

Claims (2)

[Claims] 1. An electrodeposition coating method for carrying out electrodeposition coating while transporting an object to be coated into a electrodeposition tank containing an electrodeposition paint by means of a carrier, wherein the object to be coated by the carrier is located in the electrodeposition tank. A plurality of electrodeposition coating areas are provided along the transport route of the above, and when the object to be coated passes through each electrodeposition coating area, a high voltage is sequentially applied to each of the areas being coated. An electrodeposition coating method characterized by: 2. An electrodeposition tank containing an electrodeposition coating material, a transfer means for transferring an object to be coated while immersing it in the electrodeposition tank, and a transfer means arranged along the transfer path of the object to be coated. A plurality of electrodes to which a voltage is applied between an object to be coated for forming a plurality of electrodeposition coated areas, a recognition means for recognizing the type of the object to be coated, and an object to be coated and an electrodeposition coated area In response to the output of the power source for individually applying a voltage between the electrode and the recognition means, the voltage in the electrodeposition coating region through which the article to be coated passes, the voltage corresponding to the type of the article to be coated An electrodeposition coating apparatus, comprising: a control unit that controls the output voltage of the power source so that the voltage becomes higher toward the downstream side.