JPS61163297A - Electrodeposition coating method and its coating device - Google Patents

Abstract

PURPOSE:To form a thick electrodeposition coated film at a specified site by impressing a DC voltage between a material to be painted dipped in an electro de-position paint in a paint vessel and an electrode on the other side and be tween the material and an auxiliary electrode provided at the specified site of the material to be painted. CONSTITUTION:Plural electrode rods 2 consisting of a metallic material are furnished in a cathionic electrodeposition paint M charged in a paint vessel 1, and connected to the anode side of a voltage supply source 4. An automobile body W carried by an article retainer 7 into the electrodeposition paint M through a conveyor 5 is connected to the cathode side ofthe voltage supply source 4 through frames 7a, 7b, and 7d of the retainer 7, a collector ring 7c, a feeder rail 6, etc. to impress a DC voltage between the electrode 2 and the automobile body W, and an electrodeposition coated film is formed on the surface of the automobile body W. Besides, auxiliary electrodes 10a and 10b are entrained to the vicinity of the site of the automobile body W where thick- film painting is needed, connected to the anode side of the voltage supply source 4 through collector rings 11a and 11b, feeder rails 9a and 9b, etc., and used as the counter electrode of the automobile body W.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides an electrode in an electrodeposition paint and applies a DC voltage between the electrode and the object to be coated supported by an object supporter to form a coating film. The present invention relates to an electrodeposition coating method and a coating device therefor.

[Conventional technology]

In recent years, electrodeposition coating has become widely practiced as a unique coating method. In the electrodeposition coating apparatus used in this case, the paint tank is formed in a boat shape, and the electrodeposition paint is accommodated inside the tank. Further, a conveyor is installed above the paint tank in the longitudinal direction, and a power supply rail connected to one pole of a voltage supply source is installed parallel to the conveyor only above the paint tank.

Further, the container is provided with a plurality of article supports at intervals, which support the article to be coated while being in contact with the power supply rail and carry the article into the electrodeposition paint in the paint tank.

Further, a plurality of electrodes connected to the other pole of the voltage supply source are provided in the electrodeposition paint in the paint tank.

When forming an electrocoating film on the surface of the object to be coated, the object to be coated is supported on the article support and immersed in the electrodeposition paint in the paint tank while the article support is in contact with the power supply rail. .

Along with this, a DC voltage is applied between the object to be coated and the electrodes in the electrodeposition paint, so that an electrodeposition coating film is formed on the surface of the object to be coated.

[Problems to be solved by the invention]

However, in such electrodeposition coating methods, the electrical resistance of the electrodeposition film formed on the surface of the object increases due to electroosmosis, so once the coating thickness reaches a certain level, further electrodeposition is impossible. It is difficult to form a coating film, and due to the coverage, which is one of the characteristics of electrodeposition coating, it is difficult to form an electrodeposition coating film on the areas where existing electrocoating coatings are formed, and the coating is applied only to unpainted areas. The fact is that formation takes place.

For this reason, although it is excellent in uniformly forming an electrocoated film on the surface of the object to be coated, there is a problem in that it is not possible to form an electrodeposited film only on a specific part of the object. .

Therefore, the present invention has been made to solve the above-mentioned problems, and includes providing an auxiliary electrode opposite to the object to be coated in the vicinity of a portion of the object to be coated that requires thick film coating. To do the electrodeposition coating along with the painted object.
The goal is to make the electrodeposition coating film thicker only in specific areas.

[Failure to solve the problem]

That is, in the electrodeposition coating method according to the present invention, the object to be coated supported by the article support is immersed in the electrodeposition coating of a paint tank in which the other electrode is provided as one electrode,
When applying a DC voltage between both electrodes to form an electrodeposited coating film on the surface of the object to be coated, an auxiliary electrode opposite to the object to be coated is attached near the part of the object that requires 411g coating. The coating is applied while applying a DC voltage.

Further, in the electrodeposition coating apparatus according to the present invention, the electrodeposition paint is stored inside the paint tank, and a conveyor is installed above the paint tank in the longitudinal direction, and in parallel with the conveyor. A power supply rail connected to one pole of the voltage supply is installed only above the paint bath.

Furthermore, a plurality of article supports are provided at intervals on the conveyor to support the article to be coated and carry it into the electrodeposition paint while contacting the power supply rail. Furthermore, the electrodeposition paint in the paint tank is equipped with an electrode connected to the other pole of the voltage supply source, which is placed near the parts of the workpiece that are immersed in the paint that require thick film coating. The structure is such that an auxiliary electrode of the same polarity as the electrode in the electrodeposition paint is movably disposed.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the electrodeposition coating method and its coating apparatus according to the present invention will be explained in detail based on the drawings.

(First Embodiment) FIG. 1 shows a side sectional view of a first embodiment of an electrodeposition coating apparatus according to the present invention.

In FIG. 1, ■ is a paint tank formed in a boat shape from a metal material, and inside this paint tank 1, a plurality of electrode rods 2 made of a metal material are arranged on the sides and bottom. One end thereof is connected to the anode side of the voltage supply source 4 by a conductive wire 3a. A cationic electrodeposition paint M is housed inside the paint tank l.

Also, above the paint tank 1, there is a conhair 5 facing in the long plane direction.
are installed, and are sequentially inclined downward from the loading side of the paint tank 1, are formed horizontally above the paint tank 1, and are arranged so as to be sloped sequentially upward on the unloading side. A power supply rail 6 is installed above the conveyor 5 in parallel with the conveyor 5 with an insulating member (not shown) interposed therebetween. It is connected to the cathode side of the source 4.

Further, a plurality of electrically conductive article supports 7 are suspended from the conveyor 5 at appropriate intervals for supporting automobile bodies W as objects to be painted. This article support 7 has frame bodies 7a formed in a gate shape so as to hold the automobile body W, which are arranged in the front and rear, and the frame bodies 7a are connected by horizontal pillars 7b, and the horizontal pillars 7L) It has a structure in which a support part +4'7d is fixed to the center part of which is provided a current collector 7C that contacts the power supply rail 6 and supplies power while rotating.

Further, above the power supply rail 6, there are two support members 8a, 8.
b are arranged at intervals, and the two parts thereof are connected to power supply rails 9a with an insulating member (not shown) interposed therebetween.
, 9b are provided. And one power supply rail 9
a is connected to the anode side of the voltage supply source 4 by a conductor 3C, and the other power supply rail 9b is connected to the anode side of the voltage supply source 4 by a conductor 3d.
9b +J It has the same polarity as the electrode plate 2 provided inside the paint 1.

Furthermore, two auxiliary electrodes 10a and 10b are arranged vertically in the electrodeposition paint M in the paint tank 1, and the upper auxiliary electrode 10a rotates while contacting one of the power supply rails 9a. The lower auxiliary electrode 10b is connected to the other power supply rail 9b.
It is provided on a support 12b having a current collector 11b that rotates and supplies power while contacting the current collector 11b. And both auxiliary electrodes 10
The parts a and 10b are disposed on parts of the automobile body W that require thick film coating, and are adapted to move together with the automobile body W.

First, a method for forming an electrodeposition coating film on the surface of an automobile body W, which is an object to be coated, using the electrodeposition coating apparatus configured as described above will be described.

First, the automobile body W is supported on the article support 7 suspended from the container 5, and auxiliary electrodes are placed above the ceiling section Wa and near the floor section wb of the automobile body W which requires thick film coating. , ]Ob are arranged respectively. Thereafter, the conhair 5 is activated and driven in the direction of the arrow shown in FIG.
When the article support 7 is transported to the power supply rail 6,
The current collector 7c of the article support 7 comes into contact with the article support 7 while rotating, and a cathode potential is generated in the automobile body W.

Subsequently, as the conhair 5 moves, a part of the automobile body W is carried into the electrodeposition paint M charged on the anode side and electrically connected. Then, the automobile body W is coated with electrodeposition paint M.
As the car body W is immersed in the electrocoating paint M, the voltage gradually increases by one step, and when the car body W is completely immersed in the electrocoating paint M, the voltage reaches a predetermined value, and the electrocoating action progresses. Ru. In addition, auxiliary electrodes 10a and 10b are provided near the parts of the ceiling Wa and the floor Wb that require thick film coating, and current collectors 11a and llb provided on each support 12a and 12b are provided. contacts each power supply rail 9a, 9b sequentially. At this time, each of the auxiliary electrodes 10a and 10b is at an anode potential, and electrophoresis in the vicinity of the ceiling Wa and the floor Wb becomes active, promoting the formation of an electrodeposition coating film.

In this state, a DC voltage is applied for a certain period of time, and the automobile body W on which a predetermined electrodeposited coating film has been formed is taken out of the electrocoated paint M and placed near the ceiling Wa and the floor Wb. Each auxiliary electrode 10a, 10b that has been removed is removed. Then, the article support 7 separates from the power supply I/- rule 6, and the application of voltage to the automobile body W is cut off.

In this way, the automobile body W coated with a predetermined electrodeposited film and a thick film on the ceiling Wa and floor Wh is subjected to post-processing steps such as water washing and drying steps together with the article support 7 by the J converter 5. (not shown) and is completed as a complete electrodeposited coating.

(Second Embodiment) FIG. 2 shows a side sectional view of a second embodiment of the electrodeposition coating apparatus according to the present invention.

This second embodiment is similar to the first embodiment in many respects;
Identical parts will be given the same numbers, explanations thereof will be omitted, and only differences will be described.

The difference in the second embodiment is that two voltage supply sources 20 and 21 are provided in the vicinity of the paint tank 1 separately from the voltage supply source 4 connected to the electrode rod 2 in the electrodeposition paint M and the power supply rail 6. A power supply rail 9 is arranged on the anode side of the first voltage supply source 20.
while connecting the conductor i3c of a and the second voltage supply source 2
By connecting the conductive wire 3d of the power supply rail 9b to the anode side of 1, an anode potential can be applied to each of the auxiliary electrodes 10a and 1Ob separately.
By changing the application of the anode voltage to the electrode 10b, the thickness of the electrodeposited coating 1 pattern in areas requiring thick film coating can be freely adjusted.

(Third Embodiment) FIG. 3 shows a side sectional view of a third embodiment of the electrodeposition coating apparatus according to the present invention.

This third embodiment is similar in many respects to the first embodiment;
Identical parts will be given the same numbers, explanations thereof will be omitted, and only differences will be described.

The difference in the third embodiment is that each support member 8a, 8
One power supply rail 9C19d is additionally provided at the −L portion of b with an insulating member (not shown) interposed therebetween, and each of the added power supply rails 9C19d is connected to the conducting wires 3e, 3.
f to the anode side of the voltage supply source 4 which is connected to the electrode rod 2 in the electrodeposition paint M and the power supply rail 6, and connect each of the other two power supply rails 9a and 9b to the conductor 3C13d.
It is connected to the anode side of a separately provided voltage supply source 30.

This makes it possible to apply anode potential to each of the auxiliary electrodes 10a and IOb in two stages from the two voltage supply sources 4.30, smoothing the surface of the electrodeposited film formed on the thick film coating area. be able to.

(Fourth Embodiment) FIG. 4 shows a side sectional view of a fourth embodiment of the electrodeposition coating apparatus according to the present invention.

This fourth embodiment is similar to the third embodiment in many respects;
The same number for the same part (=t L, the explanation is omitted,
Only the differences will be mentioned.

The difference in the fourth embodiment is that four voltage supply sources 40, 41 are provided in the vicinity of the paint tank 1 separately from the voltage supply source 4 connected to the electrode rod 2 in the electrodeposition paint M and the power supply rail 6. ．．
42 and 43, and connect the conductor 3C of the power supply rail 9a to the anode side of the first voltage supply source 40,
The conductive wire 3d of the power supply rail 9b is connected to the anode side of the second voltage supply source 41. Further, the conductor 3f of one power supply rail 9d is connected to the anode side of the third voltage supply source 42, and the conductor 3e of the power supply rail 9c (7) is connected to the anode side of the fourth voltage supply source 43. .

As a result, an anode potential can be applied to each auxiliary electrode 10a, lob separately, and each auxiliary electrode 10a, 10b
By changing the application of the anode voltage to the electrode, it is possible to freely adjust the jV of the electrodeposited film in areas where thick film coating is required. In addition, two voltage supply sources 40, 41, 42, .
43 becomes possible, and the surface of the electrodeposited film formed in areas where thick film coating is required can be smoothed.

In addition, in the above-mentioned first to fourth embodiments,
The automobile body W, which is the object to be painted, is charged as a cathode, and the paint tank 1 is charged.
Although the explanation has been made using a cationic electrodeposition coating in which the electrode rod 2 provided inside is anodically charged, the present invention can also be applied to anionic electrodeposition coating in which the polarity is reversed from that of the cationic electrodeposition coating.

Z [Effects of the Invention] As explained above, in the electrodeposition coating method and the coating apparatus according to the present invention, an auxiliary electrode opposite to the object to be coated is placed near a portion of the object to be coated that requires thick film coating. Since this auxiliary electrode is provided along with the object to be coated during electrodeposition coating, it is possible to make the electrodeposition coating film thick only in specific areas that are characterized by thick coating. .

In addition, in the present invention, the electrodeposition coating can be made into a thick film only in specific parts, so that the electrodeposition coating can be made into a thin film in parts where a thick film is not required. This has the effect of reducing the amount used.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a first embodiment of an electrodeposition coating apparatus according to the present invention. FIG. 2 is a side sectional view showing a second embodiment of the electrodeposition coating apparatus according to the present invention. FIG. 3 is a side sectional view showing a third embodiment of the electrodeposition coating apparatus according to the present invention. FIG. 4 is a side sectional view showing a fourth embodiment of the electrodeposition coating apparatus according to the present invention. 1------Paint tank 2------One electrode rod 4---One voltage supply source 5---One---Conhair 6---------Power supply rail 7--- --- Article support

Claims (2)

[Claims] (1) The object to be coated supported by the article support is immersed in the electrocoating paint of the paint tank provided inside with the other electrode set as one electrode, and a DC voltage is applied between the two electrodes to coat the object. When forming an electrodeposited coating film on the surface of the object to be coated, a DC voltage is applied near the part of the object to be coated that requires thick film coating while accompanied by an auxiliary electrode opposite to the object to be coated. An electrodeposition coating method characterized by painting. (2) A conveyor is constructed above the paint tank containing electrocoating paint in the longitudinal direction, and a power supply rail connected to one pole of a voltage supply source is constructed parallel to the conveyor. A plurality of article supports are provided at intervals to support the article to be coated and carry it into the electrodeposition paint while contacting the power supply rail, and the other voltage supply source is installed in the electrodeposition paint in the paint tank. In addition to providing an electrode connected to the electrode, an auxiliary electrode with the same polarity as the electrode in the electrocoating paint is movably placed near the parts of the object to be dipped in the paint that require thick film paint. Electrodeposition coating equipment characterized by: