JPH0663500A - Car body painting method - Google Patents

Abstract

(57) [Summary] [Purpose] When painting a car body, ensure that it will not be affected even if dust falls. [Composition] A coating method for forming a coating film on the surface of an automobile body 5 while moving the automobile body 5 through a pretreatment process, a coating process and a drying process, wherein the automobile body 5 is moved to each of the above steps. The ceiling portion of the automobile body 5 is downward and the floor portion is upward so as to be coated. With such a structure, even if dust or the like falls in the pretreatment process or the painting process, the dust or the like will fall inside the automobile body as the object to be coated, so touch the paint. There is no.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of painting an automobile body, which is carried out in an automobile manufacturing factory.

[0002]

2. Description of the Related Art Painting of an automobile body is performed after the iron plates formed in the respective parts in the pressing process are welded in the next welding process and after the welding is performed in the subsequent polishing process. This coating process is roughly divided into a pretreatment process for removing dust and oil adhering to the vehicle body, a coating process for performing undercoating and a main coating several times, and a drying process for drying the coating material.

There are various coating methods, and among them, there is the one disclosed in Japanese Utility Model Publication No. 57-66677 for dip coating of electrodeposition coating. As described in this publication, in the past, the article was placed on a hanger with the ceiling of the automobile body, which is the object to be coated, facing upward. Japanese Patent Publication No. 58-33029 discloses spray coating for intermediate coating and top coating. This publication also describes a technique in which a vehicle body, which is an object to be coated, is mounted on a dolly with its ceiling portion facing upward.

[0004]

As described above, in the prior art, when performing dip coating or spray coating on an automobile body, this was all done with the ceiling of the automobile body facing upward. However, in such a case, since many problems as described below occur, it is necessary to pay close attention to prevent them from occurring or a post-process for finishing, which causes problems in productivity and cost. there were. That is, the dust generated in the painting process or brought in from the outside air, the dust adhered to the hanger, and the like fall on the horizontal portion of the outer plate of the automobile body at the time of coating or transportation, and so-called dust defects occur. During dip coating, foreign matter such as iron powder, chemical conversion sludge, and electrodeposition aggregates get on the surface of the outer plate, causing defective spots. At the time of dip coating, the cleaning liquid and the electrodeposition coating are likely to accumulate on the floor with a complicated shape, and the amount of liquid taken out is large. In particular, over-dust is generated in the ceiling direction during spray painting of the inner plate, and a lot of ventilation is required to prevent the booth from becoming dirty. During spray painting, dust adhering to the inner plate and dolly rises and falls onto the horizontal part of the outer plate, causing dust defects. In order to perform cleaning, dip coating for electrodeposition coating, intermediate coating, and spray coating for top coating, it is necessary to transfer from a hanger to a truck. Since the sag of the electrodeposition coating after washing with water is poor, a large amount of water is brought into the baking oven, and the floor portion where water is likely to accumulate has a large heat capacity, so the temperature rising rate is slow. Also, a lot of energy is required for water coating. In the baking furnace for electrodeposition coating, since the hot air does not easily reach the floor, the heating rate of the floor is slow.

An object of the present invention is to provide a coating method for an automobile body, which solves the above problems of the conventional coating method in which the ceiling portion of the automobile body is placed upward.

[0006]

As a means for solving the above problems, the present invention is a coating for forming a coating film on the surface of an automobile body while moving the automobile body in a pretreatment process, a painting process and a drying process. The method is characterized in that, when the automobile body is moved to each step, the ceiling of the automobile body is supported downward and the floor is supported upward for coating.

[0007]

With this structure, even if dust or the like is dropped in the pretreatment process or the painting process, the dust will drop inside the automobile body, which is the object to be coated. There is no touch.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Reference numeral 1 denotes a processing tank, which is filled with the processing liquid 2. Above the processing tank 1, the processing tank 1
The overhead conveyor 3 is provided so that the middle part thereof has a low height in accordance with the shape of the above. A hanger 4 is attached to the overhead conveyor 3, and an automobile body 5, which is an object to be coated, is hung and moved on the floor so that the ceiling portion faces downward.

The operation will be described. The vehicle body 5 is hung on a hanger 4 with its ceiling portion facing downward as shown in the figure, and is conveyed by an overhead conveyor 3 from one side to the other side, for example, from the left side to the right side in the figure at a predetermined speed. . In this way, the car body 5 becomes the processing tank 1.
When it passes through the inside of, the dipping coating is performed by the treatment liquid 2. When the automobile body 5 leaves the treatment tank 1, the sagging of the treatment liquid 2 from the automobile body 5 is performed. When the work is performed in this manner, there is no problem even if the iron powder generated by the abrasion of the overhead conveyor 3 or the foreign matter attached to the hanger 4 falls and attaches to the floor of the automobile body 5.

FIG. 2 shows an example of the dip coating electrodeposition coating baking furnace. In this figure, the reference numeral 6 is a baking furnace, and 7 is its furnace shell. A hot air supply duct 8 is provided above the inside of the furnace shell 7 so as to discharge hot air with the nozzle 9 facing downward so that the overhead conveyor 3 passes between the left and right hot air supply ducts 8. Has become. A hanger 4 suspends an automobile body 5 as an object to be coated, and the floor of the automobile body 5 has a nozzle 9
Move to receive hot air from.

A hot air suction duct is provided at a lower portion inside the furnace shell 7.
10 is provided, and the gas inside the furnace shell 7 is sucked through the suction port 11. Outside the furnace shell 7,
A circulation duct 14 is provided with a hot air generator 12 and a fan 13.
Are connected to the hot air supply duct 8 and the hot air suction duct 10, and the hot air is circulated inside the furnace shell 7.

The operation will be described. The floor of the automobile body 5 is suspended by a hanger 4 and is conveyed by an overhead conveyor 3 located right above the floor. In the baking oven 6, the hot air whose temperature is controlled by the hot air generator 12 is a nozzle 9
Is discharged toward the floor of the automobile body 5. The hot air that has passed through the side portion of the automobile body 5 is sucked from the suction port 11 of the hot air suction duct 10 by the suction force of the fan 13, and returns to the hot air generator 12 again. In this embodiment, since the nozzles 9 can be evenly arranged corresponding to the floor of the automobile body 5, the heating rate of the floor is increased and the temperature difference from the outer plate is reduced.

3 and 4 are examples of spray painting. Explaining this, 15 is a paint booth, the inside of which is partitioned by a filter 16 and a sunscreen 17,
The upper part of the filter 16 is in the air supply chamber 18, the filter 16 and
The space between 17 is the painting chamber 19, and the lower part of the sunglass 17 is the exhaust chamber 20.
Is formed in. Air supply ducts in air supply room 18 and painting room 19
An air conditioner 23 and an air supply fan 24 are connected by 21 and 22, and an exhaust duct 26 connecting an exhaust fan 25 is connected to the exhaust chamber 20 in the middle.

An overhead conveyor 3 is provided inside the coating chamber 19, and a hanger 4 is adapted to move by suspending a floor portion of an automobile body 5 which is an object to be coated. Rotating atomizing type automatic coating devices 27, 28, 29 are provided on both sides and a lower portion of the vehicle body 5, and their nozzles 27a, 28a, 29a are directed to the vehicle body. The exhaust chamber 20 is provided with 30.

FIG. 4 is a side view showing the relationship between the nozzle 29a of the automatic coating device 29 and the automobile body 5 in FIG.
As shown in this figure, since the nozzle 29a is provided between the filters 31, the paint sprayed from the nozzle 29a toward the vehicle body 5 has a suction port 31a on the side of the filter 31.
After being sucked from the vehicle and pushed upward by the air, the air is directed to the automobile body 5, and then the air is converted downward.

The operation will be described. The floor of the automobile body 5 is suspended from the hanger 4 and is conveyed to the coating booth 15 by the overhead conveyor 3. Air conditioner at painting booth 15
Air whose temperature and humidity are controlled by 23 is fed into the coating chamber 19. After this, automatic coating equipment 27, 2
8 and 29 are activated, and the outer panel is spray-painted.
The automatic coating device 27,
The air atomizing robot coating devices 32 and 33 shown in FIG.

Here, the automatic coating device 29 for coating the horizontal portion of the outer plate is prevented from being contaminated by the paint mist by the air sent from the air supply duct 22. Since the correction coating performed by the air atomizing robot coating devices 32 and 33 is performed near the exhaust chamber 20, it is easily ventilated and the overspray does not rise so much. Thereafter, the air including the sprayed paint mist is washed by the scrubber 30 in the exhaust chamber 20 to remove the paint mist from the air. The air from which the paint mist has been removed in this way is exhausted by the exhaust duct 26.
More discharged to the outside.

FIG. 6 shows in detail the structure of the portion where the automobile body 5 is suspended. To explain this, the car body 5 is provided with hooks 5a at four corners.
5a is a free rail 3c of the overhead conveyor 3
It is hung on the hanger 4 supported by. Then, it is hooked and pulled by the pin 3d of the conveyor chain 3b on the power rail 3a. FIG. 7 shows X- of FIG.
FIG. 9 shows the X section and FIG. 9 shows the hook portion of FIG.

Although the embodiments described above are only applied to the case where the method of the present invention is applied to the coating step, the method of the present invention is not limited to this, and the pretreatment performed before the coating step. It can also be applied to the drying process performed after the process and the coating process, and by carrying out such a consistent process, a great effect can be exhibited.

[0020]

As described above, the present invention is a coating method for forming a coating film on the surface of an automobile body while moving the automobile body through the pretreatment process, the painting process and the drying process. When moving to each step,
A coating method for an automobile body is characterized in that the coating is carried out by supporting the ceiling portion of the automobile body as a lower portion and the floor portion as an upper portion. With this method, the following many effects can be achieved. Since it is possible to carry the same method from dip coating to spray coating, it is not necessary to replace the car body, and productivity is improved. In addition, equipment costs will be low. Even if it is left in the painting factory for a long time such as on a holiday, there is no accumulation of dust on the inner plate of the automobile body. Since the water drain hole on the floor of the automobile body is not necessary, the hole forming step in the press work can be omitted. Since there is no water drainage hole from the floor of the car body, the masking work for the underfloor rust preventive coating can be reduced. Moreover, the amount of waste of the masking material is reduced. Since dust does not accumulate on the car body, dusting work is unnecessary.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a method of the present invention.

FIG. 2 is a system diagram showing a case where the method of the present invention is applied to an electrodeposition coating baking furnace for dip coating.

FIG. 3 is a system diagram showing a case where the method of the present invention is applied to spray coating.

FIG. 4 is a side view showing a central portion of FIG. 3 in an enlarged manner.

FIG. 5 is a system diagram showing a process performed after the coating process shown in FIG.

FIG. 6 is a front view showing details of a portion for suspending an automobile body.

FIG. 7 is an enlarged cross-sectional view of a portion XX in FIG.

FIG. 8 is an enlarged front view of a hook portion of an automobile body.

[Explanation of symbols]

 1 Treatment Tank 2 Treatment Liquid 3 Overhead Conveyor 4 Hanger 5 Car Body 6 Baking Furnace 8 Hot Air Supply Duct 9 Nozzle 10 Hot Air Suction Duct 10

Claims (1)

[Claims] 1. A coating method for forming a coating film on the surface of an automobile body while moving the automobile body through a pretreatment process, a painting process and a drying process, wherein the automobile body is moved to each of the steps. A coating method for an automobile body, characterized in that the coating is carried out by supporting the ceiling portion of the automobile body downward and the floor portion upward.