JPH08281154A - Humidification coating and device therefor - Google Patents

Abstract

PURPOSE: To provide a humidification coating method and a device using this method which sends a humidified air with a specified humidity to an object to be coated at the time of coating, ameliorates a coating environment around the object locally to stabilize a coating condition, and enhances coating efficiency to provide a significantly improved coat finish surface. CONSTITUTION: A humidified air is sent to an object to be coated W from the surroundings of a static coating gun G. Inside a coating booth 4, a spraying member 21 and a humidity sensor are provided. Outside the coating booth 4, a humidified air blowing part and a control part 25 are provided. The humidified air blowing part is connected to the spraying member 21 by a blast duct 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention blows humidified air toward an article to be coated during electrostatic coating to locally improve the coating environment around the article to improve the finished surface of the coating and improve coating efficiency. Etc. The present invention relates to a humidifying coating method and apparatus for enhancing the above.

[0002]

2. Description of the Related Art Generally, clean air whose dust is adjusted by an air conditioner is fed into an electrostatic coating booth.

For example, as shown in FIG. 4, an electrostatic coating device that has been conventionally used in automobile coating equipment is shown in FIG.
A blower duct 1 through which clean air led from an air conditioner (not shown) circulates is provided in the upper part, and the clean air from the blower duct 1 is directed downward in the coating booth 4 via a straightening plate 2 and a filter 3. It is blowing out.

On the other hand, in the lower part of the electrostatic coating device, there are air holes 5
Is provided with a bottom plate 6 on which a conveyor 7 that conveys the article to be coated W is placed, and around the conveyor 7, the paint is sprayed toward the side surface of the article to be coated W. A side coating section 8 having a coating gun G, a top coating section (not shown) having a coating gun for spraying the coating onto the upper surface of the article W, and the like are provided.

The clean air blown from the air duct 1 into the coating booth 4 flows along the surface of the article W and the inner wall 4a of the coating booth, and is sucked into the pit 9 through the air holes 5 of the bottom plate 6. After being guided to the exhaust duct 10, it is purified by the separator 11 or the eliminator 12 in the exhaust duct 10 and discharged to the outside.

As described above, the first purpose of flowing clean air into the coating booth 4 is to coat the surface of the article W and the inner wall 4a of the coating booth 4a.
To prevent dust and spray dust from adhering to the coating to ensure coating quality, the second is to enhance the antistatic effect by maintaining an appropriate humidity in the coating booth 4, and the third is to work. It is to provide a safe and hygienic environment for people.

For this reason, the flow rate of the clean air flowing in the coating booth 4 does not adversely affect the coating efficiency of the paint sprayed on the article W, for example, about 0.3.
It is about 0.6 m / s. Further, the humidity adjustment in the coating booth 4 is also performed for the entire coating booth, and the humidity is relatively rough in the summer time of 75 to 85% and in the winter time of 75% or more.

[0008]

However, if attention is paid to the quality of the finished surface by electrostatic coating, the coating environment in the vicinity of the object to be coated is important, and the quality of the finish is determined by the environment of the entire coating booth. is not. In electrostatic coating,
If a suitable coating environment is set in the vicinity of the object to be coated, the finished surface should be improved, and it is considered that it is not always necessary to set the environment in the entire coating booth as in the past.

In addition, the flow of clean air in electrostatic coating is to positively secure the coating quality, that is, to prevent dust from adhering, to prevent static electricity, and to maintain a safe and hygienic environment. Since it is not intended to improve the finished surface of the coating, neither the result of a dramatic improvement in the finished surface of the coating nor the improvement of the coating efficiency of the coating due to the circulation of the clean air has been obtained.

Further, when considering the coating efficiency, if the clean air is simply flowed into the coating booth as described above, the paint flow may be scattered by the air flow and the coating efficiency may be lowered. .

The present invention has been made in view of the above-mentioned prior art, in which humidified air having a predetermined humidity is blown toward the object to be coated at the time of coating so that the coating environment around the object is locally localized. It is an object of the present invention to provide a humidifying coating method and apparatus which are improved to provide a stable coating environment, enhance the coating efficiency, and dramatically improve the finish surface of coating.

[0012]

In order to achieve the above object, the humidifying coating method of the present invention according to claim 1 is to blow humidified air from around the electrostatic coating gun toward an object to be coated. Characterize. The humidifying coating method of the present invention according to claim 2 is characterized in that the blowing air volume of the humidified air is controlled according to the humidity in the coating booth. The humidifying coating method of the present invention according to claim 3 is characterized in that the humidity of the humidified air is controlled according to the humidity in the coating booth. The humidifying coating device of the present invention for achieving the above object is a blowing member which is provided on an outer periphery of an electrostatic painting gun in the coating booth and blows humidified air toward an object to be coated, A humidified air blower for producing and blowing humidified air provided outside the coating booth, a blower duct for guiding the humidified air from the humidified air blower to the blowing member, and a humidity sensor for detecting atmospheric humidity in the coating booth. And a controller for controlling the humidity and / or the air volume of the humidified air blown from the humidified air blower according to the signal from the humidity sensor.

According to a fifth aspect of the present invention, there is provided a humidifying coating device which is an annular hollow nozzle made of an insulating material and concentrically provided on the outer periphery of the electrostatic coating gun.

[0014]

According to the method of the present invention as set forth in claim 1, since humidified air is blown from around the electrostatic coating gun toward the object to be coated, the humidified air causes a local coating environment around the object to be coated. Once determined, a stable coating environment is provided, and the coating efficiency is improved by preventing the paint from scattering, resulting in a dramatic improvement in the finished surface of the coating. According to the method of the present invention as set forth in claim 2, since the blowing air volume of the humidified air is controlled according to the humidity in the coating booth, even when the entire coating booth is controlled by the air conditioner, the air by the air conditioner is controlled. It is possible to create a local coating environment around the object to be coated with humidified air without being affected by the above, and to enhance the coating efficiency of the coating by preventing the scattering of the coating, and consequently improve the finished surface of the coating. According to the method of the present invention as set forth in claim 3, since the humidity of the humidified air is controlled according to the humidity in the coating booth, the local coating environment around the object to be coated can be brought into a predetermined humidity state, and Not only is the coating efficiency improved, but the finished surface of the coating is also dramatically improved. The apparatus of the present invention according to claim 4 is provided with a blowing member and a humidity sensor inside the coating booth, a humidified air blower and a controller outside the coating booth, and the humidified air blower and the blowing member are blown ducts. Since they are communicated with each other, not only can high coating efficiency and high finish coating be performed, but a coating environment suitable for the object to be coated can be created without adversely affecting the space in the coating booth.

In the device of the present invention as defined in claim 5, since the blowing member concentrically provided on the outer periphery of the electrostatic coating gun is an annular hollow nozzle made of an insulating material, it is sprayed from the electrostatic coating gun. The paint does not adhere to the blowing member, and the sprayed humidified air can be used to prevent the paint from scattering, which improves the coating efficiency of the paint and dramatically improves the finished surface of the coating.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. 1 is a schematic sectional view showing an embodiment of a humidifying coating device according to the present invention, FIG. 2 is an enlarged sectional view showing a main part of FIG. 1, and FIG. 3 is a schematic view taken along line 3-3 of FIG. It is a figure. The same members as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be partially omitted.

The humidifying coating apparatus of this embodiment is used for electrostatic coating equipment for automobile bodies, and as shown in FIG. 1, a blower duct 1 through which clean air introduced from an air conditioner flows at the top. A rectifying plate 2 and a filter 3 are provided. On the other hand, at the lower part of the coating booth 4, a conveyor 7 that conveys the article W to be coated is placed on a bottom plate 6 having air holes 5.

Around the conveyor 7, the side coating section 8 provided with a coating gun G for spraying the paint toward the side surface of the article to be coated W, and the paint is sprayed toward the upper surface of the article to be coated W. A top coating section (not shown) equipped with a coating gun is provided.

As shown in FIGS. 2 and 3, the side coating section 8 is composed of a coating gun G and a robot or other suitable means for moving the coating gun G up and down in accordance with the side surface of the object W to be coated. Drive device 8A. As the coating gun G, various types such as an airless type, an atomizing air type, or a bell type can be used. It should be noted that the symbol "1" in the figure
“0” is an exhaust duct, “11” is a separator, and “12” is an eliminator.

In particular, in this embodiment, when the paint is sprayed from the electrostatic coating gun G toward the object W to be coated, the electrostatic coating gun G of the side coating section 8 is surrounded by the electrostatic coating gun G. A humidified air blower 20 that blows humidified air having a predetermined humidity toward the article W is continuously provided.

As shown in FIGS. 2 and 3, the humidified air blower 20 includes an annular blowing member 21 for blowing humidified air from around the electrostatic coating gun G toward the object W to be coated, and outside the coating booth 4. A humidified air blower 22 for producing and blowing humidified air, a blower duct 23 for blowing humidified air from the humidified air blower 22 to the blowing member 21, and a temperature and humidity in the coating booth 4. A temperature / humidity sensor 24 attached to the side wall 4a of the coating booth 4 so as to detect it.
And a control unit 25 for controlling the humidity and / or the air volume of the humidified air according to the signal from the temperature / humidity sensor 24.

Further details will be described. The blow-out member 21 is an annular hollow nozzle fixed to the electrostatic coating gun G by a stay 26, one end of a blower duct 23 communicates with the hollow nozzle, and humidified air from a humidified air blower 22 is supplied to the blower member 21. It is designed to be guided inside. This blowing member 21 is
Since it is arranged in the vicinity of the electrostatic coating gun G, it is made of an electrically insulating material such as Delrin or another synthetic resin so that the paint sprayed from the electrostatic coating gun G does not electrostatically adhere to the blowing member 21. However, the present invention is not limited to this, and other materials may be used, and the shape is not limited to a circular ring, but may be a rectangular ring, a polygonal ring, or other various shapes. May be.

The humidified air blower 22 is provided with a humidifier 28 and a fan device 29 mounted on a base 27. The humidified air produced by the humidifier 28 is blown by the fan device 29. The air is blown to the blowing member 21 via the duct 23.

[0024] Incidentally. Since the blower duct 23 extends through the side wall 4a of the coating booth 4 and the exhaust duct 10, it is preferable to use a flexible resin pipe for ease of construction.

The temperature / humidity sensor 24 is used in the coating booth 4.
Although it is attached to the side wall 4a of the coating booth 4 and is connected to the control unit 25 by the conductive wire 30, the mounting position of the temperature / humidity sensor 24 does not necessarily have to be the side wall 4a of the coating booth 4. Any position may be used as long as it can detect the humidity. For example, it may be attached in the vicinity of the side coating section 8 or the top coating section. In addition, this temperature and humidity sensor 24
May be of any type as long as it detects the coating environment in the coating booth 4, and may be, for example, only a humidity sensor or a temperature sensor.

The controller 25 controls the temperature / humidity sensor 2
The humidifier 28 and the fan device 29 of the humidified air blower 22 are controlled on the basis of the information signal from No. 4 to control the humidity or air volume of the humidified air.

Further, the humidifying coating device is used in the coating booth 4.
Inside, the blowing member 21 and the humidity sensor 2 having a small volume are provided.
4, a relatively large humidified air blowing unit 20 and a control unit 25 are provided outside the coating booth 4, and the humidified air blowing unit 20 and the blowing member 21 are configured to communicate with each other by a blowing duct 23. Therefore, it is possible to set the coating environment suitable for the object W without adversely affecting the space in the coating booth 4.

Here, as for the condition of the humidified air blown by the humidified air blowing section 22 to the article W, that is, the preferable coating environment condition locally set around the article to be coated, with respect to humidity, electrostatic coating is used. Humidity around gun G is 70-90
%, Particularly preferably,
The range is 75 ± 5%. When the humidity around the electrostatic coating gun G is reduced to 70% or less, the electrostatic effect is reduced and the coating efficiency of the coating is deteriorated. When the humidity is 90% or more, high pressure abnormalities due to leakage frequently occur. This is because there is fear.

Regarding the air flow rate, if the effect of the air flow rate from the air conditioner on the scattering of the paint is taken into consideration, it is 0.5 to
It is preferably about 1.5 m / s.

However, both of these humidity and / or air volume do not always have to satisfy the above predetermined conditions, and if either one of them is satisfied, the coating environment around the article to be coated will be adjusted to some extent. As a result, it is possible to carry out coating with a relatively preferable finish.

Next, the operation of this embodiment will be described. The conveyor 7 operates, the article W is conveyed into the coating booth 4,
When it is conveyed to the vicinity of the side coating section 8 or the top coating section, a position detection sensor (not shown) detects the position of the article to be coated W and stops the conveyance by the conveyor 7. However, in some cases, the coating described below may be performed while moving without stopping the conveyance of the article W to be coated by the conveyor 7.

When the article W to be coated is located between the side coating portions 8 and 8, the humidified air blowing portion 22 operates and the humidity is 70-9.
Humidified air adjusted to 0% is created. Then, the humidified air passes through the blower duct 23 and has an annular blowing member 2
1 to 0.9-1.1m / from the circumference of the coating gun G
It is blown toward the object W with an air volume of about s.

As a result, the coated part of the article W is
Without being affected by the air blown out from the air conditioner, the humidified air blower 22 wraps the humidified air in which the humidity and the amount of air are adjusted to locally improve the coating environment around the object to be coated. .

When the coating gun G of the side coating section 8 is operated, the coating material is sprayed toward the side surface of the article W to be coated. Since this paint is negatively charged, when sprayed, it is electrostatically applied to the positively charged object W to form a desired coating film on the surface of the object W.

In this case, a predetermined humidified air is blown toward the object W from the blowing member 21 provided in an annular shape around the coating gun G so as to cover the periphery of the coating gun G. Therefore, the paint is prevented from scattering outward by the humidified air, and as a result, the coating efficiency of the paint is improved.

As described above, when electrostatic coating is performed while the humidified air having a predetermined humidity is blown toward the object W in the coating booth at a predetermined blowing air volume, the air introduced from the air conditioner ( 0.5 m / s), regardless of the environment inside the coating booth, the coating environment around the object to be coated is locally improved, and electrostatic coating is performed in a stable coating environment. Can be carried out, the coating efficiency of the paint is improved,
The finished surface of the coating will be dramatically improved.

In the above-mentioned embodiment, the blowing member 21
Is provided integrally with the electrostatic coating gun G, but the present invention is not limited to this, and the blowout provided around the electrostatic coating gun G is provided separately from the electrostatic coating gun G. Humidified air may be blown from the member toward the article W to be coated, and in order to locally improve the coating environment around the article to be coated, the humidity and air volume of the humidified air are used as control factors. ,
Of course, temperature may be added to these.

[0038]

As described above, according to the method of claim 1, since humidified air is blown from around the electrostatic coating gun toward the article to be coated, the coating environment around the article to be coated can be improved. It is locally improved and stabilized, and as a result, the coating efficiency is increased and the finished surface of the coating is dramatically improved.

According to the second aspect of the present invention, since the blowing air volume of the humidified air is controlled according to the humidity in the coating booth, the coating suitable for the object to be coated is not affected by the air from the air conditioner. The environment can be created, the coating efficiency is increased, and the finished surface of the coating is improved.

According to the method of claim 3, since the humidity of the humidified air is controlled according to the humidity in the coating booth, the local coating environment around the object to be coated can be brought to a predetermined humidity state. Not only does the coating efficiency increase, but the finished surface of the coating improves dramatically. According to the apparatus of claim 4, a blowing member and a humidity sensor are provided inside the coating booth, a humidified air blower and a controller are provided outside the coating booth, and the humidified air blower and the blower member are blown ducts. Since they are communicated with each other, not only high coating efficiency and high finish coating can be performed, but also the inside of the coating booth can be smoothly made and a coating environment suitable for the object to be coated can be created.

According to the apparatus of the fifth aspect, since the blowing member concentrically provided on the outer periphery of the electrostatic coating gun is an annular hollow nozzle made of an insulating material, it is sprayed from the electrostatic coating gun. The paint does not adhere to the blowing member, and the sprayed humidified air can be used to prevent the paint from scattering, which improves the coating efficiency of the paint and dramatically improves the finished surface of the coating.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a schematic view taken along line 3-3 of FIG.

FIG. 4 is a schematic sectional view showing a conventional electrostatic coating booth.

[Explanation of symbols]

4 ... Painting booth, 20 ... Humidified air blower,
21 ... Blowing member, 23 ... Blower duct, 24
... Humidity sensor, 25 ... Control part, G ... Electrostatic coating gun, W ... Object to be coated.

Claims (5)

[Claims] 1. A humidifying coating method comprising blowing humidified air from around an electrostatic coating gun toward an object to be coated. 2. The humidifying coating method according to claim 1, wherein the blowing air volume of the humidified air is controlled according to the humidity in the coating booth. 3. The manufacturing method according to claim 1, wherein the humidity of the humidified air is controlled according to the humidity in the coating booth. 4. A blowing member which is provided on the outer periphery of the electrostatic coating gun in the coating booth and blows out humidified air toward an object to be coated, and humidified air which is provided outside the coating booth to generate and blow the humidified air. A blower unit, a blower duct that guides humidified air from the humidified air blower unit to the blowing member, a humidity sensor that detects the atmospheric humidity in the coating booth, and a blown air from the humidified air blower unit based on a signal from the humidity sensor. A humidification coating device having a control unit that controls the humidity and / or the air volume of humidified air. 5. The humidifying coating apparatus according to claim 4, wherein the blowing member is an annular hollow nozzle made of an insulating material and provided concentrically on the outer periphery of the electrostatic coating gun.