JP2002119894A - Method and apparatus for rotary spraying electrostatic coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for rotary spraying electrostatic coating, which shows improved coating efficiency and improved color on a coated surface, and to average the distribution of coating pattern by preventing the interference of a coating material in the rotary spraying electrostatic coating apparatus having a plurality of bell cups. SOLUTION: The rotary spraying electrostatic coating apparatus having an air blowing port provided to blow shaping air at an angle of 0-20 deg. to the rotary axis of the bell cup is provided. The rotating directions of adjacent two bell cups in a plurality of the bell cups are reverse to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing electrostatic coating method and a rotary atomizing electrostatic coating apparatus used for coating an automobile body or the like.

[0002]

2. Description of the Related Art Conventionally, in a rotary atomizing electrostatic coating process,
When applying a metallic paint, etc., in order to enlarge the coating pattern, shaping air is blown from the back of the bell cup to the outer periphery of the bell cup in a twisting direction of 30 to 45 ° with respect to the rotation axis direction to perform coating. Was.

[0003]

<First Problem> However, when the shaping air is blown out in the twisting direction as described above, the shaping air hits the object to be coated in an oblique direction and flows laterally. Therefore, the coating efficiency is deteriorated. In addition, the metallic flakes guided by the laterally flowing shaping air are not aligned in parallel with the surface of the object to be coated, and thus have a problem of poor color.
The present invention has been made in view of such problems of the prior art, and aims at improving coating efficiency and improving the color of a painted surface. Its purpose is to provide a device.

<Second Problem> Further, in order to solve the above problem, in the present invention, the blowing direction of the shaping air is controlled from 0 ° to 20 °, and the width of the coating pattern tends to decrease accordingly. I found it. When the pattern width is reduced, the painting time is extended for a large work such as a large painting object or a large painting area. Therefore, a measure of increasing the number of bell cups is generally adopted. However, when the number of bell cups is increased, the paint ejected from each bell cup may interfere with each other and cause uneven coating.
The present invention has been made in view of such problems of the related art, and also has an object to prevent paint interference and average the paint pattern distribution.

[0005]

(1) In order to achieve the above object, a method for rotating atomizing electrostatic coating according to claim 1 is characterized in that shaping air is blown from a back surface of the rotating bell cup to form the bell cup. A rotary atomizing electrostatic coating method for guiding the atomized paint released from the inner peripheral surface tip to the surface of the object to be coated, wherein the shaping air is applied to the outer peripheral direction with respect to the rotational axis direction of the bell cup from 0 to 0. It is characterized by blowing out at an angle of 20 °.

According to another aspect of the present invention, there is provided a rotary atomizing electrostatic coating apparatus comprising: a rotatable bell cup in which paint is supplied to an inner peripheral surface; A rotary atomizing electrostatic coating apparatus having a plurality of air outlets for supplying air, wherein the air outlet is at an angle of 0 to 20 ° with respect to a rotation axis direction of the bell cup. Is provided so as to blow out.

According to the first and second aspects of the present invention, the shaping air is provided in a range of 0 to 20 with respect to the rotation axis direction of the bell cup.
It is blown out at an angle of °. The shaping air is atomized by the centrifugal force of the bell cup, controls the traveling direction of the fine particles that have protruded in the outer peripheral direction (of the bell cup), and guides the particles in a substantially vertical direction toward the surface of the workpiece. Then, the paint particles do not spread toward the outer peripheral direction of the bell cup, but collide perpendicularly to the surface of the object to be coated, and are applied in a plane parallel to the painted surface.

According to the present invention, the coating fine particles are applied to the surface of the object to be coated without flowing laterally by the shaping air, so that the coating efficiency is improved. In addition, since the paint particles such as metallic flakes are arranged in a plane parallel to the surface of the object to be coated, the tint can be improved. Further, from the viewpoint that the amount of shaping air necessary for obtaining a coating of a certain color can be reduced, the coating efficiency can be improved.

(2) In order to achieve the above object, a rotary atomizing electrostatic coating apparatus according to claim 3, wherein a plurality of rotatable bell cups whose inner peripheral surface is supplied with paint, and the respective bell cups A plurality of air outlets for supplying shaping air from the back of the rotary atomizing electrostatic coating apparatus, wherein the air outlet of the shaping air is 0 to the rotation axis direction of each bell cup. The shaping air is provided at an angle of 20 °.

In the invention according to claim 3, the air outlet is provided so as to blow the shaping air at an angle of 0 to 20 ° with respect to the rotation axis direction of each bell cup. The corresponding paint application width is reduced. The invention according to claim 3 has a plurality of bell cups and a plurality of air outlets for supplying shaping air from the back surface of each of the bell cups, so that the coating width in one coating process can be increased. Become.

According to the present invention, the coating efficiency can be improved and the tint can be improved, and the coating width can be increased to cope with an object to be coated having a large area.

(3) In order to achieve the above object, the invention according to claim 4 is characterized in that, among the plurality of bell cups, two adjacent bell cups have opposite rotation directions. .

[0013] In the invention according to claim 4, since the rotation directions of the two adjacent bell cups are opposite to each other,
The interference of the coating patterns can be prevented, and the distribution of the coating patterns can be made uniform.

According to the present invention, since a uniform coating pattern can be achieved while providing a plurality of bell cups, high quality coating with a uniform coating film thickness can be performed even for a large area coating. be able to.

(4) In order to achieve the above object,
According to a fifth aspect of the present invention, there is provided a rotary atomizer having two rotatable bell cups for supplying paint to an inner peripheral surface thereof, and a plurality of air outlets for supplying shaping air from a back surface of each of the bell cups. An electrostatic coating apparatus, wherein the air outlet is provided so as to blow the shaping air at an angle of 0 to 20 ° with respect to a rotation axis direction of each of the bell cups. The rotation directions are opposite to each other.

In the invention according to claim 5, since the two bell cups rotate in opposite directions to each other, interference of the coating patterns can be prevented, and the coating pattern distribution can be made uniform.

According to the present invention, a uniform coating pattern can be achieved while providing two bell cups, so that a large area can be coated with high quality.

[0018]

(1) According to the first and second aspects of the present invention, the coating particles are applied to the surface of the object to be coated without the lateral flow of the coating particles by shaping air, so that the coating efficiency is improved. In addition, since the paint particles such as metallic flakes are arranged in a plane parallel to the surface of the object to be coated, the tint can be improved. Further, from the viewpoint that the amount of shaping air necessary for obtaining a coating of a certain color can be reduced, the coating efficiency can be improved.

(2) According to the third aspect of the present invention, it is possible to improve the coating efficiency and the color, and also to increase the coating width to cope with an object to be coated having a large area. .

(3) According to the fourth aspect of the invention, interference of the coating patterns can be prevented, and the distribution of the coating patterns can be made uniform.

According to the present invention, since a uniform coating pattern can be achieved while providing a plurality of bell cups, high quality coating with a uniform coating film thickness can be performed even in a large area coating. Can be.

(4) According to the fifth aspect of the invention, the coating pattern can be made uniform while the two bell cups are provided, so that a large area can be coated with high quality.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. <Structure> FIG. 1 shows a first embodiment of a rotary atomizing electrostatic coating apparatus according to the present invention.
It is a figure showing an embodiment. As shown in FIG. 1, a rotary atomizing electrostatic coating apparatus 100 of the present embodiment includes a rotating bell cup 2, a plurality of shaping air outlets 1 provided on the back surface of the bell cup 2, and a bell cup. It has a paint supply path 3 for supplying paint to the tip of the inner peripheral surface, and a paint nozzle 31 for ejecting paint.

A paint such as a metallic flake is supplied to the bell cup 2 via a supply path 3. When the supplied paint is ejected from the paint nozzle 31, the supplied paint is discharged in the form of a mist toward the outside in the circumferential direction by the rotational force of the bell cup 2, and is applied to the surface of the object. At this time, the air outlet 1 provided as in the first embodiment blows out shaping air from the back surface of the bell cup 2 at an angle of 0 to 20 ° with respect to the rotation axis direction. Then, the paint spreading outward in the circumferential direction is changed in the traveling direction by the shaping air and collides in a direction substantially perpendicular to the surface of the object to be coated, and is applied. In the first embodiment, the shaping air blowing angle is 0 °.

FIG. 2 is a view for explaining the blowing angle of shaping air. As shown in FIG. 2, the blowing angle is an angle between the shaping air blowing direction S ′ and the direction of the rotating shaft 21 of the bell cup. In the invention according to the present application, the shaping air blowing angle is 0 to 20.
It is characterized by an angle of °. The outlet 1 in the present embodiment is provided so that the outlet angle is 0 °, that is, the shaping air is blown at 0 ° with respect to the rotation axis direction 21 of the bell cup 2. FIG.
FIG. 3 is a diagram illustrating an example of a blowing air outlet in the present embodiment. As shown in FIG. 3, the shaping air blow-out port 1 is
At an angle of 0 ° with respect to As a result, the paint sprayed from the bell cup 2 is guided by the flow of the shaping air in parallel with the direction of the rotation axis of the bell cup 2 and collides in a direction substantially perpendicular to the surface of the workpiece on an extension thereof. It will be.

<Operation> In order to confirm the operation of the rotary atomizing electrostatic coating apparatus 100 in the first embodiment, the coating efficiency, color, and pattern width were examined. The results are shown in FIG. 4, FIG. 5, and FIG. Specifically, FIG.
FIG. 5 is a diagram comparing the coating efficiency of the rotary atomizing electrostatic coating device of the first embodiment, FIG. 5 is a diagram comparing the tint (IV value) of the rotary atomizing electrostatic coating device of the first embodiment, FIG. 6 is a diagram comparing the pattern widths of the rotary atomizing electrostatic coating apparatus of the first embodiment (SA in the figure is an abbreviation of shaping air).

In these studies, an atomizing electrostatic coating apparatus was manufactured in which the shaping air blowing angle with respect to the rotating shaft 21 was -10 ° to 60 °, and the shaping air blowing angle was in the range of 0 ° to 20 °. A comparison was made between a certain rotary atomizing electrostatic coating apparatus 100 (first embodiment) and a conventional rotary atomizing electrostatic coating apparatus having a shaping air blowing angle of 30 ° to 45 ° (comparative example).

The coating efficiency Figure 4 shows the coating efficiency, shaping air flow rate is 50
When the shaping air flow rate is 0 Nl / min (shown by a thick line) and when the shaping air flow rate is 300 Nl / min (shown by a thin line), the shaping air blowing angle is -1.
The coating efficiency (%) was plotted with respect to the shaping air blowing angle (°) while varying from 0 ° to 60 °. As a result, when the blowing angle is 0 ° to 20 °, the coating efficiency changes in the range of 95 to 100% when the shaping air flow rate is 500 Nl / min, and when the shaping air flow rate is 300 Nl / min. The coating efficiency changed in the range of 80 to 90%. This allows
In this embodiment, a comparative example (blowing angle is 30 to 50 °)
It was found that the coating efficiency was improved as compared with the case. In particular, 0 °
It was found that the closer to, the higher the coating efficiency.

The tint Figure 5 shows the color (IV value), when the shaping air flow rate is 500 Nl / min (indicated by a thick line), in each case the shaping air flow rate is 300 Nl / min (shown by a thin line) The shading air blowing angle was changed in the range of −10 ° to 60 °, and the color (IV value) with respect to the shaping air blowing angle (°) was plotted. As a result, when the blowing angle is 0 ° to 20 °, the shaping air flow rate is 500 Nl / min.
, The coating efficiency changed in the range of 230 to 250, and when the shaping air flow rate was 300 Nl / min, the coating efficiency changed in the range of 180 to 200. Thereby, in the present embodiment, the comparative example (the blowing angle is 30
(５０50 °) than the color (IV value). In particular, the color (IV value) was improved closer to 0 °.

The pattern width 6 show a pattern width. The pattern width (mm) was plotted against the shaping air blowing angle (°) while the shaping air blowing angle was changed in the range of −10 ° to 60 °. As a result, the blowing angle is from 0 ° to 20 °
In the case, the pattern width changes in the range of 150 mm to 200 mm, and when the blowing angle is 30 ° to 45 °,
The pattern width changed within a range of 250 mm to 300 mm.
Thereby, in the present embodiment, in the comparative example (the blowing angle is 3
(0 ° to 50 °).

(1) Second Embodiment The first embodiment can improve the coating efficiency and the tint, but it can be seen that the pattern width tends to decrease with this. Was. When the pattern width is reduced, the painting time is extended for a large work such as a large painting object or a large painting area. Therefore, a measure of increasing the number of bell cups is generally adopted. However, when the number of bell cups is increased, the paint ejected from each bell cup may interfere with each other and cause uneven coating. Therefore, the rotary atomizing electrostatic coating apparatus 101 according to the second embodiment solves such a problem and averages the coating pattern distribution while preventing interference of the coating.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a diagram showing a second embodiment of the rotary atomizing electrostatic coating device of the present invention, and FIG. 8 is a diagram comparing the distribution of the coating patterns of the rotary atomizing electrostatic coating device of the second embodiment. .

<Structure> The basic operation of the rotary atomizing electrostatic coating apparatus 101 according to the second embodiment is the same as that of the first embodiment. The rotary atomizing electrostatic coating device 101 according to the second embodiment may be configured by combining two rotary atomizing electrostatic coating devices 100 according to the first embodiment. At this time, the combined rotary atomizing electrostatic coating device is
It is not limited to two, and may be connected in parallel or in a plane.

As shown in FIG. 7, the rotary atomizing electrostatic coating apparatus according to the second embodiment comprises two rotatable bell cups 1 and 2 for supplying a paint to an inner peripheral surface thereof, and each of the bells. A plurality of air outlets 1 for supplying shaping air from the back of the cup. The paint is ejected from the feed tubes 1 and 2 on the inner peripheral surfaces of the bell cups 1 and 2 via a paint supply path including a sparral hose, a cascade, and feed tubes 1 and 2. Here, the interval between the two bell cups 1 and 2 was set to 200 mm.

Further, the air outlet 1 in the present embodiment is set at 0 with respect to the rotation axis direction 21 of each of the bell cups 1 and 2.
It is provided to blow out shaping air at an angle of °. The blowing angle of the shaping air may be any value between 0 ° and 20 °. And 2
The rotation directions of the two bell cups 1 and 2 were opposite to each other.

<Operation> In order to confirm the operation of the rotary atomizing electrostatic coating apparatus 101 in the second embodiment, the distribution of the coating pattern was examined. The result is shown in FIG.
(A) and (b). FIG. 8 is a diagram comparing the distribution of the coating patterns of the rotary atomizing electrostatic coating apparatus 101 of the second embodiment. In these studies, the film thickness (μm) at each point from −250 mm to +250 mm was measured and plotted, with the position of the film thickness measurement starting from the 0 mm position.

FIG. 8A shows the distribution of the coating pattern when two bell cups are rotated in the same direction. As is clear from this figure, peaks of the film thickness are seen at the positions of −100 mm and +100 mm, and the coating pattern is non-uniform (the film thickness is non-uniform) due to interference of shaping air.
Will be.

FIG. 8B shows the distribution of the coating pattern when the rotation directions of the two bell cups are opposite to each other. As is clear from this figure, the graph as shown in FIG. 3A is flat and the coating pattern is uniform (film thickness is uniform).
It turned out to be.

The rotary atomizing electrostatic coating apparatus 10 of this embodiment
According to No. 1, the paint is guided substantially perpendicularly to the surface to be coated by the shaping air, so that the color is good, and since the shaping air does not flow laterally, the coating efficiency is high. In spite of spraying, the coating pattern becomes uniform, and it is possible to provide a rotary atomizing electrostatic coating device with a large coating pattern width, and to efficiently perform high-quality coating on large coating objects. Can be.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of a rotary atomizing electrostatic coating apparatus according to the present invention.

FIG. 2 is a diagram illustrating a blowing angle.

FIG. 3 is a diagram showing an example of a blowing air outlet in the present embodiment.

FIG. 4 is a diagram comparing the coating efficiency of the rotary atomizing electrostatic coating device of the first embodiment.

FIG. 5 is a diagram comparing the tint (IV value) of the rotary atomizing electrostatic coating device of the first embodiment.

FIG. 6 is a diagram comparing pattern widths of the rotary atomizing electrostatic coating apparatus according to the first embodiment.

FIG. 7 is a view showing a second embodiment of the rotary atomizing electrostatic coating apparatus of the present invention.

FIG. 8 is a diagram comparing the distribution of coating patterns of the rotary atomizing electrostatic coating apparatus according to the second embodiment.

[Explanation of symbols]

 100, 101: rotary atomizing electrostatic coating apparatus 1: air outlet 2: bell cup 21 (bell cup) rotating shaft 3: paint supply path 31: paint nozzle S: shaping air S ': shaping air blowing direction P: paint

Claims (5)

[Claims] 1. A rotary atomizing electrostatic coating method in which shaping air is blown from a back surface of a rotating bell cup to guide atomized paint discharged from a tip of an inner peripheral surface of the bell cup to an object surface. A rotary atomizing electrostatic coating method in which the shaping air is blown at an angle of 0 to 20 ° in an outer peripheral direction with respect to a rotation axis direction of the bell cup. 2. A rotary atomizing electrostatic coating apparatus comprising: a rotatable bell cup for supplying paint to an inner peripheral surface thereof; and a plurality of air outlets for supplying shaping air from a back surface of the bell cup. A rotary atomizing electrostatic coating device, wherein the air outlet is provided so as to blow the shaping air at an angle of 0 to 20 ° with respect to the rotation axis direction of the bell cup. 3. A rotary atomizing electrostatic coating having a plurality of rotatable bell cups for supplying paint to an inner peripheral surface thereof, and a plurality of air outlets for supplying shaping air from a back surface of each of the bell cups. A rotary atomizing electrostatic coating device, wherein the air outlet is provided so as to blow the shaping air at an angle of 0 to 20 ° with respect to the rotation axis direction of each of the bell cups. 4. The rotary atomizing electrostatic coating apparatus according to claim 3, wherein two adjacent bell cups of the plurality of bell cups have opposite rotation directions. 5. A rotatable 2 in which paint is supplied to the inner peripheral surface.
A rotary atomizing electrostatic coating apparatus having two bell cups and a plurality of air outlets for supplying shaping air from the back of each bell cup, wherein the air outlet is a rotating shaft of each of the bell cups. A rotary atomizing electrostatic coating apparatus provided so as to blow the shaping air at an angle of 0 to 20 ° with respect to a direction, wherein the two bell cups are rotated in opposite directions.