JP3755398B2 - Rotary atomizing electrostatic coating equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotary atomizing electrostatic coating apparatus used for coating a car body or the like.
[0002]
[Prior art]
In the rotary atomizing electrostatic coating process in which the shaping air is blown toward the outer periphery of the bell cup, the shaping air hits obliquely, causing problems such as a reduction in coating efficiency and a deterioration in color. In order to solve this problem, an inventor has proposed an invention in which the shaping air is blown at an acute angle with respect to the rotation axis of the bell cup (Japanese Patent Application No. 2000-313407).
[0003]
[Problems to be solved by the invention]
<First issue>
However, when the shaping air blowing angle is set to an acute angle, the coating pattern width decreases accordingly, and when the coating object is large or the coating area is large, the coating time is extended. There's a problem.
Further, in response to this problem, even if the inner diameter of the bell cup is simply enlarged, the distribution of the coating film thickness becomes non-uniform (doughnut shape), and the quality of the coating is lowered.
[0004]
<Second problem>
Furthermore, in the present invention, in order to solve the above-described problem, a plurality of bell cups having different inner peripheral diameters are provided in a concentric circle shape to increase the pattern width and make the film thickness uniform. The coating film thickness differs between the painting and the painting by the outer peripheral bell cup, which causes a problem that the coating quality deteriorates as a whole.
The present invention has been made in view of such problems of the prior art, and an object thereof is to provide a rotary atomizing electrostatic coating apparatus capable of performing high-quality coating while expanding a pattern width. To do.
[0005]
[Means for Solving the Problems]
(1) In order to achieve the above object, the rotary atomizing electrostatic coating apparatus of the present invention is characterized in that a plurality of bell cups are provided substantially concentrically.
In the present invention, since the plurality of bell cups are provided so as to be substantially concentrically overlapped by two, three or more layers, they are supplied to the inner peripheral surface of each overlapping bell cup. The paint passes through the inner surface and jumps out from the outer edge, and when viewed from the direction of the object to be painted, the atomized paint is blown out from multiple circles. Then, the atomized paint fine particles are uniformly spread widely and are applied to the object to be coated.
According to this invention, the inner diameter of the bell cup can be enlarged to increase the width of the coating pattern, and the coating pattern can be made uniform. An apparatus can be provided.
[0006]
(2) In order to achieve the above object, in the rotary atomizing electrostatic coating apparatus of the present invention , the air outlet for supplying the shaping air from the back surface of the bell cup has 0 to 0 relative to the rotation axis direction of the bell cup. It is provided to blow out the shaping air at an angle of 20 °.
In this invention, shaping air is blown at an angle of 0 to 20 ° with respect to the rotation axis direction of the bell cup. This shaping air controls the traveling direction of the fine particles atomized by the centrifugal force of the bell cup and jumps out in the outer peripheral direction (of the bell cup), and guides it in a substantially vertical direction toward the surface to be coated. Then, the coating fine 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 parallel to the coating surface.
According to the present invention, since the coating fine particles are applied to the surface of the object to be coated without being caused to flow laterally by the shaping air, it is possible to provide a rotary atomizing electrostatic coating apparatus having high coating efficiency. In addition, since metallic flakes and the like are arranged in parallel to the surface of the object to be coated, it is possible to improve the tint, and from the viewpoint of obtaining a paint with a certain tint, a rotating fog with high coating efficiency. An electrostatic coating apparatus can be provided.
When multiple bell cups are stacked on a concentric circle, the coating efficiency can be improved while increasing the pattern width. As a result, the number of bell cups installed is reduced, and the painting time is shortened. It is possible to provide a rotary atomizing electrostatic coating apparatus that enhances coating quality.
[0007]
(3) In order to achieve the above object, the rotary atomizing electrostatic coating apparatus of the present invention is characterized by comprising drive control means for controlling the rotational drive of the plurality of bell cups.
In the present invention, since the rotation driving of the plurality of bell cup which is provided on the rotary atomizing electrostatic coating apparatus that are controlled, respectively, it is possible to adjust the area of the bell cup blowing paint, for large painted surface All bell cups from the inner circumference to the outer circumference can be driven, and a small painted surface can be handled by driving only the inner circumference bell cup. Also, the bell cup drive can be turned on and off according to the coating thickness and paint application density (for example, every other bell cup installed is driven). The drive control of the cup can be performed. According to this invention, since coating can be performed according to the width of the pattern, it is possible to provide a rotary atomizing electrostatic coating apparatus that can prevent overspray and save paint used.
[0008]
(4) In order to achieve the above object, the rotary atomizing electrostatic coating apparatus of the present invention is characterized in that the drive control means controls the number of rotations of the plurality of bell cups.
In this invention, since the rotation speed of the bell cup is controlled by the drive control means, the bell cup can be driven at an appropriate rotation speed according to the size of the outer circumference of the bell cups stacked concentrically. .
According to the present invention, there is provided a rotary atomizing electrostatic coating apparatus capable of eliminating uneven coating film thickness distribution caused by overlappingly providing bell cups having different inner diameters and capable of performing high quality coating. Can be provided.
[0009]
(5) In order to achieve the above object, in the rotary atomizing electrostatic coating apparatus of the present invention , the drive control means rotates the bell cup so that the peripheral speeds of the plurality of bell cups are substantially the same. Each of the numbers is controlled.
In the present invention, the rotational speed of the bell cup is controlled by the drive control means so that the peripheral speeds of the bell cups are substantially the same. The force applied to the paint particles at the outer edge of the cup is constant. That is, since the magnitude of the force applied to make the paint finer is equal, the fine particle diameter of the paint at the time of application is substantially the same even with bell cups having different inner diameters, and the quality of the painted surface is improved. .
According to the present invention, it is possible to provide a rotary atomizing electrostatic coating apparatus capable of uniforming the particle diameter of the fine particles popping out from the bell cups stacked concentrically and capable of performing high-quality coating. it can.
[0010]
(6) In order to achieve the above object, the rotary atomizing electrostatic coating apparatus of the present invention has a paint supply control means for controlling the supply of paint to a plurality of bell cups.
In this invention, since the paint supply of the bell cup is performed for each bell cup, the bell cups provided in a concentric circle shape can be functioned independently. According to the present invention, only the inner bell cup of a plurality of bell cups is functioned, only the outer bell cup is functioned, all bell cups are functioned, or every other bell cup is functioned, and the functional form is changed. In addition, since the application pattern can be changed according to the area to be coated, it is possible to provide a rotary atomizing electrostatic coating apparatus that can prevent overspray and save paint.
[0011]
【The invention's effect】
(1) According to the present invention , the inner diameter of the bell cup can be increased to increase the width of the coating pattern and the coating pattern can be made uniform. An atomizing electrostatic coating apparatus can be provided.
[0012]
(2) According to the present invention , it is possible to provide a rotary atomizing electrostatic coating apparatus with high coating efficiency because coating fine particles are applied to the surface of an object to be coated without flowing laterally by shaping air. In addition, since coating fine particles such as metallic flakes are arranged in parallel to the surface of the object to be coated, it is possible to improve the tint, and also from the viewpoint of obtaining a paint with a certain tint, the coating efficiency is also high. A high rotary atomizing electrostatic coating apparatus can be provided.
When multiple bell cups are stacked on a concentric circle, the coating efficiency can be improved while increasing the pattern width. As a result, the number of bell cups installed is reduced, and the painting time is shortened. It is possible to provide a rotary atomizing electrostatic coating apparatus that enhances coating quality.
[0013]
(3) According to the invention of claim 3, since it is possible to perform coating according to the width of the pattern width, a rotary atomizing electrostatic coating apparatus capable of preventing overspray and saving paint used. Can be provided.
[0014]
(4) According to the present invention , it is possible to eliminate uneven coating film thickness distribution caused by overlapping bell cups having different inner diameters, and to perform rotary atomization electrostatic that can perform high-quality coating. A painting device can be provided.
[0015]
(5) According to the present invention, there is provided a rotary atomizing electrostatic coating apparatus capable of uniforming the particle diameter of the fine particles popping out from the bell cups stacked concentrically and performing high quality coating. can do.
[0016]
(6) According to the present invention , among the plurality of bell cups, only the inner bell cup functions, only the outer bell cup functions, all the bell cups function, or every other bell cup functions. Since the functional form can be changed and the application pattern can be changed according to the area to be coated, it is possible to provide a rotary atomizing electrostatic coating apparatus that can prevent overspray and save paint.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a rotary atomizing electrostatic coating apparatus according to the present invention, FIG. 2 is a diagram for explaining a blowing angle, and FIG. 3 is a rotary atomizing electrostatic coating according to this embodiment. FIG. 4 is a diagram for comparing the coating efficiency of the apparatus, FIG. 4 is a diagram for comparing colors (IV values) of the rotary atomizing electrostatic coating apparatus of the present embodiment, and FIG. 5 is a rotary atomization of the embodiment. FIG. 6 is a diagram for comparing pattern widths of electrostatic coating apparatuses, and FIG. 6 is a diagram illustrating an example of rotation speed information in which the rotation speed of the bell cup and the atomization diameter of the paint are associated with each other according to the inner diameter of the bell cup. FIG. 7 is a diagram for comparing the distribution of coating patterns of the rotary atomizing electrostatic coating apparatus of the present embodiment.
[0018]
<Configuration>
FIG. 1 is a diagram showing an embodiment of the rotary atomizing electrostatic coating apparatus of the present invention. As shown in FIG. 1, in the rotary atomizing electrostatic coating apparatus 100 of the present embodiment, a rotary shaft 21 is rotatably supported in a housing 6 by a motor not shown in the drawing, and the rotary shaft 21 extends in the distal direction. Bell cups 2 (2A, 2B) are provided. The rotation mechanism of the bell cup 2 may be one that rotates the bell cup 2 by rotating the rotation shaft by a motor, or may rotate the bell cup 2 by an air flow. In the present embodiment, two bell cups 2 are provided, and a first bell cup 2A (inner side) and a second bell cup 2B (outer side) are provided. Although the number of bell cups is shown in the present embodiment as two, the number of bell cups is not limited and may be any number.
[0019]
The bell cup 2 is rotationally driven, stopped, and controlled by the drive control means 4. This drive control may act on the rotating shaft of the bell cup or may act on the air turbine 4 that rotates the bell cup.
[0020]
An annular shaping air ring 7 is provided for each bell cup 2 between the housing 6 and the bell cup 2. An annular shaping air passage is formed in the vicinity of the shaping air ring 7 and the bell cup 2 side. The shaping air is supplied from a plurality of air outlets 1 provided on the back surfaces of the bell cups 2A and 2B along the outer peripheries of the bell cups 2A and 2B. This shaping air is preferably supplied from the back surface of each bell cup, but when the interval between the concentric bell cups 2 is narrow, the shaping air ring 7 and the shaping air outlet are appropriately selected. 1 can be configured together and the shaping air supply path can be integrated.
[0021]
In addition, it is preferable that the shaping air blowing angles supplied through the plurality of supply paths as described above are all 0 to 20 degrees, but the shaping air blowing angles supplied from the back of any bell cup are preferable. Can be set to 0 degrees to 20 degrees, or only the blowing angle of shaping air supplied from the back surface of the bell cup 2B located on the outermost side among the plurality of bell cups 2 can be set to 0 degrees to 20 degrees. is there. In this case, the outer shaping air forms a so-called air curtain that wraps the atomized paint blown out from all the inner bell cups 2A, 2B.
[0022]
Here, the outlet for shaping air will be described with reference to FIG. FIG. 2 is a diagram illustrating the blowing angle of shaping air. As shown in FIG. 2, the blowing angle is an angle formed by the shaping air blowing direction S ′ and the direction of the rotating shaft 21 of the bell cup. The invention according to the present application is characterized in that the shaping air blowing angle is set to an angle of 0 to 20 °. The blowout port 1 (outside of the bell cup 2B (outer peripheral side)) in the present embodiment shown in FIG. 1 has a blowing angle of 0 °, that is, shaping air is 0 ° with respect to the rotational axis direction 21 of the bell cup 2. It is provided to be blown out.
[0023]
Moreover, it has the coating material supply path 3 which supplies a coating material to the inner peripheral surface front-end | tip of a bell cup, and the coating material nozzle 31 from which a coating material ejects. The paint such as metallic flakes is supplied to the plurality of bell cups 2A and 2B via the supply path 3. The supply of the paint is controlled by a trigger valve 5 which is a paint supply control means 5. The trigger valve 5 controls the supply to the bell cups 2A and 2B.
[0024]
<Action>
Next, the operation will be described. When the paint supplied to the bell cups 2A and 2B is ejected from the paint nozzle 31, it is discharged in the form of a mist toward the outside in the circumferential direction by the rotational force of the bell cups 2A and 2B, and on the surface of the object. Apply to. At this time, the air outlet 1 provided as in the present embodiment blows 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 substantially vertical direction with respect to the surface of the object to be coated, and is applied parallel to the surface of the paint. In this embodiment, the shaping air blowing angle is set to 0 °.
[0025]
In order to confirm the effect | action of the rotary atomization electrostatic coating apparatus 100 in this embodiment, the coating efficiency, the color, and the pattern width were examined. The results are shown in FIG. 3, FIG. 4, and FIG. Specifically, FIG. 3 is a diagram for comparing the coating efficiency of the rotary atomizing electrostatic coating apparatus of the present embodiment, and FIG. 4 is a color (IV value) of the rotary atomizing electrostatic coating apparatus of the present embodiment. FIG. 5 is a diagram for comparing the pattern widths of the rotary atomizing electrostatic coating apparatus of the present embodiment (SA in the figure is an abbreviation for shaping air).
[0026]
These studies were made by creating a rotary atomizing electrostatic coating apparatus in which the shaping air blowing angle is in the range of −10 ° to 60 ° with respect to the rotating shaft 21, and the shaping air blowing angle is in the range of 0 ° to 20 °. The rotary atomizing electrostatic coating apparatus 100 in this embodiment (this embodiment) is compared with a conventional rotary atomizing electrostatic coating apparatus (comparative example) in which the shaping air blowing angle is in the range of 30 ° to 45 °. It was.
[0027]
Application efficiency
FIG. 3 shows the coating efficiency. When the shaping air flow rate is 500 Nl / min (indicated by a thick line) and when the shaping air flow rate is 300 Nl / min (indicated by a thin line), the shaping air blowing angle is −10. The coating efficiency (%) was plotted against the shaping air blowing angle (°) by changing the angle in the range of 60 ° 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 was in the range of 80 to 90%.
Thereby, in this embodiment, it turned out that the coating efficiency improves rather than a comparative example (a blowing angle is 30-50 degrees). In particular, it was found that the coating efficiency is improved near 0 °.
[0028]
Color
FIG. 4 shows the color (IV value), the shaping air blowing angle when the shaping air flow rate is 500 Nl / min (shown by a thick line) and when the shaping air flow rate is 300 Nl / min (shown by a thin line). Was varied in the range of −10 ° to 60 °, and the color (IV value) against the shaping air blowing angle (°) was plotted.
As a result, when the blowing angle is 0 ° to 20 °, the coating efficiency changes in the range of 230 to 250 when the shaping air flow rate is 500 Nl / min, and the coating efficiency is changed when the shaping air flow rate is 300 Nl / min. The landing efficiency was in the range of 180 to 200.
Thereby, in this embodiment, it turned out that a color (IV value) improves rather than a comparative example (a blowing angle is 30-50 degrees). In particular, the color (IV value) was improved near 0 °.
[0029]
Pattern width
FIG. 5 shows the pattern width. The shaping air blowing angle was changed in the range of −10 ° to 60 °, and the pattern width (mm) was plotted against the shaping air blowing angle (°).
As a result, when the blowing angle was 0 ° to 20 °, the pattern width changed from 150 mm to 200 mm, and when the blowing angle was 30 ° to 45 °, the pattern width changed from 250 mm to 300 mm.
Thereby, in this embodiment, it turned out that pattern width becomes smaller than a comparative example (a blowing angle is 30-50 degrees).
[0030]
Film thickness distribution
By providing a plurality of bell cups 2A, 2B, etc., having different inner diameters in a concentric circle shape, and blowing out shaping air with a blowing angle of 0 to 20 degrees from the back, the coating width is increased and the coating efficiency is improved. Although it was possible to improve the tint, it was found that the coating film thickness tends to be nonuniform.
If the coating film thickness is not uniform, the coating quality may be deteriorated.
Therefore, the rotary atomizing electrostatic coating apparatus 100 of the present embodiment solves such a problem and controls the number of rotations of the bell cup 2 to average the coating film thickness.
[0031]
When rotating at the same rotational speed, if the inner diameter of the bell cup 2 is different, the peripheral speed of the bell cup 2 is different, and the force (centripetal force, centrifugal force) applied to the paint particles at the outer edge of the bell cup 2 is different. Arise. As a result, a difference occurs in the fine particle diameter of the paint particles that are made fine by the rotational force of the bell cup. In FIG. 6, the paint atomization diameter for each rotation speed of the bell cup 2 is specifically shown for two bell cups (50φ, 150φ) having different inner diameters. As shown in FIG. 6, when the bell cups (50φ and 150φ) having different inner diameters are rotated at the same rotation speed (10 Krpm), the atomization diameter of the paint sprayed from the bell cup 2A having the inner diameter of 50φ becomes 25 μm. The atomization diameter of the paint sprayed from the 150φ bell cup 2B was 17 μm. In the rotation at the same rotational speed, the bell cup 2b having a larger inner diameter has a higher peripheral speed, and the force received by the paint fine particles at the outer edge of the bell cup 2B increases. If coatings having different atomization diameters are applied at the same time, the coating film thickness becomes non-uniform.
[0032]
On the other hand, even if the inner diameters of the bell cups 2 are different, the atomization diameter may be the same if the peripheral speed is the same. As shown in FIG. 6, when the bell cup 2A having an inner diameter of 50φ is rotated at a rotation speed of 10K rpm and when the bell cup 2B having an inner diameter of 150φ is rotated at a rotation speed of 30K rpm, the bell cup 2A is applied. The atomization diameter of the paint is the same as 17 μm.
[0033]
Thus, if the rotation speed of the bell cups 2A and 2B is controlled so that the atomization diameters are the same, the atomization diameters of the paints ejected from the plurality of bell cups 2 become equal, and the coating film becomes uniform. High quality painting can be performed.
[0034]
FIG. 7 shows the film thickness distribution of the paint applied by a plurality of bell cups having different inner diameters. FIG. 7 is a diagram for comparing distributions of coating patterns of the rotary atomizing electrostatic coating apparatus of the present embodiment. In order to examine the quality of the coating, the thickness (μm) at each point from −250 mm to +250 mm was measured and plotted with respect to the coating thickness with respect to the 0 mm point. In FIG. 7, the film thickness distribution when a bell cup with an inner diameter of φ50 is rotated at a rotation speed of 10 Krpm is shown by a two-dot chain line, and the film thickness distribution when a bell cup with an inner diameter of φ150 is rotated at a rotation speed of 10 Krpm is shown by a one-dot chain line. Indicated. As shown in FIG. 7, when the inner diameter of the bell cup is small, the coating pattern has a peak near the zero point. However, if the inner diameter of the bell cup is simply increased, the coating pattern becomes a donut shape. Even if these two bell cups are combined and applied at the same time, it is not possible to apply the film with a uniform film thickness.
[0035]
On the other hand, the coating pattern indicated by the solid line in FIG. 7 is a case where a bell cup with an inner diameter φ150 is rotated at a rotational speed of 10 Krpm and a bell cup with an inner diameter φ50 is rotated at a rotational speed of 30 Krpm. As described above, by appropriately controlling the rotation speed, the peripheral speeds of the bell cups 2A and 2B having different inner diameters can be made the same. As a result, coating with a uniform film thickness is performed while expanding the coating pattern. Can do.
[0036]
The embodiment described above is described for facilitating the understanding of the present invention, and is 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 diagram showing an embodiment of a rotary atomizing electrostatic coating apparatus of the present invention.
FIG. 2 is a diagram for explaining a blowing angle.
FIG. 3 is a diagram comparing the coating efficiency of the rotary atomizing electrostatic coating apparatus of the present embodiment.
FIG. 4 is a diagram for comparing colors (IV values) of the rotary atomizing electrostatic coating apparatus of the present embodiment.
FIG. 5 is a diagram for comparing pattern widths of the rotary atomizing electrostatic coating apparatus of the present embodiment.
FIG. 6 is a diagram illustrating an example of rotation speed information in which the rotation speed of the bell cup and the atomization diameter of the paint are associated with each other according to the inner diameter of the bell cup.
FIG. 7 is a diagram for comparing distributions of coating patterns of the rotary atomizing electrostatic coating apparatus of the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Rotary atomization electrostatic coating apparatus 1 ... Air outlet 2 ... Bell cup 2A ... 1st bell cup 2B ... 2nd bell cup 21 ... (Bell cup) rotating shaft 3 ... Paint supply path, feed tube 31 ... Paint nozzle 4 ... drive control means, air turbine 41 ... rotation control function 5 ... paint supply control means (trigger valve)
6 ... Housing 7 ... Shaping air ring S ... Shaping air S '... Shaping air blowing direction P ... Paint

Claims (6)

A rotary atomizing electrostatic coating apparatus, wherein a plurality of bell cups are provided substantially concentrically, and drive control means for controlling the rotational driving of each of the plurality of bell cups is provided.   The rotary mist according to claim 1, wherein an air outlet for supplying shaping air from the back of the bell cup is provided so as to blow out the shaping air at an angle of 0 to 20 ° with respect to the rotation axis direction of the bell cup. Electrostatic coating equipment. The rotary atomizing electrostatic coating apparatus according to claim 1 or 2, wherein inner diameters of the plurality of bell cups are different . The rotary atomizing electrostatic coating apparatus according to claim 1 , wherein the drive control unit controls the number of rotations of the plurality of bell cups. The rotating mist according to any one of claims 1 to 3, wherein the drive control means controls the number of rotations of the bell cups so that the peripheral speeds of the plurality of bell cups are substantially the same. Electrostatic coating equipment.   6. The rotary atomizing electrostatic coating apparatus according to claim 1, further comprising paint supply control means for controlling supply of the paint to the plurality of bell cups.

Images