JP2024007917A - Coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method for obtaining a coated component which is excellent in appearance.

SOLUTION: A coating method for coating a vehicle-body component 10 comprising an outer plate and an inner plate comprises: an outer-plate first coating step of coating the outer plate with an achromatic first coating material to form an outer-plate first coated layer; an outer-plate second coating step of coating the outer-plate first coated layer with a second coating material to form an outer-plate second coated layer; and an inner-plate coating step of coating the inner plate with a second coating material to form an inner-plate second coated layer. The outer-plate first coating step is executed prior to the outer-plate second coating step and the inner-plate coating step.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a painting method, and more particularly, to a painting method for painting vehicle body parts.

Vehicle body parts such as automobile bodies include an outer panel and an inner panel. The outer and inner panels are usually first electrocoated (primer coat), then intermediate coated, and then top coated. On the other hand, in order to reduce costs, consideration is being given to omitting the intermediate coating.

For example, the following methods have been proposed as coating methods that omit intermediate coating. In this method, first, a first paint is applied onto the inner plate surface of an automobile body to form a first paint film that develops an external paint film color (first paint film forming step). Next, a second paint is applied onto the outer panel surface to form a second paint film having base-hiding properties (second paint film forming step). Next, a third paint that develops an external paint film color is applied onto the second paint film to form a third paint film (third paint film forming step). In this method, when the third paint is applied to the outer plate surface, the third paint is encouraged to wrap around the inner plate surface. In other words, even if a second paint (e.g., achromatic paint) that has a base-hiding property adheres to the inner plate surface, the second paint (e.g., achromatic paint) can be replaced with a third paint that develops the external coating color. It is coated with paint (for example, chromatic paint) to prevent deterioration in aesthetic appearance (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2010-234186

However, in the above painting method, the third paint (e.g., chromatic paint) that develops the external paint film color covers a part of the second paint (e.g., achromatic paint) attached to the inner plate surface. It may stay. That is, the third paint may not be able to cover all of the second paint adhered to the inner plate surface. As a result, the aesthetic appearance of the member (painted part) may deteriorate.

The present invention is a coating method for obtaining coated parts with excellent appearance.

The present invention [1] is a coating method for painting a vehicle body part including an outer panel and an inner panel, in which the outer panel is coated with an achromatic first paint to form a first outer panel paint layer. a second outer panel painting step of applying a second paint to the first outer panel paint layer to form a second outer panel paint layer; and an inner panel painting step of applying a paint to form a second inner panel coating layer, wherein the first outer panel coating step is performed before the second outer panel coating step and the inner panel coating step. Includes painting methods.

The present invention [2] provides the above-mentioned [2], wherein the inner panel painting step is performed after the first outer panel painting step, and the second outer panel painting step is performed after the inner panel painting step. 1].

The present invention [3] includes a main painting process of painting the main paint on the vehicle body parts, and a sub-painting process of painting the sub-paint on the car body parts, and at least the main painting process includes the first painting of the outer panel. step, the second outer panel painting step, and the inner panel painting step, and the sub-painting step includes the painting method described in [1] above, which is carried out before or after the main painting step. I'm here.

According to the coating method of the present invention, painted parts with excellent appearance can be obtained.

FIG. 1 is a schematic diagram showing a first embodiment of the coating method of the present invention. FIG. 2 is a schematic diagram showing a second embodiment of the coating method of the present invention. FIG. 3 is a schematic diagram showing a third embodiment of the coating method of the present invention. FIG. 4 is a schematic diagram showing a fourth embodiment of the coating method of the present invention.

1. First Embodiment (1) Overall configuration of painting line FIG. 1 is a schematic diagram showing a first embodiment of the painting method of the present invention. In the painting method shown in FIG. 1, for example, in a painting line 1, unpainted car body parts 10 (unpainted parts) are painted to obtain painted car body parts 10 (parts to be painted).

The vehicle body part 10 includes an outer plate and an inner plate. More specifically, the vehicle body part 10 is formed by assembling an outer panel and an inner panel. Examples of the vehicle body parts 10 include a body main body, a door panel, a roof panel, and composite parts thereof.

The painting line 1 is an industrial facility for painting vehicle body parts 10. The coating line 1 includes a conveyor (not shown), an electrodeposition coating line 2, and a colored coating line 3.

The conveyor is a conveyance device that conveys the vehicle body part 10 in a predetermined direction. In FIG. 1, the direction of conveyance of a conveyor (not shown) is indicated by an arrow. The electrodeposition coating line 2 and the colored coating line 3 are sequentially arranged along the conveyance direction of the conveyor.

The electrodeposition coating line 2 is equipment for painting the vehicle body parts 10 with electrodeposition paint. The electrodeposition coating line 2 has an electrodeposition coating booth 21. Although not shown, the electrodeposition coating booth 21 includes an electrodeposition bath, a transfer robot, and a power supply unit. The electrodeposition tank stores an electrodeposition solution. The transport robot transports the car body part 10 in a predetermined direction while immersing the car body part 10 in the electrodeposition liquid. The power supply unit supplies power to the vehicle body part 10 in the electrodeposition liquid.

The colored painting line 3 is equipment for painting the vehicle body parts 10 with colored paint. Colored paints include base paints and clear paints.

The base paint includes a first paint to be described later and a second paint to be described below. The first paint is an achromatic paint, which will be described in detail later, and is applied only to the outer panel of the vehicle body part 10. Further, the second paint is a chromatic paint or an achromatic paint, which will be described in detail later, and is applied to both the inner panel and the outer panel of the vehicle body part 10.

The clear paint is a transparent (light-transmitting) paint, which will be described in detail later, and is applied to both the inner and outer panels of the vehicle body part 10.

More specifically, the color coating line 3 includes a base coating booth 31, a preliminary drying booth 35, a clear coating booth 36, and a baking booth 39. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

In the colored painting line 3, the vehicle body parts 10 are first painted with a base paint, and then painted with a clear paint. Note that the colored painting line 3 is not equipped with an intermediate coating booth. In other words, the colored painting line 3 does not apply intermediate coating to the vehicle body parts 10.

The base coating booth 31 is a facility for coating the vehicle body parts 10 with base paint. The base painting booth 31 includes a base painting upstream part 32, a base painting midstream part 33, and a base painting downstream part 34. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

The base coating upstream section 32 is defined on the upstream side of the base coating booth 31 in the transport direction. The base coating upstream section 32 includes, for example, a coating device for coating the outer panel of the vehicle body part 10 with the first paint.

The first paint is a base paint and is an achromatic base concealing paint. The first paint is applied to the outer panel and hides the base of the outer panel of the vehicle body part 10. Note that the first paint is not applied to the inner plate.

The first paint may be, for example, a water-based paint or an oil-based paint. More specifically, the first paint contains, for example, a first solvent, a first resin, a first curing agent, and a first pigment.

The first solvent dissolves and/or disperses the first resin, the first curing agent, and the first pigment. Examples of the first solvent include an aqueous solvent and/or an oily solvent. Aqueous solvents include, for example, water, alcohols and ethers. Examples of oily solvents include toluene, xylene, esters and ketones. These can be used alone or in combination of two or more. The first solvent is preferably an aqueous solvent, more preferably water. That is, preferably the first paint is a water-based paint.

The first resin is dissolved and/or dispersed in the first solvent. The first resin is appropriately selected depending on the type of solvent. Examples of the first resin include acrylic resin, polyester resin, alkyd resin, urethane resin, epoxy resin, and acid-modified epoxy resin. These can be used alone or in combination of two or more.

The first curing agent is dissolved and/or dispersed in the first solvent and cures (crosslinks) the first resin. The first curing agent is appropriately selected depending on the type of the first resin. Examples of the first curing agent include block polyisocyanate, melamine resin, and urea resin. These can be used alone or in combination of two or more.

The first pigment is dissolved and/or dispersed in a solvent and colors the first paint. The first pigment is an achromatic pigment. Examples of achromatic pigments include carbon black, zinc oxide, and titanium oxide. These can be used alone or in combination of two or more.

If the first pigment is an achromatic pigment, the outer panel is painted with an achromatic color in the first outer panel painting step.

The blending ratio of the first solvent, first resin, first curing agent, and first pigment is appropriately set depending on the purpose and use. Further, the first paint can contain known additives, if necessary. Additives include, for example, ultraviolet absorbers, shock absorbers, and curing catalysts. The solid content concentration of the first paint is, for example, 20% by mass or more and 50% by mass or less.

The coating device for applying the first paint is not particularly limited, and includes known coating devices. Examples of the coating device include an air spray coating device, an airless spray coating device, a bell coating device, and an electrostatic coating device. These can be used alone or in combination of two or more.

The base coating midstream section 33 is divided between the base coating upstream section 32 and the base coating downstream section 34 in the conveyance direction. The base coating midstream section 33 includes, for example, a coating device for coating the inner plate of the vehicle body part 10 with the second paint.

The second paint is a base paint, and is a paint that determines the external color of the vehicle body part 10. The second paint is applied to both the outer panel and the inner panel, as will be described later. The second paint may be an achromatic paint or a chromatic paint. The second paint is appropriately selected depending on the desired color. The second paint is preferably a chromatic paint.

The second paint may be, for example, a water-based paint or an oil-based paint. More specifically, the second paint contains, for example, a second solvent, a second resin, a second curing agent, and a second pigment.

Examples of the second solvent include the above-mentioned aqueous solvents and/or the above-mentioned oily solvents. These can be used alone or in combination of two or more. The second solvent is preferably an aqueous solvent, more preferably water. That is, preferably the second paint is a water-based paint.

Examples of the second resin include acrylic resin, polyester resin, alkyd resin, urethane resin, epoxy resin, and acid-modified epoxy resin. These can be used alone or in combination of two or more.

The second curing agent is dissolved and/or dispersed in the second solvent and cures (crosslinks) the second resin. The second curing agent is appropriately selected depending on the type of the second resin. Examples of the second curing agent include block polyisocyanate, melamine resin, and urea resin. These can be used alone or in combination of two or more.

The second pigment is dissolved and/or dispersed in the second solvent and colors the second paint. Examples of the second pigment include achromatic pigments, chromatic pigments, and metallic pigments. Examples of achromatic pigments include carbon black, zinc oxide, and titanium oxide. Examples of chromatic pigments include cadmium red, molybdenum red, titanium yellow, chrome yellow, cobalt blue, and Prussian blue. Examples of the metallic pigment include aluminum powder, flaky aluminum oxide, pearl mica, and flaky mica. These can be used alone or in combination of two or more.

Preferably, the second pigment includes a chromatic pigment and/or a metallic pigment. If the second pigment is a chromatic pigment and/or a metallic pigment, the inner plate is painted with a chromatic color and/or metallic in the inner plate coating process. More preferred examples of the second pigment include chromatic pigments.

The blending ratio of the second solvent, second resin, second curing agent, and second pigment is appropriately set depending on the purpose and use. Further, the second paint can contain known additives, if necessary. Additives include, for example, ultraviolet absorbers, shock absorbers, and curing catalysts. The solid content concentration of the second paint is, for example, 20% by mass or more and 50% by mass or less.

The coating device for applying the second paint is not particularly limited, and includes known coating devices. Examples of the coating device include an air spray coating device, an airless spray coating device, a bell coating device, and an electrostatic coating device. These can be used alone or in combination of two or more.

The base coating downstream section 34 is defined on the downstream side of the base coating booth 31 in the transport direction. The base coating downstream section 34 includes, for example, a coating device for coating the outer panel of the vehicle body part 10 with the second paint.

The second paint applied to the outer panel of the vehicle body part 10 is the same as the second paint applied to the inner panel. In other words, the same type of second paint is used in the base coating midstream section 33 and the base coating downstream section 34.

The coating device for applying the second paint is not particularly limited, and includes known coating devices. Examples of the coating device include an air spray coating device, an airless spray coating device, a bell coating device, and an electrostatic coating device. These can be used alone or in combination of two or more.

The pre-drying booth 35 is a facility for pre-drying the base paint. The pre-drying booth 35 is equipped with, for example, a blower. The blower blows hot air and/or cold air onto the vehicle body part 10. Thereby, the blower dries (uncures) the first outer coating layer, the second outer coating layer, and the second inner coating layer.

The clear paint booth 36 is a facility for applying clear paint to the vehicle body parts 10. The clear coating booth 36 includes a clear coating upstream section 37 and a clear coating downstream section 38. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

The clear coating upstream section 37 is defined on the upstream side of the clear coating booth 36 in the transport direction. The clear coating upstream section 37 includes, for example, a coating device for coating the inner plate of the vehicle body part 10 with a clear coating.

The clear paint is not particularly limited, and any known transparent (light-transmissive) paint can be used. The clear paint may be, for example, a water-based paint or an oil-based paint. More specifically, it contains a clear solvent, a clear resin, and a clear curing agent.

Examples of the clear solvent include the above-mentioned aqueous solvents and/or the above-mentioned oily solvents. Examples of the clear resin include acrylic resin, polyester resin, alkyd resin, urethane resin, epoxy resin, and acid-modified epoxy resin. These can be used alone or in combination of two or more. Examples of the clear curing agent include block polyisocyanates, melamine resins, and urea resins. These can be used alone or in combination of two or more.

The blending ratio of the clear solvent, clear resin, and clear curing agent is appropriately set depending on the purpose and use. Further, the clear paint can contain known additives, if necessary. Additives include, for example, ultraviolet absorbers, shock absorbers, and curing catalysts. Further, the clear paint can contain the above-mentioned pigments within a range that does not impair transparency. The solid content concentration of the clear paint is, for example, 30% by mass or more and 70% by mass or less.

The coating device for applying the clear paint is not particularly limited, and includes known coating devices. Examples of the coating device include an air spray coating device, an airless spray coating device, a bell coating device, and an electrostatic coating device. These can be used alone or in combination of two or more.

The clear coating downstream section 38 is defined on the downstream side of the clear coating booth 36 in the transport direction. The clear coating downstream section 38 includes, for example, a coating device for coating the outer panel of the vehicle body part 10 with a clear coating.

The clear paint applied to the outer panel of the vehicle body part 10 is the same as the clear paint applied to the inner panel described above. In other words, the same type of clear paint is used in the clear coating upstream section 37 and the clear coating downstream section 38.

The coating device for applying the clear paint is not particularly limited, and includes known coating devices. Examples of the coating device include an air spray coating device, an airless spray coating device, a bell coating device, and an electrostatic coating device. These can be used alone or in combination of two or more.

The baking booth 39 is a facility for drying the clear paint and baking (thermally curing) the base paint and the clear paint.

The baking booth 39 includes, for example, a heating device. The heating device is not particularly limited, and includes known heating devices. Examples of the heating device include a hot air heating device, an infrared heating device, and a high frequency heating device. These can be used alone or in combination of two or more.

The length of the colored coating line 3 (transport distance of the vehicle body part 10) is appropriately set depending on the purpose and use. The length of the colored coating line 3 (transport distance of the vehicle body parts 10) is, for example, 100 m or more and 150 m or less.

(2) Painting method The vehicle body part 10 is painted, for example, in the above-mentioned painting line 1 while being conveyed in a predetermined direction by a conveyor (not shown). The method for painting the vehicle body part 10 will be described in detail below.

In this method, the vehicle body part 10 is first transported to the electrodeposition coating line 2. In the electrodeposition coating line 2, the vehicle body parts 10 are electrocoated (electrodeposition coating process).

That is, when the car body part 10 is transported to the electrodeposition coating line 2, the car body part 10 is immersed in the electrodeposition liquid while being transported in a predetermined direction, and is also supplied with electricity. As a result, the outer and inner panels of the vehicle body part 10 are each electrocoated. As a result, an electrodeposition layer (undercoat layer) is formed on the surface of the vehicle body part 10.

Next, in this method, the electrocoated vehicle body part 10 is conveyed to the colored coating line 3 (see arrow) without being subjected to intermediate coating, for example. In the color coating line 3, the outer and inner panels of the vehicle body parts 10 are colored (base coat and clear coat) by the following method while being conveyed by a conveyor (not shown) (color coating process).

More specifically, the electrocoated vehicle body part 10 is subjected to base painting in the base painting booth 31 (base painting process).

In the base painting booth 31, the vehicle body part 10 is first transported to the upstream part 32 for base painting. In the base painting upstream portion 32, the outer panel of the vehicle body component 10 is painted with the first paint. That is, the first paint is applied onto the electrodeposited layer (undercoat layer) of the outer panel (first outer panel coating step).

More specifically, in the base painting upstream section 32, the outer panel of the vehicle body part 10 is painted with the first paint by a worker and/or a robot. Note that the coating conditions are appropriately set depending on the purpose and use.

In this way, an undried paint layer (outer panel first paint layer) made of the first paint is formed on the electrodeposited layer (undercoat layer) of the outer panel. The outer panel first paint layer is an achromatic paint layer. Further, the first paint layer of the outer panel is a base concealing layer that hides the base (undercoat layer) of the outer panel.

The thickness of the first paint layer of the outer panel is, for example, 10 μm or more. Further, the thickness of the first paint layer of the outer panel is 100 μm or less, preferably 50 μm or less.

Next, the vehicle body part 10 is transported to the base painting midstream section 33 of the base painting booth 31. In the base painting midstream section 33, the inner plate of the vehicle body part 10 is painted with the second paint. That is, the second paint is applied onto the electrodeposited layer (undercoat layer) of the inner plate (inner plate coating process).

More specifically, in the base painting midstream section 33, the inner plate of the vehicle body part 10 is painted with the second paint by a worker and/or a robot. Note that the coating conditions are appropriately set depending on the purpose and use.

In this way, an undried paint layer (inner plate second paint layer) made of the second paint is formed on the electrodeposited layer (undercoat layer) of the inner plate. The inner plate second paint layer is preferably a chromatic paint layer. The inner plate second paint layer is a coloring layer that gives off the appearance color of the inner plate.

The thickness of the inner plate second paint layer is, for example, 10 μm or more. Moreover, the film thickness of the inner plate second paint layer is 100 μm or less, preferably 50 μm or less.

Next, in this method, the vehicle body part 10 is transported to the base painting downstream section 34 of the base painting booth 31. In the base painting downstream section 34, the outer panel of the vehicle body part 10 is painted with the second paint. In other words, the second paint layer is applied onto the first paint layer of the outer panel (second coating step of the outer panel).

More specifically, in the base painting downstream section 34, the outer panel of the vehicle body part 10 is painted with the second paint by a worker and/or a robot. Note that the coating conditions are appropriately set depending on the purpose and use.

In this way, an undried paint layer (outer panel second paint layer) made of the second paint is formed on the outer panel first paint layer. The second outer panel paint layer is preferably a chromatic paint layer. The second paint layer for the outer panel is a coloring layer that gives the outer panel an appearance color.

The thickness of the second paint layer of the outer panel is, for example, 10 μm or more. Further, the thickness of the second paint layer of the outer panel is 100 μm or less, preferably 50 μm or less.

In this way, in the base painting booth 31, the outer panel of the vehicle body part 10 is base coated with the above-mentioned first paint and the above-mentioned second paint. Further, the inner plate of the vehicle body part 10 is base coated with the above-mentioned second paint.

Next, in this method, the base-painted vehicle body part 10 is transported to a pre-drying booth 35 (see arrow). In the pre-drying booth 35, the first paint and the second paint are pre-dried (uncured) (pre-drying step).

More specifically, in the pre-drying booth 35, for example, a blower blows hot air and/or cold air onto the first outer paint layer, the second outer paint layer, and the second inner paint layer. be done. As a result, the outer panel first paint layer, the outer panel second paint layer, and the inner panel second paint layer are dried. Drying conditions are not particularly limited. For example, the drying temperature is, for example, 20 to 100°C. The air blowing speed is, for example, 0.3 to 10.0 m/s.

By the above drying, the first outer coating layer and the second outer coating layer form a wet base layer (exterior wet base layer) on the electrodeposited layer of the outer panel of the vehicle body component 10. Moreover, by the above-mentioned drying, the inner plate second paint layer forms a wet base layer (inner plate wet base layer) on the electrodeposited layer of the inner plate of the vehicle body component 10.

Next, in this method, the vehicle body part 10 is transported to the clear coating booth 36 (see arrow). In the clear coating booth 36, the vehicle body parts 10 are subjected to clear coating (clear coating process).

In the clear coating booth 36, the vehicle body parts 10 are first transported to an upstream clear coating section 37. In the clear coating upstream portion 37, the inner plate of the vehicle body part 10 is coated with clear paint. That is, a clear paint is applied on the inner plate wet base layer (inner plate clear coating process).

More specifically, in the clear coating upstream section 37, the inner plate of the vehicle body part 10 is coated with clear paint by a worker and/or a robot. Note that the coating conditions are appropriately set depending on the purpose and use.

In this way, an undried paint layer (inner plate clear paint layer) made of clear paint is formed on the inner plate wet base layer. The inner plate clear paint layer is preferably a transparent paint layer.

The thickness of the inner plate clear paint layer is, for example, 10 μm or more. Further, the thickness of the inner plate clear paint layer is 100 μm or less, preferably 50 μm or less.

Next, in this method, the vehicle body part 10 is conveyed to the clear coating downstream section 38 of the clear coating booth 36. In the clear coating downstream section 38, the outer panel of the vehicle body component 10 is coated with clear paint. In other words, a clear paint is applied onto the wet base layer of the outer panel (outer panel clear coating process).

More specifically, in the clear coating downstream section 38, the outer panel of the vehicle body part 10 is coated with clear paint by a worker and/or a robot. Note that the coating conditions are appropriately set depending on the purpose and use.

In this way, an undried paint layer (outer plate clear paint layer) made of clear paint is formed on the outer plate wet base layer. The outer plate clear paint layer is preferably a transparent paint layer.

The thickness of the outer plate clear paint layer is, for example, 10 μm or more. Further, the thickness of the outer plate clear layer is 100 μm or less, preferably 50 μm or less.

Then, in this method, the vehicle body part 10 is transported to the baking booth 39 (see arrow). In the baking booth 39, the vehicle body part 10 is heated by a heating device (a baking process).

The heating method is not particularly limited, and examples include hot air heating, infrared heating, and high frequency heating. Heating conditions are not particularly limited. For example, the heating temperature is, for example, 80 to 170°C. Further, the heating time is, for example, 20 to 60 minutes.

By such heating (baking), the clear paint is dried and the base paint (first paint and second paint) and clear paint are thermally cured.

As a result, a cured coating film of the first paint, a cured coating film of the second paint, and a cured coating film of the clear paint are formed on the outer panel of the vehicle body component 10. Further, a cured coating film of the second paint and a cured coating film of the clear paint are formed on the inner plate of the vehicle body part 10.

As described above, the vehicle body part 10 is colored and painted. As a result, a painted vehicle body part 10 (painted part) is obtained.

(3) Effects In the above painting method, the first outer panel painting step is performed before the second outer panel painting step and the inner panel painting step. Therefore, according to the above-described painting method, it is possible to obtain the vehicle body part 10 with excellent appearance.

That is, in the conventional painting method, the inner panel is first painted with the second paint, and then the outer panel is painted with the first paint and the second paint. That is, in the conventional painting method, first, the second paint is applied to the inner plate, and a second paint layer of the inner plate is formed in accordance with the external appearance color. Next, in the conventional painting method, a first paint is applied to the outer panel to form a first outer panel paint layer that hides the base. Thereafter, in the conventional painting method, a second paint is applied to the outer panel to form a second outer panel paint layer corresponding to the external appearance color. If the first paint and the second paint are applied in this order, the first paint may be scattered onto the second paint layer of the inner plate when the first paint is applied to the outer plate. In other words, the second paint layer of the inner plate, which gives off the exterior color, may be contaminated by the first paint layer that hides the base. In such a case, the appearance of the vehicle body part 10, especially the appearance of the inner plate, deteriorates.

In addition, in such a case, when applying the second paint to the outer panel, it is considered that the second paint is also applied over the first paint scattered on the inner panel. In other words, it is considered to cover the first paint splashed on the inner plate with the second paint. However, when covering the entire surface of the first paint splashed on the inner plate with the second paint, it takes time and cost.

On the other hand, in the above-mentioned painting method, the outer panel is first painted with the first paint, then the inner panel is painted with the second paint, and then the outer panel is painted with the second paint.

When the first paint and the second paint are applied in this order, the first paint that is scattered on the inner panel when the first paint is applied to the outer panel will be removed when the inner panel is coated with the second paint. When painted with a second paint, it is covered with a second paint. Therefore, the entire surface of the first paint splashed on the inner plate can be covered with the second paint while reducing labor and cost. As a result, a vehicle body part 10 with excellent appearance can be obtained.

(4) Modifications In the above painting method, the colored paint can include a main paint and a sub paint.

For example, when the car body part 10 is painted in two-tone color, the colored paint can include a paint (main color paint) that emits a predetermined color (main color) as a main paint, and further, as a sub-paint, It can include a paint (subcolor paint) that emits a color (subcolor) different from the predetermined color.

Further, for example, when the car body part 10 is painted with a high design, the colored paint can include the above-mentioned first paint and second paint as the main paint, and further, the first paint and the second paint as the sub-paints. A third paint different from the paint can be included.

Hereinafter, as modified examples, a second embodiment and a third embodiment in which the vehicle body part 10 is painted in two-tone colors will be described. Further, as a modification, a fourth embodiment in which the vehicle body part 10 is painted with a high design will be described.

2. Second Embodiment (1) Overall configuration of painting line FIG. 2 is a schematic diagram showing a second embodiment of the painting method of the present invention. In the painting method shown in FIG. 2, for example, in the painting line 1, an unpainted vehicle body part 10 (unpainted part) is first painted with the main color and then painted with the sub color. As a result, the vehicle body part 10 is painted in two-tone color.

Note that two-tone color refers to a combination of a main color and a sub color that is different from the main color. The main color occupies a relatively wide area of the vehicle body part 10, for example. In the vehicle body part 10, a portion painted in the main color may be referred to as a main color portion. The sub-color occupies a relatively narrow range of the vehicle body part 10, for example. In the vehicle body part 10, a portion painted in a sub color may be referred to as a sub color portion.

In the vehicle body component 10, the area of the main color portion is, for example, 50 area % or more, preferably 70 area % or more with respect to the total painted area of the vehicle body component 10. Further, in the vehicle body component 10, the area of the sub-color portion is, for example, 50 area % or less, preferably 30 area % or less, with respect to the total painted area of the vehicle body component 10.

The painting line 1 shown in FIG. 2 includes an electrodeposition painting line 2 and a colored painting line 3 for painting the vehicle body parts 10 in two-tone colors.

The electrodeposition coating line 2 is the same as the electrodeposition coating line 2 in the first embodiment described above. In the electrocoating line 2, the outer and inner panels of the vehicle body part 10 are electrocoated.

The color painting line 3 is equipment for first painting the vehicle body parts 10 with a main color paint (main paint) and then painting with a sub color paint (sub paint).

More specifically, the colored painting line 3 includes a main painting line 4, a masking line 6, and a sub-painting line 5. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

The main painting line 4 is equipment for painting the vehicle body parts 10 with a main color paint (main paint). The main color paint (main paint) includes a base paint (hereinafter referred to as main base paint) and a clear paint (hereinafter referred to as main clear paint).

The main base paint includes, for example, the above-mentioned first paint (hereinafter referred to as main first paint) and the above-mentioned second paint (hereinafter referred to as main second paint). The main first paint is applied only to the outer panel of the vehicle body part 10, similar to the first paint in the first embodiment. Further, the main second paint is applied to both the outer panel and the inner panel of the vehicle body component 10, similarly to the second paint of the first embodiment.

The main clear paint is applied to both the outer and inner panels of the vehicle body part 10, similarly to the clear paint of the first embodiment.

More specifically, the main coating line 4 includes a base coating booth 41, a pre-drying booth 45, a clear coating booth 46, and a baking booth 49. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

The main painting line 4 first paints the vehicle body parts 10 with a main base paint, and then paints them with a main clear paint. Note that the main painting line 4 is not equipped with an intermediate coating booth. In other words, the main painting line does not apply intermediate coating to the vehicle body parts 10.

The base painting booth 41 is the same as the base painting booth 31 in the first embodiment described above. Further, the pre-drying booth 45 is the same as the pre-drying booth 35 in the first embodiment described above. Further, the clear coating booth 46 is the same as the clear coating booth 36 in the first embodiment described above. Further, the baking booth 49 is the same as the baking booth 39 in the first embodiment described above.

In the second embodiment, the length of the main painting line 4 (transport distance of the vehicle body parts 10) is appropriately set depending on the purpose and use. The length of the main painting line 4 is substantially the same as the length of the colored painting line 3 (transport distance of the vehicle body part 10) in the first embodiment. The length of the main painting line 4 is, for example, 100 m or more and 150 m or less.

The masking line 6 is equipment for masking a part of the vehicle body part 10. The masking line 6 has a masking booth 61. In the masking booth 61, a part of the vehicle body part 10 is masked with a masking material by a worker and/or a robot. Examples of the masking material include a masking film, a masking tape, and a masking sheet. These can be used alone or in combination of two or more.

The sub-painting line 5 is equipment for painting the vehicle body parts 10 with a sub-color paint (sub-paint). The sub-color paint (sub-paint) includes a base paint (hereinafter referred to as sub-base paint) and a clear paint (hereinafter referred to as sub-clear paint).

The sub-base paint includes, for example, the above first paint (hereinafter referred to as sub-first paint) and the above-mentioned second paint (hereinafter referred to as sub-second paint). The sub-first paint is applied only to the outer panel of the vehicle body part 10, similarly to the first paint of the first embodiment. Further, the sub-second paint is applied to both the outer panel and the inner panel of the vehicle body component 10, similarly to the second paint of the first embodiment.

The sub-clear paint is applied to both the outer and inner panels of the vehicle body part 10, similarly to the clear paint of the first embodiment.

More specifically, the sub-painting line 5 includes a base painting booth 51, a pre-drying booth 55, a clear painting booth 56, and a baking booth 59. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

The sub-painting line 5 first paints the vehicle body parts 10 with a sub-base paint and then with a sub-clear paint. Note that the sub-painting line 5 is not equipped with an intermediate coating booth. In other words, the sub-painting line does not apply intermediate coating to the vehicle body parts 10.

The base painting booth 51 is the same as the base painting booth 31 in the first embodiment described above. Further, the pre-drying booth 55 is the same as the pre-drying booth 35 in the first embodiment described above. Further, the clear coating booth 56 is the same as the clear coating booth 36 in the first embodiment described above. Further, the baking booth 59 is the same as the baking booth 39 in the first embodiment described above.

In the second embodiment, the length of the sub-painting line 5 (transport distance of the vehicle body part 10) is appropriately set depending on the purpose and use. The length of the sub-painting line 5 in the second embodiment is shorter than the length of the main painting line 4 (transport distance of the vehicle body parts 10). The length of the sub-painting line 5 is, for example, 30 m or more and less than 60 m.

(2) Painting method The vehicle body parts 10 are painted in two-tone colors, for example, by the above-mentioned painting line 1 while being conveyed in a predetermined direction by a conveyor (not shown). The method for painting the vehicle body part 10 will be described in detail below.

In this method, the vehicle body part 10 is first transported to the electrodeposition coating line 2. In the electrodeposition coating line 2, the vehicle body parts 10 are electrocoated using the same method as in the first embodiment. As a result, an electrodeposition layer (undercoat layer) is formed on the surface of the vehicle body part 10 (electrodeposition coating process).

Next, in this method, the electrocoated vehicle body part 10 is transported to the main painting line 4 (see arrow). In the main painting line 4, main color paint (main paint) is applied to the vehicle body parts 10 (main painting process).

More specifically, in the main painting line 4, for example, the vehicle body parts 10 are transported by a conveyor (not shown). Then, the outer and inner panels of the vehicle body part 10 are painted with the main color paint (main paint) in the same manner as the color painting process in the first embodiment.

That is, in the base painting upstream section 42 of the main painting line 4, the outer panel of the vehicle body part 10 is first painted with the main first paint (achromatic paint). Next, in the base painting midstream section 43, the inner plate of the vehicle body part 10 is painted with the main second paint. Next, in the base painting downstream section 44, the outer panel of the vehicle body part 10 is painted with the main second paint. Next, the vehicle body part 10 is pre-dried in the pre-drying booth 45.

Next, in the clear coating upstream section 47, the inner plate of the vehicle body part 10 is coated with the main clear coating. Next, in the clear coating downstream section 48, the outer panel of the vehicle body part 10 is coated with the main clear coating. Thereafter, the vehicle body part 10 is heated (baked) in the baking booth 49.

In this way, the vehicle body part 10 is painted (main paint) with the main color paint (main paint).

On the other hand, in the main painting line 4, the main color paint (main paint) may scatter onto unpainted sub-color parts. However, the scattered main color paint (main paint) is covered with a sub color paint (sub paint) by the following method.

That is, in this method, the main painted vehicle body part 10 is conveyed to the masking line 6 (see arrow). In the masking line 6, a part (main color part) of the vehicle body part 10 is masked. That is, in the masking line 6, the main collar portion of the vehicle body part 10 is covered with a known masking material (masking step).

As a result, at the masking line 6, the remaining portion (sub-color portion) of the above-mentioned portion of the vehicle body component 10 is exposed from the masking material. That is, in the masking line 6, the unpainted sub-color portion of the vehicle body part 10 is exposed from the masking material. Hereinafter, the portion exposed from the masking material will be referred to as a non-masking portion.

Next, in this method, the vehicle body part 10 is transported to the sub-painting line 5 (see arrow). In the sub-painting line 5, a sub-color paint (sub-paint) is applied to an unpainted sub-color part (non-masking part) (sub-painting process).

More specifically, in the sub-painting line 5, for example, vehicle body parts 10 are conveyed by a conveyor (not shown). Then, the non-masking portion of the vehicle body part 10 is painted with a sub-color paint (sub-paint) in the same manner as the color painting process in the first embodiment.

That is, in the base painting upstream portion 52 of the sub-painting line 5, the non-masking portion of the outer panel of the vehicle body component 10 is first painted with the sub-first paint (achromatic paint). Next, in the base painting midstream portion 53, the non-masking portion of the inner plate of the vehicle body component 10 is painted with the sub-second paint. Next, in the base painting downstream section 54, the non-masking portion of the outer panel of the vehicle body component 10 is painted with the sub-second paint. Next, the vehicle body part 10 is pre-dried in the pre-drying booth 55.

Next, in the clear coating upstream section 57, the non-masking portion of the inner plate of the vehicle body component 10 is coated with a sub-clear coating. Next, in the clear coating downstream section 58, the non-masking portion of the outer panel of the vehicle body component 10 is coated with a sub-clear coating. Thereafter, the masking material is removed, and the vehicle body part 10 is heated (baked) in the baking booth 59.

In this way, the non-masking portion of the vehicle body part 10 is painted (sub-painting) with the sub-color paint (sub-paint).

Note that in the sub-painting line 5, the portion covered with the masking material is not painted (sub-painted) with the sub-color paint (sub-paint) and is maintained in a main-painted state.

(3) Effects In the second embodiment described above, the vehicle body part 10 is painted in two-tone colors using a main color paint (main paint) and a sub color paint (sub paint). According to the above coating method, a vehicle body part 10 having an excellent appearance can be obtained.

In particular, in the above method, the main painting process and the sub-painting process include a first outer panel painting process, a second outer panel painting process, and an inner panel painting process. The first outer panel painting process is performed before the second outer panel painting process and the inner panel painting process. Therefore, according to the above-mentioned painting method, a vehicle body part 10 having an excellent appearance can be obtained.

Furthermore, in the second embodiment described above, the sub-painting process is performed after the main painting process. That is, in the second embodiment described above, the vehicle body component 10 is first subjected to main painting, then the main color portion is masked, and then the vehicle body component 10 is sub-painted. In such a case, the area of the portion exposed from the masking material (non-masking portion) is relatively small. Therefore, compared to the second embodiment described above, the amount of sub-paint used is smaller.

Therefore, in the second embodiment, the consumption amount of the sub-paint can be reduced compared to the third embodiment (in other words, the sub-paint is applied first and then the main paint is applied), which will be described later. As a result, the cost derived from the sub-paint can be reduced and environmental friendliness can be improved.

3. Third Embodiment (1) Overall configuration of painting line FIG. 3 is a schematic diagram showing a third embodiment of the painting method of the present invention. In the painting method shown in FIG. 3, for example, in the painting line 1, an unpainted vehicle body part 10 (unpainted part) is first painted with a sub color, and then painted with a main color. As a result, the vehicle body part 10 is painted in two-tone color.

More specifically, the painting line 1 shown in FIG. 3 includes an electrodeposition painting line 2 and a colored painting line 3 in order to apply two-tone color painting to the vehicle body parts 10.

The electrodeposition coating line 2 is the same as the electrodeposition coating line 2 in the first embodiment described above. In the electrocoating line 2, the outer and inner panels of the vehicle body part 10 are electrocoated.

The color painting line 3 is equipment for first painting the vehicle body parts 10 with a sub-color paint (sub-paint), and then painting it with a main-color paint (main paint).

More specifically, the colored painting line 3 includes the above-mentioned sub-painting line 5, the above-mentioned masking line 6, and the above-mentioned main painting line 4. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

That is, the main painting line 4 and the sub-painting line 5 in the third embodiment are arranged opposite to the main painting line 4 and the sub-painting line 5 in the second embodiment.

In the third embodiment, the length of the main painting line 4 (transport distance of the vehicle body parts 10) is appropriately set depending on the purpose and use. The length of the main painting line 4 is substantially the same as the length of the colored painting line 3 (transport distance of the vehicle body part 10) in the first embodiment. The length of the main painting line 4 is, for example, 100 m or more and 150 m or less.

In the third embodiment, the length of the sub-painting line 5 (transport distance of the vehicle body part 10) is appropriately set depending on the purpose and use. The length of the sub-painting line 5 in the third embodiment is longer than the length of the sub-painting line 5 in the second embodiment, and shorter than the length of the main painting line 4 (transport distance of the vehicle body part 10). In the third embodiment, the length of the sub-painting line 5 is, for example, 60 m or more and 130 m or less.

(2) Painting method The vehicle body parts 10 are painted in two-tone colors, for example, by the above-mentioned painting line 1 while being conveyed in a predetermined direction by a conveyor (not shown). The method for painting the vehicle body part 10 will be described in detail below.

In this method, the vehicle body part 10 is first transported to the electrodeposition coating line 2. In the electrodeposition coating line 2, the vehicle body parts 10 are electrocoated using the same method as in the first embodiment. As a result, an electrodeposition layer (undercoat layer) is formed on the surface of the vehicle body part 10 (electrodeposition coating process).

Next, in this method, the electrocoated vehicle body part 10 is transported to the sub-painting line 5 (see arrow). In the sub-painting line 5, a sub-color paint (sub-paint) is applied to the vehicle body parts 10 (sub-painting process).

More specifically, in the sub-painting line 5, for example, vehicle body parts 10 are conveyed by a conveyor (not shown). Then, the remaining portions of the outer and inner panels of the vehicle body part 10 are painted with a sub-color paint (sub-paint) in the same manner as the color painting process in the first embodiment (sub-painting process).

That is, in the base painting upstream section 52 of the sub-painting line 5, the outer panel of the vehicle body part 10 is first painted with the sub-first paint (achromatic paint). Next, in the base painting midstream section 53, the inner plate of the vehicle body part 10 is painted with the sub-second paint. Next, in the base painting downstream section 54, the outer panel of the vehicle body component 10 is painted with the sub-second paint. Next, the vehicle body part 10 is pre-dried in the pre-drying booth 55.

Next, in the clear coating upstream section 57, the inner plate of the vehicle body part 10 is coated with a sub-clear coating. Next, in the clear coating downstream section 58, the outer panel of the vehicle body part 10 is coated with a sub-clear coating. Thereafter, the vehicle body part 10 is heated (baked) in the baking booth 59.

In this way, the vehicle body part 10 is painted (main painting) with the mesa color paint (sub paint).

On the other hand, in the sub-painting line 5, the sub-color paint (sub-paint) may scatter onto the unpainted main color portion. However, the scattered sub-color paint (sub-paint) is covered with the main color paint (main paint) by the following method.

That is, in this method, the sub-painted vehicle body part 10 is conveyed to the masking line 6 (see arrow). In the masking line 6, a part (sub-color part) of the vehicle body part 10 is masked. That is, in the masking line 6, the sub-color portion of the vehicle body part 10 is covered with a known masking material (masking step).

As a result, at the masking line 6, the remaining portion (main collar portion) of the above-mentioned portion of the vehicle body component 10 is exposed from the masking material. That is, in the masking line 6, the unpainted main color portion of the vehicle body part 10 is exposed from the masking material. Hereinafter, the portion exposed from the masking material will be referred to as a non-masking portion.

Then, in this method, the vehicle body part 10 is transported to the main painting line 4 (see arrow). In the main painting line 4, the main color paint (main paint) is applied to the unpainted main color part (non-masking part) (main painting process).

More specifically, in the main painting line 4, for example, the vehicle body parts 10 are transported by a conveyor (not shown). Then, the non-masking portions of the vehicle body part 10 are painted with the main color paint (main paint) in the same manner as the color painting process in the first embodiment.

That is, in the base painting upstream section 42 of the main painting line 4, first, the non-masking portion of the outer panel of the vehicle body component 10 is painted with the main first paint (achromatic paint). Next, in the base painting midstream part 43, the non-masking part of the inner plate of the vehicle body part 10 is painted with the main second paint. Next, in the base painting downstream section 44, the non-masking portion of the outer panel of the vehicle body component 10 is painted with the main second paint. Next, the vehicle body part 10 is pre-dried in the pre-drying booth 45.

Next, in the clear coating upstream section 47, the non-masking portion of the inner plate of the vehicle body component 10 is coated with the main clear coating. Next, in the clear coating downstream section 48, the non-masking portion of the outer panel of the vehicle body component 10 is coated with the main clear coating. Thereafter, the masking material is removed, and the vehicle body part 10 is heated (baked) in the baking booth 49.

In this way, the non-masking portions of the vehicle body part 10 are painted (main paint) with the main color paint (main paint).

In the main painting line 4, the portion covered with the masking material is not painted with the main paint (main paint) and is maintained in a sub-painted state.
(3) Effects Also in the third embodiment described above, the vehicle body part 10 is painted in two-tone color using the main color paint (main paint) and the sub color paint (sub paint). According to the above coating method, a vehicle body part 10 having an excellent appearance can be obtained.

In particular, in the above method, the main painting process and the sub-painting process include a first outer panel painting process, a second outer panel painting process, and an inner panel painting process. The first outer panel painting process is performed before the second outer panel painting process and the inner panel painting process. Therefore, according to the above-mentioned painting method, a vehicle body part 10 having an excellent appearance can be obtained.

Furthermore, in the third embodiment described above, the sub-painting process is performed before the main painting process. That is, in the third embodiment described above, first, the vehicle body component 10 is sub-painted, then the sub-color portion is masked, and then the vehicle body component 10 is main-painted. In such a case, since the masking material is placed only in the sub-color portion, the amount of masking material used is smaller than in the second embodiment described above.

Therefore, in the third embodiment, the amount of masking material consumed can be reduced compared to the second embodiment described above (that is, the main paint is applied first, and then the sub paint is applied). As a result, the cost derived from the masking material can be reduced and environmental friendliness can be improved.

4. Fourth Embodiment (1) Overall configuration of painting line FIG. 4 is a schematic diagram showing a fourth embodiment of the painting method of the present invention. In the painting method shown in FIG. 4, for example, in the painting line 1, an unpainted vehicle body part 10 (unpainted part) is painted with a high design.

In high-design painting, for example, the colored paint includes the above-mentioned first paint and second paint as the main paint, and further includes a third paint different from the first paint and the second paint as the sub-paint. Note that the third paint is, for example, a top coat that is applied over the second paint in high design painting.

The third paint may be an achromatic paint or a chromatic paint. The third paint is appropriately selected depending on the desired color. The third paint is preferably a chromatic paint.

The third paint may be, for example, a water-based paint or an oil-based paint. More specifically, the third paint contains, for example, a third solvent, a third resin, a third curing agent, and a third pigment.

Examples of the third solvent include the above-mentioned aqueous solvents and/or the above-mentioned oily solvents. These can be used alone or in combination of two or more. The third solvent is preferably an aqueous solvent, more preferably water. That is, preferably the third paint is a water-based paint.

Examples of the third resin include acrylic resin, polyester resin, alkyd resin, urethane resin, epoxy resin, and acid-modified epoxy resin. These can be used alone or in combination of two or more.

The third curing agent is dissolved and/or dispersed in the third solvent and cures (crosslinks) the third resin. The third curing agent is appropriately selected depending on the type of the third resin. Examples of the third curing agent include block polyisocyanate, melamine resin, and urea resin. These can be used alone or in combination of two or more.

The third pigment is dissolved and/or dispersed in the third solvent and colors the third paint. Examples of the third pigment include achromatic pigments, chromatic pigments, and metallic pigments. Examples of achromatic pigments include carbon black, zinc oxide, and titanium oxide. Examples of chromatic pigments include cadmium red, molybdenum red, titanium yellow, chrome yellow, cobalt blue, and Prussian blue. Examples of the metallic pigment include aluminum powder, flaky aluminum oxide, pearl mica, and flaky mica. These can be used alone or in combination of two or more.

Preferably, the third pigment includes a chromatic pigment and/or a metallic pigment. If the third pigment is a chromatic pigment and/or a metallic pigment, the inner plate is painted with a chromatic color and/or metallic in the inner plate coating process. More preferred examples of the third pigment include chromatic pigments.

The blending ratio of the third solvent, the third resin, the third curing agent, and the third pigment is appropriately set depending on the purpose and use. Further, the third paint can contain known additives, if necessary. Additives include, for example, ultraviolet absorbers, shock absorbers, and curing catalysts. The solid content concentration of the third paint is, for example, 20% by mass or more and 50% by mass or less.

The third paint is applied, for example, in the base painting booth 51 of the sub-painting line 5 described above.

More specifically, in the highly designed painting shown in FIG. 4, the painting line 1 in the second embodiment is commonly used as the painting line 1. That is, the coating line 1 includes the above-mentioned electrodeposition coating line 2 and the colored coating line 3. Further, the colored painting line 3 includes a main painting line 4, a masking line 6, and a sub painting line 5. These are sequentially arranged along the flow direction (arrow direction) of the conveyor, as shown in FIG.

(2) Painting method The vehicle body part 10 is painted with a high design, for example, by the above-mentioned painting line 1 while being conveyed in a predetermined direction by a conveyor (not shown). The method for painting the vehicle body part 10 will be described in detail below.

In this method, the vehicle body part 10 is first transported to the electrodeposition coating line 2. In the electrodeposition coating line 2, the vehicle body parts 10 are electrocoated using the same method as in the first embodiment. As a result, an electrodeposition layer (undercoat layer) is formed on the surface of the vehicle body part 10 (electrodeposition coating process).

In this method, for example, the painting line 1 in the second embodiment is used. That is, the painting line 1 can be shared between the second embodiment (two-tone painting) and the fourth embodiment (high design painting). Then, the vehicle body part 10 is first transported to the electrodeposition coating line 2. In the electrodeposition coating line 2, the vehicle body parts 10 are electrocoated using the same method as in the first embodiment (electrodeposition coating process).

Next, in this method, the electrocoated vehicle body part 10 is transported to the main painting line 4 (see arrow). In the main painting line 4, the first paint and the second paint (main paint) are applied to the vehicle body parts 10 (main painting process).

More specifically, in the main painting line 4, for example, the vehicle body parts 10 are transported by a conveyor (not shown). Then, in the base painting booth 41, the outer and inner panels of the vehicle body part 10 are painted with the first paint and the second paint (main paint) in the same manner as the color painting process in the first embodiment.

Next, the vehicle body part 10 passes through the pre-drying booth 45 without being pre-dried.

Next, the vehicle body part 10 passes through the clear coating booth 46 without being coated with clear coating.

Next, the vehicle body part 10 passes through the baking booth 49 without being baked.

Next, the vehicle body part 10 passes through the masking booth 61 without being masked.

Next, the vehicle body part 10 is transported to the sub-painting line 5 (see arrow). In the sub-painting line 5, a third paint (sub-paint) is applied to the vehicle body parts 10 (sub-painting process, high-design top-coating process).

More specifically, the vehicle body part 10 passes through the base painting upstream section 52. Then, the inner plate of the vehicle body part 10 is painted with the third paint in the base painting midstream section 53 by an operator and/or a robot. That is, the third paint for high design painting is applied over the second paint for the inner panel. Note that the coating conditions are appropriately set depending on the purpose and use.

Thereafter, the vehicle body part 10 is transported to the base painting downstream section 54. Then, the outer panel of the vehicle body part 10 is painted with the third paint in the base painting downstream section 54 by an operator and/or a robot. That is, the third paint for high design painting is applied over the second paint for the outer panel. Note that the coating conditions are appropriately set depending on the purpose and use.

Next, the vehicle body part 10 is pre-dried in the pre-drying booth 55. Next, in the clear coating upstream section 57, the inner plate of the vehicle body part 10 is coated with clear coating. Next, in the clear coating downstream section 58, the outer panel of the vehicle body part 10 is coated with a clear coating. Thereafter, the vehicle body part 10 is heated (baked) in the baking booth 59.

In this way, the vehicle body part 10 is painted with a high design using the first paint, the second paint, and the third paint.

(3) Effects In the fourth embodiment described above, the vehicle body part 10 is painted with a high design using the first paint, the second paint (main paint), and the third paint. According to the above-described coating method, a vehicle body part 10 having a particularly excellent appearance can be obtained.

Although the embodiment has been described in which the third paint (sub-paint) is a top coat in high-design painting, the third paint may be an undercoat in high-design paint. In such a case, the painting line 1 in the third embodiment may be employed as the painting line 1. That is, the third paint may be applied first in the sub-painting line 5, and then the first paint and the second paint may be applied in the main painting line 4.

Further, in the fourth embodiment described above, the painting line 1 in the second embodiment is used as the painting line 1, but the painting line 1 in the third embodiment, for example, is used as the painting line 1. Good too.

Further, in the fourth embodiment described above, the first paint and the second paint are applied in the base painting booth 41, and the third paint is applied in the base painting booth 51, but these combinations are not particularly limited. Not done. For example, the first paint may be applied in the base paint booth 41, and the second paint and the third paint may be applied in the base paint booth 51.

Furthermore, in the above description, the first outer panel painting step is performed before the second outer panel painting step and the inner panel painting step in the base painting step.

That is, in the above description, first, the first outer panel painting step is performed, then the inner panel painting step is performed, and then the second outer panel painting step is performed.

However, the order of the second outer panel painting step and the inner panel painting step is not particularly limited. That is, the first outer panel painting process may be performed first, then the second outer panel painting process may be performed, and then the inner panel painting process may be performed.

From the viewpoint of obtaining a more excellent appearance, preferably, first, the first outer panel painting step is performed, then the inner panel painting step is performed, and then the second outer panel painting step is performed. That is, preferably, the inner panel painting step is performed after the first outer panel painting step and before the second outer panel painting step. Further, the second outer panel painting step is performed after the first outer panel painting step and after the inner panel painting step. This makes it possible to obtain a particularly good appearance on the outer panel.

1 Paint line 2 Electrodeposition paint line 3 Colored paint line 10 Car body parts 21 Electrodeposition paint booth 31 Base paint booth 32 Base paint upstream part 33 Base paint midstream part 34 Base paint downstream part 35 Pre-drying booth 36 Clear paint booth 37 Clear paint Upstream section 38 Clear coating downstream section 39 Baking booth

Claims (3)

A painting method for painting a vehicle body part comprising an outer panel and an inner panel, the method comprising:
an outer panel first painting step of coating the outer panel with an achromatic first paint to form an outer panel first paint layer;
a second outer panel painting step of applying a second paint to the first outer panel paint layer to form a second outer panel paint layer;
an inner plate painting step of applying the second paint to the inner plate to form a second inner plate paint layer;
A painting method, wherein the first outer panel painting step is performed before the second outer panel painting step and the inner panel painting step. The inner panel painting step is performed after the outer panel first painting step,
The painting method according to claim 1, wherein the second outer panel painting step is performed after the inner panel painting step. a main painting process of applying a main paint to the vehicle body parts;
a sub-painting step of applying a sub-paint to the vehicle body parts;
At least the main painting step includes the first outer panel painting step, the second outer panel painting step, and the inner panel painting step,
The painting method according to claim 1, wherein the sub-painting process is performed before or after the main painting process.