Painting system and painting method using the same

Abstract

To form a uniform thin film in painting using indium paint, minimize paint consumption, shorten painting time, and downsize painting equipment. [Solution] A painting system that paints a workpiece W by forming an undercoat layer with primer paint, then a middle coat layer with indium paint, and then a top coat layer with topcoat paint. The system is equipped with a workpiece fixing means 2 that fixes the workpiece, a spray gun device 6 having three support arms 63 equipped with an undercoat spray gun 7a that sprays the primer paint, a middle coat spray gun 7b that sprays the indium paint, and a top coat spray gun 7c that sprays the topcoat paint, a paint supply means that supplies paint to each spray gun, and a paint filling means that fills each paint supply means with paint. The paint supply means that supplies the indium paint is mounted on a painting robot, and the support arm is rotated to change the spray gun used.

Description

[Technical Field]

[0001] The present invention relates to a coating system using indium paint and a coating method using the same, and more particularly to a coating system and a coating method using the same that, when coating with indium paint, makes it possible to minimize the amount of indium paint used by eliminating paint waste, shorten coating time, and further make it possible to downsize the coating equipment. [Background technology]

[0002] There have been a wide variety of methods for adding value to products to increase consumer purchasing power, and in recent years, the use of mirror-like designs on products has become increasingly common. For example, mirror designs are being applied to vehicle parts such as automobile door mirrors, office automation equipment, and home appliances.

[0003] Conventionally, plating and vapor deposition processes have been known as means for imparting a mirror-like design to products, but plating has the drawback of placing a heavy burden on the environment in terms of wastewater treatment and the like.

[0004] Furthermore, in the case of vapor deposition processing, special equipment is required, the equipment is large-scale and costly, and furthermore, because it is a batch type, continuous line production is not possible.

[0005] Therefore, spray-on plating (mirror coating systems) have been developed as a way to solve the problems mentioned above with vapor deposition processing. This plating mirror coating system began with the first generation silver mirror coating (a reaction between silver nitrate and ammonium), followed by the second generation silver colloid and silver complex.

[0006] However, these first and second generation methods had problems with weather resistance, corrosion resistance, and paint unit cost, making it difficult to deploy them for industrial use. Therefore, the "Indium Mirror Coating System," which uses indium paint with excellent weather resistance and corrosion resistance, was born as a third generation method to solve these problems of the first and second generations.

[0007] To briefly explain indium, as is well known, it is a rare metal with atomic number 49 and chemical symbol In. When indium is in its pure form, it is soft and silvery-blue-white in color, and is stable at room temperature. It also has a low melting point, making it easy to handle. It is electrically conductive and transparent, possessing the unusual property of being able to transmit millimeter waves when formed into a thin film, and it also has excellent weather resistance and corrosion resistance.

[0008] This indium paint is made from an indium suspension, and can be sprayed to achieve a mirror finish (mirror coating). It can be applied at low temperatures (80°C) and is suitable for a wide range of substrates, making it suitable for any material. Furthermore, as mentioned above, indium has excellent weather resistance and corrosion resistance, making it suitable for use on automotive exterior parts, which have been difficult to apply in the past.

[0009] In recent years, the housings of mobile phones, electronic devices, and information terminals, as well as automobile parts (front grilles, bumpers), have come to require not only mirrored designs but also radio wave transparency, and indium paint, which uses indium with radio wave transparency, can meet these requirements. Mobile phones, electronic devices, and information terminals have antennas inside their housings, so they need to be radio wave transparent. Furthermore, antennas for various radar devices, such as those used for distance measurement, are installed near automobile front grilles and bumpers, so radio wave transparency is also required. Indium paint, which uses indium with radio wave transparency, can be used to paint these parts. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 7146311 Summary of the Invention [Problem to be solved by the invention]

[0011] In order to stabilize the mirror surface properties of the mirror layer and maximize its effectiveness, it is necessary to uniformly conceal the base and form a film that is as thin as possible. With indium paint, it is sufficient to be able to conceal the base, so the thickness of the mirror layer can be at the 400 nm (nanometer) level. However, with conventional hand-sprayed painting and mesh painting, it has been pointed out that applying a thin coat results in unevenness, making it difficult to apply a uniform, thin coat.

[0012] , Furthermore, since indium is expensive like silver, it is important to minimize the consumption of indium paint in order to popularize coating methods using indium paint for industrial use. Therefore, a challenge in the field of indium coating has traditionally been to provide a coating method that minimizes the consumption of indium paint.

[0013] Incidentally, painting a workpiece involves a process of applying paint to the workpiece and a drying process of drying the paint applied to the workpiece and baking it onto the workpiece. However, the drying process for typical paint involves blowing hot air at around 80 degrees onto the workpiece for 30 to 40 minutes, which has been pointed out as a problem that lengthens the painting time.

[0014] In this regard, as mentioned above, indium paint only needs to be able to conceal the base, so a film thickness of 400 nm (nanometers) is sufficient, and therefore, unlike normal paint, the drying time can be as short as about 5 minutes of blowing hot air at about 80 degrees, but even when using indium paint, a drying process is essential, which lengthens the painting time. Furthermore, in order to dry the paint in the drying oven, it is first necessary to raise the temperature inside the oven, which takes about 30 to 40 minutes, so there is a problem that the overall drying time is long even when using indium paint.

[0015] Furthermore, in coating using indium paint, rather than applying the indium paint directly to the workpiece, a process is generally adopted in which a primer paint is first applied to the workpiece, then an indium paint is applied on top of the primer paint to form a mirror layer, and then a top coat paint is applied to the mirror layer to complete the coating. However, if the same spray gun is used for the primer paint, indium paint, and top coat paint, the spray gun must be cleaned every time the paint is changed, which is time-consuming and labor-intensive. Therefore, in indium paint, a spray gun for the primer paint, a spray gun for the indium paint, and a top coat are provided separately, and the coating time is shortened by eliminating the spray gun cleaning process. However, simply installing three spray guns in a coating device can be problematic in that the coating device becomes large.

[0016] Therefore, the present invention aims to solve these problems associated with painting using indium paint, and to provide a painting system and a painting method using the same that can form a uniform thin film, minimize paint consumption, shorten painting time, and further enable the painting equipment to be made smaller. [Means for solving the problem]

[0017] The coating system of the present invention comprises: A coating system for coating a workpiece by applying a primer paint to form an undercoat layer as a first layer, then applying an indium paint to form a middle coat layer as a second layer, and then applying a top coat paint to form a top coat layer as a third layer, a workpiece fixing means for mounting a workpiece to be coated; a spray gun device including three spray guns for spraying paint toward a workpiece attached to a workpiece fixing means; a coating robot for moving the spray gun according to preset trajectory data; a paint supply means for supplying paint to each of the spray guns; a paint hose connecting the paint supply means and the spray gun; a paint filling means for filling each of the paint supply means with paint, The workpiece fixing means is The apparatus includes a rotatable rotation shaft and a fixing jig connected to the rotation shaft, and the workpiece can be revolved around the rotation shaft by rotating the rotation shaft with the workpiece fixed to the fixing jig; The spray gun device is The coating device comprises a main body that is attached to a coating robot, and a support that is rotatably connected to the tip of the main body, and the support has three long support arms to each of which a spray gun is attached when coating a workpiece, and the support arms are connected to each other at their base ends so that their tips are radially arranged with their tips facing outward, and the positions of the spray guns attached to the support arms can be changed by rotating the support. The spray guns attached to the three support arms are: an undercoat spray gun for spraying the primer paint, a middle coat spray gun for spraying the indium paint, and a top coat spray gun for spraying the top coat paint; The paint supply means is The spray gun for the undercoat is provided with an undercoat paint supply means for supplying an undercoat paint to the undercoat spray gun, an indium paint supply means for supplying an indium paint to the middle coat spray gun, and a topcoat paint supply means for supplying a topcoat paint to the topcoat spray gun, The paint hose is The apparatus comprises an undercoat paint supply hose connecting the undercoat spray gun and a primer paint supply means, an indium paint supply hose connecting the middle coat spray gun and an indium paint supply means, and a topcoat paint supply hose connecting the topcoat spray gun and a topcoat paint supply means, the paint filling means comprises an undercoat paint filling means for filling the undercoat paint supply means with an undercoat paint, an indium paint filling means for filling the indium paint supply means with an indium paint, and a topcoat paint filling means for filling the topcoat paint supply means with a topcoat paint; The indium paint supply means is mounted on the painting robot, After filling the primer paint supply means with primer paint, filling the indium paint supply means with indium paint, and filling the top coat paint supply means with top coat paint, Fix the workpiece to the fixture, By rotating the support part, the position of the undercoat spray gun is adjusted so that it can spray paint toward the workpiece. While the workpiece is revolving around the rotating shaft, an undercoat layer is formed by spraying primer paint from an undercoat spray gun onto the revolving workpiece. Next, by rotating the support part, the position of the middle coat spray gun is adjusted to a position where the paint can be sprayed toward the workpiece, and then the indium paint is sprayed from the middle coat spray gun to form a middle coat layer as a mirror layer; The support part is then rotated to adjust the position of the top coat spray gun to a position where the paint can be sprayed toward the workpiece, and the top coat paint is then sprayed from the top coat spray gun to form a top coat layer, thereby painting the workpiece.This is a painting system characterized by this.

[0018] In the coating method of the present invention, A coating method for coating a workpiece by forming an undercoat layer as a first layer by applying a primer paint, forming a middle coat layer as a second layer by applying an indium paint, and forming a top coat layer as a third layer by applying a top coat paint, The spray gun device comprises a workpiece fixing means for mounting a workpiece to be painted, three spray guns for spraying paint toward the workpiece mounted on the workpiece fixing means, a painting robot for moving the spray guns according to preset trajectory data, paint supply means for supplying paint to the spray guns, a paint hose connecting the paint supply means and the spray guns, and paint filling means for filling the paint supply means with paint, the workpiece fixing means comprises a rotatable rotation shaft and a fixing jig connected to the rotation shaft, and by rotating the rotation shaft with the workpiece fixed to the fixing jig, the workpiece can revolve around the rotation shaft; The spray gun device is The coating device comprises a main body that is attached to a coating robot, and a support that is rotatably connected to the tip of the main body, and the support has three long support arms to each of which a spray gun is attached when coating a workpiece, and the support arms are connected to each other at their base ends so that their tips are radially arranged with their tips facing outward, and the positions of the spray guns attached to the support arms can be changed by rotating the support. the spray guns attached to the three support arms are an undercoat spray gun for spraying a primer paint, a middle coat spray gun for spraying an indium paint, and a top coat spray gun for spraying a top coat paint; the paint supply means comprises an undercoat paint supply means for supplying an undercoat paint to the undercoat spray gun, an indium paint supply means for supplying an indium paint to the middle coat spray gun, and a topcoat paint supply means for supplying a topcoat paint to the topcoat spray gun; The paint hose comprises an undercoat paint supply hose connecting the undercoat spray gun and a primer paint supply means, an indium paint supply hose connecting the middle coat spray gun and an indium paint supply means, and a top coat paint supply hose connecting the top coat spray gun and a top coat paint supply means, the paint filling means comprises an undercoat paint filling means for filling the undercoat paint supply means with an undercoat paint, an indium paint filling means for filling the indium paint supply means with an indium paint, and a topcoat paint filling means for filling the topcoat paint supply means with a topcoat paint; The indium paint supply means is mounted on the painting robot, Filling the primer paint into the primer paint supply means, filling the indium paint into the indium paint supply means, and filling the top coat paint into the top coat paint supply means; Fix the workpiece to the fixture, By rotating the support part, the position of the undercoat spray gun is adjusted so that it can spray paint toward the workpiece. While the workpiece is revolving around the rotating shaft, an undercoat layer is formed by spraying primer paint from an undercoat spray gun onto the revolving workpiece. Next, by rotating the support part, the position of the middle coat spray gun is adjusted to a position where the paint can be sprayed toward the workpiece, and then the indium paint is sprayed from the middle coat spray gun to form a middle coat layer as a mirror layer; The support part is then rotated to adjust the position of the top coat spray gun to a position where the paint can be sprayed toward the workpiece, and the top coat layer is formed by spraying the top coat paint from the top coat spray gun, thereby painting the workpiece. [Effects of the Invention]

[0019] The coating system and coating method of the present invention, which uses the same, is completed by forming three layers: an undercoat as the first layer to improve adhesion between the base and the coating film; a middle coat as the second layer that forms a mirror layer; and a top coat as the third layer that protects the coated surface and enhances color variation. The paint is sprayed using a spray gun, and the middle coat is made of indium paint.Furthermore, the coating system performs rotary coating by revolving the workpiece to be coated, and applying paint to the revolving workpiece.Furthermore, the coating robot is equipped with a paint supply means that supplies indium paint to the spray gun.

[0020] As described above, in the coating system of the present invention, a three-layer coating is applied using a spray gun to form an undercoat, middle coat, and top coat, and because the middle coat is an indium paint, a mirror finish (mirror coating) can be achieved by spray coating, and coating can be performed at low temperatures (80°C) on a wide range of substrates and on any material. Indium also has excellent weather resistance and corrosion resistance, making it possible to paint automotive exterior parts that have previously been difficult to use. Furthermore, because indium is radio wave transparent, the present invention, which uses indium paint, makes it possible to obtain radio wave transparent coated products.

[0021] In this case, the present invention paints the workpiece by rotating the workpiece attached to the workpiece fixing means and spraying paint onto the revolving workpiece using a spray gun. Therefore, unlike painting with a brush or hand-sprayed paint, it is possible to form a uniform thin film at the nano level and minimize the amount of paint used.

[0022] Furthermore, the present invention is equipped with three spray guns: an undercoat spray gun, a middle coat spray gun, and a top coat spray gun. The undercoat is formed using the undercoat spray gun, the middle coat is formed using the middle coat spray gun, and the top coat is formed using the top coat spray gun. This eliminates the need to clean the spray guns each time the paint used for painting is changed, thereby shortening the painting time.

[0023] In this case, the present invention provides a spray gun device that includes a device main body that is attached to the painting robot and a support part that is rotatably connected to the device main body and has three support arms with spray guns attached to the tips of the arms, and the position of the spray gun is changed by rotating the support part. Therefore, unlike when three spray guns are simply attached to the painting robot, it is possible to make the painting system smaller.

[0024] Furthermore, in the coating device of the present invention, a syringe pump that supplies indium paint to the spray gun is mounted on the coating robot, so the distance from the syringe pump to the spray gun can be shortened, minimizing the paint remaining in the paint hose and achieving paint reduction. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a diagram showing an image of an embodiment of a coating system of the present invention. [Figure 2] FIG. 2 is a diagram for explaining a painting robot used in an embodiment of the painting system of the present invention. [Figure 3] 1 is a diagram illustrating a spray gun device used in an embodiment of the coating system of the present invention. FIG. [Figure 4] FIG. 2 is a diagram illustrating a spray gun used in an embodiment of the coating system of the present invention. [Figure 5]1 is a diagram illustrating an indium paint supply means and an indium filling means used in an embodiment of the coating system of the present invention. FIG. [Figure 6] 10A and 10B are diagrams illustrating another form of indium paint filling means used in an embodiment of the painting system of the present invention. [Figure 7] FIG. 2 is a diagram illustrating a primer coating paint supply means and a primer coating paint filling means used in an embodiment of the coating system of the present invention. [Figure 8] 1 is a diagram for explaining the operation of an indium paint supply means used in an embodiment of the coating system of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] The coating system of the present invention is a coating system for coating workpieces by applying a primer paint to form an undercoat layer as the first layer, applying an indium paint to form a middle coat layer as the second layer, and applying a top coat paint to form a top coat layer as the third layer.

[0027] The coating system of the present invention includes a workpiece fixing means for mounting a workpiece to be coated, a spray gun device equipped with three spray guns for spraying paint toward the workpiece mounted on the workpiece fixing means, and a coating robot for moving the spray guns according to preset trajectory data.The coating system of the present invention also includes a paint supply means for supplying paint to the spray guns, a paint filling means for filling the paint supply means with paint, and a paint hose connecting the paint supply means and the spray guns.

[0028] The work fixing means comprises a rotating shaft that can be rotated freely and a fixing jig connected to the rotating shaft. The fixing jig is used to fix the work to be painted to the rotating shaft, and by rotating the rotating shaft with the work fixed to the fixing jig, the work can revolve around the rotating shaft.

[0029] The spray gun device equipped with three spray guns includes a main body that is attached to a painting robot and a support that is rotatably connected to the tip of the main body, and the support has three long support arms to which a spray gun is attached when painting a workpiece. The support arms are connected to each other at their base ends so that they are arranged radially with their tips facing outward, and the positions of the spray guns attached to the support arms can be changed by rotating the support.

[0030] The three spray guns are an undercoat spray gun for spraying primer paint, a middle coat spray gun for spraying indium paint, and a top coat spray gun for spraying top coat paint. The undercoat spray gun sprays the primer paint to form an undercoat layer as the first layer, the middle coat spray gun sprays the indium paint to form a mirror layer as the second layer, and the top coat spray gun sprays the top coat paint to form a top coat layer as the third layer.

[0031] In addition, the paint supply means for supplying paint to the spray guns includes a primer paint supply means for supplying primer paint to the undercoat spray gun, an indium paint supply means for supplying indium paint to the middle coat spray gun, and a top coat paint supply means for supplying top coat paint to the top coat spray gun, and the indium paint supply means is mounted on the painting robot.

[0032] The paint hoses include a primer paint supply hose that connects the undercoat spray gun and primer paint supply means, an indium paint supply hose that connects the middle coat spray gun and indium paint supply means, and a top coat paint supply hose that connects the top coat spray gun and top coat paint supply means.

[0033] Furthermore, the paint filling means includes a primer paint filling means for filling the primer paint supply means with primer paint, an indium paint filling means for filling the indium paint supply means with indium paint, and a top coat paint filling means for filling the top coat paint supply means with top coat paint.

[0034] In these configurations, the coating system of the present invention fills the primer paint supply means with primer paint, fills the indium paint supply means with indium paint, and fills the topcoat paint supply means with topcoat paint, then fixes the workpiece to the fixing jig and rotates the support part to adjust the position of the undercoat spray gun to a position where it can spray the paint toward the workpiece, and while the rotation shaft is rotated to revolve the workpiece, the primer paint is sprayed from the undercoat spray gun toward the revolving workpiece to form an undercoat layer, next rotates the support part to adjust the position of the middle coat spray gun to a position where it can spray the paint toward the workpiece, and then sprays indium paint from the middle coat spray gun to form a middle coat layer as a mirror layer, and then rotates the support part to adjust the position of the top coat spray gun to a position where it can spray the paint toward the workpiece, and then sprays the top coat paint from the top coat spray gun to form a topcoat layer, thereby coating the workpiece.

[0035] Here, the indium paint supply means comprises heating means for heating the indium paint filled in the indium paint supply means, and the indium paint supply hose connecting the middle coat spray gun and the indium paint supply means has heat insulating properties, and the indium paint filled in the indium paint supply means is heated by heating the indium paint supply means with the heating means, and then the heated indium paint is supplied to the middle coat spray gun via the indium paint supply hose and sprayed from the middle coat spray gun. In this way, the indium paint in a heated and increased temperature state is applied to the workpiece while maintaining that temperature, and the evaporation time of the volatile components contained in the indium paint can be shortened, so that the drying time of the indium paint applied to the workpiece can be shortened or omitted, making it possible to shorten the coating time.

[0036] In addition, the indium paint supply means may be a syringe pump having a cylindrical syringe body with an opening at the tip, a piston inserted into the syringe body so as to be able to move back and forth freely, and a piston rod connected to the surface of the piston opposite the opening, and the space formed between the piston and the opening is used as a paint filling space into which paint is filled, and by moving the piston toward the opening when the paint filling space is filled with paint, the indium paint filled in the paint filling space is released from the opening.

[0037] Furthermore, it is preferable that the indium paint supply means be equipped with heating means for heating the indium paint filled in the indium paint supply means, and that the indium paint supply hose connecting the middle coat spray gun and the indium paint supply means be provided with thermal insulation properties.In this case, it is preferable that the heating means for heating the indium paint supply means be composed of a heating medium container containing a heating medium, a heating medium supply hose wrapped around the outer periphery of the syringe body and connected at both ends to the heating medium container, a heat source for heating the heating medium contained in the heating medium container, and a pump for circulating the heating medium contained in the heating medium container through the heating medium supply hose, and that the indium paint in the syringe body be heated by heating the heating medium to a predetermined temperature using the heat source and circulating the heated heating medium through the heating medium supply hose.

[0038] Furthermore, the indium paint filling means for filling the paint filling space of the indium paint supply means with indium paint comprises a main body portion filled with indium paint and a discharge portion formed in the main body portion, and by connecting the discharge portion of the indium paint filling means to an opening of the syringe pump serving as the indium paint supply means, the discharge portion communicates between the paint filling space and the inside of the main body portion, and by retracting the piston of the indium paint supply means in this state to create negative pressure inside the syringe body, the indium paint filled in the main body portion is filled via the discharge portion into the paint filling space of the syringe pump serving as the indium paint supply means.

[0039] Furthermore, the indium paint filling means may also be composed of a main body made of an expandable material and filled with indium paint, a discharge portion formed in the main body, and a storage case that hermetically houses the main body with the discharge portion exposed to the outside, and by connecting the discharge portion of the indium paint filling means to an opening of a syringe pump serving as indium paint supply means, the discharge portion communicates between the paint filling space and the inside of the main body, and by retracting the piston of the indium paint supply means in this state to create negative pressure inside the syringe body, the indium paint filled in the main body may be filled via the discharge portion into the paint filling space of the syringe pump serving as indium paint supply means.

[0040] In the coating method of the present invention, a coating system configured as described above is used, where the primer coating supply means is filled with primer coating, the indium coating supply means is filled with indium coating, the top coating supply means is filled with top coating, and the support part is rotated to adjust the position of the undercoat spray gun to a position where the coating can be sprayed toward the workpiece, and the rotation shaft is rotated to cause the workpiece to revolve, while the primer coating is sprayed from the undercoat spray gun toward the revolving workpiece to form an undercoat layer, next the support part is rotated to adjust the position of the middle coat spray gun to a position where the coating can be sprayed toward the workpiece, and then indium coating is sprayed from the middle coat spray gun to form a middle coat layer as a mirror layer, and thereafter the support part is rotated to adjust the position of the top coat spray gun to a position where the coating can be sprayed toward the workpiece, and then the top coat layer is formed by spraying the top coat coating from the top coat spray gun, thereby coating the workpiece. [Example]

[0041] An embodiment of the coating system of the present invention will be described with reference to the drawings. FIG. 1 is an image diagram for explaining the coating system of this embodiment, in which 1 denotes the coating system of this embodiment and W denotes the work to be coated.

[0042] The coating system 1 of this embodiment includes a workpiece fixing means for mounting the workpiece W to be coated, a spray gun device equipped with three spray guns for spraying paint toward the workpiece W mounted on the workpiece fixing means, a coating robot for moving the spray guns according to trajectory data preset by teaching, a paint supply means for supplying paint to the spray guns, a paint hose connecting the paint supply means to the spray guns, and a paint filling means for filling the paint supply means.The coating system paints the workpiece by applying a primer paint to the workpiece to form an undercoat layer as a first layer, then applying an indium paint to form a middle coat layer as a second layer, and then applying a top coat paint to form a top coat layer as a third layer.The undercoat layer is a layer for improving adhesion between the base and the paint film, the middle coat layer is a layer for forming a mirror layer to achieve a mirror finish, and the top coat layer is a layer for protecting the painted surface and enhancing color variation.

[0043] The workpiece fastening means will be explained with reference to Fig. 1. In Fig. 1, the workpiece fastening means is designated by 2. The workpiece fastening means 2 is provided with a rotating shaft 3, which is erected in the coating booth so as to be rotatable and removable.

[0044] A fixing jig 4 is connected radially to the upper part of the rotating shaft 3 toward the outer periphery of the rotating shaft 3, and a workpiece W is attached to the tip of this fixing jig means 4. Therefore, the workpiece W is arranged in a circle around the rotating shaft 3.

[0045] In this configuration, by rotating the rotation axis 3 with the workpiece W fixed to the fixing jig 4, the workpiece W can revolve around the rotation axis 3. In the drawing, four workpieces W are fixed to one workpiece fixing means 2, but in the present invention, the number of workpieces W fixed to the workpiece fixing means 2 is not limited to four, and may be more or less than four.

[0046] Although not shown in the drawings, the painting system of this embodiment has a rotating table for supplying workpieces inside the painting booth, and the rotating shaft 3 of the workpiece fixing means 2 is erected on this rotating table so that it can be rotated and removed freely.

[0047] The rotary table for supplying workpieces can be fitted with multiple rotary shafts. In the embodiment shown in Fig. 1, a total of four rotary shafts can be fitted, two on the front side and two on the rear side, and four workpieces are attached to fixing jigs connected to each rotary shaft. Therefore, a set of four workpieces is attached to each rotary shaft. In this embodiment, paint is sprayed onto a set of workpieces (referred to as "front workpieces") attached to fixing jigs connected to each of the two front rotary shafts, and while the front workpieces are being painted, the workpieces are attached to and detached from the fixing jig connected to the rear rotary shaft. The workpieces to be painted are switched by rotating the rotary table 180 degrees.

[0048] Next, in the drawing, reference numeral 5 denotes a painting robot, and in this embodiment, the painting robot 5 is a stationary painting robot. The painting robot 5 will be described with reference to FIG. 2, which is a perspective view of the painting robot 5.

[0049] 2, the painting robot 5 has a main body pillar 51, a first arm 52 is connected to the upper side of the main body pillar 51 so as to be freely rotatable in the vertical direction, and a second arm 53 is connected to the tip of the first arm 52 so as to be freely rotatable in the vertical direction. A long, round rod-shaped ball screw spline 54 is connected to the tip of the second arm 53. The ball screw spline 54 is movable in the width direction of the second arm 53, i.e., in the left-right direction, and is also rotatable in the circumferential direction, and spray gun devices 6 are attached to both ends of the ball screw spline 54.

[0050] Therefore, in this embodiment, a pair of spray gun devices 6 is provided, and each spray gun device is used to spray paint onto each of the front workpieces to paint them. In this embodiment, the turntable for supplying the workpieces is rotatably arranged below the painting robot 5 (see workpiece transport means 7 in JP 2021-45712 A).

[0051] Next, the spray gun device 6 will be described with reference to FIG. 1. In the figure, the spray gun device 6 has a device main body 61, and this device main body 61 is attached to the ball screw spline 54 of the painting robot 5.

[0052] A support part 62 is rotatably connected to the tip of the device main body part 61, and the support part 62 has a plurality of support arms 63. Therefore, when the support part 62 rotates, the support arms 63 also rotate in the same direction as the support part 62. The rotation direction of the support part 62 is the longitudinal direction of the ball screw spline 54, i.e., a direction perpendicular to the circumferential direction of the ball screw spline 54, and therefore the support arms 63 rotate like a propeller of the device main body part 61.

[0053] The support arms 63 will be described with reference to Figure 3. Figure 3 is a view of the support unit 62 from the side of the workpiece fastening means 2. As shown in the figure, the support unit 62 has three long support arms 63. The three support arms 63 are connected to each other at their base ends and arranged radially with their tips pointing toward the outer periphery. The three support arms 63 are adjacent to each other at equal angles, and therefore the angles between the support arms 63 are the same (approximately 120 degrees). A spray gun 7 is attached to the tip of each of the three support arms 63 with its paint nozzle facing forward so that paint can be sprayed toward the workpiece W.

[0054] The spray gun 7 includes an undercoat spray gun 7a for spraying a primer paint to form an undercoat layer as a first layer, a middle coat spray gun 7b for spraying an indium paint to form a mirror layer as a second layer, and a top coat spray gun 7c for spraying a top coat paint to form a top coat layer as a third layer, and the undercoat spray gun 7a, middle coat spray gun 7b, and top coat spray gun 7c are each attached to the tip of each of the three support arms 63. Therefore, by rotating the support part 62, the spray gun that sprays paint toward the workpiece can be switched, making it possible to form all of the undercoat layer, middle coat layer, and top coat layer using the same spray gun device 6.

[0055] The painting robot 5 moves the spray gun 7 together with the spray gun device 6 by rotating the first arm 52 and the second arm 53 up and down, and moving the ball screw spline 54 left and right and rotating it circumferentially according to a trajectory that has been preset by teaching, thereby reliably painting the areas of the workpiece that require painting.

[0056] The structure of spray gun 7 used in this embodiment will be briefly explained with reference to Figure 4. Figure 4 is a cross-sectional view illustrating the structure of spray gun 7. The spray gun used in this embodiment is similar to an atomizing spray gun generally used in painting, and has a paint supply passage 71 formed therein. Paint supply passage 71 has a paint receiving port 71a for receiving paint and a paint ejection port 71b for spraying the received paint toward the workpiece, and paint ejection port 71b is opened and closed by advancing and retracting needle 72 with needle advance / retract air supplied through needle advance / retract air supply passage 75.

[0057] The spray gun 7 used in this embodiment is also formed with an atomizing air supply passage 73 for atomizing the paint ejected from the paint ejection port 71b and spraying it toward the workpiece. The tip of this atomizing air supply passage 73 opens at an arbitrary location around the paint ejection port 71b, and the base end is connected to an atomizing air supply means (not shown). When air is supplied, atomizing air is supplied to the periphery of the paint ejection port 71b via the atomizing air supply passage 73, making it possible to atomize the paint ejected from the paint ejection port 71b.

[0058] Furthermore, the spray gun 7 used in this embodiment is formed with a pattern air supply passage 74 for changing the spray pattern of the paint atomized by the atomizing air to any desired pattern, and the tip of the pattern air supply passage 74 opens outside the tip opening of the atomizing air supply passage 73, and the base end is connected to a pattern air supply means (not shown).When air is supplied, pattern air is supplied around the tip opening of the atomizing air supply passage 73 via the pattern air supply passage 74, making it possible to change the spray pattern of the paint atomized by the atomizing air.

[0059] The undercoat spray gun 7a, middle coat spray gun 7b, and top coat spray gun 7c have the same configuration, so a duplicated description will be omitted. Also, although not shown, a paint supply path for supplying paint to the spray gun 7 and an air supply path for supplying various types of air (atomization air, pattern air, and needle advance / retract air) to the spray gun are formed within the device main body 61 and support arm 63 of the spray gun device 6. Therefore, paint and various types of air can be supplied to the spray gun 7 through the inside of the spray gun device 6, eliminating the need to directly connect a paint hose or air hose to the spray gun from the outside.

[0060] Next, the paint supply means will be described. In this embodiment, the paint supply means includes an undercoat paint supply means for supplying an undercoat paint to the undercoat spray gun, an indium paint supply means for supplying an indium paint to the middle coat spray gun, and a topcoat paint supply means for supplying a topcoat paint to the topcoat spray gun. In this embodiment, all of the paint supply means are syringe pumps. In Figure 1, 10 is a primer paint syringe as the undercoat paint supply means, 10b is a topcoat paint syringe as the topcoat paint supply means, and 8 is an indium paint syringe as the indium paint supply means.

[0061] Although not shown in the figures, in this embodiment, the undercoat spray gun 7a and the primer paint syringe 10 are connected by a primer paint supply hose, the middle coat spray gun 7b and the indium paint syringe 8 are connected by an indium paint supply hose, and the top coat spray gun 7c and the top coat paint syringe 10b are connected by a top coat paint supply hose, and further, the indium paint supply hose is an insulated hose with thermal insulation properties.

[0062] In addition, in this embodiment, the paint filling means comprises an undercoat paint filling means for filling the undercoat paint syringe 10 with the undercoat paint, an indium paint filling means for filling the indium paint syringe 8 with the indium paint, and a topcoat paint filling means for filling the topcoat paint syringe 10b with the topcoat paint, but in Figure 1 the undercoat paint filling means, indium paint filling means and topcoat paint filling means are omitted.

[0063] Next, the indium paint supply means will be described with reference to Fig. 5. Fig. 5 is a partial cross-sectional view showing the configuration of an indium paint syringe 8, in which 8 is the indium paint syringe, and indium paint syringe 8 has a cylindrical syringe body 81, and an opening 82 that opens to the outside and communicates with the interior of syringe body 81 is formed at the tip of syringe body 81. A piston 83 is inserted into syringe body 81 so as to be able to move back and forth, and a piston rod 84 is connected to the surface of piston 83 on the side opposite opening 82, and the space formed between piston 83 and opening 82 serves as a paint filling space 85 into which paint is filled.

[0064] With this configuration, the paint filling space 85 is filled with indium paint, and by connecting the paint supply path formed in the main body 61 of the spray gun device 6 to the opening 82 with a paint hose and moving the piston 83 toward the opening 82, the paint filled in the paint filling space 85 is released from the opening 82 into the paint hose, and the indium paint is supplied to the spray gun 7 through the paint hose, the main body 61 of the device, and the paint supply path formed in the support arm 63.

[0065] 1, the indium paint syringe 8 is shown at 8. That is, in this embodiment, the indium paint syringe 8 is attached to the main body pillar 51 of the painting robot 5. Therefore, the indium paint supply hose connecting the middle coat spray gun 7b and the indium paint supply means 8 can be shortened, which reduces the amount of paint remaining in the hose and the amount of expensive indium paint used, thereby reducing costs.

[0066] 5, reference numeral 17 denotes a heated hose constituting heating means for heating the indium paint filled in the indium paint syringe 8. That is, in this embodiment, the indium paint syringe 8 is equipped with heating means, and this heating means heats the indium paint filled in the indium paint syringe 8, and the indium paint in a heated state is applied to the workpiece. This makes it possible to speed up the evaporation time of the volatile components contained in the indium paint, and shorten or eliminate the drying time of the indium paint applied to the workpiece.

[0067] The heating means will now be described with reference to Fig. 8. Fig. 8 is a diagram for explaining the heating means, in which 8 denotes an indium paint supply syringe. Also, 16 denotes an indium paint supply hose, and as described above, indium paint supply hose 16 is an insulated hose. As described above, this embodiment has a heating hose 17 for heating the indium paint filled in indium paint syringe 8. This heating hose 17 is wrapped around the outer periphery of syringe body 81, and a heating medium is passed through the inside of heating hose 17 to heat indium paint syringe 8, thereby heating the indium paint filled in indium paint syringe 8.

[0068] That is, in the figure, a tank is provided as a heating medium storage section 19 for storing a heating medium, and water is stored in this tank. The tank 19 is further provided with a heater 20 as a heat source, and water is stored in the tank 19, and this water is heated by the heater 20 to become hot water.

[0069] Meanwhile, both ends of the heated hose 17 are positioned within the tank 19, and a pump 18 is disposed on the heated hose 17 near the tank. As a result, by driving the pump 18 while heating the water in the tank 19 with the heater 20, the heated heating medium is circulated through the heated hose wound around the syringe body 81. As a result, the indium paint in the indium paint syringe 8 is heated to a predetermined temperature, and the heated indium paint is sprayed onto the workpiece to coat it.

[0070] In this way, the volatile components contained in the indium paint applied to the workpiece evaporate more quickly than at room temperature, so the drying time of the indium paint applied to the workpiece can be shortened or eliminated, thereby shortening the painting time. Also, as mentioned above, since the indium paint supply hose 6 connecting the middle coat spray gun 7b and the indium paint syringe 8 is an insulated hose, the indium paint heated in the indium paint syringe 8 can be sprayed toward the workpiece while being supplied to the middle coat spray gun 7b while maintaining its temperature, and can be applied to the workpiece.

[0071] In the above description, water is used as the heating medium, but water is not necessarily required. Gas may be used, and the gas may be heated and passed through the heating hose.

[0072] Furthermore, when heating the heating medium, the inside of a paint booth is generally an explosion-proof area and it is not possible to install ordinary heaters or the like that are not explosion-proof. Therefore, in this embodiment, indium paint syringe 8 is attached to main body pillar 51 of paint robot 5. If the syringe body were to be heated directly with a heater or the like, the heating means such as a heater would need to be explosion-proofed, which would be costly. However, the heating means in this embodiment is configured so that heating hose 17 is wrapped around the outer periphery of syringe body 81 and the heating medium is passed through heating hose 17 to heat indium paint syringe 8. Therefore, heaters, pumps, etc. can be placed outside the paint booth, which makes it possible to reduce costs.

[0073] Next, the indium paint filling means for supplying indium paint to the indium paint syringe 8 will be described. In Fig. 5, the indium paint filling means 9 has a main body 91, and this main body 91 is filled with indium paint.

[0074] Furthermore, the main body 91 is formed with a connecting portion 92 that can be connected to the opening 82 of the indium paint syringe 8, and this connecting portion 92 opens to the outside and communicates with the main body 91. In the figure, reference numeral 93 denotes an open / close valve. In this embodiment, the main body 91 is a hard container made of metal, resin, or the like.

[0075] When filling indium paint into the indium paint syringe 8 using the indium paint filling means 9 configured in this manner, the connecting part 92 is connected to the opening 82 of the indium paint syringe 8, thereby connecting the paint filling space 85 to the inside of the main body 91 via the connecting part 92, the opening / closing valve 93 is opened, and in this state the piston 83 of the indium paint syringe 8 is moved back to create a negative pressure inside the syringe main body 81.The indium paint filled in the main body 91 then moves via the connecting part 92 and the opening 82 to the paint filling space 85 of the indium paint syringe 8, thereby making it possible to fill the indium paint into the paint filling space 85 of the indium paint syringe 8.

[0076] Therefore, in this embodiment, the indium paint syringe 8 is filled with indium paint by directly connecting the connecting portion 92 of the indium paint filling means 9 to the opening 82 of the indium syringe 8 without using a paint filling hose, thereby eliminating the residual paint that would remain in the filling hose if a paint filling hose were used, and eliminating waste of indium paint.

[0077] Next, Fig. 6 is a partial cross-sectional view illustrating another configuration 9b of the indium filling means, and the indium paint filling means 9b shown in Fig. 6 has a main body 94 made of a stretchable material and filled with indium paint. The main body 94 is formed with a connecting part 95 that communicates with the main body 94 and opens to the outside.

[0078] The main body 94 is housed in a storage case 96 with the connecting portion 95 exposed to the outside, and the connecting portion 95 is provided with an opening / closing valve 97. In this embodiment, the storage case 96 is a hard container made of resin or the like, and is used to hold the main body 94 made of a stretchable material.

[0079] When filling indium paint into the indium paint syringe 8 using the indium paint filling means 9b configured in this manner, the connecting part 95 is connected to the opening 82 of the indium paint syringe 8, thereby connecting the paint filling space 85 to the inside of the main body 94 via the connecting part 95, and the opening / closing valve 99 is opened.In this state, the piston 83 of the indium paint syringe 8 is moved back to create a negative pressure inside the syringe main body 81.The indium paint filled in the main body 94 then moves via the connecting part 95 and the opening 82 to the paint filling space 85 of the indium paint syringe 8, making it possible to fill the indium paint into the paint filling space 85 of the indium paint syringe 8.

[0080] Therefore, indium paint filling means 9b shown in Fig. 6 also fills indium paint by directly connecting connecting part 95 to opening 82 of indium syringe 8, thereby eliminating the paint that would otherwise remain in the filling hose when a filling hose is used, and preventing waste of indium paint. Furthermore, indium paint filling means 9b shown in Fig. 6 has main body 94 filled with indium paint formed from an expandable material, which has the advantage of making main body 4 easy to transport and store, and also making the paint easy to handle.

[0081] In FIG. 5 , an actuating plate 88 is attached to piston rod 84 and is threaded onto a ball screw 87 connected to the shaft of a motor 86. By driving motor 86 and rotating ball screw 87, actuating plate 88 reciprocates at a constant speed along ball screw 87, thereby allowing piston 83 to freely move back and forth within syringe body 81 via piston rod 84.

[0082] Next, the primer paint syringe for supplying primer paint to the undercoat spray gun and the primer paint filling means for filling the primer paint into the primer paint syringe will be explained with reference to Figure 7. Figure 7 is a partial cross-sectional view showing the configuration of a primer paint syringe 10, and in Figure 7, 10 is the primer paint syringe.

[0083] The primer paint syringe 10 comprises a cylindrical syringe body 101 with a discharge portion 102 at its tip, a piston 103 inserted into the syringe body 101 so as to be able to move back and forth, and a piston rod 104 connected to the surface of the piston 103 on the side opposite the discharge portion 102, and the space formed between the piston 103 and the discharge portion 102 serves as a paint filling space 105 into which the paint is filled. The discharge portion 102 communicates with the inside of the syringe body 101 and is open to the outside, and is formed in the syringe body 101 in a state where it protrudes from the syringe body 101, and furthermore, an opening and closing valve 108 is provided in the discharge portion 102.

[0084] Then, the paint filling space 105 is filled with primer paint, the paint supply passage formed in the main body 61 of the spray gun device 6 is connected to the release section 102 with a paint hose, the opening / closing valve 108 is opened, and in this state the piston 103 is moved forward toward the release section 102, thereby releasing the paint filled in the paint filling space 105 from the release section 102 and supplying the primer paint to the spray gun 7 through the paint hose, the main body 61 of the device, and the paint supply passage formed in the support arm 63.

[0085] Next, the primer coating filling means for filling the primer coating syringe 10 configured as described above will be described. In Figure 7, reference numeral 11 denotes the primer coating filling means, which comprises a paint tank 12, a paint filling hose 13 that connects the paint filling space 105 with the paint tank 12, and a paint filling valve 14 and a paint filling pump 15 provided midway along the paint filling hose 13. A paint filling passage 106 is formed inside the piston rod 104, and a filling port 107 that is continuous with the paint filling passage 106 is formed in the piston 103. That is, the primer paint filling means 11 in this embodiment is composed of a paint tank 12, a filling hose 13, a filling pump 15, a filling valve 14, a paint filling passage 106 and a filling port 107, and the tip portion of the filling hose 12 is connected to the paint filling passage 106 formed in the piston rod 104, thereby connecting the paint tank 12 and the paint filling space 105 via the filling hose 12.

[0086] With the primer paint in the paint tank 12, the open / close valve 108 is closed, the filling valve 14 is opened, and the filling pump 15 is driven while the piston 103 is retracted, thereby filling the primer paint in the paint tank 12 through the paint filling passage 106 and the filling port 107 into the paint filling space 105 of the primer paint supply syringe 10. With the primer paint filled, the open / close valve 108 is opened, the filling valve 14 is closed, and the piston 103 is advanced toward the discharge portion 102, thereby discharging the paint filled in the paint filling space 105 from the discharge portion 102 and supplying the primer paint to the spray gun 7 through the paint hose, the device main body 61, and a paint supply passage formed in the support arm 63. The tip of the filling hose 13 may be connected to the paint filling space 105, thereby connecting the paint tank 12 and the paint filling space 105 via the filling hose 13.

[0087] In the primer paint syringe 10 shown in FIG. 7, an actuating plate 88 is attached to a piston rod 104 and threaded onto a ball screw 87 connected to the shaft of a motor 86. By driving the motor 86 and rotating the ball screw 87, the actuating plate 88 moves back and forth at a constant speed along the ball screw 87, thereby allowing the piston 103 to move back and forth freely within the syringe body 101 via the piston rod 104.

[0088] In this embodiment, the topcoat paint syringe 10b and the topcoat paint filling means are configured similarly to the primer paint syringe 10 and the primer paint filling means 11, so a duplicated description will be omitted.

[0089] Next, we will explain the painting method using the painting system of this embodiment configured as described above.When painting a workpiece in this embodiment, first, using the method described above, primer paint is filled into the primer paint syringe 10, indium paint is filled into the indium paint syringe 8, and top coat paint is filled into the top coat paint syringe 10b.

[0090] Then, by heating the indium paint syringe 8 with the heating means, the indium paint filled in the indium paint syringe 8 is heated to a predetermined temperature. That is, the water in the tank 19 is heated to hot water by the heater 20, and then the pump 18 is driven to circulate the hot water in the tank 19 through the heating hose 17 wrapped around the syringe body 81, thereby raising the temperature of the indium paint in the indium paint syringe 8 to a predetermined temperature and maintaining the predetermined temperature.

[0091] At the same time, the workpiece W is attached to the fixing jig 4 of the workpiece fixing means 2, thereby fixing the workpiece W to the workpiece fixing means 2, and then the rotary table for supplying the workpiece is rotated to move the workpiece to be painted forward so that the paint can be sprayed and painted.

[0092] Next, by rotating the support part 62, the position of the undercoat spray gun 7a is adjusted to a position where it can paint the workpiece W. Then, by rotating the rotary shaft 3, the workpiece W is revolved, and at the same time, primer paint is supplied from the primer paint syringe 10 to the undercoat spray gun 7a, and various types of air (atomization air, pattern air, air for moving the needle forward and backward) are supplied, whereby the primer paint is sprayed from the undercoat spray gun 7a toward the revolving workpiece W, forming an undercoat layer on the workpiece W. This undercoat layer improves adhesion between the base and the paint film.

[0093] Next, after the undercoat layer is formed, spraying of the primer paint from the undercoat spray gun 7a is stopped, and rotation of the rotary shaft 3 is stopped to stop the revolution of the workpiece W. Then, the turntable for supplying the workpiece is rotated, and the workpiece W on which the undercoat layer has been formed is moved backward, and then moved to a drying process where the primer paint is dried.

[0094] Then, the workpiece W, on which the primer paint has dried, is fixed to the workpiece fixing means 2 on the rear side of the workpiece supply turntable, and the workpiece supply turntable is rotated to move the workpiece W forward so that the paint can be sprayed and applied. The support part 62 is then rotated to switch the spray gun in use and adjust the position of the middle coat spray gun 7b to a position where the workpiece W can be painted. The rotation shaft 3 is then rotated to revolve the workpiece W, and indium paint is supplied from the indium paint syringe 8 to the middle coat spray gun 7b, and various air sources (atomization air, pattern air, and needle advance / retract air) are supplied. The indium paint is sprayed onto the workpiece W from the middle coat spray gun 7b, forming a middle coat layer as a mirror layer on the workpiece W. This middle coat layer then forms a mirror layer, achieving a mirror finish. The indium paint only needs to be heated to a predetermined temperature when spraying the indium paint; therefore, it does not need to be heated immediately after filling the indium paint syringe 8 with the indium paint.

[0095] Next, after the mirror layer has been formed in this manner, the spraying of the indium paint from the middle coat spray gun 7b is stopped, and the rotation of the rotary shaft 3 is stopped to stop the revolution of the workpiece W. Then, the turntable for supplying the workpiece is rotated, and the workpiece W on which the mirror layer has been formed is moved backward, and then moved to a drying step to dry the indium paint.

[0096] Then, after the indium paint has dried, the workpiece W is fixed to the rear workpiece fixing means 2 on the workpiece supply turntable, and the workpiece supply turntable is rotated to move the workpiece W forward so that the paint can be sprayed and applied. The support part 62 is then rotated to switch the spray gun in use and adjust the position of the topcoat spray gun 7c to a position where the workpiece W can be painted. The rotary shaft 3 is then rotated to revolve the workpiece W, and the topcoat paint is supplied from the topcoat paint syringe 10b to the topcoat spray gun 7c, while various types of air (atomization air, pattern air, and needle advance / retract air) are supplied. The topcoat paint is sprayed onto the workpiece W from the topcoat spray gun 7c, forming a topcoat layer on the workpiece W. The topcoat layer enhances the protection and color variation of the painted surface.

[0097] Next, after the top coat layer is formed, the spraying of the top coat paint from the top coat spray gun 7c is stopped, and the rotation of the rotary shaft 3 is stopped to stop the revolution of the workpiece W. Then, the turntable for supplying the workpiece is rotated, and the workpiece W on which the top layer has been formed is moved backward, and then moved to the drying process to dry the top coat paint, thereby completing the painting of the workpiece.

[0098] The primer paint may be any paint suitable for the material of the workpiece, such as general-purpose plastic material, light metal, or engineering plastic.

[0099] Furthermore, various experiments have shown that the mirror layer as a middle layer formed from indium paint can maximize the mirror effect by uniformly concealing the substrate and forming as thin a film as possible. That is, while indium paint is good at concealing the substrate, it is expensive, so in this example, the thickness of the mirror layer is set to about 400 nanometers. As mentioned above, indium paint is a paint made from an indium suspension and can achieve a mirror-like finish (mirror coating) by spray coating, but since it is a commercially available product, detailed description will be omitted. In this example, the indium paint used was ECOMIRROR49 (Ecomiror 49), a product name manufactured by Musashi Paint Holding Co., Ltd.

[0100] In this example, the top coat paint used to form the top layer is a clear paint (color clear paint) with any color, and by changing the color of the top coat paint, a wide variety of variations are possible, as well as a variety of mirror finishes such as matte finishes and various colors. However, since colored clear paints are already commercially available, detailed explanations will be omitted.

[0101] Thus, in this invention, in a painting process that is completed by forming three layers: an undercoat layer as the first layer to improve adhesion between the base and the paint film, a middle coat layer as the second layer that forms a mirror layer, and a top coat layer as the third layer to protect the painted surface and increase color variation, the paint is sprayed using a spray gun, and the middle coat is applied with indium paint.Furthermore, the painting system revolves the workpiece to be painted, and paint is applied to this revolving workpiece, performing rotary painting.Furthermore, the painting robot is equipped with a paint supply means that supplies indium paint to the spray gun.

[0102] As a result, it is possible to achieve a mirror finish (mirror coating) by spray painting, and it is possible to paint a wide range of substrates at low temperatures (80°C), regardless of the material. Indium also has excellent weather resistance and corrosion resistance, making it possible to paint automotive exterior parts, which have previously been difficult to use. Furthermore, because indium is permeable to radio waves, the present invention, which uses indium paint, makes it possible to obtain painted products that are permeable to radio waves.

[0103] Furthermore, the workpiece is painted by rotating the workpiece attached to the workpiece fixing means and spraying paint onto the revolving workpiece using a spray gun. This makes it possible to form a uniform thin film at the nano level, unlike painting with a brush or a hand-sprayed paint, and minimizes the amount of paint used.

[0104] In addition, in this embodiment, three spray guns are provided: an undercoat spray gun, a middle coat spray gun, and a top coat spray gun. The undercoat is formed using the undercoat spray gun, the middle coat is formed using the middle coat spray gun, and the top coat is formed using the top coat spray gun. This eliminates the need to clean the spray guns each time the paint used for painting is changed, thereby shortening the painting time.

[0105] In this embodiment, the spray gun device includes a device main body that is attached to the painting robot and a support part that is rotatably connected to the device main body and has three support arms with spray guns attached to the tips of the arms, and the position of the spray gun is changed by rotating the support part. Therefore, unlike when three spray guns are simply attached to the painting robot, it is possible to make the painting system smaller.

[0106] Furthermore, because the painting robot is equipped with a syringe pump that supplies indium paint to the spray gun, the distance from the syringe pump to the spray gun can be shortened, minimizing the amount of paint remaining in the paint hose and achieving paint reduction.

[0107] Furthermore, in this embodiment, when filling the indium paint syringe with indium paint, the indium paint filling means 9, 9b are directly connected to the indium paint syringe to fill the indium paint, making it unnecessary to use a paint filling hose.This eliminates the residual paint that would remain in the filling hose if a paint filling hose were used, and prevents waste of indium paint.

[0108] Furthermore, in this embodiment, when spraying the indium paint onto the workpiece, the indium paint in the indium paint syringe 8 is heated by the heating means, and the indium paint is applied to the workpiece while maintaining the temperature of the indium paint due to the insulating properties of the indium paint supply hose 16. This speeds up the evaporation time of the volatile components contained in the indium paint after it has been applied to the workpiece, thereby shortening or eliminating the drying time of the indium paint applied to the workpiece and enabling the coating time to be reduced. [Industrial Applicability]

[0109] The coating system and coating method of the present invention can be generally applied to coating systems and coating methods that use indium paint. [Explanation of symbols]

[0110] 1. Painting system 2 Workpiece fixing means 3 Rotation Axis 4 Fixing jig 5 Painting robot 51 Main pillar 52 First Arm 53 Second Arm 54 Ball screw spline 6 Spray gun device 61 Device main body 62 Support part 63 Support arm 7. Spray gun 7a Undercoat spray gun 7b Middle coat spray gun 7c Topcoat spray gun 71 Paint supply path 72 Needle 73 Atomization air supply path 74 Pattern air supply path 75 Needle air supply path 8 Indium Paint Syringes 81 Syringe body 82 Opening 83 Piston 84 Piston rod 85 Paint filling space 86 Motor 87 Ball screw 88 Actuating plate 9, 9b Indium paint filling means 91, 94 Main body 92, 95 Connection part 93, 97 Opening and closing valves 96 Storage Case 10 Primer syringe 10b Topcoat paint supply syringe 101 Syringe body 102 Emission part 103 Piston 104 Piston rod 105 Paint filling space 106 Paint filling path 107 Filling port 108 Opening and closing valve 11 Primer paint filling means 12 Paint tank 13 Filling hose 14 Filling valve 15 Filling pump 16 Indium paint supply hose 17 Heated Hose 18 Pump 19 Tank (heating medium storage section) 20 Heater double work

Claims

1. A coating system for coating a workpiece by applying a primer paint to form an undercoat layer as a first layer, then applying an indium paint to form a middle coat layer as a second layer, and then applying a top coat paint to form a top coat layer as a third layer, a workpiece fixing means (2) for mounting a workpiece (W) to be coated; a spray gun device (6) having three spray guns (7) for spraying paint toward a workpiece (W) attached to a workpiece fixing means (2); a coating robot (5) for moving the spray gun (7) according to preset trajectory data; a paint supply means (8, 10, 10b) for supplying paint to each of the spray guns (7); a paint hose (16) connecting the paint supply means (8, 10, 10b) and the spray gun (7); and paint filling means (9, 9b, 11) for filling paint into each of the paint supply means (8, 10, 10b), The workpiece fixing means (2) is The apparatus comprises a rotatable rotating shaft (3) and a fixing jig (4) connected to the rotating shaft (3), and by rotating the rotating shaft (3) with the workpiece (W) fixed to the fixing jig (4), the workpiece (W) can revolve around the rotating shaft (3); The spray gun device (6) The coating device comprises a device main body (61) mounted on a coating robot (5), and a support part (62) rotatably connected to the tip of the device main body (61), and the support part (62) has three long support arms (63) to each of which a spray gun (7) is mounted when coating a workpiece, and the support arms (63) are connected to each other at their base ends so that their tips are radially arranged with their tips facing the outer periphery, and the positions of the spray guns (7) mounted on the support arms (63) can be changed by rotating the support part (63). The spray guns mounted on the three support arms (63) are: an undercoat spray gun (7a) for spraying an undercoat paint, a middle coat spray gun (7b) for spraying an indium paint, and a top coat spray gun (7c) for spraying a top coat paint; The paint supply means is The spray gun (7a) for applying undercoat paint is provided with an undercoat paint supply means (10), an indium paint supply means (8) for supplying indium paint to the spray gun (7b) for applying middle coat paint, and a topcoat paint supply means (10b) for supplying topcoat paint to the spray gun for applying top coat paint, The paint hose (16) The system comprises an undercoat paint supply hose connecting the undercoat spray gun (7a) and a primer paint supply means (10), an indium paint supply hose connecting the middle coat spray gun (7b) and an indium paint supply means (8), and a topcoat paint supply hose connecting the topcoat spray gun (7c) and a topcoat paint supply means (10b), The paint filling means comprises an undercoat paint filling means (11) for filling the undercoat paint supply means (10) with an undercoat paint, an indium paint filling means (9, 9b) for filling the indium paint supply means (8) with an indium paint, and a topcoat paint filling means for filling the topcoat paint supply means (10b) with a topcoat paint, The indium paint supply means (8) is mounted on the painting robot (5), After filling the primer paint supply means (10) with primer paint, filling the indium paint supply means (8) with indium paint, and filling the top coat paint supply means (10b) with top coat paint, The workpiece (W) is fixed to the fixing jig (4), By rotating the support part (62), the position of the undercoat spray gun (7a) is adjusted to a position where the paint can be sprayed toward the workpiece (W), While the workpiece (W) is revolved by rotating the rotary shaft (3), an undercoat layer is formed by spraying an undercoat paint from an undercoat spray gun (7a) toward the revolving workpiece (W); Next, by rotating the support part (62), the position of the middle coat spray gun (7b) is adjusted to a position where the paint can be sprayed toward the workpiece (W), and then the indium paint is sprayed from the middle coat spray gun (7b) to form a middle coat layer as a mirror layer; The support part (62) is then rotated to adjust the position of the top coat spray gun (7c) to a position where the paint can be sprayed toward the work (W), and then the top coat paint is sprayed from the top coat spray gun (7c) to form a top coat layer, thereby painting the work.

2. 2. The coating system according to claim 1, wherein the indium paint supply means (8) is provided with a heating means (20) for heating the indium paint filled in the indium paint supply means (8), and an indium paint supply hose (16) connecting the middle coat spray gun (7b) and the indium paint supply means (8) has heat insulating properties.

3. 2. The coating system according to claim 1, wherein the indium paint supply means (8) is a syringe pump having a cylindrical syringe body (81) with an opening (82) at its tip, a piston (83) inserted into the syringe body (81) so as to be able to move back and forth, and a piston rod (84) connected to the surface of the piston (83) on the side opposite the opening (82), wherein the space formed between the piston (83) and the opening (82) is a paint filling space (85) into which paint is filled, and when the paint filling space (85) is filled with paint, the piston (83) is moved forward toward the opening (82) to release the paint filled in the paint filling space (85) from the opening (82).

4. The indium paint supply means (8) The syringe pump comprises a cylindrical syringe body (81) with an opening (82) at its tip, a piston (83) inserted into the syringe body (81) so as to be able to move back and forth, and a piston rod (84) connected to the surface of the piston (83) on the side opposite the opening (82), wherein the space formed between the piston (83) and the opening (82) is a paint filling space (85) into which paint is filled, and when the piston (83) is advanced toward the opening (82) with the paint filled in the paint filling space (85), the paint filled in the paint filling space (85) is discharged from the opening (82), and the syringe pump comprises heating means (20) for heating the indium paint filled in the indium paint supply means (8), 2. The coating system according to claim 1, wherein an indium paint supply hose (16) connecting the middle coat spray gun (7b) and the indium paint supply means (8) has heat insulating properties.

5. The heating means (20) a heating medium storage section (19) that stores a heating medium; a heating medium supply hose (17) wound around the outer periphery of the syringe body (81) and having both ends connected to the inside of a heating medium storage section (19); a heat source (20) for heating the heating medium accommodated in the heating medium accommodation section (19); a pump (18) for circulating the heating medium contained in the medium container (19) through a heating medium supply hose (17); The coating system according to claim 4, characterized in that the indium paint in the syringe body (81) is heated by circulating the heated heating medium through a heating medium supply hose (17) while the heating medium is heated to a predetermined temperature by a heating source (20).

6. The indium paint filling means (9) comprises a main body (91) filled with indium paint, and a connecting portion (92) formed on the main body (91); 4. The coating system according to claim 3, wherein the connecting portion (92) of the indium paint filling means (9) is connected to the opening (82) of the indium paint supply means (8) to communicate the paint filling space (85) with the inside of the main body (91) through the connecting portion (92), and in this state, the piston (83) of the indium paint supply means (8) is moved backward to create a negative pressure inside the syringe body (81), thereby filling the indium paint filled in the main body (91) of the indium paint filling means (9) into the paint filling space (85) of the indium paint supply means (8) through the connecting portion (92).

7. The indium paint filling means (9b) comprises a main body (94) formed of an expandable material and filled with indium paint, a connecting part (95) formed on the main body (94), and a storage case (96) that stores the main body (94) in a sealed state with the connecting part (95) exposed to the outside, 4. The coating system according to claim 3, wherein the connecting portion (95) of the indium paint filling means (9b) is connected to the opening (82) of the indium paint supply means (8) to communicate the paint filling space (85) with the inside of the main body (94) through the connecting portion (95), and in this state, the piston (83) of the indium paint supply means (8) is moved backward to create a negative pressure inside the syringe body (81), thereby filling the indium paint filled in the main body (94) of the indium paint filling means (9b) into the paint filling space (85) of the indium paint supply means (8) through the connecting portion (95).

8. A coating method for coating a workpiece by applying a primer paint to form an undercoat layer as a first layer, applying an indium paint to form a middle coat layer as a second layer, and applying a top coat paint to form a top coat layer as a third layer, The coating system comprises a workpiece fixing means (2) for mounting a workpiece (W) to be coated, a spray gun device (6) having three spray guns (7) for spraying paint toward the workpiece (W) mounted on the workpiece fixing means (2), a coating robot (5) for moving the spray guns (7) according to preset trajectory data, paint supply means (8, 10, 10b) for supplying paint to the spray guns (7), a paint hose (16) connecting the paint supply means (8, 10, 10b) and the spray guns (7), and paint filling means (9, 9b, 11) for filling the paint supply means (8, 10, 10b) with paint, The workpiece fixing means (2) comprises a rotatable rotation shaft (3) and a fixing jig (4) connected to the rotation shaft (3), and by rotating the rotation shaft (3) with the workpiece (W) fixed to the fixing jig (4), the workpiece (W) can revolve around the rotation shaft (3); The spray gun device (6) The coating device comprises a device main body (61) mounted on a coating robot (5), and a support part (62) rotatably connected to the tip of the device main body (61), and the support part (62) has three long support arms (63) to each of which a spray gun (7) is mounted when coating a workpiece, and the support arms (63) are connected to each other at their base ends so that their tips are radially arranged with their tips facing the outer periphery, and the positions of the spray guns (7) mounted on the support arms (63) can be changed by rotating the support part (63). The spray guns attached to the three support arms (63) are an undercoat spray gun (7a) for spraying a primer paint, a middle coat spray gun (7b) for spraying an indium paint, and a top coat spray gun (7c) for spraying a top coat paint, The paint supply means comprises an undercoat paint supply means (10) for supplying an undercoat paint to the undercoat spray gun (7a), an indium paint supply means (8) for supplying an indium paint to the middle coat spray gun (7b), and a topcoat paint supply means (10b) for supplying a topcoat paint to the topcoat spray gun, The paint hose (16) comprises an undercoat paint supply hose connecting the undercoat spray gun (7a) and a primer paint supply means (10), an indium paint supply hose connecting the middle coat spray gun (7b) and an indium paint supply means (8), and a top coat paint supply hose connecting the top coat spray gun (7c) and a top coat paint supply means (10b), The paint filling means comprises an undercoat paint filling means (11) for filling the undercoat paint supply means (10) with an undercoat paint, an indium paint filling means (9, 9b) for filling the indium paint supply means (8) with an indium paint, and a topcoat paint filling means for filling the topcoat paint supply means (10b) with a topcoat paint, The indium paint supply means (8) is mounted on the painting robot (5), using a painting system characterized in that: Filling the primer paint supply means (10) with primer paint, filling the indium paint supply means (8) with indium paint, and filling the top coat paint supply means (10b) with top coat paint; The workpiece (W) is fixed to the fixing jig (4), By rotating the support part (62), the position of the undercoat spray gun (7a) is adjusted to a position where the paint can be sprayed toward the workpiece (W), While the workpiece (W) is revolved by rotating the rotary shaft (3), an undercoat layer is formed by spraying an undercoat paint from an undercoat spray gun (7a) toward the revolving workpiece (W); Next, by rotating the support part (62), the position of the middle coat spray gun (7b) is adjusted to a position where the paint can be sprayed toward the workpiece (W), and then the indium paint is sprayed from the middle coat spray gun (7b) to form a middle coat layer as a mirror layer; Thereafter, the support part (62) is rotated to adjust the position of the top coat spray gun (7c) to a position where the paint can be sprayed toward the work (W), and then the top coat paint is sprayed from the top coat spray gun (7c) to form a top coat layer, thereby coating the work.

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