JP2603245B2 - Painting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a coating method.

(Prior art and its problems) When coating an object to be coated, for example, the outer surface of an automobile body,
The method includes a preparation step of removing dust adhering to the article, a step of applying a paint to the article, and a drying step of drying the applied paint. This drying step is performed in two steps, for example, in a thermosetting paint, a setting step and a baking step, and the setting step is performed before the baking step at a lower temperature than the baking step, for example, room temperature or pre-baking. As described above, the baking is performed in an atmosphere at a temperature of 40 ° C to 60 ° C (the baking temperature in the baking step is usually around 140 ° C).

The object to be coated usually undergoes the above-described preparation step, coating step, and drying step while being conveyed by a conveying means such as a cart, but the posture of the object to be coated is maintained at a predetermined position in each step. It is being done as it is.

By the way, as one criterion for evaluating the quality of a painted surface, there is smoothness (flatness). The greater the smoothness, the smaller the degree of unevenness of the painted surface, and the better the painted surface. It is already known that the smoothness of the painted surface can be improved by increasing the thickness of the coating film, that is, the thickness of the applied paint.

On the other hand, there is a "drip" of the paint as an obstacle to the quality of the painted surface. This dripping occurs when the applied paint flows downward due to gravity and causes 1
The greater the film thickness of the coating applied at a time, the more easily “sagging” occurs. Since the cause of “sagging” is ultimately the effect of gravity, the so-called vertical surface of the object to be coated extends vertically. It is likely to occur.

Therefore, the thickness of the coating material to be applied to the surface extending in the horizontal direction, that is, the so-called horizontal surface, of the object to be coated on which the “sagging” of the coating does not become a problem can be made larger than the vertical surface. Even if the thickness of the coating on the horizontal surface is the same as the thickness of the coating on the vertical surface, the unevenness is reduced by a slight flow of paint that does not cause dripping on the horizontal surface, and the vertical surface is smooth. The degree of smoothness better than the degree is obtained.

In view of the above, conventionally, in order to obtain a painted surface with as large a smoothness as possible while preventing "sagging" of the paint, painting has been performed using a paint with as low fluidity as possible. The so-called "sag limit" in which "sag" of the paint occurs on the vertical surface was, for example, about 40 [mu] m in the thickness of the coating film of the thermosetting paint. More specifically, the “sag” of the paint is likely to occur in the setting step and the baking step, particularly in the baking step, and the thickness of the paint applied in the painting step is determined so that “sag” does not occur at this time. The maximum value of the determined thickness, that is, the sag limit value is about 40 μm. Therefore, in order to obtain a coated surface with a much higher degree of smoothness, in the conventional coating method, it is necessary to repeat a series of steps from the coating step to the baking step a plurality of times, for example, twice coating. was there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coating method capable of obtaining a coated surface with even greater smoothness if the thickness of the coating film is the same. And

(Means for Solving the Problems, Function) The present invention basically relates to the fluidity of the paint by appropriately changing the direction of gravity acting on the paint applied to the object to be coated. Is positively utilized so as to obtain a painted surface having a higher smoothness if the film thickness is the same. Specifically, the configuration is as follows. That is, in a method of applying a paint on the surface of the object to be coated, the object to be coated is rotatably supported about a substantially horizontal axis, and at a predetermined rotation position in the rotatably supported state. A vertical surface extending substantially perpendicularly, and a non-circular cross-section having a horizontal surface that extends so as to intersect the vertical surface and forms a corner at the boundary with the vertical surface, and paint dripping occurs on the vertical surface A coating step of applying a paint on the surface of the object to be coated so as to have a film thickness of, and a drying step of curing the paint on the surface of the object to be applied. Before the sagging is caused by gravity, the object to be coated is started to rotate about a substantially horizontal axis, and the rotation in this case is such that at least before the paint sagging of the applied paint is caused by the gravity, the vertical surface is substantially shifted from the substantially vertical state. Rotate at the speed to move to the horizontal state Is performed at a speed lower than the speed at which paint dripping occurs due to centrifugal force caused by the centrifugal force, and the rotation of the object to be coated is performed in such a manner that the rotation is performed alternately between the normal rotation and the reverse rotation. The rotation angles of the rotation and the reverse rotation are each at least as large as the rotation angle at which the posture can be changed between the substantially vertical state and the substantially horizontal state.

As described above, in the present invention, the direction of gravity acting on the paint applied to the object to be coated is changed by rotating the object to be coated in the horizontal direction. Without drying.

According to the present invention, it is possible to obtain a very good painted surface whose smoothness far exceeds the level which has been conventionally regarded as the limit by making the thickness of the coating applied at one time much thicker than before. it can.

Also, even if the thickness of the coating film is the same as before,
By utilizing the fluidity of the paint, it is possible to obtain an excellent painted surface having less unevenness, that is, a greater smoothness.

Furthermore, if it is intended to obtain a coated surface having the same smoothness, for example, the same smoothness as that obtained by a conventional coating method, the thickness of the paint to be applied can be made thinner than the conventional one, The amount of paint used can be reduced by the amount that can be made thinner.

Of course, paints that cause "sags" even with thin coatings
What is necessary is just to obtain from the conventional paint by reducing the component which obstructs fluidity by a predetermined ratio.

In addition to this, in the present invention, since the rotation of the object to be coated is performed while reversing, a situation where a large amount of the paint locally stays at the corners of the object to be coated, that is, the obtained painted surface Among them, it is possible to prevent a situation in which the coating film is locally thickened only at the corners and rises. Explaining this point, the paint before drying tends to locally concentrate on the corner on the delay side in the rotation direction due to the customary use of the rotation of the object to be coated, and the paint concentrated on this corner has the surface. There is a tendency to maintain the same position by tension. However,
In the present invention, since the rotation of the object to be coated is performed while reversing the rotation, the concentration itself of the paint on the corner is prevented, and even if the paint is once concentrated, the paint flows and diffuses away from the corner again by the reversal. (Of course, this flow diffusion is in a range that does not cause dripping). As a result, it is possible to reliably prevent a situation in which only the coating film at the corner portion is locally greatly raised.

As described above, according to the present invention, it is possible to obtain a high-quality painted surface having not only good smoothness but also no swelling at corners.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Overview of Overall FIG. 1 shows the overall steps in the case of coating an automobile body W as an object to be coated, and the steps are indicated by P1 to P4.

First, the body W, which has been subjected to a known undercoating by electrodeposition coating, is sent to the preparation process P1 while being held by the carriage D. In the preparation process P1, dust inside and outside the body W is removed by, for example, air blow or vacuum suction. Next, after the paint is sprayed on the body W in the step P2, the paint is dried in the setting step P3 and the baking step P4.

When the processes P1 to P4 are for intermediate coating, after the process P4, the body W is sent to the process for top coating. In addition, steps P1 to P4
Is for overcoating, the body W is transported to the assembly line in a known manner.

Dust Removal The dust removal in the process P1 may be performed while rotating the body W around the horizontal axis l, as shown in FIG. That is, for example, first, after the rotation of the body W is stopped in the state shown in FIG. 2A to remove dust, the posture of the body W is changed to the state shown in FIG. It stops at the position and the dust is removed again. In this way,
As shown in (c), (d), (i) of FIG. 2, dust is removed while the body W is intermittently rotated.

As described above, by removing the dust while rotating the body W, the dust attached to the closed cross section such as the inner corner of the loop panel or the side sill of the body W, that is, the body W must be rotated. It is possible to completely remove dust that does not fall.

The rotation range of the body W is 36 as shown in FIG.
The rotation may be 0 °, but may be adjusted to the rotation angle range of the body W in the drying process described later.

Spraying and drying of paint First, spraying of paint at P2 is performed so that the thickness of the coating film is equal to or greater than the sag limit. That is, in a thermosetting paint generally used in the past, the maximum thickness of the paint that does not cause “sag”, that is, the sag limit value is about 40 μm, but in the process P2, it is far more than this sag limit of 40 μm. The paint is sprayed to give a thick coating (for example, 65 μm).

After P2, the process proceeds to the setting step of P3. In this setting step P3, the body W is rotated in the horizontal direction while performing the reversal in the maximum angle range of 360 ° shown in FIGS. 2 (a) to 2 (i). That is, the body W is rotated about a rotation axis l extending in the horizontal direction. In the embodiment, the rotation axis l extends in the front-rear direction of the body W. The temperature atmosphere in the setting step P3 is room temperature in the embodiment, but is 40 ° C. to 60 ° C.
An appropriate temperature can be set in a temperature range lower than the temperature atmosphere in the subsequent baking step P4. Of course, this setting step P3 is for preliminarily evaporating the low-boiling components in the paint, thereby causing pinholes on the painted surface due to the rapid evaporation of the low-boiling components in the next baking step P4. Is prevented.

In the baking step P4, for example, the paint is baked in a 140 ° C. temperature atmosphere. Also in this P4, the body W is rotated in the horizontal direction while performing the inversion similarly to the setting step of P3.

Due to the horizontal rotation of the body W at P3 and P4 described above, the paint is dried without dripping even if the paint is sprayed to a thickness greater than the sag limit at P2. As a result, a high-quality coated surface having extremely high smoothness, which cannot be obtained by the conventional coating method, can be obtained. Further, since the reversal is performed, it is possible to prevent a situation in which only the painting process of the corner portion of the body W becomes extremely thick and swells.

The reason why the body W is rotated in both the steps P3 and P4 is that the thermosetting paint that causes dripping is used in both the steps P3 and P4. In the case of the powder paint, the baking step P4 is performed.
In the case of a two-component curable paint, it is sufficient to perform this rotation only in the setting step.

Here, the inversion of the body W may be performed, for example, as follows. That is, when one cycle of the rotation of the body W with reversal is considered with the position of FIG. 2A as a reference position, the forward rotation direction (clockwise direction in FIG. 2) and the reverse rotation direction from the state of FIG. May be rotated by a predetermined angle with each other. For example, if both the predetermined angles are 90 °, the body W
In FIG. 2, the posture change of (a) → (b) →
(C) → (b) → (a) (i) → (h) → (g) →
(H) → (i) (a) is one cycle. Of course, the inversion is performed in the states (c) and (g). Also,
As another example, if both the predetermined angles are 135 °, 1
The cycle is (a) → (b) → (c) → (d) → (c)
→ (b) → (a) (i) → (h) → (g) → (f) →
(G) → (h) → (i) (a). The inversion at this time is performed in the cases of (d) and (f).

Of course, the predetermined angle may be determined so that the direction of gravity acting on the paint (particularly, the paint applied on the vertical surface) is changed, and the shape of the object to be coated, particularly the position of the corner, is taken into consideration. . Therefore, FIGS. 2 (a) to (b), (c),
(D) and then to (i) in order (after 360 [deg.] Rotation), and then reverse rotation, such as 360 [deg.] Rotation, can be set as appropriate.

In addition, the change of the bogie D is performed between P2 and P3, and P3,
It is preferable that the paint is not attached to the carriage D used in the drying process in P4. That is, in P2, a considerable amount of paint is sprayed on the cart D. However, if the paint D is used as it is and the process is shifted to the drying step, the paint adhered to the cart D is This is because, as the vehicle travels, D is peeled off to a considerable extent and becomes dust, which may impair the quality of the painted surface.

FIG. 3 shows the effect of the coating film thickness on the sag limit when focusing on a thermosetting coating material.
In FIG. 3, the coating thickness is 40 μm, 53 μm, 65
The three cases of μm are shown. It is understood that, in any of these thicknesses, a "drip" peak occurs both at the beginning of the setting step and at the beginning of the printing step. In addition, the sag limit usually means a value when a sag of 1 to 2 mm is generated in one minute (a paint surface is defective if sag of 2 mm / min or more is visually observed). Maximum coating thickness obtained in the range is 40μm with conventional paint
It is about.

On the other hand, FIG. 4 shows the influence on the smoothness when the body W is rotated in the horizontal direction and when it is not. A in FIG. 4 shows a state in which the body W is not rotated (conventional coating method). FIG. 4B shows a case where the body W is rotated by 90 ° and then reversed (forward and reverse rotation between FIGS. 2 (a) and (c)). FIG. 4C shows
The case where the body W is rotated by 135 ° and then reversely rotated (forward and reverse rotation between FIGS. 2 (a) and (d)) is shown. 4th
FIG. D shows a case in which the body W is rotated 180 ° and then reversed (forward and reverse rotation between FIGS. 2 (a) and (e)). FIG. 4E shows a case where the body W is continuously rotated in the same direction (FIGS. 2 (a), (b),
(C)... (I) are taken in this order, and the process returns to (a) again).

As is apparent from FIG. 4, if the thickness of the coating film is the same, it is better to rotate the body W (FIG. 4, B, C, D,
E) When the rotation is not performed (FIG. 4A), a greater smoothness can be obtained.

As is known, the IG at the mapping sharpness shown in FIG.
(Image gloss) is 100 with mirror surface (black glass)
It indicates the ratio of sharpness to that, and also PGD
Is a value at which the smoothness of the painted surface decreases as the degree of discrimination of the reflected image decreases from 1.0.

The test conditions of the data shown in FIG. 3 and FIG. 4 are as follows. These test conditions show the conditions when overcoating is performed at P2.

a. Paint: Melamine alkyd (black) Viscosity: 22 seconds / 20 ° C with Ford Cup # 4 b. Coating machine: Mini Bell (16,000 rpm) shaping air ..
_2, 0kg / cm ₂ c. Discharge amount: spraying divided into two times, the first time: 100cc / min The second time: 150 to 200cc / min d. Setting time: 10 minutes × normal temperature e. Baking conditions: 140 ° C x 25 minutes f. Substrate smoothness: 0.6 (PGD value) (intermediate coating, on PE tape) g. Rotating or reversing operation range: Setting (10 minutes) to baking (10 minutes) h. Coating material: Painted on the side of a 30 cm square cylinder, rotatably supported at the center. I. Rotation speed of the object to be coated: 6 rpm, 30 rpm, 60 rpm. Did not occur.

Next, a specific example of a jig used to support the body W so as to be rotatable in the horizontal direction with respect to the carriage D will be described.

FIG. 5 shows a front jig attached to the front of the body W.
Shows 1F. The jig 1F includes a pair of left and right mounting brackets 2, a pair of left and right stays 3 welded to the left and right brackets 2, a connecting bar 4 for connecting the pair of left and right stays 3, and a connecting bar 4. And an integrated rotation shaft 5. In such a jig 1F, the bracket 2 is
It is fixed to a front strength member of the body W, for example, a front end of the front side frame 11. That is, since a bracket 12 for mounting a bumper (not shown) is usually welded to the front side frame 11, the bracket 2 is bolted (not shown) to the bracket 12 on the body W side.
Use to fix.

On the other hand, the rear jig 1R attached to the rear of the body W
Is shown in FIG. The rear jig 1R has the same configuration as the front jig 1F, and the components corresponding to the front jig 1F are denoted by the same reference numerals. This rear jig
To attach the 1R to the body W, the bracket 2 is attached to the floor frame 13 as a strength member at the rear end of the body W.
By fixing with bolts. Of course, at the rear end of the floor frame 13, a bumper mounting bracket is welded in advance because the bumper is generally mounted, so that the rear jig 1R is Mounting can also be performed.

When the jigs 1F and 1R are attached to the body W, the rotating shafts 5 are positioned on the same straight line extending in the front-rear direction of the body W. This same straight line becomes the rotation axis l of the body W. Preferably, this rotation axis l is the center of gravity G of the body W (see FIG. 7).
Through. It should be noted that the rotation axis l passes through the center of gravity G, thereby preventing a large fluctuation in the rotation speed when the body W rotates. This prevents the body W from receiving an impact due to the rotation fluctuation, which is more preferable for preventing dripping.

The front and rear jigs 1F and 1R are for the type of vehicle (the type of body W)
A special one is prepared in advance in accordance with.

Dolly This is a dolly that is used in at least P1, P3, and P4 and has a function of rotating the body W.

In FIG. 7, the trolley D has a base 21, and this base 21
Is mounted on the road surface 23. The base 21 has a single front support extending sequentially upward from the front side to the rear side (from right to left in FIG. 7) in the traveling direction.
24, two intermediate struts 25, 26 and one rear strut 27, and a space between the intermediate struts 25, 26 and the rear strut 27 is a support space 28 with a large space in the front-rear direction. .

The body W is disposed in the support space 28, and its front portion is rotatably supported on the intermediate support 26 using the front jig 1F, while its rear portion uses the rear jig 1R. Then, it is rotatably supported by the rear column 27.

The front and rear jigs 1F and 1R (the rotating shaft 5) can be freely disengaged from the columns 26 and 27 from above and below, and the rear jig is also provided.
1R is immovably engaged in the direction of the rotation axis l. For this reason, the notch 26a which opens in the upper end surface is formed in the intermediate support | pillar 26 (refer FIG. 10-12), The notch 27a which opens in the upper support surface is formed in the rear support | pillar 27. (First
FIG. 0, FIG. 14, FIG. 15). These two notches 26a, 27a
Is large enough to fit the rotating shafts 5 of the jigs 1F and 1R. The flange 5a is attached to the rotating shaft 5 of the rear jig 1R.
On the other hand, a notch 27b having a shape corresponding to the flange portion 5a communicating with the notch 27a is formed in the rear support column 27. As a result, the rear jig 1R has the notch
It is disengaged from the vertical direction with respect to 27a, 27b, and is immovable in the front-rear direction with respect to the rear support column 27 by the stopper action of the flange portion 5a. The application of the rotational force to the body W is performed via the rotary shaft 5 of the front jig 1F.
(See also FIG. 5).

A stay 29 protrudes downward from the base 21, and a tow wire 30 is connected to a lower end of the stay 29. The wire 30 is of an endless type and is driven in one direction by a motor (not shown), whereby the carriage D is driven in a predetermined transport direction. Of course, the motor is installed at a safe place from the viewpoint of explosion protection.

In the embodiment, the rotation of the body W is performed using the movement of the bogie D, that is, using the displacement of the bogie D with respect to the traveling road surface 23. The rotation take-out mechanism 31 for taking out the displacement of the cart D as a rotation is configured as follows. That is, the rotating take-out mechanism 31 includes a rotating shaft 32 that extends vertically and is rotatably supported on the base 21, a sprocket 33 fixed to a lower end of the rotating shaft 32, and a sprocket 33.
And a chain 34 meshed with. The chain 34 is arranged in parallel with the wire 30 so as to be stationary with respect to the traveling road surface 23. Thus, when the trolley D is pulled through the wire 30, the chain 34 is immovable, so that the sprocket 33 meshing with the chain 34 and thus the rotary shaft 32 is rotated. The chains 34 are alternately arranged left and right with respect to the sprockets 33 in the transport direction so as to be inverted.

A transmission mechanism 35 for transmitting the rotation of the rotation shaft 32 to (the rotation shaft 5 of) the front jig 1F is configured as follows. In other words, the transmission mechanism 35 includes a casing 36 fixed to the rear surface of the front support 24, a rotating shaft 37 that extends in the lateral direction (front-rear direction) and is rotatably supported by the casing 36,
It has a pair of bevel gears 38 and 39 for interlocking the rotation shaft 37 and the upper rotation shaft 32, and a connection shaft 40 held rotatably with respect to the intermediate support 25 and slidably in the front-rear direction. The connecting shaft 40 is spline-coupled to the rotating shaft 37 (the engaging portion is indicated by reference numeral 41 in FIG. 7). When the rotating shaft 32 is rotated, the connecting shaft 40 is also rotated. become. Of course, the rotation shaft 37 and the connection shaft 40 are installed so as to be located on the rotation axis l.

The connecting shaft 40 is disengaged from the rotating shaft 5 of the front jig 1F. That is, as shown in FIGS. 10 to 12, a cross-shaped connecting portion 5b is formed at the tip of the rotary shaft 5 for the front jig 1F, while the connecting shaft 40 has As shown in FIGS. 10 and 13, a box portion 40a having an engagement recess 40c into which the connecting portion 5b is fitted without play is formed. Thus, for example, the rod 43 is
By sliding the connecting shaft 40 through the connector, the box portion 40a (engaging recess 40c) and the connecting portion 5b are disengaged, and the connecting shaft 40 and the rotating shaft 5 can be integrally rotated during the engagement. It is said. As shown in FIG. 10, the rod 43 is fitted into an annular groove 40b formed on the outer periphery of the box 40a so as not to hinder the rotation of the connecting shaft 40.

With the above configuration, the body W is lowered with respect to the bogie D while the connecting shaft 40 is displaced to the right in FIG. 7, so that the rotary shafts 5 of the front and rear jigs 1F and 1R are It is rotatably supported by the columns 26 and 27 and is immovable in the front-rear direction. Thereafter, the connecting shaft 40 (locking recess 40c) is engaged with (the connection portion 5b of) the rotating shaft 5 in the front jig 1F.
Thus, if the trolley D is pulled through the wire 30, the body W will be rotated about the predetermined horizontal axis l. The removal of the body W from the carriage D may be performed in a procedure reverse to the procedure described above.

Supplementary Explanation and Modified Examples Next, supplementary explanations related to the present invention and modified examples of the trolley, the painting method, and the like will be sequentially described.

When the next top coat is applied after the middle coat, water sharpening after the baking step for the middle coat can be omitted. In this case, the body W may be rotated only in one of the intermediate coating step and the top coating step. That is, the quality of the final painted surface obtained after the top coat is determined by the quality of the middle coat, but when the body W is rotated with the middle coat, the finish level of the middle coat is reduced. Since the height can be increased, the conventional water sharpening is unnecessary. In addition, if the body W is rotated with the top coat, the poor finish of the middle coat can be covered with the good top coat without performing water sharpening with the middle coat.

In the case where the body W is rotated with the top coat and a thin coating film is formed with a top coat having a small sag limit, a so-called color middle coat may be performed. As a result, even if the intermediate paint can be seen through the top paint,
There is no bearing in terms of hue.

The switching of the rotation and the stop of the body W irrespective of the traveling and the stop of the bogie D and the switching of the change of the rotation direction can be performed by using a special actuator such as an air motor, for example. it can. First, in the example of FIG. 7, a pair of first and second chains (corresponding to the chain 34) are provided on the sprocket 33 from the opposite side in the radial direction, and each chain can be driven appropriately. I will do it. With such a configuration, the rotation of the body W is controlled according to the following driving mode.

The first chain is stopped and the second chain is free: In this case, the body W is rotated in one direction as the bogie D travels.

First chain free and second chain stop: In this case, the body W is rotated in the opposite direction as the carriage D travels.

Both chains are free: in this case, the body W is not rotated with the movement of the truck D.

Driving the first chain in one direction and freeing the second chain: In this case, the body W is rotated in one direction even when the carriage D is stopped.

Driving the first chain in the other direction and freeing the second chain (the same applies when the first chain is free and the second chain is driven in the other direction): In this case, even if the bogie D is stopped,
The body W is rotated in the direction opposite to the above case.

Note that the above is the same even when a rack bar is used instead of the chain. When the rack bar is always arranged in a fixed state (in this case, the traveling of the bogie D is a prerequisite for the rotation of the body W), the rack bar is intermittently arranged, or the position at which the rack bar is arranged is left and right By setting arbitrarily, the body W can be rotated in an arbitrary direction according to the traveling position of the cart D, and the rotation of the body W can be stopped at an arbitrary position.

(Effects of the Invention) As is apparent from the above description, the present invention utilizes the application of a coating material having a thickness greater than the sagging limit and the rotation of the object to be coated, so that the same coating material thickness can be obtained. It is also possible to obtain a high quality painted surface with high smoothness.

In addition, by performing reversal when rotating the object to be coated, a large amount of paint is prevented from concentrating on the corner of the object to be coated, and the coating film becomes extremely thick only at the corner. Is prevented.

[Brief description of the drawings]

FIG. 1 is an overall process diagram showing one embodiment of the present invention. FIG. 2 is a view showing a state of a posture change accompanying rotation of an automobile body as an object to be coated. FIG. 3 and FIG. 4 are graphs showing the relationship among paint thickness, sag, smoothness of the painted surface, and rotation. 5 and 6 are perspective views showing examples of jigs used for rotating the body. FIG. 7 is a side view showing an example of a bogie for body transportation in which the body is rotated. FIG. 8 is a partially cutaway plan view showing a state of the bogie below the traveling path. FIG. 9 is a sectional view taken along line X9-X9 in FIG. FIG. 10 is a side cross-sectional view showing a connecting portion between the rotating jig and the bogie. FIG. 11 is a sectional view taken along the line X11-X11 in FIG. FIG. 12 is a plan view of FIG. FIG. 13 is a sectional view taken along line X13-X13 of FIG. FIG. 14 is a sectional view taken along line X14-X14 of FIG. FIG. 15 is a plan view of FIG. P1 to P4: Process W: Body (substrate to be coated) l: Rotation axis D: Transport cart 1F, 1R: Rotating jig

Continuation of the front page (56) References JP-A-54-61933 (JP, A) JP-A-57-100939 (JP, A) JP-A-60-223717 (JP, A) JP-B-61-53112 (JP, A) , B2)

Claims (1)

(57) [Claims] 1. A method of applying a coating material on a surface of an object to be coated, wherein the object to be coated is rotatably supported about a substantially horizontal axis, and a predetermined state in the rotatably supported state is provided. At the rotation position, the cross-section has a non-circular shape having a vertical surface extending substantially perpendicularly and a horizontal surface extending so as to intersect the vertical surface and forming a corner at a boundary between the vertical surface and the vertical surface. And a drying step of curing the paint on the surface of the object to be coated so as to have a film thickness greater than or equal to the thickness of the surface of the object to be applied. Before the paint dripping of the paint is generated by gravity, the object to be coated is started to rotate about a substantially horizontal axis, and in this case, the rotation is performed at least before the paint dripping of the applied paint is caused by the gravity. At the speed of transition from the Is performed at a speed lower than the speed at which paint dripping occurs due to centrifugal force caused by the centrifugal force, and the rotation of the object to be coated is performed in such a manner that the rotation is performed alternately between the normal rotation and the reverse rotation. A coating method, wherein each of the rotation angles of the rotation and the reverse rotation is at least equal to or larger than the rotation angle at which the posture of the vertical surface can be changed between a substantially vertical state and a substantially horizontal state.