JP2021053584A - Coating device - Google Patents

Abstract

To form a coating film that is as thin as possible and has few irregularities while suppressing or preventing clogging of a high-viscosity paint in a slit, even when the discharge amount and application speed of the high-viscosity paint are limited.SOLUTION: A tip shape of a nozzle 3 of a coating device is an arc in a plan view. An ellipticity (Y/X) of the arc is 1.00 or more and 1.15 or less. An opening dimension of a slit 8 is 0.3 mm or more and 0.5 mm or less in an entire range in a longitudinal direction of the slit 8 (a width direction of the nozzle 3), and an opening area of the opening of the slit 8 in the front view is 6.0 mm 2 or more and 11.00 mm 2 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coating device for discharging a highly viscous paint as a strip-shaped film and applying it to a coating target (for example, an automobile-related part).

For example, Patent Document 1 discloses a coating nozzle used for coating a highly viscous paint, and Patent Document 2, for example, discloses a method for applying a highly viscous paint.

In Patent Documents 1 and 2, the paint supplied from the introduction passage is temporarily stored in the internal space of the coating nozzle supported by the robot arm, and the paint is radiated from the slit of the coating nozzle to the vehicle body or the like of an automobile. I try to spray paint.

Examples of the highly viscous paint include acrylic resin-based paints, polyester resin-based paints, urethane resin-based paints, epoxy resin-based paints, and melamine resin-based paints.

Japanese Patent No. 5060599 (Japanese Patent Laid-Open No. 2012-11284) Japanese Unexamined Patent Publication No. 2002-273317

In Patent Documents 1 and 2, when the discharge amount is low, that is, the coating pressure is low, any coating device capable of increasing the moving speed (coating speed) of the coating nozzle by the robot arm (for example, 1200 mm / sec or more) is acceptable. It is possible to form a coating film that is extremely thin (for example, 1.4 mm or less) and has few irregularities, but if the coating device is such that the coating speed cannot be increased as described above, the coating device is as described above. It is difficult to form a coating film.

In view of such circumstances, the present invention can be applied even when the discharge amount and application speed of the high-viscosity paint are limited while suppressing or preventing clogging of the high-viscosity paint in the slit. An object of the present invention is to provide a coating apparatus capable of forming a coating film that is extremely thin and has few irregularities.

The present invention is a coating device for applying a highly viscous paint to a coating target as a strip-shaped film, and has a nozzle for discharging the highly viscous paint, and the highly viscous paint is supplied to the inside of the nozzle. A supply path to be provided and a slit for discharging the highly viscous paint supplied from this supply path as a strip-shaped film while radially spreading outward are provided, and the tip shape of the nozzle is flat. It is an arc in the visual view, and when the width direction of the nozzle is X and the direction orthogonal to the width direction is Y, the ellipticity (Y / X) of the arc is 1.00 or more and 1.15 or less. The opening dimension of the slit is 0.3 mm or more and 0.5 mm or less in the entire range in the longitudinal direction of the slit (the width direction of the nozzle), and the opening of the slit is opened in the front view. area, is characterized in that there is a 6.0 mm ² or more 11.00 mm ² or less.

By specifying the ellipticity, the opening size of the slit, and the opening area in this way, the clogging of the highly viscous paint in the slit can be suppressed or prevented, and then the discharge amount and the coating speed of the highly viscous paint can be increased. Even in such a limited case, it is possible to increase the discharge pressure, so that it is possible to form a coating film that is as thin as possible and has few irregularities.

By the way, the highly viscous paint has a viscosity of 0.1 Pa · s / 20 ° C. or higher at a ^{shear rate of 9400 s -1.}

The opening area is set in a numerical range in which the shear rate of the high-viscosity paint passing through the slit is 7000 to 40,000 s ^{-1 with respect to the discharge amount of the high-viscosity paint of 4000 to 5000 cc / min.}

Further, the distance from the opening of the slit to the coating target is 35 mm or more and less than 50 mm.

Furthermore, the shape of the opening of the slit in front view is a rectangle as a basic shape, and the region from one end of one long side to a predetermined position toward the center and the other end of the one long side to a predetermined position toward the center. The shape is such that each region is an inclined surface and the region sandwiched between the two inclined surfaces is a flat surface.

According to the present invention, after suppressing or preventing clogging of the highly viscous paint in the slit, the discharge pressure is increased even when the discharge amount and the coating speed of the highly viscous paint are limited. Therefore, it is possible to provide a coating device capable of forming a coating film that is as thin as possible and has few irregularities.

It is a perspective view which shows the use example of one Embodiment of the nozzle provided in the coating apparatus which concerns on this invention. It is a top view of the nozzle of FIG. It is a front view of the nozzle of FIG. It is the figure which looked at the cross section (4)-(4) of FIG. 2 from the direction of an arrow. It is the figure which looked at the cross section (5)-(5) of FIG. 3 from the direction of an arrow. It is a figure for demonstrating each part of the nozzle of FIG. 2 in detail. It is a top view of another embodiment of the nozzle provided in the coating apparatus which concerns on this invention. It is a front view of the nozzle of FIG. It is the figure which looked at the cross section (9)-(9) of FIG. 7 from the direction of an arrow. It is a figure which looked at the cross section (10)-(10) of FIG. 8 from the direction of an arrow. It is a figure for demonstrating each part of the nozzle of FIG. 7 in detail. It is a graph which shows the relationship between the discharge amount of the highly viscous paint and the shear rate in the nozzle of Examples 1 to 4 of this invention.

Hereinafter, the best embodiment for carrying out the present invention will be described in detail with reference to the accompanying drawings.

1 to 6 show an embodiment of the present invention. In the figure, 1 is a robot arm, 2 is a coating target, and 3 is a nozzle.

The robot arm 1 is used in a coating facility for applying a highly viscous paint as a band-shaped film on the surface of a coating target 2 (for example, an automobile body). In FIG. 1, the coated film (coating film) is designated by a reference numeral P.

The highly viscous paint has a ^{viscosity of 0.1 Pa · s / 20 ° C. or higher at a shear rate of 9400 s -1} , and is, for example, an acrylic resin paint, a polyester resin paint, an epoxy resin paint, and a melamine resin paint. Although paints and the like can be mentioned, other highly viscous paints may be used.

The nozzle 3 is supported by a robot arm 1, and the robot arm 1 allows the nozzle 3 to be freely moved with respect to an application target 2 such as a vehicle body.

Although not shown in detail, the nozzle 3 is supplied with a highly viscous paint stored in a material container through a filter to remove foreign matter, and the pressure and temperature of the highly viscous paint are appropriately maintained. The discharge amount from the nozzle 3 is adjusted by a metering pump.

Then, as a coating method using the nozzle 3, as shown in FIG. 1, the nozzle 3 is slit in the nozzle 3 while being slowly linearly moved in a predetermined direction while maintaining a predetermined distance from the surface of the coating target 2. A coating film P having a predetermined thickness is obtained by radially ejecting the highly viscous paint from No. 8 so as to be wide and applying the discharged highly viscous paint as a band-shaped film on the surface of the coating target 2.

In this coating method, the robot arm 1 is freely moved with respect to the coating target 2, so that the distance between the nozzle 3 and the surface of the coating target 2 and the coating position of the nozzle 3 on the surface of the coating target 2 are controlled for coating. It can be applied while changing the width, coating film thickness, etc.

Hereinafter, the configuration of the nozzle 3 will be described in detail.

As shown in FIGS. 1 and 2, the nozzle 3 has a substantially bell-shaped combination of a substantially half-moon shape and a rectangular shape in a plan view, and a rectangular plank shape in a front view and a side view.

Specifically, the nozzle 3 has a configuration in which a body 4, a cover 5, and a spacer 6 called a pattern blade are combined.

The tip shape of the nozzle 3 is an arc in a plan view as shown in FIGS. 1 and 2. The arc may have any shape such as an arc, an ellipse, a hyperbola, or a convex curve such as a parabola. In this embodiment, the ellipticity (Y / X) of the arc is 1.00, that is, an arc. X is the radius in the width direction (X-axis direction) of the nozzle 3, and Y is the radius in the direction orthogonal to the width direction (Y-axis direction).

The body 4 has a rectangular portion 41 and a crescent-shaped portion 42 in a plan view, and the rectangular portion 41 is formed thicker than the crescent-shaped portion 42, whereby the crescent-shaped portion 42 is lower than the rectangular portion 41. There is a step like this.

The cover 5 is made of a flat plate having the same shape as the half-moon shaped portion 42 of the body 4. The cover 5 is attached to the half-moon shaped portion 42 of the body 4 via a spacer 6 by a bolt 11 and a washer 12.

The spacer 6 is a thin plate for separating the half-moon shaped portion 42 and the cover 5 in the body 4, and is formed to be significantly thinner than the cover 5. The spacer 6 has the same shape as the rest of the half-moon shaped portion 42 shown in FIG. 5, excluding the fan-shaped region.

The body 4 is provided with a female screw hole (not shown) into which the bolt 11 is screwed, and the cover 5 and the spacer 6 are provided with an insertion hole (not shown) into which the bolt 11 is inserted. There is.

Further, in order to easily position the cover 5 and the spacer 6 with respect to the body 4, the half-moon shaped portion 42 of the body 4 has a positioning pin 7, and the cover 5 and the spacer 6 have a positioning pin 7 for fitting. Positioning holes (not shown) are provided respectively.

Further, a slit 8, an internal space 9, and an introduction passage 10 are provided inside the nozzle 3.

The slit 8 is an opening for discharging the highly viscous paint supplied from the introduction passage 10 and the internal space 9 as a strip-shaped film while radially spreading outward, and is provided by the body 4, the cover 5, and the spacer 6. Made. The detailed shape of the slit 8 will be described in detail later.

The internal space 9 is formed by the body 4 and the cover 5, and the opening on the downstream side thereof is formed in a fan shape in a plan view.

The introduction passage 10 is a passage for introducing the highly viscous paint, and is provided inside the rectangular portion 41 of the body 4. The introduction passage 10 is connected to the internal space 9, and the internal space 9 is connected to the slit 8. The above-mentioned internal space 9 and the introduction passage 10 form the supply path described in the claims.

Next, the details of the slit 8 described above will be described.

First, the slit 8 is formed in a fan shape as shown in FIGS. 5 and 6 in a plan view, and the slit 8 is formed in a curved band shape near the opening.

Specifically, as shown in FIG. 6, the above-mentioned plan view fan-shaped slit 8 expands at a predetermined angle α from the introduction passage 10 side toward the opening side. This angle α is called the internal angle of the slit 8.

The internal angle α is assumed to be an isosceles triangle whose low side is the chord 8c which connects one end 8a and the other end 8b with a straight line and the low angle is β (hereinafter, also referred to as a slit angle) in the arc of the nozzle 3. It can be said that this is the angle between the two isosceles triangles 8d and 8e.

Further, the slit 8 is formed as an opening shape like a substantially trapezoid as shown in FIG. 3 when viewed from the front.

Such an opening-shaped slit 8 is formed between the recess 43 of the body 4 and the cover 5 facing each other. The recess 43 is provided in the half-moon shaped portion 42 of the body 4.

In the recess 43, the region corresponding to the middle of the arc of the nozzle 3 is the flat surface 43a, and the regions on both sides of the flat surface 43a are the inclined surfaces 43b and 43c, respectively.

The flat surface 43a is formed deepest, and the both inclined surfaces 43b and 43c are inclined so as to gradually become shallower from the end edge near the flat surface 43a toward both end edges in the longitudinal direction of the slit 8. .. The flat surface 51a is appropriately set to be larger than about 1/3 of the total length dimension of the slit 8 in the longitudinal direction, and the both inclined surfaces 51b and 51c are set to be about 1 of the total length dimension of the slit 8 in the longitudinal direction. It is set appropriately smaller than / 3.

As shown in FIG. 3, the opening of the slit 8 formed by the recess 43 of the body 4 and the cover 5 has a rectangular shape as a basic shape, and a region from one end of one of the long sides to a predetermined position toward the center. The region from the other end of the one long side to the predetermined position near the center is an inclined surface (inclined surfaces 43b and 43c of the recess 43), and the region sandwiched between the two inclined surfaces is a flat surface (the recess 43). It has a shape similar to that of a flat surface 43a).

Incidentally, if the opening shape of the slit 8 in front view is made substantially trapezoidal as shown in FIG. 3, it can be said that it is advantageous in the following points.

In the case of the slit 8 having such a shape, as shown in FIG. 1, the highly viscous paint applied to the coating object 2 becomes a band-shaped film (referred to as a coating film P), but the short length in the band-shaped coating film P The film thickness on one end side and the other end side in the manual direction becomes thinner.

When the wide area surface of the coating target 2 is applied by sequentially applying such a strip-shaped coating film P next to each other in the lateral direction, the coating films P are applied so as not to generate a gap between the adjacent coating films P. When both ends of P in the lateral direction are overlapped, the film thickness of the entire coating film P can be made uniform.

Next, for example, FIGS. 7 to 11 show other embodiments of the present invention. In this embodiment, the differences from the embodiments shown in FIGS. 2 to 6 are that the arc at the tip of the nozzle 3 is mainly elliptical, and the portion (recess 51) equivalent to the recess 43 of the body 4 is covered with the cover 5. It is provided. Other configurations are basically the same as those of the embodiments shown in FIGS. 2 to 6.

Specifically, the ellipticity (Y / X) is 1.15, that is, an ellipse. The half-moon shaped portion 42 of the body 4 has a flat surface as a whole, and a recess 51 is provided on the inner surface of the cover 5.

In the recess 51, the region corresponding to the middle of the arc of the nozzle 3 is the flat surface 51a, and the regions on both sides of the flat surface 51a are the inclined surfaces 51b and 51c, respectively.

In the recess 51, the flat surface 51a is formed deepest, and the both inclined surfaces 51b and 51c are inclined so as to gradually become shallower from the end edge near the flat surface 51a toward both end edges in the longitudinal direction of the slit 8. Has been done.

The flat surface 51a is appropriately set to be larger than about 1/3 of the total length dimension of the slit 8 in the longitudinal direction, and the both inclined surfaces 51b and 51c are set to be about 1 of the total length dimension of the slit 8 in the longitudinal direction. It is set appropriately smaller than / 3.

A slit 8 as a discharge port for highly viscous paint is provided between the concave portion 52 of the cover 5 having such a shape and the half-moon shaped portion 42 of the body 4 facing each other.

The slit 8 is formed as a fan shape as shown in FIGS. 10 and 11 in a plan view, and is formed as an opening shape such as a substantially trapezoidal shape as shown in FIG. 8 in a front view. The slit 8 near the opening is formed as a curved band.

Here, in the present invention, in the nozzle 3 as shown in the above two embodiments, clogging of the highly viscous paint in the slit 8 is suppressed or prevented, and the discharge rate is, for example, 4000 to 5000 cc / min. And even when the coating speed (also referred to as the moving speed of the nozzle 3 or the gun speed) is limited to, for example, 1000 mm / sec or less, the coating is as thin as possible (for example, 1.4 mm or less) and has few irregularities. In order to apply the film P to the coating target 2, each part of the nozzle 3 described above is devised.

Specifically, the nozzle 3 is required to have the following conditions (1)-(5).

(1) Suppressing or preventing clogging of highly viscous paint in the slit 8. Specifically, first, as shown in FIGS. 3 and 8, the opening dimension (referred to as the end diameter) A on one end side and the other end side in the longitudinal direction of the slit 8 is set to 0.3 mm or more, and the second In addition, the opening dimension (referred to as an intermediate diameter) B in the middle in the longitudinal direction of the slit 8 is set to 0.3 mm or more and 0.5 mm or less.

The end diameter A is preferably determined based on the amount of opening of the mesh of the filter (not shown) used for removing foreign matter in the highly viscous paint. Incidentally, since the opening amount of the eyes can be set to, for example, 0.35 mm in consideration of productivity, the end diameter A is set to 0.3 mm or more in consideration of this point.

(2) Secure a predetermined coating width (for example, 90 mm) even with a low discharge amount. Specifically, the outer shape of the open end of the slit 8 of the nozzle 3 is an arc, and the ellipticity (Y / X) of the arc is 1.00 or more and 1.15 or less.

As shown in FIGS. 6 and 11, X is the radius in the width direction (X-axis direction) of the nozzle 3, that is, the distance from the center of curvature O of the arc to one end point 3a of the arc, and Y is In the nozzle 3, the radius in the direction orthogonal to the width direction, that is, the distance from the center of curvature O of the arc to the maximum protruding end (or also referred to as the midpoint) 3b of the arc.

(3) Secure a predetermined coating pressure even with a low discharge rate. Specifically, first, the opening area of the slits 8 (discharge port area) and 6.0 mm ² or more 11.00 mm ² or less, the second, the internal angle α of the slit 8 and 100 °.

The numerical values of the opening area, as shown in FIG. 12, the high relative discharge rate 4000~5000cc / min viscous paint, high shear rate viscosity paint 7000s ^-1 or more to pass through the slit 8 40000s ^-1 It is set as follows.

Further, setting the opening area to the above value is advantageous in reducing the coating film thickness of the high viscosity paint to 1.4 mm or less, and further setting the internal angle α to the above value is advantageous for the high viscosity paint. It is advantageous in securing the coating width of 90 mm.

(4) The appearance of the coating film P should be good. Specifically, the shear rate of the highly viscous paint discharged from the slit 8 is set to 7000s ^-1 or more and 40,000s ^-1 or less.

(5) Make the film thickness distribution of the coating film P uniform. Specifically, the distance (gun distance) from the slit 8 to the coating target 2 is 35 mm or more and 50 mm or less.

Specific examples included in such conditions include Examples 1 to 4 as shown in Table 1 below. Incidentally, Example 3 corresponds to the embodiment shown in FIGS. 2 to 6, and Example 4 corresponds to the embodiment shown in FIGS. 7 to 11. Examples 1 and 2 are the same as the basic configuration of Example 4, but some conditions are changed as shown in Table 1.

As a result, no clogging of the highly viscous paint in the slit 8 was observed in all of Examples 1 to 4. Further, in Examples 1 to 4, it was confirmed that the coating width of the formed coating film P could be 90 mm. Further, the minimum film thickness of the coating film P to be formed is 0.65 mm in Example 1, 0.70 mm in Example 2, 0.8 mm in Example 3, and 1.00 mm in Example 4. became. Then, it was confirmed that the surface unevenness of the coating film P was smooth by visual inspection of the appearance.

As described above, according to the coating apparatus of the embodiment to which the present invention is applied, clogging of the highly viscous paint in the slit 8 is suppressed or prevented, and then the discharge amount and the coating speed of the highly viscous paint are limited. Even in such a case, since the discharge pressure can be increased, it is possible to form the coating film P which is as thin as possible and has few irregularities.

The present invention is not limited to the above embodiment, and can be appropriately modified within the scope of claims and within the scope equivalent to the scope.

For example, in the above embodiment, an example in which the opening shape of the slit 8 in front view is substantially trapezoidal as shown in FIGS. 3 and 8 is given, but the present invention is not limited to this. For example, the opening shape of the slit 8 in the front view is not shown, but can be a constant dimension, that is, a rectangle in the entire range in the longitudinal direction of the slit 8 (the width direction of the nozzle 3).

INDUSTRIAL APPLICABILITY The present invention can be suitably used for a coating device for applying a highly viscous paint as a band-shaped film to a coating target.

1 Robot arm 2 Application target 3 Nozzle 4 Body
41 Rectangle part
42 Half-moon shape
43 Recess
43a flat surface
43b Inclined surface on one end side
43c Inclined surface on the other end 5 Cover 6 Spacer 7 Positioning pin 8 Slit 9 Internal space 10 Introduction passage 11 Bolt 12 Washer

Claims (1)

A coating device for applying high-viscosity paint to an object to be coated as a band-shaped film.
It has a nozzle that discharges the highly viscous paint,
Inside the nozzle, there is a supply path to which the high-viscosity paint is supplied, and a slit for discharging the high-viscosity paint supplied from this supply path as a strip-shaped film while radially spreading outward. It is provided,
The tip shape of the nozzle is an arc in a plan view.
When the width direction of the nozzle is X and the direction orthogonal to the width direction is Y, the ellipticity (Y / X) of the arc is 1.00 or more and 1.15 or less.
The opening dimension of the slit is 0.3 mm or more and 0.5 mm or less in the entire range in the longitudinal direction of the slit (the width direction of the nozzle), and the opening area of the slit opening in front view is determined. coating apparatus characterized by being the 6.0 mm ² or more 11.00 mm ² or less.

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