JPH07204542A - Coating method and device therefor - Google Patents

Abstract

PURPOSE:To effectively form boundaries with a good cut at one side end edge with simple constitution by adding air flow to a liquid film from a diagonal direction to make coating with the liquid film of a non-atomized state at one of both end edges of the liquid film and coating in the atomized state in the part near the other end. CONSTITUTION:An airless liquid injection nozzle 1 suitable for wide angle sectorial injection provided with an approximate saddle shape nozzle by an inside groove having an almost V-shaped section and an outside groove intersecting with this groove in a crossed state. The control air flow is gushed in the state of holding the liquid film from an air nozzle 2 disposed outside the side to be formed with the end edge of the good cut of the sectorial or tape-shaped liquid film while a coating material is injected from a short distance under a low pressure. The air flow is added to the liquid film from the diagonal direction in such a manner that the end edge on the side opposite to the side formed with the end edge of the good cut of the liquid film is widened in angle and is atomized. As a result, the part near one of both end edges of the sectorial liquid film is coated with the non-atomized liquid film and the part near the other end edge is coated in the atomized state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film formed by using a fan-shaped liquid film jet nozzle, in which one end edge has a well-cut boundary and the other side is gradually made into a thin film state. The present invention relates to a coating method and device that can be applied.

[0002]

2. Description of the Related Art In many cases, so-called masking or taping means is often used to form one edge on a boundary with a good cut by spray coating. However, this method not only requires a great deal of work but also a coating film. Due to the drawback that the edge portion of the sheet is easily peeled off, a method of forming a boundary with a good cut at one side edge has recently been implemented by spray coating as much as possible. There are mainly three types of conventional spray coatings of this type. First, the technique of using a fan-shaped spray nozzle with a special airless structure is
For example, Japanese Examined Patent Publication No. 52-26256 and Japanese Unexamined Patent Publication No. 61-16
1157 and Japanese Utility Model Application Laid-Open No. 52-117607, and secondly, an airless fan-shaped spray nozzle is used to spray the nozzle in a state of being inclined with respect to the surface to be coated. Such a technique is disclosed in, for example, JP-A-60
A technique disclosed in Japanese Patent Laid-Open No. 183067, and thirdly, in which an air flow biased to one side with respect to the nozzle axis from the periphery of an airless fan-shaped spray nozzle is jetted, is disclosed in, for example, JP-A-60-28841. Gazette, JP-A-61-1
No. 61157, etc.

[0003]

The first technique of the prior art described above has a drawback that the nozzle manufacturing is difficult and expensive because it requires a fan-shaped spray nozzle having a special structure, and the second technique. Is an area in which no tail is generated in the fan-shaped spray, and is applied to the surface to be coated.
Sprays are usually prone to spattering on the edges where tails do not occur, so it is actually extremely difficult to form a coating on the boundary edges with good cuts. A biased air flow is ejected to surround the fan-shaped spray so that the spray itself is biased by the air flow, and the film thickness at one edge is made thicker with the bias. However, it is difficult to control the direction and strength of the air flow because the air flow is added from the entire circumference of the spray, and it is easy for some of the spray to scatter even at the edge of the thick film side. Therefore, it is not satisfactory as a coating means for forming a boundary with a good edge cut.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a coating method and apparatus capable of effectively forming a well-defined boundary of one side edge with a simple structure.

[0005]

In order to achieve the above object, the present invention has a wide-angled nozzle having a substantially saddle-shaped nozzle with an internal groove having a substantially V-shaped cross section and an external groove intersecting the internal groove in a cross state. Adopting an airless jet nozzle suitable for fan-shaped jetting, while spraying a relatively high-viscosity paint from a short distance of several mm to several tens of mm under a low pressure of several kg / cm ² , the fan-shaped liquid An air flow is added from an oblique direction so that one side of the fan-shaped liquid film is widened and atomized to both side surfaces of the one-side edge portion of the fan-shaped liquid film. The coating method and apparatus are characterized in that the side portion is coated with a liquid film in a non-atomized state, and the other side portion is coated in the atomized state.

[0006]

A relatively high-viscosity coating material of several kg / amount is obtained from an airless jet nozzle equipped with a saddle-shaped nozzle by an internal groove having a substantially V-shaped cross section and an external groove intersecting the internal groove in a crossed state.
When jetted under a low pressure of about cm ^2, the liquid film near the nozzle orifice is fan-shaped, gradually changing its angle forward and changing to a parallel tape shape, where it becomes coarse-grained spray. Or, after reducing the width from the tape state,
Because it converges to one point and becomes a fan-shaped coarse particle spray from there,
By setting the distance from the nozzle to the surface to be coated to a short distance of several mm to several tens of mm, the part near the one edge of the fan-shaped liquid film before the jet is atomized from the liquid film state is atomized. Instead, it reaches the surface to be coated as it is and forms boundaries with good cuts, and the liquid film is spread and atomized by the air flow supplied obliquely to both side surfaces near the edge on the other side. When the thickness gradually decreases, it reaches the surface to be coated and is coated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the coating apparatus shown in the drawings. In FIG. 3, when the vehicle body portion B that has already been painted P is partially coated with a coating p of a different color, such as the side seal portion at the bottom of the vehicle body in an automobile, do not stain the already painted portion P. Therefore, as shown in FIGS. 1 to 3, the airless wide-angle fan-shaped jet nozzle 1 of the airless type is used as the device of the present invention.
A gun 3 provided with a control air nozzle 2 and a control air nozzle 2 is provided so as to be movable relative to a surface W to be painted, that is, the vehicle body portion B, and the gun 3 is provided with a pressure regulator 5 from a paint supply source 4.
The pressurized paint is supplied from the liquid supply passage 8 via the valve 6 and the heater 7, and is circulated back to the paint tank 11 via the return passage 9 and the throttle valve 10, whereby a constant pressure of about 4 to 6 kg / cm ² is constantly applied. The pressure paint can be supplied to the spray nozzle 1 at a constant temperature, and the gun 3 is supplied with air from a pressurized air supply source 12 via a pressure regulator 13 to an air supply passage 14.
To supply pressurized air to the air nozzles 2, 2 to 0.4
Pressurized air having a constant pressure of about 0.6 kg / cm ² can be blown to a specific portion of the coating liquid film.

The airless wide-angle fan-shaped spray nozzle 1 for spraying the gun 3 is, for example, Japanese Utility Model Publication No. 1-278.
No. 81 or Japanese Utility Model Publication No. 2-5881 is the most suitable nozzle, that is, as shown in FIGS. 4 to 6, an inner groove 15 having a V-shaped cross section and a front end are provided in a portion near the front end of the main body 14. It is a model in which a substantially saddle-shaped injection port 17 formed by relatively shallowly intersecting with a cross section engraved on the surface is formed so as to face the trapezoidal external groove 16 in a crossing relationship.
According to this, there is an advantage that a so-called tail, which is likely to be generated in a portion near the edge, is not considered, and a jet having a remarkably wide angle can be obtained. The external groove 16 in the jet nozzle 1 is
The cross-sectional shape may be V-shaped, U-shaped, U-shaped, or V-shaped with a rounded tip.

As the control air nozzles 2 and 2, for example, as shown in FIGS. 1 and 2, in order to atomize the fan-shaped liquid film jetted from the jet liquid nozzle 1 while spreading it near the edges, The air nozzles 2 and 2 having a relatively small diameter, which are obliquely inwardly directed, are provided on both sides of the fan-shaped liquid film near the tip of the liquid nozzle 1 and slightly forward thereof, and are directed forward by a small angle, and the direction of the axis of the air nozzles 2 and 2 is directed. , Both air nozzles 2, 2
Of the fan-shaped or tape-shaped liquid film passing through both sides of the edge close to the air nozzle so as to intersect at an edge portion on the other side or at a portion close to the edge at an acute angle. Since the generated air flow gradually diffuses to a larger diameter than the nozzle diameter in the propulsion process, the intersecting position due to the orientation of the axis may be inside or outside the portion near the edge of the liquid film.

A nozzle member 19 is attached to the tip of the gun 3 by means of a retaining nut 18, and a protrusion 20 is formed on one front end of the nozzle member 19, and the air nozzles 2 and 2 are formed in the protrusion 20. Set up,
In addition, the pressurized air from the air supply passage 14 is supplied to the air nozzles 2 and 2 through an air supply passage 21 that is provided to communicate with the rear side, and the air nozzles 1 and 2 eject the pressurized air.
The fan-shaped jetted liquid film is fixed to the axial center portion of the tip 9 of the jet nozzle 1 so that the fan-shaped jet liquid film is a plane of symmetry of the air nozzles 2, 2. Is provided on the rear side so as to communicate with each other, and further, an opening / closing valve 23 is provided in the liquid supply chamber 22 so as to be opened and closed by advancing and retracting by an air actuator or the like, so that the pressurized paint from the paint supply source 4 is supplied. While being constantly circulated in the chamber 22, it is possible to jet the liquid from the jet liquid nozzle 1 in a timely manner under the operation of the opening / closing valve 23.

According to the above structure, first, under the condition that the air supply is stopped, the paint having the viscosity of 40 seconds is applied from the jet nozzle 1 to the Ford cup # 4 at a pressure of 4.0 kg / cm ² . If the spraying distance from the nozzle of the spray nozzle 1 to the surface W to be coated is set to 10 mm and the relative movement speed between the gun 3 and the surface W to be coated is 800 mm / sec while performing the coating, As shown in FIG. 7, a tape-shaped coating film with good cuts at both edges is obtained, but splashes are recognized on the outside of both edges.

In addition, when pressurized air having an air pressure of 0.4 kg / cm ² is supplied to the air nozzles 2 and 2 and coating is performed under the same conditions as above, As shown in FIG. 8, it was found that one side was formed with well-cut edges and the other side was atomized while spreading, resulting in a coating film having a gradually decreasing thickness. Moreover, because the control air flow added from the air nozzles 2, 2 is added to both sides of the atomized edge so as to sandwich the liquid film from both sides, the ejector caused by the control air flow also ejects droplets that are likely to occur outside the edge. Since it guides in the direction of the coating film by the action, almost no stains due to the droplets were observed on the outside of the well-cut edge. Therefore, by applying additional coating to the portion where the film thickness is gradually reduced in FIG. 8 by a normal coating method,
It is easy to obtain a uniform and wide-area coating with a sharp edge thickness.

[0013]

As described above, according to the present invention,
It has the following effects. a. By adopting an airless jet nozzle that can obtain a wide-angle fan-shaped jet, the paint is sprayed in a liquid film state from a very close distance to the surface to be coated that moves relatively, while one edge is The coating film is formed almost as it is, and the part near the other edge is spread and atomized by the control air flow so that the coating film is formed in a gradually decreasing state. A liquid film that is not sprayed on the edge gives a well-defined boundary coating surface, and the other edge is coated to a gradually decreasing film thickness that does not produce a step, and therefore, it is usually applied to the gradually decreasing part of the film thickness. By applying additional coating according to the coating method of No. 1, it is possible to easily obtain a coating having a uniform film thickness with a sharp edge on one side. b. The control air flow that spreads and atomizes the part near the edge is passed from the outside on the opposite side of the edge of the liquid film on the side to be spread and atomized to the vicinity of the edge on the other side through both sides of the edge. Since the impact was added from an oblique direction, the control air from both sides that were relatively close to each other caused a weaker inward movement from the outside toward the one edge of the liquid film at the middle portion due to the ejector effect. An air flow is generated, and paint splashes that are slightly floating near the edges are guided toward the paint surface to prevent stains due to the paint splash outside the boundaries of the paint surface. c. Since the control air flow is added to the state that the liquid film is sandwiched from both sides by the air nozzle, the edge of the liquid film is spread and atomized under the condition of being surrounded by the air flow, thus preventing the scattering of fog droplets. As a result, the coating efficiency is improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of essential parts showing a coating method by a coating apparatus of the present invention.

FIG. 2 is a partially cutaway front view showing a main part of a coating apparatus.

FIG. 3 is a side view showing a system of the coating device.

FIG. 4 is a vertical cross-sectional side view illustrating a liquid jet nozzle applied to the present invention.

FIG. 5 is a cross-sectional plan view of a jet nozzle.

FIG. 6 is a front view of a jet nozzle.

FIG. 7 is a diagram of a coating film pattern by a jet nozzle when control air is not supplied.

FIG. 8 is a pattern diagram of a coating film formed by a jet nozzle when control air is supplied.

[Explanation of symbols]

 1 Fountain Nozzle 2 Air Nozzle 3 Gun 4 Paint Supply Source 8 Liquid Supply Channel 12 Pressurized Air Supply Source 14 Air Supply Channel 15 Internal Groove 16 External Groove 17 Jet Port W Surface to be Painted

Claims (2)

[Claims] 1. A wide-angle opening having a substantially saddle-shaped injection port formed by relatively shallowly intersecting the inner groove having a substantially V-shaped cross section and the outer groove formed on the front end face so as to face each other in a crossing relationship. Adopting a fan-shaped jet liquid nozzle, spraying paint from a short distance under a low pressure, and an air nozzle provided on the outside of the fan-shaped or tape-shaped liquid film on the well-cut edge of the liquid film. While jetting a controlled air flow from the side to sandwich the liquid film, the air flow is directed obliquely so that the edge of the liquid film opposite to the side that forms the well-cut edge is widened and atomized. The coating is characterized in that one end of both ends of the liquid film is coated with the liquid film that is not atomized, and the other portion is painted under the atomized state. Method. 2. A relatively shallow crossing is formed in a portion near the front end so that an internal groove (15) having a substantially V-shaped cross section and an external groove (16) engraved on the front end face are opposed to each other in a crossing relationship. A gun (3) equipped with a jet nozzle (1) of a type having a substantially saddle-shaped nozzle (17) and air nozzles (2), (2) for control is provided relatively to the surface to be coated (W). The gun (3) is movably provided, and pressurized paint can be supplied to the spray nozzle (1) from the paint supply source (4) through the liquid supply path (8), and the gun (3) is provided. The compressed air can be supplied to the air nozzles (2) and (2) from the compressed air supply source (12) through the air supply path (14).
The control air nozzles (2), (2) are provided forward in the vicinity of the tip of the jet nozzle (1) in an obliquely inward and forward direction with plane symmetry with respect to the liquid film, and the air flow is The axes of both air nozzles (2) and (2) have edges close to the air nozzles of the liquid film so as to adapt to the spread atomization of the liquid film ejected from the liquid jet nozzle (1) toward one edge of the liquid film. A coating device that is set so that it passes through both sides of the other side and intersects at an acute angle near the edge of the other side.