JP2002248418A - Method for coating surface of plasma-sprayed metal layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a inexpensively method for coating the surface of a plasma- sprayed metal layer without foaming the paint. SOLUTION: The plasma-sprayed metal layer of an article 4 to be coated is heated in a heating device 10 to be brought to a temperature higher than that of the paint applied to the plasma-sprayed metal layer before the surface of the plasma-sprayed metal layer is coated with the paint.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a surface of a sprayed metal layer on the surface of the sprayed metal layer on an object to be coated.

[0002]

2. Description of the Related Art Conventionally, when coating the surface of a sprayed metal layer, as shown in JP-B-52-10406,
In many cases, dedicated sealing treatment coating is performed.

[0003]

However, when only the two-component polyurethane paint is applied to the surface of the sprayed metal layer by a thickness of about 30 μm, air bubbles remain on the surface, and the air bubbles are crushed and water or the like is crushed. Penetrated, the sealing performance deteriorated, and the rust prevention life was shortened. For this reason, a method has been adopted in which a dedicated undercoat is applied, a very diluted paint is applied in advance, and foaming is reduced.

[0004] In addition, even when a paint other than the two-component polyurethane paint is used, in order to shorten the drying time, the paint is often cured by using a heating device such as a baking / drying device after the application. In this case, after applying paint on the surface of the sprayed metal layer and heating it with a baking drying device, the air inside the porous sprayed metal layer is pushed out, it is heated and hardened, and bubbles are generated on the surface. There were remaining issues.

[0005] In the case of a paint used for drying at room temperature, there is a problem that the influence is further increased, resulting in a poor appearance.

[0006] The application of a dedicated undercoat has been a factor in increasing costs such as coating time and coating cost.

An object of the present invention is to provide a method for coating a surface of a sprayed metal layer, which can apply a coating to the surface of the sprayed metal layer at low cost without foaming.

[0008]

SUMMARY OF THE INVENTION The present invention is to improve a method of coating the surface of a sprayed metal layer, in which the surface of the sprayed metal layer is coated.

In the method for coating the surface of a sprayed metal layer according to the present invention, the sprayed metal layer of an object to be coated is heated to a temperature higher than the temperature of the coating material for coating the sprayed metal layer, and then the coating is performed with the coating material. It is characterized in that the surface of the sprayed metal layer is coated.

[0010] By heating the sprayed metal layer of the object to be coated as described above, the air inside the porous sprayed metal layer is heated, and in this state, the coating material having a temperature lower than the temperature of the sprayed metal layer. By spraying, the air inside the porous sprayed metal layer is rapidly cooled and contracts, and the paint soaks into the porous sprayed metal layer and simultaneously pushes out the air existing inside the sprayed metal layer to the outside . Since the air inside is pushed out before the paint dries, no air bubbles remain and a clean surface can be painted.

In this case, it is preferable that the temperature of the surface of the heated sprayed metal layer is higher by 10 to 30 ° C. than the temperature of the coating material to be applied.

As the paint, it is preferable to use a quick-drying normal-temperature paint made of a polyurethane resin.

[0013]

1 and 2 show an example of an embodiment of a coating apparatus for performing a method for coating a sprayed metal layer surface according to the present invention. FIG. 1 is a plan view, and FIG. It is a longitudinal cross-sectional view of FIG.

The coating apparatus according to the present embodiment includes a trolley conveyor 1 erected at a predetermined height in a loop shape as shown in the figure, and hangers 2 are supported on the conveyor 1 at predetermined intervals. An object 4 such as a metal transformer case is sequentially suspended from the hangers 2 at the loading position 3 by an operator. The surface of each object to be coated 4 is covered with a sprayed metal layer. The object 4 to be coated is conveyed to the coating position 5 by traveling of the conveyor 1, and the coating of the sprayed metal layer is performed by the coating gun 6a of the coating robot 6. The periphery of the painting position 5 is surrounded by a painting booth 7 for containing paint. The coating booth 7 is provided with an opening 8 through which the conveyor 1, the hanger 2 and the workpiece 4 pass. Although not shown, the hanger 2 is located at the coating position 5 when the coating is performed by the coating gun 6a.
Is provided with a hanger rotation mechanism for rotating the hanger together with the object 4. A painting mechanism 9 is constituted by the painting robot 6, the painting booth 7, a hanger rotation mechanism (not shown), and the like.

At a position before the object 4 is conveyed to the coating position 5 on the conveyor 1, a heating device 10 for heating the object 4 is provided. The heating device 10 rotates a fan 12 by a motor 11 to generate wind, and the wind generates
The air heated indirectly by 3 is conveyed by a duct 14 to an object 4 such as a transformer case that has reached the painting position 5 and blown into the object 4 to heat the object 4 to be coated. The surface of the sprayed metal layer sprayed on the surface of the object 4 is heated to a temperature higher than the temperature of the above-described paint applied to the surface of the sprayed metal layer.

A location adjacent to the loading position 3 of the conveyor 1 is an unloading position 15 so that the worker can remove the painted object 4 from the hanger 2. In this example, a worktable 16 is provided between the arrival position 3 and the unloading position 15, and a worker placed on the worktable 16 performs loading and unloading operations. Although not shown, a lifter that lifts the work 4 toward the hanger 2 and lowers the work 4 from the hanger 2 is installed at the loading position 3 and the unloading position 15.

Next, a coating method using such a coating apparatus will be described.

Prior to this coating step, the surface of the object to be coated 4 such as a transformer case is sprayed in a spraying step and covered with a sprayed metal layer. Thermal spraying is performed by arc spraying or flame spraying. For example, in arc spraying, a voltage of 14 to 25 V is applied between two metal wires, and these metal wires are melted by an arc generated at the tips of the two metal wires to form droplets. It is carried on the high-speed flow of the compressed gas from behind and is conveyed to the object to be coated 4 and adhered to form a sprayed metal layer, thereby forming a rust-proof and corrosion-resistant layer. The sprayed metal layer is
For example, a zinc-aluminum alloy
It is applied with a film thickness of μm. This sprayed metal layer is not a film having no pores, but a porous film.

In this way, the coating object 4 having the sprayed metal layer on the surface is sequentially suspended on the hanger 2 by the operator at the loading position 3. The workpiece 4 suspended by the hanger 2 is conveyed by the conveyor 1, and when reaching the coating position 5, the air heated from the duct 14 of the heating device 10 is removed from the workpiece 4.
To be heated to heat the object to be coated 4. The temperature of the hot air to be heated is preferably, for example, about 70 to 100 ° C. The temperature of the heated sprayed metal layer is one more than the temperature of the paint to be applied.
Raise the temperature by about 0 to 30 ° C.

When the heated object 4 reaches the coating position 5, the object 4 is sprayed by the coating gun 6a of the coating robot 6 while the hanger 2 is rotated together with the object 4 by a hanger rotating mechanism (not shown). A normal temperature paint is sprayed on the surface of the metal layer to apply the paint.

As the paint to be applied, for example, a two-component polyurethane paint which does not require heat drying and which is dry at room temperature and quick-drying is used. The two-part polyurethane paint comprises a paint base, a curing agent and a thinner, and these are mixed at an appropriate mixing ratio. Fast drying refers to a coating material in which the thinning thinner has a high volatility, and the coating surface dries quickly, thereby shortening the touchable drying time. What is room temperature dry paint?
A paint that is dried at room temperature without special heating after coating.

By heating the sprayed metal layer of the article to be coated 4 in this manner, the air inside the porous sprayed metal layer is heated, and in this state, the temperature is lower than the temperature of the sprayed metal layer. By spraying the paint, the air inside the porous sprayed metal layer is rapidly cooled and shrinks, and the paint soaks into the porous sprayed metal layer, and at the same time, the air existing inside the sprayed metal layer to the outside. Extrude. Since the air inside is pushed out before the paint dries, no air bubbles remain and a clean surface can be painted.

When a volatile solvent such as a thinner is not used in the paint, an electric heater or a far-infrared heater can be used as a heat source of the heating device 10.

[0024]

In the method for coating the surface of a sprayed metal layer according to the present invention, since the sprayed metal layer of the object to be coated is heated, the air inside the porous sprayed metal layer is heated, In this state, by spraying paint at a temperature lower than the temperature of the sprayed metal layer, the air inside the porous sprayed metal layer is rapidly cooled and shrunk, and the paint penetrates the porous sprayed metal layer and simultaneously sprays. The air existing inside the metal layer is pushed out, so that a clean surface free of air bubbles can be applied.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of an embodiment of a coating apparatus for performing a method for coating a sprayed metal layer surface according to the present invention.

FIG. 2 is a longitudinal sectional view of FIG.

[Explanation of symbols]

 Reference Signs List 1 trolley conveyor 2 hanger 3 loading position 4 workpiece 5 coating position 6 coating robot 6a coating gun 7 coating booth 8 opening 9 coating mechanism 10 heating device 11 motor 12 fan 13 steam heater 14 duct 15 unloading position 16 work table

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D075 BB23X CA47 DA23 DB01 DB05 DB07 DC18 EB38 4K031 AA01 AA08 AB02 AB09 CB08 CB31 DA01 DA03 FA01 FA09

Claims (3)

[Claims] In a method of coating a surface of a sprayed metal layer on a surface of a sprayed metal layer, the sprayed metal layer of the object to be coated is heated, and a temperature of a coating material applied to the sprayed metal layer is heated. A method for coating the surface of a sprayed metal layer, comprising coating the surface of the sprayed metal layer with the paint after raising the temperature to a higher temperature. 2. The method for coating a surface of a sprayed metal layer according to claim 1, wherein the temperature of the heated sprayed metal layer is higher by 10 to 30 ° C. than the temperature of the steam heater to be applied. 3. The method for coating the surface of a sprayed metal layer according to claim 1, wherein the coating material is a quick-drying room temperature drying coating material made of a polyurethane resin.