Coating method

Abstract

A coating method comprising: an electrostatic coating step of electrostatically coating a metal object supported by a metal hanger grounded to the ground; and a laser irradiation step of, after removing the object from the hanger, burning out, by laser irradiation, a coating material having adhered in the electrostatic coating step to a contact portion, said contact portion being the portion of the hanger that was in contact with the object in the electrostatic coating step.　

Description

Painting method

[0001] The present invention relates to a painting method.

[0002] Conventionally, there is a technique of electrostatically painting an object to be painted suspended from a hanger grounded to the ground (see, for example, Patent Document 1).

[0003] Japanese Patent Laid-Open No. 10-263461

[0004] When electrostatically painting, paint may adhere to the hanger. When such a hanger is reused, the paint adhering to the contact portion with the object to be painted may cause insufficient electrical conduction between the hanger and the object to be painted, and there is a possibility that the object to be painted cannot be sufficiently painted. Therefore, when reusing such a hanger, it is desirable to remove the adhering paint, but the working time and cost increase.

[0005] Therefore, an object of the present invention is to provide a painting method that enables the reuse of a hanger used for electrostatic painting in a short time and at a low cost.

[0006] The above object can be achieved by an electrostatic painting step of electrostatically painting a metal object to be painted supported by a metal hanger grounded to the ground, and after removing the object to be painted from the hanger, the paint adhering in the electrostatic painting step to the contact portion of the hanger that was in contact with the object to be painted in the electrostatic painting step is burned away by laser irradiation, and a laser irradiation step.

[0007] The electrostatic painting step and the laser irradiation step may be executed while the hanger is being conveyed by a conveying device.

[0008] According to the present invention, it is possible to provide a painting method that enables the reuse of a hanger used for electrostatic painting in a short time and at a low cost.

[0009] FIGS. 1A and 1B are explanatory views of the painting method of this embodiment. FIG. 2A is a view showing the tip of the hanger before the execution of the laser irradiation step, and FIG. 2B is a view showing the tip of the hanger after the execution of the laser irradiation step.

[0010] Figures 1A and 1B are explanatory diagrams of the painting method in this embodiment. As shown in Figure 1A, the object to be painted W is suspended from the tip of a hanger 5. The hanger 5 moves along the overhead conveyor 1, thereby transporting the object to be painted W to a predetermined position. Although Figure 1A shows only one hanger 5 and the object to be painted W, multiple hangers 5 and the objects to be painted W suspended from them are transported by the overhead conveyor 1. The overhead conveyor 1 is an example of a transport device.

[0011] Both the hanger 5 and the object to be painted W are made of metal. The hanger 5 is electrically connected to and supports the object to be painted W. The overhead conveyor 1 is grounded, and as a result, the hanger 5 is also grounded. Therefore, the object to be painted W is also grounded via the hanger 5, and the surface of the object to be painted W is positively charged. The grounding method can be a known method. In the electrostatic gun 10, the paint is negatively charged. Paint is sprayed from the electrostatic gun 10 toward the object to be painted W. The paint is powder coating. The electrostatic painting process is carried out in this manner. During the painting process, paint adheres to the hanger 5 as well as the object to be painted W.

[0012] After the electrostatic coating process is completed, the object to be coated W is removed from the hanger 5. The hanger 5 is then transported by the overhead conveyor 1 to the installation position of the laser irradiation device 20, as shown in Figure 1B. The laser L is irradiated from the laser irradiation device 20 to the tip of the hanger 5, specifically to the contact area between the hanger 5 and the laser irradiation device 20. In this way, the laser irradiation process is performed.

[0013] Figure 2A shows the tip of the hanger 5 before the laser irradiation process. Figure 2B shows the tip of the hanger 5 after the laser irradiation process. The paint P attached to the tip of the hanger 5 shown in Figure 2A is the paint attached in the electrostatic coating process described above. As described above, in the electrostatic coating process, the hanger 5 is grounded and the surface of the hanger 5 is positively charged. For this reason, paint easily adheres to the hanger 5. As shown in Figure 2B, the paint P is burned off by irradiating the tip of the hanger 5 with the laser L. For this reason, when the hanger 5 that has undergone the laser irradiation process is reused, conductivity between the hanger 5 and the object to be coated W can be ensured. As a result, the surface of the new object to be coated W can be sufficiently positively charged via the reused hanger 5, and electrostatic coating can be sufficiently performed on the new object to be coated W.

[0014] As described above, the paint P adhering to the hanger 5 can be easily burned off by laser irradiation. Therefore, the hanger 5 can be reused in a short time and at low cost. For example, by arranging the overhead conveyor 1 to circulate between the area where the electrostatic coating process is performed and the area where the laser irradiation process is performed, the hanger 5 can be reused while maintaining the state in which it is transported to the overhead conveyor 1. This reduces the working time compared to, for example, the case where the hanger 5 is removed from the overhead conveyor 1 and the laser irradiation process is performed.

[0015] The wavelength, power output, and focal length of the laser used in the laser irradiation process can be appropriately changed depending on the distance from the laser irradiation device 20 to the hanger 5, the material of the hanger 5, and the paint used. Alternatively, after performing the electrostatic coating process and removing the object to be coated W from the hanger 5, another object to be coated W may be attached to the same hanger 5, and the electrostatic coating process may be performed multiple times before the laser irradiation process is executed.

[0016] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims.

Claims

1. A painting method comprising: an electrostatic painting step of electrostatically painting a metal object to be painted supported by a metal hanger grounded to earth; and a laser irradiation step of, after removing the object to be painted from the hanger, burning off the paint that adhered to the contact portion of the hanger that was in contact with the object to be painted during the electrostatic painting step by irradiating it with a laser.

2. The painting method according to claim 1, wherein the electrostatic painting process and the laser irradiation process are performed while the hanger is being transported by a transport device.

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