WO2009008557A1

WO2009008557A1 - Plasma excitation gas cleaning method and plasma excitation gas cleaning apparatus

Info

Publication number: WO2009008557A1
Application number: PCT/JP2008/062980
Authority: WO
Inventors: Hiromitsu Oda; Keiichi Iida; Takayuki Moroto; Tamio Hara
Original assignee: Toyota Jidosha Kabushiki Kaisha; Nissin Kiko Co., Ltd.; Toyota School Foundation
Priority date: 2007-07-12
Filing date: 2008-07-11
Publication date: 2009-01-15
Also published as: JP2009018260A

Abstract

Cleaning effects to a surface to be cleaned is improved irrespective of existence of a recess on the surface. A plasma irradiation apparatus (1) configuring the plasma excitation gas cleaning apparatus cleans a surface (11a) to be cleaned by irradiating the surface (11a) with a plasma excitation gas (P/G) from a plasma irradiation nozzle (2). The plasma irradiation nozzle (2) is provided with a gas jetting nozzle (3) having a jetting port (3a) arranged to surround the outer circumference of the nozzle. At the time of applying the plasma excitation gas (P/G) from the plasma irradiation nozzle (2), a nitrogen gas (N/G) is jetted from the jetting port (3a) of the gas jetting nozzle (3). Thus, the cleaning surface (11a) is irradiated with the plasma excitation gas (P/G) by having the outer circumference of the applying plasma excitation gas (P/G) surrounded with a gas curtain (G/C).

Description

Plasma-excited gas cleaning method and plasma-excited gas cleaning apparatus

The present invention relates to a plasma excited gas cleaning method and a plasma excited gas cleaning apparatus for cleaning a surface to be cleaned by irradiating with plasma excited gas.

Light

Fine

Background art

Conventionally, as this type of technology, for example, technologies described in Patent Documents 1 to 3 below are known. In particular, in Patent Document 1, a plasma irradiator having a nozzle capable of irradiating a plasma gas flow (plasma excitation gas) to a required region of an electrical component is used, and plasma excitation gas is applied to the region. A cleaning method for cleaning by irradiation is described. Further, in Patent Document 2, ITO glass is positioned between opposing electrodes, a processing gas is allowed to flow between the electrodes, and a glow discharge plasma is generated between the electrodes to activate the processing gas. Thus, it is described that the ITO glass surface is cleaned with a plasma excitation gas.

Here, as an object to be cleaned, it is conceivable that oil and fat components and the like adhering to the substrate surface before the plastic coating are cleaned and removed with a plasma excitation gas. It is also possible to incorporate this cleaning method into a plastic molding production line. It is conceivable to employ the technique described in Patent Document 1 or 2 for this cleaning method.

Patent Document 1 Japanese Unexamined Patent Publication No. 2 0 0 2-2 8 5 9 7

Patent Document 2 Japanese Patent Laid-Open No. 2 0 0 4— 1 2 1 9 3 9

Patent Document 3 Japanese Patent Publication No. 6 2-5 5 1 2 0 Disclosure of Invention Problems to be solved by the invention

However, in the cleaning methods described in Patent Documents 1 and 2, the substrate surface of the recessed portion where the plasma irradiator, the nozzle, and the counter electrode cannot be approached is difficult to be exposed to the plasma excitation gas, and dirt such as oil and fat components is present. There is a concern that it cannot be completely removed. If the surface of the substrate is painted as a post-process in such a state that the dirt cannot be completely removed, the appearance quality of the coated product may be impaired.

The present invention has been made in view of the above circumstances, and the object thereof is to provide a plasma-excited gas cleaning method and a plasma-excited gas cleaning that can improve the cleaning effect of the surface to be cleaned regardless of the presence or absence of a recess. Provided with the equipment. Means for solving the problem

(1) To achieve the above object, the first aspect of the present invention is a plasma excited gas cleaning method for cleaning a surface to be cleaned by irradiating the surface to be cleaned with a plasma excitation gas from a plasma irradiation nozzle. The purpose is to irradiate the surface to be cleaned with the plasma excitation gas while surrounding the periphery of the plasma excitation gas to be irradiated with the gas curtain.

According to the configuration of the above invention, the surface to be cleaned is irradiated with the plasma excitation gas from the plasma irradiation nozzle, so that the plasma acts on the contaminant on the surface to be cleaned to cause a chemical change, and the contaminant is cleaned. Removed from the surface. Here, since the outer periphery of the plasma excitation gas irradiated from the plasma irradiation nozzle is surrounded by the gas curtain, the plasma excitation gas is blocked from the outside air, and the reach distance of the plasma excitation gas is extended. For this reason, the cleaning effect of the surface to be cleaned can be improved regardless of the presence or absence of dents.

(2) In order to achieve the above object, in the configuration (1), it is preferable that the pressure of the gas injected from the gas injection nozzle is higher than the pressure of the plasma excitation gas irradiated from the plasma irradiation nozzle. According to the configuration of the above invention, in addition to the operation of the above configuration (1), since the pressure of the gas injected from the gas injection nozzle is higher than the pressure of the plasma excitation gas, the gas curtain has the momentum of the plasma excitation gas. It will not be destroyed by. For this reason, in addition to the effect of the above configuration (1), the outside air can be reliably shut off by the gas curtain.

(3) In order to achieve the above object, another aspect of the present invention is a plasma excited gas cleaning apparatus for cleaning a surface to be cleaned by irradiating the surface to be cleaned with a plasma excitation gas from a plasma irradiation nozzle. A gas injection nozzle having an injection port provided so as to surround the outer periphery of the plasma irradiation nozzle is provided, and when the plasma excitation gas is irradiated from the plasma irradiation nozzle, the gas is injected from the injection port of the gas injection nozzle. The purpose.

According to the configuration of the above invention, the surface to be cleaned is irradiated with the plasma excitation gas from the plasma irradiation nozzle, so that the plasma acts on the contaminant on the surface to be cleaned to cause a chemical change, and the contaminant is cleaned. Removed from the surface. Here, since the injection port of the gas injection nozzle is provided so as to surround the outer periphery of the plasma irradiation nozzle, a gas curtain that surrounds the plasma excitation gas is formed by the gas injected from the gas injection nozzle. Accordingly, since the outer periphery of the plasma excitation gas irradiated from the plasma irradiation nozzle onto the surface to be cleaned is surrounded by the gas curtain, the plasma excitation gas is blocked from the outside air, and the reach distance of the plasma excitation gas is extended. For this reason, the cleaning effect of the surface to be cleaned can be improved regardless of the presence or absence of the dent.

(4) In order to achieve the above object, in the configuration (3), the pressure of the gas injected from the gas injection nozzle is preferably higher than the pressure of the plasma excitation gas irradiated from the plasma irradiation nozzle.

According to the configuration of the above invention, in addition to the operation of the above configuration (3), the pressure of the gas injected from the gas injection nozzle is higher than the pressure of the plasma excitation gas. It will not be destroyed by. For this reason, in addition to the effect of the above configuration (3), the outside air is secured by the gas curtain. Brief description of the drawings

FIG. 1 is a cross-sectional view showing a part of a plasma irradiator constituting a plasma excited gas cleaning apparatus.

FIG. 2 is a plan view showing the front end surface of the plasma irradiator.

FIG. 3 is a sectional view showing a part of the plasma irradiator.

Figure 4 is a flowchart showing the bumper production process.

FIG. 5 is a sectional view showing a part of the plasma irradiator. Explanation of symbols

1 Plasma irradiator

2 Plasma irradiation nozzle

2 a Irradiation port

3 Gas injection nozzle

3 a injection port

1 1 Pampa

1 1 a Base surface

1 2 dent

1 2 a Base surface

P / G plasma excitation gas

N / G Nitrogen gas

BEST MODE FOR CARRYING OUT THE INVENTION G / C Gas Curtain

DETAILED DESCRIPTION Hereinafter, an embodiment of a plasma excitation gas cleaning method and a plasma excitation gas cleaning apparatus according to the present invention will be described in detail with reference to the drawings.

In this embodiment, before the plastic product is painted, The case where the substrate surface is cleaned by irradiating the surface to be cleaned with plasma excitation gas will be described in detail. FIG. 1 is a cross-sectional view showing a part of the plasma irradiator 1 constituting the plasma excited gas cleaning apparatus of this embodiment. FIG. 2 shows a plan view of the tip surface of the irradiator 1. The plasma irradiator 1 includes a plasma irradiation nozzle 2 and a gas injection nozzle 3 provided so as to surround the outer periphery of the plasma irradiation nozzle 2. This plasma irradiator 1 irradiates plasma excitation gas P / G from a plasma irradiation nozzle 2 to a plastic product (in this case, a “plastic bumper for automobiles”) 1 1 substrate surface 1 1 a Thus, the substrate surface 1 1 a is cleaned. As shown in FIG. 2, the irradiation port 2a of the plasma irradiation nozzle 2 has a circular shape. The injection port 3a of the gas injection nozzle 3 has an annular shape surrounding the outer periphery of the irradiation port 2a. A predetermined gap 4 is provided between the plasma irradiation nozzle 2 and the gas injection nozzle 3. When the plasma excitation gas PZG is irradiated from the irradiation port 2 a of the plasma irradiation nozzle 2, nitrogen gas N / G is injected from the injection port 3 a of the gas injection nozzle 3.

In this embodiment, the plasma excitation gas P / G is generated by plasma excitation of nitrogen gas. In this embodiment, the plasma excitation gas P Z

G is generated by the following configuration. That is, a plasma irradiation nozzle 2 and a torch (not shown) provided in the nozzle 2 are provided. One of the plasma irradiation nozzle 2 and the torch functions as a cathode and the other functions as an anode. At the time of cleaning, pulse discharge is generated between the nozzle 2 and the torch while supplying nitrogen gas for reaction into the plasma irradiation nozzle 2. Thereby, the nitrogen gas in the plasma irradiation nozzle 2 is heated and ionized to form a plasma state in which ions and electrons are formed. The nitrogen gas (plasma excited gas) P / G thus excited by plasma is ejected as a plasma jet from the irradiation port 2a of the plasma irradiation nozzle 2, and is irradiated onto the base surface 11a of the bumper 11. By using “pulse discharge” as described above, The discharge current stays inside the torch (discharge is limited to the inside of the torch only), and as a result, the heat load on the substrate surface 11a can be reduced. In this embodiment, the flow rate of the nitrogen gas supplied to the plasma irradiation nozzle 2 is set to, for example, “3 5 (liter / minute)”. Further, the internal pressure of the nitrogen gas plasma irradiation nozzle 2 is set to, for example, “1.03 to 1.06 (atmospheric pressure)”. Here, in addition to nitrogen gas, oxygen, argon gas or air can be used as the reaction gas.

In this embodiment, the nitrogen gas N / G injected from the gas injection nozzle 3 is supplied with the nitrogen gas pressurized to a high pressure by a pump. In this embodiment, the flow rate of the nitrogen gas N / G supplied to the gas injection nozzle 3 is, for example, “35 to 700 (liter / min) j, and the supply pressure is, for example,“ 1.0 8 ( Barometric pressure) ”. In this embodiment, the pressure of the nitrogen gas N / G injected from the gas injection nozzle 3 is set higher than the pressure of the plasma excitation gas P / G irradiated from the plasma irradiation nozzle 2. The optimum pressure difference is considered to be about “3 (k g f)”. Again, in addition to the nitrogen gas NZG, oxygen, argon gas and air can be used.

In this embodiment, when the substrate surface 1 1 a is cleaned by irradiating the substrate surface 1 1 a with the plasma excitation gas P ZG from the plasma irradiation nozzle 2 by using the plasma irradiator 1 described above, the irradiation is performed. A plasma excitation gas cleaning method is performed in which the substrate surface 11 a is irradiated with the plasma excitation gas PZG while the outer periphery of the plasma excitation gas PZG is surrounded by a gas curtain G / C made of nitrogen gas N / G.

According to the plasma-excited gas cleaning method and plasma-excited gas cleaning apparatus in this embodiment described above, the plasma-excited gas P / G from the plasma-irradiated nozzle 2 of the plasma irradiator 1 is the base material of the plastic pump 11. By irradiating the surface 1 1 a, the plasma acts on contaminants such as oil and fat components on the substrate surface 1 1 a to cause a chemical change. Removed from the ground surface 1 1 a. Here, in this plasma irradiator 1, since the injection port 3a of the gas injection nozzle 3 is provided so as to surround the outer periphery of the irradiation port 2a of the plasma irradiation nozzle 2, as shown in FIG. The nitrogen gas NZG injected from the injection nozzle 3 forms a gas curtain G / C that surrounds the plasma excitation gas PZG. Therefore, the outer periphery of the plasma excitation gas PZG irradiated from the plasma irradiation nozzle 2 to the substrate surface 1 1 a is surrounded by the gas curtain GZC and is blocked from the outside air, and the reach of the plasma excitation gas PZG is extended. For this reason, as shown in FIG. 1, not only the flat substrate surface 1 1 a of the plastic bumper 11 but also the tip of the plasma irradiator 1 can be brought closer as shown in FIG. The substrate surface 1 2 a in the recess 1 2 of the bumper 1 1 can also be suitably cleaned. In this sense, it is possible to improve the cleaning effect of the substrate surface 1 1 a and 1 2 a of the bumper 1 1 regardless of the presence or absence of the recess 1 2. In addition, since the nitrogen gas NZG forming the gas curtain GZC collides with the substrate surface lla, 12 a vigorously, it is possible to obtain the effect of blowing off the pollutant by that momentum. In that sense, the cleaning effect can be further improved as compared with the case of cleaning with only the plasma excitation gas PZG.

Further, in this embodiment, since the pressure of the nitrogen gas N / G injected from the gas injection nozzle 3 is higher than the pressure of the plasma excitation gas PZG, the gas curtain G / C collapses with the momentum of the plasma excitation gas PZG. There is nothing. For this reason, the plasma excitation gas P / G can be reliably shielded from the outside air by the gas curtain GZC. In this sense, the reliability of cleaning using this plasma excited gas cleaning method and plasma excited gas cleaning apparatus can be improved.

Here, the case where the above-described plasma excited gas cleaning method and plasma excited gas cleaning apparatus are incorporated in a plastic bumper production line will be described. Fig. 4 shows a flowchart of the production process for this pump. The following explanation is based on the numbers shown in Fig. 4. First, in step (1), a bumper is injection molded. Next, in step (2), wiping (alcohol degreasing) of the back surface of the bumper substrate is performed. This process requires three workers. Next, in step (3), the bumper surface is masked in preparation for the subsequent coating. This process requires three workers. Next, in the step (4), air blow is performed. This process requires two workers. Thereafter, in step (5), plasma-excited gas cleaning is performed in order to remove oil and fat components on the substrate surface. In the past, in order to remove fats and oils, etc., as shown in (5,), the surface of the substrate was wiped, which required three workers. On the other hand, in this embodiment, the same purpose of removing oil and fat components and the like can be achieved by plasma-excited gas cleaning. In addition, by automating this cleaning with a mechanical device, it is possible to save labor by the operator as in the past. As an example of this automation, the above-described plasma irradiator 1 is held in a robot, and the irradiator 1 is moved close to the product surface by the robot and moved back and forth and right and left. It is also possible to move the plasma irradiator 1 up and down with a robot in accordance with the uneven shape of the product surface.

Thereafter, in the step (6), a primer is applied to the cleaned substrate surface. In this way, the oil and fat components adhering to the substrate surface can be removed by plasma-excited gas cleaning before the coating of the bumper. As a result, it is possible to paint the substrate surface of the bumper as a post process with the dirt completely removed, and to improve the appearance quality as a product after painting.

The present invention is not limited to the above-described embodiment, and a part of the configuration can be changed as appropriate without departing from the spirit of the invention.

For example, in the above embodiment, as shown in FIGS. There was a gap 5 between the excitation gas PZG and the gas curtain GZC. However, as shown in Fig. 5, both gaps were made so that no gap was generated between the plasma excitation gas P / G and the gas curtain G / C. PZG and G / C may be approached. In this case, the injection port 3a of the gas injection nozzle 3 may be brought closer to the irradiation port 2a of the plasma irradiation nozzle 2, and the injection angle of the nitrogen gas NZG may be greatly inclined inward. Industrial applicability

As is clear from the above description, according to the present invention, there is provided a plasma-excited gas cleaning method for cleaning a surface to be cleaned by irradiating the surface to be cleaned with a plasma-excited nozzle from a plasma irradiation nozzle. It is possible to provide a plasma excited gas cleaning method capable of improving the cleaning effect on the surface to be cleaned regardless of whether or not there is any. In addition, a plasma excited gas cleaning apparatus that cleans the surface to be cleaned by irradiating the surface to be cleaned from the plasma irradiation nozzle to improve the cleaning effect of the surface to be cleaned regardless of the presence or absence of dents. It is possible to provide a plasma excited gas cleaning method and a plasma excited gas cleaning apparatus that enable the above.

Claims

The scope of the claims

1. A plasma-excited gas cleaning method for cleaning a surface to be cleaned by irradiating the surface to be cleaned from a plasma irradiation nozzle with a gas curtain surrounding the irradiated plasma-excited gas. However, the plasma excitation gas cleaning method is characterized in that the surface to be cleaned is irradiated with the plasma excitation gas.

2. The plasma-excited gas cleaning method according to claim 1, wherein the pressure of the gas injected from the gas injection nozzle is higher than the pressure of the plasma-excited gas irradiated from the plasma irradiation nozzle.

3. A plasma excited gas cleaning device for cleaning the surface to be cleaned by irradiating the surface to be cleaned from the plasma irradiation nozzle with an injection port provided so as to surround the outer periphery of the plasma irradiation nozzle. A plasma-excited-gas cleaning apparatus comprising: a gas-injecting nozzle comprising: a gas-injecting gas from the injection port of the gas-injecting nozzle when the plasma-exciting gas is irradiated from the plasma-irradiating nozzle.

4. The plasma excited gas cleaning apparatus according to claim 3, wherein the pressure of the gas injected from the gas injection nozzle is higher than the pressure of the plasma excited gas irradiated from the plasma irradiation nozzle.