JP3434712B2 - Solid surface cleaning method and solid surface cleaning apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a solid surface cleaning method and a solid surface cleaning apparatus.

[0002]

2. Description of the Related Art In a manufacturing process of a limit switch, a small electromagnetic relay, and an electronic device in which a part of a pattern conductor on a printed circuit board is used as a contact contact portion of the switch, although it is extremely rare, for example, a material to be used is used. Small glass fiber pieces and resin pieces generated from the above, and further foreign matter such as dust contained in the air may adhere to the contact surface, which may reduce the reliability of the opening / closing operation.

As a conventional technique for overcoming this kind of problem, Japanese Patent Laid-Open No. 6-5145 discloses an air flow between contacts in order to remove foreign matters adhering to the fixed contact surface and the movable contact surface of a small switch. It is proposed to blow off the foreign matter adhering to the contact surface by spraying.

[0004]

However, according to a number of experiments conducted by the present inventors, the blow-off of foreign matter adhering to a contact by an air flow has a small adhering area between the foreign matter and the contact like a short fiber having a complicated shape. When foreign matter rises considerably from the contact surface, the air flow collides strongly with the foreign matter, so the foreign matter removal effect is at a satisfactory level.
Columnar or planar foreign matter such as minute glass fiber pieces and resin pieces adhere firmly to the contact surface, and the amount of foreign matter rising from the contact surface is small, so high-speed air flow can be blown from any direction However, many experiments have shown that a certain proportion of foreign matter cannot be removed from the contact surface.

The adhesion of foreign matter to the contact surface should be eradicated from the viewpoint of the reliability of the switch, but it cannot be realized unless the manufacturing process is cleaned at a level comparable to that of the semiconductor integrated circuit manufacturing process, for example. It used to be considered. Of course, in addition to the above-mentioned spraying of the high-speed air stream, various known cleaning methods, spraying of a water stream or a gas-liquid two-phase stream, and various liquid cleaning such as ultrasonic cleaning may be adopted. However, the method of using a large amount of such liquid is
It is difficult to employ because of the difficulty of reprocessing spent liquid and the inability to easily and inexpensively dry switches or articles having surfaces to be cleaned.

The present invention has been made in view of the above-mentioned problems, and a solid surface cleaning method and a solid surface cleaning method which can realize a remarkably excellent removal rate by a method having a simple process and easy to use. It is an object of the present invention to provide a conventional solid surface cleaning device.

[0007]

According to the method for cleaning a solid surface according to claims 1 and 2, which solves the above problems, first, a predetermined amount of liquid is adhered to a cleaning region of a solid surface requiring cleaning. After that, a gas flow is blown to the cleaning area to blow off the liquid. As a result of the experiment, it was found that foreign matter having a flat plate-like or cylindrical surface and adhering to the cleaning region could be removed very well.

The first reason for improving the foreign matter removability is that when the liquid comes into contact with the foreign matter, the cohesive force of the liquid causes the foreign matter to be taken into the liquid, and / or the minute difference between the foreign matter and the cleaning region. It was possible to observe by experiment that this is because the liquid penetrates into the gap due to the capillary phenomenon and the action of lifting the foreign substance occurs. From this point, as the liquid, water or the like, which is excellent in the balance between the wettability with foreign matters and the cleaning region and the surface tension, is suitable.

The second reason for the improvement of the foreign matter removability is that when a predetermined contact force is generated between the foreign matter and the liquid due to the above-mentioned wetting, a liquid having a larger shape than that of the foreign matter is relatively opposed from the gas flow. It is considered that a large mechanical force acts on the foreign matter to blow off the foreign matter together with the liquid. Therefore, according to this configuration, it is possible to significantly improve the foreign substance removal effect compared with the conventional one, and moreover, the amount of liquid used is extremely small because it is sufficient to cover the cleaning region, and the liquid use cost is low, It was possible to realize a foreign matter removal method having excellent practicability by simplifying the apparatus configuration and processing steps related to liquid use, including subsequent drying, and reducing the cost related to liquid use.

[0010] In further accordance with the configuration of claim 1, wherein the solid has a pair of cleaning region facing at a narrow gap with each other. By doing so, the liquid can adhere to both of these cleaning regions between the pair of cleaning regions due to the capillary phenomenon, so that the passage of the gas flow can be made smaller than in the case of one-sided deposition of the liquid. It can be largely blocked and the liquid can be blown off well. Furthermore, since a pair of cleaning regions can be processed at the same time, it is possible to shorten the process while reducing the liquid usage amount and the gas usage amount.

[0011] In further accordance with the configuration of claim 2, wherein the solid comprises a contact member that electrical continuity is made, cleaned region comprises a surface region that electrical continuity is made. By doing so, cleaning of the surface is required for electrical continuity, and the contact space that is close to the surface is often narrow and cleaning processing is not easy to be performed at low cost and with extremely high reliability. As a result, the contact failure can be significantly reduced compared to the conventional case.

According to the structure of claim 3, in the solid surface cleaning method of claim 2 , the contact member further comprises:
It faces at least another contact member (movable contact member), which is electrically conducted upon contact, with a narrow gap. According to this structure, the surfaces of both contact members facing the narrow gap and not easily cleaned can be satisfactorily cleaned by the action of the first aspect .

According to the structure of claim 4, in the solid surface cleaning method according to claim 3 , the cleaning area is further reduced to 0.
Since the liquid droplets face each other with a distance of 1 to 3 mm, the liquid droplets can easily adhere to both cleaning regions, and foreign substances in both cleaning regions can be easily removed. According to the configuration of claim 5, in the solid surface cleaning method according to any one of claims 1 to 4 , the liquid contains water as a main component or all of them, so that a large surface tension and wettability of water are utilized. In addition, the material cost can be reduced. In particular, when water that is almost similar to pure water is used, the residual liquid can be removed by a simple process called evaporation, and the manufacturing cost can be further reduced.

According to the structure of claim 6, in the solid surface cleaning method according to any one of claims 1 to 5 , further, an air flow injected from a high pressure air nozzle is used as the gas flow. The device configuration and cost can be reduced. Further, according to the solid surface cleaning apparatus of claim 7 , after the water droplet is dropped between one of the fixed contacts and the movable contact and is blown off thereafter, the movable contact is moved by, for example, energizing a coil, and further thereafter. Since the water droplet is dropped between the other fixed contact and the movable contact and blown off thereafter, both the normally closed contact and the normally open contact can be easily cleaned.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the solid surface cleaning method of the present invention and the solid surface cleaning apparatus using the same will be described with reference to the following examples.

[0016]

Embodiment 1 An embodiment in which the solid surface cleaning device of the present invention is applied to cleaning the contact surface of a small relay will be described below with reference to FIG. Reference numeral 1 denotes a conveyor, and the electromagnetic relays 2 are conveyed on the conveyor 1 at regular intervals. Reference numeral 3 is a water drop dropping device, and 4 is a high-speed air blowing device. The interval between the water drop dropping device 3 and the high-speed air blowing device 4 is set to an integral multiple of the electromagnetic relay arrangement pitch, and the electromagnetic relay 2 is directly below the water drop dropping device 3 and the high-speed air blowing device 4 due to the interval operation of the conveyor 1. Stop in place.

The high-speed air blowing device 4 has a rectangular box-shaped cover 41 having an open bottom surface, an air nozzle 42 fixed to the center of the ceiling surface of the cover 41 and hanging down inside the cover 41, and an air nozzle on the ceiling surface of the cover 41. It has an air supply duct 43 and an exhaust duct 44 that are provided with 42 in between.
The water drop dropping operation of the water drop dropping device 3 will be described in more detail with reference to the explanatory view of FIG.

The electromagnetic relay 2 has a base 21, a normally open contact 22 and a normally closed contact 23 which are housed in the base 21 so as to face each other, and a movable contact 24 provided between these two contacts 22 and 23. Although the movable contact 24 is in contact with the normally closed contact 23, the normally open contact 22 and the normally closed contact 23, which are fixed contacts, are opened and closed by energizing an exciting coil (not shown) when used, as is well known.

In FIG. 2, at least the upper surface of the base 21 of the electromagnetic relay 2 is formed with an opening 25 immediately above the gap between the fixed contacts 22 and 23, and the tip of the pipe of the water drop dropping device 3 is formed. 31 is provided immediately above this opening 25, and the tip of the pipe tip 31 faces the opening 25. (Water Droplet Drop Step) The water droplet drop device 3 is supplied with water from a closed water tank (not shown) through the pipe 32. The water drop dropping device 3 has a built-in electromagnetic cylinder, and a single drop of water is dropped through the opening 25 into the gap between the normally open contact 22 and the movable contact 24 by one energization of this electromagnetic cylinder. It is like this. One water drop dropped in this gap covers the surfaces of the normally open contact 22 and the movable contact 24 facing each other, and is held in the gap by a so-called capillary phenomenon. A plurality of water droplets may be dropped as long as the dropped water droplets are held in the gap between the normally open contact 22 and the movable contact 24. (High-speed air blowing step) The air nozzle 42 of the high-speed air blowing device 4 is connected to a high-pressure air tank (compressed air source) not shown through a solenoid valve not shown.

The electromagnetic relay 2 on which the water droplets have been dropped is conveyed by the conveyor 1 to a position immediately below the air nozzle 42 of the high-speed air blowing device 4 and then by the pair of chuck pieces 51 of the chuck device 5 which operates by a pneumatic cylinder or the like. It is pinched and prohibited from moving on the conveyor 1. After that, the above-mentioned high-speed air blowing device 4 descends from above onto the conveyor 1, and the electromagnetic relay 2 moves the chuck device 5 in the cover 41.
It will be fixed in.

The air nozzle 42 then injects a high velocity air stream into the gap between the normally open contact 22 and the movable contact 24. Thereby, the surface of the normally open contact 22 or the movable contact 24
The foreign matter adhering to the surface of is normally blown away with water droplets, and the surfaces of the normally open contact 22 and the movable contact 24 are cleaned. The exhaust duct 44 always strongly absorbs the air in the base 21 during the high-speed airflow injection, and the foreign matter and water droplets blown off by the exhaust duct 44 are discharged to the outside from the exhaust duct 44.

After that, high-temperature dry air is jetted from the air supply duct 43 to the electromagnetic relay 2 to remove residual moisture adhering to the electromagnetic relay 2. After that, the high-speed air blowing device 4 is lifted up, the chuck of the electromagnetic relay 2 by the chuck device 5 is released, and the conveyor 1 is operated. It has been found that the solid surface cleaning apparatus of this embodiment can improve the defect rate of the electromagnetic relay, which is rarely caused by foreign matter remaining on the contact surface, by two digits or more.

Since the control of the conveyor 1, the water drop dropping device 3, the high-speed air blowing device 4 and the chuck device 5 can be performed by a simple sequence control device, the illustration of the control circuit is omitted. Further, a large number of electromagnetic relays may be slid adjacent to each other in a row along the guide plate, and in a state where water droplets are respectively dropped on the large number of electromagnetic relays 2, a high-speed airflow is applied to each of these electromagnetic relays 2 at once. May be sprayed. In addition, instead of the electromagnetic relay 2, the present invention can be applied to cleaning contacts of limit switches and various small switches, and further cleaning surfaces of fine precision parts.

In the cleaning of the contacts of the electromagnetic relay 2, one water droplet may have a size of, for example, about 0.5 to 1 cc, so that the short glass fiber or the like, which has been difficult to remove in the past, is completely removed. It has become possible.

[0025]

Second Embodiment Another embodiment will be described below. In the above embodiment, the cleaning of the surface of the normally open contact 22 and the surface of the movable contact 24 on the side of the normally open contact 22 has been described, but another set of the water drop dropping device 3 and the high-speed air blowing device 4 is added. However, by using these with the exciting coil of the electromagnetic relay 2 energized, the surface of the normally closed contact 23,
In addition, the surface of the movable contact 24 on the normally closed contact 23 side can be cleaned in the same manner as above.

[0026]

Third Embodiment Another embodiment will be described below. In the above-described embodiment, the water drop dropping device 3 and the high-speed air blowing device 4 are arranged at different positions to carry the electromagnetic relay 2 at intervals.
The continuous operation of the conveyor, the water drop dropping device 3 and the high-speed air blowing device 4 are integrally provided to provide the same electromagnetic relay 2
May be treated, and alcohol or other liquid may be used in place of water.

[0027]

[Experimental Example 1] A relay having a contact diameter of about 2.8 mm and a gap interval of about 0.5 mm was used.
A sample having three glass short fibers having a length of 100 to 200 μm attached was prepared. A commercially available glass fiber was cut and used, and the glass fiber was adhered with tweezers.
Next, after about 0.01 ml of water was dropped into the gap and held therein, 4.5 kg / square cm of high pressure air was jetted into the gap for 5 seconds from a position 1 cm from the gap by a nozzle having an opening diameter of 3 mm. .

Further, during this high-pressure air injection, the gap is closed by energizing for 0.25 seconds, and then the energization is interrupted for 0.25 seconds to open the gap twice, and then 0.0
80 operating cycles of 25 seconds energization and 0.025 seconds interruption
Conducted once. As a result, 90 samples (total foreign matter 27
In 0), no foreign matter, that is, short glass fibers adhered to the surfaces of both contacts facing this gap, and the removal rate was 100%.

[0029]

[Experimental Example 2] Next, an experiment was conducted on 90 samples under the same conditions as in Experimental Example 1, omitting the operation cycle of 0.025 second energization and 0.025 second interruption. As a result, in all the samples, no foreign matter, that is, short glass fibers adhered to the contact surface, and the removal rate was 100%.

[0030]

[Experimental Example 3] Next, an experiment was conducted on 90 samples under the same conditions as in Experimental Example 1 except that all the energization cycles were omitted. As a result, in all of the samples, no foreign matter, that is, short glass fibers adhered to the contact surface, and the removal rate was 10%.
It was 0%.

[0031]

[Experimental Example 4] Next, under the same conditions as in Experimental Example 2 described above, human skin (about 300 μm × about 10) was used instead of the short glass fiber.
0 μm × about 100 μm) was used, and 20 samples were tested by omitting the total of 5 energization cycles. As a result, in all the samples, no foreign matter, that is, human skin was attached to the contact surface, and the removal rate was 100%.

[0032]

[Comparative Experimental Example 1] Next, an experiment was conducted on 90 samples under the same conditions as in Experimental Example 2 above except that no water droplet was dropped.
As a result, among all the samples, the number of samples in which three foreign substances (glass short fibers) remain 1, the number of samples in which two foreign substances remain 12, the number of samples in which one foreign substance remains 42, the number of samples in which all foreign substances can be removed 35
Met.

[0033]

[Comparative Experimental Example 2] Next, the cleaning treatment carried out in Comparative Experimental Example 1 was repeated four more times for the sample in which the foreign matter remained in Comparative Experimental Example 1. As a result, there was no change except that the number of samples in which one foreign matter remained was 41. That is, what can be inferred from these Comparative Experimental Examples 1 and 2 is that
Foreign matter that is easily peeled off and adheres can be removed by one high-pressure air injection, but foreign matter that cannot be removed by one high-pressure air injection can hardly be removed by repeating high-pressure air injection many times thereafter. That is.

[0034]

[Comparative Experimental Example 3] Next, an experiment was conducted under the same conditions as in Comparative Experimental Example 1, changing the blast air from room temperature (28 ° C) to 68 ° C and setting the number of samples to 30. As a result, among all the samples, the number of samples in which three foreign substances (glass short fibers) remained was 1, the number of samples in which two foreign substances remained was 3, and the number of samples in which one foreign substance remained was 15. From this result, it was found that heating the jet air had no effect.

[0035]

[Comparative Experimental Example 4] Next, an experiment was performed on 90 samples under the same conditions as in Experimental Example 1 except that the dropping of water was not performed.
As a result, the number of samples with 3 foreign matters (short glass fibers) remaining 0,
Number of samples with 2 foreign matters left 0, Number of samples with 1 foreign matter left 18,
The number of samples was 72, in which all foreign substances could be removed.

From this example, the above-mentioned energization for 0.025 seconds, 0.
In the operation cycle of 025 second interruption, the movable contact hits the fixed contact at a high speed, so it is considered that the contact vibrates and the foreign substance peeling effect is improved. It was found that the residual rate was high and the practicality was poor.

[0037]

[Comparative Experimental Example 5] Next, 90 samples were tested under the same conditions as in Comparative Experimental Example 4 except that the above operation cycle was repeated 100 times. As a result, foreign matter (glass short fibers)
Is 3 remaining samples 0, 2 foreign particles remaining 0 sample, 1 foreign object remaining 17 samples, all foreign particles removed 73
Met.

From this example, it can be seen that, unless water droplets are dropped, it is not very effective even if the above operation cycle is continued many times in the high-speed airflow injection state. (Modification) A modification will be described with reference to FIG. 6
Is a conductive metal plate, 7a is a contact fixed to the conductive metal plate 6,
Reference numeral 8 is a foreign substance, and 9 is a water drop covering the contact 7 a and the foreign substance 8. In this embodiment, the water droplet covers only one contact, but it is clear that the effect is substantially the same as in the case of the first embodiment. (Modification) Another modification will be described with reference to FIG.

Reference numeral 10 is a printed circuit board, 7 is a pattern conductor formed on the printed circuit board, 7b is a contact portion formed on the pattern conductor 8, 8 is a foreign substance, and 9 is a contact portion 7b.
And the water droplets that cover the foreign matter 8. Also in this mode, the water droplet covers only one contact, but it is clear that the effect is substantially the same as in the case of the first embodiment.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a cleaning device to which a solid surface cleaning method of the present invention is applied.

FIG. 2 is a schematic explanatory view of the water drop dropping device 3 shown in FIG.

FIG. 3 is a schematic explanatory view of the high-speed air blowing device 4 shown in FIG.

FIG. 4 is a schematic side view showing a modified mode.

FIG. 5 is a schematic side view showing a modified mode.

[Explanation of symbols]

1 is a conveyor (conveyor) 2 is an electromagnetic relay 3 is a water drop dropping device (liquid dropping means) 4 is a high-speed air blowing device 42 is an air nozzle 43 is an air supply duct (drying means) 44 is an exhaust duct (liquid storage mechanism)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01H 11/00 H01H 11/00 A H05K 3/26 H05K 3/26 A (58) Fields investigated (Int.Cl. ⁷ , DB (Name) B08B 3/04 B08B 5/00 B08B 5/02 C23G 5/00 F26B 21/00 H01H 11/00 H05K 3/26

Claims (7)

(57) [Claims] 1. At a cleaning area of a solid surface to be cleaned.
A liquid attaching step of attaching a fixed amount of liquid, and then the above
Blow off the liquid by blowing a gas stream on the cleaning area
A gas flow blowing step, wherein the solid has a pair of the cleaning regions facing each other with a narrow gap therebetween, the method for cleaning a solid surface. 2. A solid surface having a cleaning area to be cleaned.
A liquid attaching step of attaching a fixed amount of liquid, and then the above
Blow off the liquid by blowing a gas stream on the cleaning area
A gas flow spraying step, wherein the solid includes a contact member that is electrically connected, and the cleaning region includes a surface region that is electrically connected. . 3. The solid surface cleaning method according to claim 2 , wherein the solid includes a pair of contact members that face each other with a narrow gap therebetween and are electrically connected when they are in contact with each other, and the cleaning region is A method for cleaning a solid surface, comprising surface areas of the contact members which are in contact with each other. 4. The solid surface cleaning method according to claim 3 , wherein the two contact members face each other with a distance of 0.1 to 3 mm. 5. A solid surface cleaning method according to any one of claims 1 to 4, the main component or all components of the liquid solid surface cleaning method characterized by comprising the water. 6. The solid surface cleaning method according to any one of claims 1 to 5, wherein the gas stream is a solid surface cleaning method characterized by comprising the air flow. 7. A liquid pipe, the tip of which is connectable to a liquid tank so as to be arranged above a cleaning region including a pair of fixed contact surfaces of an electromagnetic relay and a movable contact surface therebetween, and from the tip of the liquid pipe. Liquid dropping means for dropping a predetermined amount of liquid to the cleaning area, an air nozzle connected to a compressed air source for blowing an air flow to the cleaning area, and control for controlling the liquid dropping means and high-speed air flow interrupting means The control means moves the movable contact after dropping water droplets between the fixed contact and the movable contact on one side and blowing it off thereafter, and then moves the movable contact to the fixed contact on the other side. A solid surface cleaning device, characterized in that water droplets are dropped between the movable contacts and blown off thereafter.