JPH0718478A - Washing method and vacuum drying device for small parts, such as electric contacts points - Google Patents

Abstract

PURPOSE:To efficiently wash and dry electric contact points attached with oil-components and dirt from the hands by subjecting the electric contact points to a rinsing treatment by pure water after ultrasonic cleaning, then drying he electric contact points by the vacuum drying device having a specific construction at the time of washing the electric contact points. CONSTITUTION:The many electric contact points S stuck with fats and oils, etc., are put into a cage 10 and are put into a washing tank 1 from which a washing liquid flows over, by which the electric contact points are ultrasonically washed. The cage 10 is pulled up from this washing tank 1 and is immersed into plural rinsing tanks 1 from which the pure water flows over where the electric contact points are subjected to rinsing. The pure water heated to a prescribed temp. by a hot pure water tank 20 is put into the rinsing tank of the final stage in such a case, by which the electric contact points S are kept at the same temp. as the temp. of this pure water. The heated electric contact points S are pulled up together with the cage 10 from the final rinsing tank 20 and are rapidly transferred into the vacuum drying device 5 in a manner as not to allow the temp. of the electric contact point S to fall. The electric contact points are thus heated to the same temp. as the temp. of the hot pure water. The heat of the water drops sticking to the surfaces of the electric contact points S is uniformly evaporated in the reduced pressure atmosphere and the electric contact points S are dried in a pollution-free manner without leaving stains, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is for cleaning metal linear, rod-shaped or lump shaped small parts (hereinafter referred to as "small parts such as electric contacts") used for electric parts such as electric contacts and electronic parts. In particular, the present invention relates to improvement of the drying process for washing.

[0002]

2. Description of the Related Art As is well known, in the case of small parts such as electrical contacts, in order to prevent functional deterioration or functional failure during use and to improve product yield, the surface is cleaned to remove dust and foreign substances up to the micron order. Need to be removed.

An example of a conventional method for cleaning electrical contacts is shown in FIG. The basic steps of any type of wet cleaning are the same, and processing is performed in the order of "cleaning" with a cleaning liquid, "rinsing" with pure water, and "drying".

In the cleaning of electric contacts, the main purpose is to clean the surface of oil and organic contaminants such as hand dust.
Freon and isopropylene alcohol (I
A solvent such as PA) is used as the cleaning liquid. Then, in the cleaning step, a large number of electrical contacts S are accommodated in the basket 10 and immersed in the cleaning tank 1 in which the above-described cleaning liquid overflows for a predetermined time. Cleaning includes rocking cleaning and ultrasonic cleaning.

Then, the pure water is immersed in the overflowing rinse tank 2 for rinsing. Several rinsing tanks 2 are provided, and rinsing is usually performed a plurality of times.

In the drying process, depending on the drying method, when the electrical contact S to which pure water adheres is dried by hot air or the like as it is, residual components in water and dust in the taken-in atmosphere become stains. Since it is likely to remain, a drying method is performed in which water on the surface of the electrical contact S is replaced with a solvent and dried. In this method, the pure water on the surface of the electrical contact S is replaced with CFC or IPA having a low latent heat of vaporization, and the CFC or IPA thus replaced is pulled out from the vapor atmosphere and dried.

That is, first, the plurality of replacement tanks 3 arranged in the subsequent stage of the rinse tank 2 are filled with a solvent of CFC or IPA, and the electric contacts S are immersed in the plurality of replacement tanks 3.
Fluorocarbon or IPA solvent is substituted and adheres to the surface of the. Then, this electric contact S is put in the drying tank 4 together with the basket 10.

A heated freon or IPA solvent is stored at the bottom of the drying tank 4, and the inside of the tank is filled with high-temperature steam of freon or IPA so that the internal electrical contact S is heated. ing. Cooling coil at the top opening of the tank
41 is arranged to trap the Freon or IPA vapor and prevent the vapor from leaking out of the tank.

The electric contact S is housed in the drying tank 4 together with the basket 10 and then slowly pulled up. At this time, the electrical contact S is heated by the high temperature steam in the tank, and the fluorocarbon or IPA adhering to the surface is completely evaporated and the drying is completed.

By the way, recently, the destruction of the ozone layer due to CFCs has become a problem, and in the field of industrial machinery, there is a growing tendency to use CFCs as little as possible. Furthermore, such as the conclusion of an international treaty that regulates the use of CFCs,
The move to abolish Freon is urgent.

On the other hand, since IPA is a combustible organic solvent, it is difficult to handle, and high purity one tends to be high in cost and running cost. Therefore, avoid using IPA if possible. There is a strong demand.

As a method that does not use a solvent such as chlorofluorocarbon or IPA, it is possible to apply a reduced-pressure heat drying method that is performed for cleaning metal products. This reduced pressure heating and drying method is a method in which an object to be dried is placed in a reduced pressure atmosphere and further heated by radiant heating with light energy.

However, as a result of a study by the present inventors,
It was found that even with this method, small spots on the order of micron remained and the electrical contact deteriorated or failed.

[0014]

SUMMARY OF THE INVENTION Therefore, the present invention is directed to a method for cleaning small parts such as electrical contacts which does not use a solvent such as CFC or IPA and which can reduce the remaining stains, and a vacuum drying device used in this method. Is to provide.

[0015]

In the method of cleaning small parts such as electrical contacts according to the present invention for solving the above-mentioned problems, ultrasonic cleaning is performed in the cleaning step, and the rinse step is finally warmed to a predetermined temperature. Immerse small parts such as electrical contacts in pure water, place small parts such as electrical contacts in a decompressed atmosphere during the drying process, and at the same temperature as the control temperature of the pure water heated in the rinse process. It is characterized by being held at.

In the drying step in this cleaning method, it is preferable to quickly rotate or reciprocate small parts such as electric contacts.

Similarly, in the vacuum drying apparatus for small parts such as electric contacts of the present invention for solving the above problems, small parts such as electric contacts heated to a predetermined temperature by being immersed in a hot pure water tank are carried in. A depressurizing chamber, an exhaust system for depressurizing the inside of the depressurizing chamber, and a heating mechanism for keeping small components such as electric contacts carried in at the control temperature of the hot pure water tank. is there.

In the decompression chamber of this decompression drying apparatus, it is preferable to provide a drive mechanism for rapidly rotating or reciprocating small parts such as electrical contacts.

[0019]

As described above, in the method for cleaning small parts such as electric contacts of the present invention, since the temperature of the small parts such as electric contacts is kept at the same temperature as the control temperature warmed in the rinsing step in the drying step, the electric contacts, etc. The heat of water droplets adhering to the surface of the small parts is not taken away by the small parts such as electrical contacts, and the inside and outside of the small parts such as the electrical contacts are uniformly evaporated by the reduced pressure atmosphere. Therefore, stains and the like do not remain. And
In this drying step, if small parts such as electrical contacts are swiftly rotated or reciprocated, the drying can be completed in a short time. Further, according to the vacuum drying apparatus for small parts such as electric contacts of the present invention as described above, the above cleaning method can be efficiently performed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for cleaning small parts such as electric contacts according to the present invention will be described with reference to FIG.
In the cleaning step, a large number of electric contacts S are accommodated in the basket 10 and immersed in the cleaning tank 1 in which the cleaning liquid overflows, and ultrasonic cleaning is performed. In the rinsing step, pure water is immersed in the overflow rinsing tank 2 for rinsing. Several rinse tanks 2 are provided, and rinsing is performed a plurality of times. Then, after this, the conventional solvent replacement is not performed, and instead, the rinse with warm pure water is performed in the final step of the rinse step. That is, the rinse tank at the last stage is the warm pure water tank 20, and the pure water accumulated is warmed to a predetermined temperature (hereinafter, referred to as warm pure water temperature). By immersing in the warm pure water tank 20 for about 120 seconds, the temperature of the electrical contact S becomes almost the same as the temperature of pure water.
As a mechanism for heating the pure water in the warm pure water tank 20, the tank 20
This can be achieved by providing a heater inside or on the bottom plate. Further, it may be heated in advance to a predetermined temperature in another warm pure water tank or the like provided with a temperature adjusting mechanism and then supplied to the warm pure water tank 20 in a heated state.

Next, the electric contacts S together with the basket 10 are carried into the vacuum drying device 5. This loading is completed in a short time in order to prevent the temperature of the electrical contact S from decreasing. Then, in the reduced pressure drying device 5, the electrical contact S is heated so as to be kept at the same temperature as the hot pure water temperature of the pure water heated in the hot pure water tank 20.
As a result, the heat of the water droplets adhering to the surface of the electric contact S is not taken away by the electric contact S, and the heat is uniformly evaporated in the reduced pressure atmosphere. Therefore, the electrical contact S is dried without leaving stains or the like. Into the rinse tank 2 and the warm pure water tank 20 shown in FIG. 1, new pure water is gradually introduced by an inflow pipe (not shown), and overflowed gradually by an overflow pipe (not shown). It is supposed to do.

An embodiment of the reduced pressure drying apparatus of the present invention used in the above-described cleaning method of FIG. 1 will be described with reference to FIG. 2. This reduced pressure drying apparatus 5 includes a decompression chamber 52 having an opening / closing lid 51 on the upper part thereof. An exhaust system for reducing the pressure inside the decompression chamber 52
53, a basket holder 55 arranged in the center of the decompression chamber 52 for holding the basket 10 accommodating the electrical contacts S, a rotating shaft 56 for rotating the basket holder 55, and a rotating shaft 56 arranged outside the decompression chamber 52. A rotating mechanism 57 for rotating and heating for maintaining the temperature of the electric contact S at the hot pure water temperature of the hot pure water tank 20 while preventing the surface of the electric contact S from being cooled by vaporization heat provided on the inner surface of the opening / closing lid 51. Lamp 54a, an electric contact S provided on the inner peripheral side of the body of the decompression chamber 52 for evaporating water that has been shaken off by the centrifugal force generated by the rotation of the basket 10 and for evaporating the water falling under the basket holder 55. The heating mechanism 54 is composed of a heating heater 54c for heating, and a controller (not shown) that controls these units.

The basket holder 55 is a basket containing the electrical contacts S.
It has a structure that can hold the basket 10 without rattling even when it rotates. The rotating shaft 56 is fixed to the lower surface of the basket 10 holder 55, and a rotating mechanism outside the device is provided via a mechanical seal 52a arranged at the opening of the bottom surface of the decompression chamber 52.
Connected to 57. This mechanical seal 52a has several
It is well known that it can withstand a reduced pressure of about 10 Torr. To control the temperature of the electrical contact S, a temperature monitor such as a thermistor (not shown) is attached to the inner wall surface of the decompression chamber 52.

The vacuum pump 53a used in the exhaust system 53 for decompressing the decompression chamber 52 is a rotary pump, but is a water-sealed pump in which water is sealed instead of oil. The water ring pump is used to prevent oil from entering the decompression chamber 52 and contaminating the electrical contact S due to backflow.
Therefore, the vacuum pump 53a is provided with a water circulation system 53b, and the water circulation system 53b is provided with a water tank 53c. Moreover, the water tank 53c is provided with a cooling coil for keeping the water supplied to the vacuum pump 53a at a predetermined low temperature.

The operation of the reduced pressure drying device 5 having the above structure will be described below. First, the opening / closing lid 51 is opened, and the electrical contacts S warmed to the predetermined warm pure water temperature as described above are put together with the basket 10 in the decompression chamber 52.
It is carried into the inside of the container and attached to the basket holder 55 to hold it. Next, after closing the opening / closing lid 51, a drive signal is sent from the controller to the rotating mechanism 57, and the basket holder is sent via the rotating shaft 56.
Rotate 55. After that, the operation of the vacuum pump 53a is started and the temperature control of the electrical contact S by the heating lamp 54a is started. The inside of the decompression chamber 52 is decompressed by the vacuum pump 53a to a pressure of about 70 Torr, for example. Also,
The rotation speed of the basket 10 by the rotation mechanism 57 is, for example, 100 to 1000.
It is about rpm, preferably about 500 to 800 rpm. The electrical contact S is held, for example, for about 5 minutes in such a state that the pressure is reduced and the temperature of the pure water is kept at a predetermined value. As a result, excess water is discharged from the cluster of the electrical contacts S in the basket 10 and vaporized by decompression, and the electrical contacts S do not cool. afterwards,
The rotation by the rotating mechanism 57 is stopped, the leak valve 59 is opened to return to atmospheric pressure, and then the opening / closing lid 51 is opened. Then, the electric contacts S together with the basket 10 are taken out from the decompression chamber 52 by a transfer arm (not shown) and sent to an unloader unit (not shown). The outer shape of the basket holder 55 is preferably a flyhole shape. This is to prevent the decompression chamber 52 from being touched due to bias in rotation when the electric contacts S are put in at a maximum of 5 kg at a time.

Water droplets scattered from the electric contacts S when the basket holder 55 is rotated are evaporated by the heaters 54b and 54c for heating, but the water droplets that have not been evaporated and have fallen to the bottom of the decompression chamber 52 are exhaust pipes. To reach the vacuum pump 53a, finally reach the water tank 53c, and be discharged from an overflow pipe (not shown).

Next, the drying mechanism in the above-mentioned vacuum drying device will be described. The characteristic feature of this reduced-pressure drying apparatus is that the electric contact S is maintained at the same management temperature, that is, the same temperature as the management temperature of the warm pure water tank 20 that preheats the electric contact S.
First, on the surface of the electrical contact S carried into the decompression chamber 52, water droplets of pure water having a temperature equal to the temperature of hot pure water are attached. At this time, if the temperature of the electrical contact S is not controlled as in this device, the temperature of the electrical contact S is lowered and the heat of the water droplets of the hot pure water is taken by the electrical contact S. As a result, a slight temperature difference occurs between the moisture in the surface layer of the lump of the electrical contact S and the moisture inside the lump of the electrical contact S. As shown in FIG. 3, when the temperature of water becomes low, the value of vapor pressure also becomes low. That is, the temperature difference of the water droplets means the difference in the decompression pressure of the required atmosphere. Even if a temperature difference does not occur, it is clear that the heat required for evaporation, that is, latent heat, is absorbed by the electrical contact S, so that the evaporation state becomes non-uniform in the upper and lower portions of the water droplet.

In the conventional reduced-pressure heating and drying, stains are likely to remain on the surface of the electrical contact S after the drying because the heat in the water droplets is absorbed by the electrical contact S. However, in the vacuum drying apparatus of the present embodiment, since the electrical contact S is held at the same temperature as the temperature of the water drop, the heat of the water drop causes the heat of the electrical contact S to rise.
Therefore, the temperature difference between the water drops does not occur. As a result, the water droplets evaporate uniformly at the originally planned vapor pressure,
The stains are not left. The values of the hot pure water temperature and vapor pressure at this time will be described with reference to FIG. 3. For example, when the water temperature is 50 ° C., the vapor pressure is about 70 Torr. Therefore, the temperature of the hot pure water in the hot pure water tank is set to 50 ° C., and the ultimate pressure of the decompression chamber 52 is set to slightly exceed 70 Torr. In this way, the ultimate pressure required in the decompression chamber 52 is determined according to the hot pure water temperature. Incidentally, the control temperature of this warm pure water tank is appropriately determined in the range of about 20 to 80 ° C in the case of pure copper, but 40 ° C.
-60 ° C is preferred. Condensation problems occur below 20 ° C,
On the other hand, when the temperature is 60 ° C or higher for 2 minutes or longer, the surface of pure copper discolors, and at 90 ° C or higher, the surface changes to black in a few seconds.
In the case of pure silver, 30 ° C or higher is preferable. The control temperature is 10
Metals that can be dried at temperatures above 0 ° C (for example,
Although there are brass parts), it is not a good idea because it causes a large energy loss.

Next, another embodiment of the reduced pressure drying apparatus of the present invention will be described with reference to FIG.
Only the structure of the bottom surface of 52 is different, and the other structure is the same as that of the embodiment shown in FIG.

The bottom of the vacuum chamber 52 of the vacuum dryer of this embodiment is provided with a ring-shaped recess 52b so as to surround the central mechanical seal 52a. The exhaust pipe of the exhaust system 53 is provided with the recess 52b.
Connected to the part. In this way, the recess 52
The reason for forming b is that the water droplets scattered from the electrical contact S are preferably discharged when they fall to the bottom without being evaporated by the heater 54c for heating. Also in the vacuum drying apparatus of this embodiment, the water droplets discharged from the exhaust pipe reach the water tank 53c via the water-sealed vacuum pump 53a.

As described above, in the cleaning method and the reduced pressure drying apparatus of this embodiment, the temperature of the electrical contacts S and the water droplets attached to the electrical contacts S is warmed to a predetermined temperature and the decompression chamber 52 is used.
Since the controlled temperature is maintained inside the container, the heat of the water droplets adhering to the surface of the electrical contact S is not taken by the electrical contact S, and is uniformly evaporated by the reduced pressure atmosphere. Therefore, it is possible to perform washing and drying without remaining stains.

Further, in the vacuum drying apparatus of the above-mentioned embodiment, in addition to such stain-free drying, the electrical contact S is further rotated, so that the drying of the electrical contact S is completed in a short time. In addition to the rotation, the electrical contact S can also be quickly reciprocated to dry in a short time.

In the vacuum drying apparatus of the above embodiment, the means for holding the temperature of the electrical contact S is not limited to the heating lamp 54a, and many other heating means can be used. The point is that any means may be used as long as it is not a source of dust and the like.

[0034]

As described above, in the method for cleaning small parts such as electric contacts of the present invention, the temperature of the small parts such as electric contacts is kept at the same temperature as the control temperature warmed in the rinsing step in the drying step, The heat of the adhered water drops is not taken away by small parts such as electrical contacts, and is evaporated uniformly in a reduced pressure atmosphere. Therefore, stains and the like do not remain. Then, in this drying step, if small parts such as electrical contacts are swiftly rotated or reciprocated, the drying can be completed in a short time and the efficiency is good. Further, according to the vacuum drying apparatus for small parts such as electric contacts of the present invention, the above cleaning method can be efficiently performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a cleaning method for small parts such as electrical contacts according to the present invention.

FIG. 2 is a diagram showing an embodiment of a reduced pressure drying apparatus of the present invention used in the cleaning method of FIG.

FIG. 3 is a diagram for explaining the mechanism of the reduced pressure drying apparatus shown in FIG. 2, and shows the relationship between water temperature and vapor pressure when the temperature of the electrical contact is 0 ° C. or higher.

FIG. 4 is a diagram showing another embodiment of the reduced pressure drying apparatus of the present invention.

FIG. 5 is an explanatory diagram of a conventional method for cleaning electrical contacts.

[Explanation of symbols]

 1 Cleaning Tank 2 Rinsing Tank 5 Vacuum Drying Device 20 Hot Pure Water Tank 52 Vacuum Chamber 54 Heating Mechanism 57 Rotating Mechanism S Electrical Contact

Claims (4)

[Claims] 1. A cleaning process for cleaning small parts such as electrical contacts with a predetermined cleaning liquid, a rinsing process for removing the cleaning liquid with pure water after this cleaning process, and a drying process for drying small parts such as electrical contacts after this rinsing process. In the cleaning method for small parts such as electrical contacts consisting of a process, in the rinsing step, the small parts such as electrical contacts are soaked in deionized water that has been warmed to a specified temperature, and in the drying process, the small parts such as electrical contacts are decompressed. A method for cleaning small parts such as electrical contacts, characterized in that they are arranged in an atmosphere and the small parts such as electric contacts are held at the same temperature as the control temperature of pure water warmed in the rinsing process. 2. In the drying step, the small parts such as electric contacts are placed in a reduced pressure atmosphere, and the temperature of the small parts such as electric contacts is maintained at the same temperature as the control temperature of the pure water heated in the rinsing step. 2. A small component such as an electrical contact is swiftly rotated or reciprocally moved by means of.
A method for cleaning small parts such as the described electrical contacts. 3. A decompression chamber into which small parts such as electrical contacts heated to a predetermined temperature by being immersed in a warm pure water tank are introduced, an exhaust system for decompressing the inside of this decompression chamber, and the introduced electricity. A reduced pressure drying apparatus comprising: a heating mechanism for maintaining small parts such as contacts at a control temperature of the hot pure water tank. 4. The reduced-pressure drying apparatus according to claim 3, further comprising a drive mechanism for rapidly rotating or reciprocating small parts such as electrical contacts inside the decompression chamber.