JPS625675B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cleaning electronic parts, mechanical parts, etc.

Conventionally, when cleaning electronic parts, mechanical parts, etc., an appropriate solvent is used depending on the type of contamination, such as flux, oil, abrasive powder, etc., and the object to be cleaned is immersed in the solvent, or the object is immersed in the solvent or sprayed with solvent vapor or spray. This was done by focusing on For example, when cleaning flux with a solvent after soldering a circuit board, most of the methods used are one-tank cleaning using steam cleaning or immersion cleaning, and two-tank cleaning using a combination of these. However, the one-tank type cleaning has disadvantages such as the cleaning solution gets dirty quickly, making it difficult to control the cleaning time, and making it difficult to remove the stains from the objects to be cleaned. Further, in the case of two-tank cleaning, when immersion cleaning is performed first, the cleaning liquid in the immersion cleaning tank becomes heavily contaminated, and the cleaning ability decreases significantly as the throughput increases. On the other hand, when steam cleaning is performed for the first time, the cleaning liquid in the steam cleaning tank is heavily contaminated, but clean steam always hits the object to be cleaned.
However, in this case as well, it is not possible to completely remove dirt by steam cleaning alone, so dirt gradually accumulates in the next immersion tank, and the cleaning ability decreases as the throughput increases.

As described above, all of the conventional cleaning methods have the problem that the cleaning liquid gets dirty, and therefore the stains on the object to be cleaned are not completely removed, and it is not efficient as it takes a lot of time to replace the cleaning liquid.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional methods, it is an object of the present invention to provide a cleaning method that requires minimal replacement of cleaning fluid and can perform efficient and complete cleaning.

That is, in the cleaning method of the present invention, the same type of cleaning liquid is placed in the first and second steam cleaning tanks and the immersion ultrasonic cleaning tank; the cleaning liquid is turned into steam in both steam cleaning tanks, and is condensed at the upper part of the tank to perform immersion ultrasonic cleaning. Return it to the tank,
The cleaning liquid is sent from the lower part of at least the first steam cleaning tank to the purifier and the cleaning liquid purified by distillation is returned to the immersion ultrasonic cleaning tank, and the cleaning liquid overflows from the immersion ultrasonic cleaning tank to at least one of the steam cleaning tanks. The object to be cleaned is cleaned in the order of the first steam cleaning tank, the immersion ultrasonic cleaning tank, and the second steam cleaning tank.

The method will now be explained in detail with reference to the drawings. The accompanying drawing shows an example of a cleaning device for carrying out the method. This cleaning device includes a first steam cleaning tank 10,
It includes an immersion ultrasonic cleaning tank 20 and a second steam cleaning tank 30. Each tank contains an appropriate amount of a similar cleaning solution, such as Freon. First steam cleaning tank 1
0 cleaning liquid 11 is heated by a heater 12 and becomes vapor. The portion of the steam that does not contribute to cleaning is condensed by the condenser coil 13 at the top of the tank, and the clean cleaning liquid is sent to the immersion ultrasonic cleaning tank 20 through the circulation path 14. Similar movement of the cleaning liquid is performed in the second steam cleaning tank 30 by the heater 32, the condenser coil 33, and the circulation path 34.

The object to be cleaned (not shown) is taken into a hanger 2 attached to a conveyor 1 and is automatically attached by a device 3 to a first steam cleaning tank 10 and an immersion ultrasonic cleaning tank 2.
0 and the second steam cleaning tank 30 in this order, and is automatically removed from the hanger 2 by the take-out device 4.
This intake device 3 and extraction device 4 are known in the art. In the first steam cleaning tank 10, the high-temperature cleaning liquid vapor hits the object to be cleaned at room temperature and condenses, and when it falls as droplets, dirt on the surface is washed away. Therefore, the cleaning ability is maintained until the object to be cleaned reaches the steam temperature, and the steam is always clean and free of dirt. In this first steam cleaning tank 10, approximately
Removes 80-90% of dirt. The object to be cleaned then enters an immersion ultrasonic cleaning bath 20, where remaining dirt is removed by the action of an ultrasonic oscillator 22. The object to be cleaned, which has been cooled again to approximately room temperature in the immersion ultrasonic cleaning tank 20, is finally finished cleaned in a second steam cleaning tank 30.
The holding time in each tank varies depending on the type of the object to be cleaned, the degree of dirt, etc., but is usually 2 minutes, 1 minute, and 2 minutes in that order.

The first steam cleaning tank 10 is the one where the cleaning liquid is most contaminated by the above cleaning process. Therefore, at least the cleaning liquid 11 in the first steam cleaning tank 10 is supplied to the pipe 1 at the bottom of the tank.
5 to a purifier (not shown) where it is purified by distillation. The cleaning liquid 31 of the second steam cleaning tank 30 and further the cleaning liquid 21 of the immersion ultrasonic cleaning tank 20 may also be sent to the same purification device for cleaning. All of the cleaning liquid thus cleaned is sent to the immersion ultrasonic cleaning tank 20. Therefore, clean cleaning liquid is always supplied to the immersion ultrasonic cleaning tank 20 from the circulation channels 14 and 34 and the purification device. Therefore, with this method, the immersion ultrasonic cleaning tank 20 can be kept almost clean. The cleaning liquid 21 of the immersion ultrasonic cleaning tank 20 to which a clean cleaning liquid is always supplied is the first one.
and overflows into both or one of the second steam cleaning tanks 10 and 30. When overflowing to only one side, it is preferable to overflow to the second steam cleaning tank 30 and sending the cleaning liquid 31 from this tank to the first steam cleaning tank 10 through the pipe 35. In this preferred embodiment, the typical flow rate of the cleaning fluid is, for example, assuming a total cleaning fluid volume of approximately 500.
Approximately 50/Hr from the first steam cleaning tank 10 to the septic tank,
Approximately 50/- from the septic tank to the immersion ultrasonic cleaning tank 20
Hr, about 40
/Hr, about 130/Hr from the immersion ultrasonic cleaning tank 20 to the second steam cleaning tank 30, and the second steam cleaning tank 3
90/Hr from 0 to the first steam cleaning tank.

Although the specific example has been described above using an apparatus equipped with a tact conveyor with a hanger, it is also possible to use an apparatus equipped with a net conveyor without a hanger or a crank motion method for conveying the processed material. An automatic cleaning method equipped with such a conveyance means is preferable because the cleaning liquid does not affect the human body, but manual cleaning may of course be used.

Furthermore, this method is suitable for cleaning to remove flux after soldering a printed circuit board.

According to the present invention, complete cleaning can be performed in a short time, cleaning liquid can be easily managed, and therefore productivity and reliability can be improved. In the present invention, there is less dirt in the cleaning liquid, and therefore the frequency of liquid replacement is much less than in the past. Specifically, it is necessary to replace the cleaning solution in the first steam cleaning tank and the septic tank, and as a result of a printed circuit board cleaning experiment, it was found that the cleaning solution was not replaced until the cleaning area was approximately 3 m ² / and the number of prints was approximately 14,000 sheets. A good cleaning effect was obtained without any problems.

[Brief explanation of the drawing]

The drawing is a schematic sectional view showing a specific example of a cleaning device for carrying out the present method. 10...first steam cleaning tank, 20...immersion ultrasonic cleaning tank, 30...second steam cleaning tank.

Claims (1)

[Claims] 1 A first steam cleaning tank containing the same type of cleaning liquid, an immersion ultrasonic cleaning tank, and a second steam cleaning tank are installed in this order; the cleaning liquid evaporated from the first and second steam cleaning tanks is condensed on the cleaning tank. and return it to the central immersion ultrasonic cleaning tank;
Overflow only to the steam cleaning tank; supply the cleaning liquid from the second steam cleaning tank to the first steam cleaning tank; send the dirty cleaning liquid from the lower part of the first steam cleaning tank to the purification device and distill it to obtain the purified cleaning liquid is returned to the central immersion ultrasonic cleaning tank; and, while circulating the cleaning liquid in this way, the object to be cleaned is returned to the first steam cleaning tank,
A cleaning method characterized by cleaning in the order of an immersion ultrasonic cleaning tank and a second steam cleaning tank.