JPH0344833B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device for cleaning flux from a printed circuit board.

[Prior art]

After manufacturing, printed circuit boards are stored with pre-flux applied to prevent oxidation on the surface of the copper foil, and post-flux for soldering is applied after electronic components are attached. These fluxes are cleaned with a cleaning solution after soldering. The flux used is one containing components such as rosin resin, solid wax, and activator, and the cleaning liquid used is a fluorocarbon solvent containing alcohol.

An example of a conventional printed circuit board cleaning device will be explained with reference to FIG. 1 is a cleaning device, which is divided into a first tank 2, a second tank 3, and a third tank 4.
The first tank 2 is equipped with an ultrasonic generator 5 and a heater 6 at the bottom, and contains cleaning liquid. The second tank 3 contains cleaning liquid. Heater 7 is installed in the third tank 4.
A small amount of cleaning liquid is stored near the bottom, the cleaning liquid is evaporated by the heater 7, and the upper parts of the first tank 2 and the second tank 3 are covered with the vapor of the cleaning liquid to prevent the items to be washed from drying out during transfer. It is adapted to form a steam zone 8. 9 is a wire mesh pedestal for preventing splashes. 10 is a cooling coil and steam zone 8
The steam zone 8 is secured by condensing and trapping steam attempting to escape upwards, preventing the steam from escaping to the outside.

The cleaning liquid condensed in the cooling coil 10 is collected in the gutter 11, and after the water is separated by the water separator 12, it is led to the second tank 3. The increased amount of cleaning liquid in the second tank 3 overflows over the partition wall 13 and enters the first tank 2, and is further led to the third tank 4 via an overflow pipe 14 where it evaporates again.

In order to clean a printed circuit board with such a cleaning device 1, the suspended printed circuit board 15 is lowered by the transfer means 16, passed through the steam zone 8, and cleaned with steam, and then immersed in the first tank 2. The ultrasonic generator 5 applies ultrasonic waves to the cleaning liquid heated by the heater 6 to clean the flux. Next, the printed circuit board 15 is lifted up, passes through the steam zone 8, and is immersed in the second tank 3 for further cleaning. Next, the printed circuit board 15 is lifted up, passes through the steam zone 8, is steam-cleaned in the third bath 4, and is then lifted up to complete the cleaning.

[Problem that the invention seeks to solve]

However, such conventional methods have a problem in that a white residue is generated during cleaning, and this residue does not come off even with cleaning, so it is necessary to further wipe off the residue after cleaning. It was hot.

SUMMARY OF THE INVENTION An object of the present invention is to provide a printed circuit board cleaning device that solves the above-mentioned problems of the conventional devices, does not generate white residue, and does not require wiping.

[Means for solving problems]

The inventors conducted extensive research to solve this problem, and found that when the flux passes through the steam zone, it degreases or changes in quality.
It was confirmed that this white residue was generated, and the present invention was made based on the knowledge obtained at that time.

As a means for solving the above-mentioned problems, the present invention provides a printed circuit board cleaning device equipped with a cleaning tank containing a cleaning liquid and having at least one of a heater, an ultrasonic generator, and a circulating filtration device. The upper end of the cooling coil of the cooling means provided to cool the space in contact with the liquid surface of the cleaning tank is above the liquid level of the cleaning tank, and the lower end of the cooling coil is below the liquid level of the cleaning tank. It is an object of the present invention to provide a printed circuit board cleaning device characterized in that it is installed as follows.

[Effect]

In the first invention, the present invention is provided with a cooling means for cooling the space in contact with the liquid surface of the cleaning tank (first tank), so that the vapor of the cleaning liquid generated from the cleaning tank (first tank) is condensed. removed. Further, in the second invention, since the second cooling means is provided above the steam zone of the steam tank, the vapor of the cleaning liquid generated from the steam tank is captured above the steam tank, and the cleaning Tank (first tank) does not reach above the liquid level. Therefore, no vapor layer is formed above the liquid level in the cleaning tank (first layer), and the printed circuit board inserted into the cleaning layer (first tank) does not come into contact with steam before the flux is cleaned. , can prevent white residue from occurring. Even when steam cleaning is performed in a steam tank, most of the flux is removed in the cleaning tank (first tank), so no white residue is generated even when the printed circuit board enters the steam zone in the next process.

The present invention can be applied to a device having only one cleaning tank, a device having a cleaning tank and a steam tank, and a device having an additional cleaning tank. Also,
The cleaning tank is equipped with at least one of a heater, an ultrasonic generator, or a circulating filtration device. For example, if it has only a heater, it is a high-temperature immersion cleaning tank, and if it has a heater and an ultrasonic generator, it is a high-temperature ultrasonic cleaning tank. These devices raise the temperature of the cleaning solution and encourage the generation of steam. According to the present invention, the generated steam is immediately cooled, condensed, and removed.

〔Example〕

Embodiments of the present invention will be described using the drawings.

In FIG. 1, a second tank 3 and a third tank 4 are partitioned by a high partition wall 20, and a cooling coil 10 is provided above the partition wall 20, extending above the first tank 2. A cooling coil 17 as a first cooling means for cooling the space in contact with the liquid surface is provided on the side above the liquid surface of the first tank 2 as a cleaning liquid. A partitioned storage tank 19 is provided to store the condensate condensed by the cooling coil 17. Further, the lower end of the cooling coil 17 is installed so as to be below the liquid level of the first tank, so that the steam generated from the first tank 2 does not form a steam zone.

A cooling coil 22 is provided above the steam zone 8 as a second cooling means.

23 is a separated water outlet for the water separated by the water separator 12. 24 is a separated water outlet for water separated on the surface of the condensed cleaning liquid in the storage tank 19.

The effect will be explained.

The steam generated in the third tank 4 fills up to the bottom of the cooling coil 22 to form a steam zone 8. The cleaning liquid that touches the cooling coil 22 and condenses is sent to the water separator 1.
2, and after separating the moisture in the air, enters the second tank 3, and then overflows the second tank 3 and enters the first tank 2. The cleaning liquid evaporated by the heater 6 is cooled and condensed by the cooling coil 17, enters the storage tank 19, passes through the overflow pipe 14, enters the third tank 4, and evaporates again. The water separated to the liquid surface in the storage tank 19 is discharged from the separated water outlet 24.

In this case, the steam in the space above the liquid level of the first tank 2 is cooled by the cooling coil 17 and condensed, so it is removed, and the steam generated in the third tank 4 is cooled by the cooling coil 22 and condensed. Therefore, the liquid level of the first tank 2 does not reach above the liquid level, so no vapor layer is formed above the liquid level of the first tank 2, and the printed circuit board descending to be cleaned in the first tank 2 15
The flux is not exposed to steam before being cleaned, which can prevent white residue from forming.

FIG. 2 shows another embodiment. The cooling coil 17 is arranged to surround the space in contact with the liquid surface of the first tank 2, so that the steam condensation effect in this space is further ensured, and the amount of steam remaining in this space is extremely small. Further, the cleaning liquid is designed to overflow from the entire circumference of the first tank 2. A partition wall 25 is provided in the storage tank 19 to ensure separation of water and cleaning liquid. 26 is a partition wall for overflow.

The above description has been made regarding the case where the first tank 2 is a high temperature ultrasonic cleaning tank, but the same applies to the case where the first tank 2 is a high temperature immersion cleaning tank without the ultrasonic generator 5. Further, even when the first tank 2 is equipped with a circulation filtration device, the temperature of the cleaning liquid increases and steam generation is promoted, so the structure as in the above embodiment can be applied effectively.

〔Effect of the invention〕

In the present invention, the upper end of the cooling coil of the cooling means provided to cool the space in contact with the liquid surface of the cleaning tank is above the liquid level of the cleaning tank, and the lower end of the cooling coil is above the liquid level of the cleaning tank. By arranging it so that the flux on the printed circuit board is at the bottom, it is possible to provide a printed circuit board cleaning device that does not produce a white residue and does not require wiping off the residue when cleaning the flux of the printed circuit board, which is extremely important in practical terms. It can be effective.

[Brief explanation of drawings]

1 and 2 are cross-sectional explanatory views of an embodiment of the present invention, and FIG. 3 is a cross-sectional explanatory view of a conventional example. 1... Cleaning device, 2... First tank, 3... Second tank, 4... Third tank, 5... Ultrasonic generator, 6, 7
... Heater, 8 ... Steam zone, 9 ... Wire mesh pedestal, 10 ... Cooling coil, 11 ... Gutter, 12 ...
Water separator, 13... partition, 14... overflow pipe, 15... printed circuit board, 16... transfer means, 17... cooling coil, 18... partition, 19...
... Storage tank, 20 ... Partition wall, 21, 22 ... Cooling coil, 23, 24 ... Separated water outlet, 25, 26 ...
...bulkhead.

Claims (1)

[Scope of Claims] 1. A printed circuit board cleaning device comprising a cleaning tank containing a cleaning liquid and having at least one of a heater, an ultrasonic generator, or a circulating filtration device, comprising: a space in contact with the liquid surface of the cleaning tank; The cooling means is characterized in that the cooling coil is installed such that the upper end of the cooling coil is above the liquid level of the cleaning tank, and the lower end of the cooling coil is below the liquid level of the cleaning tank. Printed circuit board cleaning equipment. 2. A printed circuit board cleaning device comprising a cleaning tank containing a cleaning liquid and having at least one of a heater, an ultrasonic generator, or a circulating filtration device, and a steam tank that generates vapor of the cleaning liquid to perform steam cleaning, In order to cool the space in contact with the liquid surface of the cleaning tank, the upper end of the cooling coil as a first cooling means is above the liquid level of the cleaning tank, and the lower end of the cooling coil is below the liquid level of the cleaning tank. 1. A printed circuit board cleaning apparatus, comprising: a second cooling means for cooling a space above a steam zone of the steam tank.