JPH0697712B2 - Cleaning method of mounted printed circuit board - Google Patents

Description

TECHNICAL FIELD The present invention relates to cleaning of a mounted printed circuit board in which electronic components are mounted on a printed circuit board or a printed wiring board, and the mounted printed circuit board is cleaned with a small solution of a cleaning agent. Regarding the method.

[Prior Art] As is well known, in the cleaning method of cleaning the mounted printed circuit board after mounting the electronic parts on the printed circuit board, CFC has been widely used, but destruction of the ozone layer by CFC is a serious environmental problem. It is well known that it causes humans and threatens the survival of humankind. Therefore, it has been an urgent task to develop an effective cleaning method that can clean the mounted printed circuit board without causing environmental problems.

[Problems to be Solved by the Invention] In the present invention, a small solution of a cleaning agent is used for cleaning a mounted printed circuit board, so that the mounting printed circuit board can be reliably cleaned without causing environmental problems. I focused on what I could do.

However, when a small solution of the cleaning agent is used, the aqueous solution of the cleaning solution invades between the printed circuit board and the electronic component, so that the aqueous solution is hard to evaporate, so that it takes time to dry and the working efficiency is low, Further, there was a problem in quality control due to generation of stains after drying. Incidentally, JP-A-55-8618
As described in Japanese Patent Laid-Open Publication No. 7-28288 or Japanese Patent Laid-Open Publication No. 55-140288, an adhesive is interposed in the gap between the printed circuit board and the electronic component to seal the gap so that the gap can be maintained during cleaning. It may be possible to prevent the aqueous solution of the cleaning liquid from entering. However, since those disclosed in these publications are intended to bond and fix the electronic component on the substrate for the purpose of improving the placement accuracy of the electronic component, for example, when the placement of the electronic component is changed on the substrate. The electronic components cannot be easily removed from the board, and it is difficult to rearrange the electronic components.

[Purpose] The method for cleaning a mounted printed circuit board according to the present invention has been made in view of the above problems. The object of the method is not to cause an environmental problem, and moreover, the mounted printed circuit board can be reliably cleaned. Work efficiency is high, there are no undried parts in the gap between the electronic components and the printed circuit board, there are no stains after drying, there is no problem in quality control, and it is easy to relocate electronic components even after cleaning. It is to provide a cleaning method capable of

[Means for Solving the Problems] In order to achieve such an object, the present invention provides a method for cleaning a mounted printed circuit board, wherein a mounted printed circuit board having electronic components mounted on a printed circuit board with a gap is cleaned. The electronic component is applied to the printed circuit board after applying a volatile and hydrophobic coating agent to a portion of the electronic component facing the gap so that the gap is sealed when the electronic component is mounted on the printed circuit board. After mounting, wash with an alkaline detergent, a higher alcohol detergent with a flash point of 100 ° C or higher or an aqueous solution of a neutral detergent, and after washing, use the volatility of the coating agent to remove the coating agent from the gap. It is characterized by being removed.

[Operation] According to the present invention, a volatile and hydrophobic coating agent is applied to a portion of the electronic component facing the gap, the electronic component is mounted on a printed circuit board, and then an aqueous solution of the cleaning agent is applied. Wash with. With this configuration, even if the aqueous solution of the cleaning agent is intended to enter the gap between the electronic component and the printed circuit board during cleaning, the hydrophobicity of the coating agent sealed in the gap causes the invasion of the aqueous solution of the cleaning agent. On the other hand, after the cleaning, the coating agent is volatilized and removed from the gap by the volatilization action of the coating agent.

[Embodiment] Hereinafter, a method for cleaning a mounted printed circuit board according to an embodiment of the present invention will be described with reference to the drawings. Mounted printed circuit board 7
As shown in FIG. 2, the electronic component 2 is mounted on the printed circuit board 6 with a gap.

As shown in FIG. 1, a roller supported by a lever 5d via rollers 5a, 5b, 5c that contact each other with respect to a portion of the electronic component 2 attached to the mount tape 1 at equal intervals and facing the gap. After coating the volatile and hydrophobic coating agent 4 contained in the container 3 by 5, the electronic component 2 is mounted on the printed circuit board shown in FIG. 2 with the coating agent 4 side of the electronic component 2 facing. Here, when the above-mentioned coating agent 4 is applied to the electronic component 2, the coating agent 4 is applied so that the gap is sealed when the electronic component 2 is mounted on the printed circuit board 6.

Next, the electronic component 2 is soldered to the printed circuit board 6 to form the mounting printed board 7. Further, the mounting printed board 7 is treated with an alkaline cleaner, a higher alcohol cleaner having a flash point of 100 ° C. or higher, or a neutral detergent. Washed with an aqueous solution,
Remove dirt. At this time, even if the aqueous solution of the cleaning agent tries to enter the gap, the hydrophobicity of the coating agent 4 sealed in the gap prevents the invasion of the aqueous solution of the cleaning agent. The volatilization of the coating agent causes the coating agent to volatilize and be removed from the gap.

Even when the electronic component 2 is mounted on the printed wiring board 8 shown in FIG. 3, the mounting printed circuit board 7 can be washed with the cleaning agent aqueous solution to remove dirt by performing the above-described operation.

Therefore, since the aqueous solution of the cleaning agent does not enter between the printed wiring board 6 and the electronic component 2 due to the action of the hydrophobic coating agent 1 of the electronic component 2, the drying is completed in a short time in the next drying step. In addition, the work efficiency is high, and there is no stain after drying, and the quality problem is eliminated. Further, after cleaning, the coating agent is volatilized and removed from the gap by the volatilization action of the coating agent 4, so that a jig or the like is inserted into the gap to easily remove the electronic component 2 from the printed circuit board 6. As a result, the electronic component 2 can be easily rearranged.

[Effect] As described above, according to the method for cleaning a mounted printed circuit board of the present invention, at the time of cleaning, it is possible to prevent the aqueous solution of the cleaning agent from entering the gap between the electronic component and the printed circuit board. Therefore, it is not necessary to dry the aqueous solution of the cleaning agent that has penetrated into the gap in the drying step after washing as in the conventional case. Therefore, the drying time can be shortened and the working efficiency is improved, and the gap or the like can be removed. In addition, since the coating agent is removed from the gap after cleaning, a jig or the like can be inserted into the gap to easily remove the electronic component from the printed circuit board.
Therefore, the electronic components can be easily rearranged.

[Brief description of drawings]

1 to 3 are views showing an embodiment of a method for cleaning a mounted printed circuit board according to the present invention, and FIG. 1 shows a state in which a volatile and hydrophobic coating agent 4 is applied to an electronic component by a roller 5. The side view shown. FIG. 2 is a side view showing a state where electronic components are mounted on a printed circuit board. FIG. 3 is a side view showing a state where electronic components are mounted on a printed circuit board. The reference numerals in the figure are: 1 mount tape 2 electronic parts 3 container 4 volatile and hydrophobic coating agent 5 coating roller 6 printed circuit board 7 mounting printed circuit board 8 ... Printed circuit boards are shown.

Claims (1)

[Claims] 1. A method for cleaning a mounted printed circuit board, wherein a mounted printed circuit board having an electronic component mounted on the printed circuit board with a gap left between the printed circuit board and the printed circuit board is cleaned. After applying a volatile and hydrophobic coating agent so that the gap is sealed at the time of mounting on the printed circuit board, the electronic component is mounted on a printed circuit board, and then, an alkaline cleaning agent, a flash point of 100 ℃ or more. A method for cleaning a mounted printed circuit board, comprising: cleaning with an aqueous solution of a higher alcohol-based cleaning agent or a neutral detergent, and then, after cleaning, removing the coating agent from the gap using the volatility of the coating agent.