JPS61142788A - Method and apparatus for cleaning one side of printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method and apparatus for cleaning the back surface of a printed circuit board.

[Background of the invention]

For printed circuit boards related to computers and communication devices, which require reliability such as accuracy and longevity of parts, it becomes necessary to clean the back side after soldering. FIG. 1 shows an external view of an automatic cleaning device conventionally used for cleaning the back side of printed circuit boards. In this cleaning device 1, when a printed circuit board carried by a conveyor 4 passes over the upper surface of a cleaning liquid tank 2, only the back surface of the printed circuit board is cleaned by a jet of cleaning liquid and a brush 3 that rotates while contacting the back surface of the printed circuit board. It is.

However, due to problems with the stability of the cleaning liquid level and the rotational vibration of the rotating brush 3, the cleaning liquid 5 may rise to the top surface from the edge 8 of the printed circuit board 60 or through holes 9 without plating, as shown in FIG. be. For this reason, automatic cleaning cannot be performed on parts where there is a possibility that the mounted parts 7 may become defective due to adhesion or immersion in the cleaning liquid 5, and the back side must be cleaned manually with a brush or the like. Ta. Alternatively, in an automatic soldering machine where soldering and cleaning are performed on the same line, parts that cannot be put on the cleaning machine must be removed, automatic soldering must be performed first, and then the parts must be soldered manually. Ta. Therefore, there are disadvantages in that the process becomes complicated and the time required to assemble the electronic package increases.

Regarding cleaning equipment for printed circuit boards, please refer to Japanese Patent Application Laid-open No. 55
Although there is a Japanese Patent No. 41718, this invention does not describe the content of improving the cleaning ability of printed circuit boards, but does not describe the content of preventing infiltration of cleaning liquid, which is suitable for single-sided cleaning of printed circuit boards.

[Purpose of the invention]

The present invention aims to improve the conventional printed circuit board cleaning apparatus as described above, and to provide a method and apparatus for single-sided cleaning of a printed circuit board, in which there is no fear that the cleaning liquid will infiltrate the upper surface of the printed circuit board.

[Summary of the invention]

The present invention provides an apparatus for cleaning the back surface of a printed circuit board, which is provided with a cover that covers the entire top surface of the printed circuit board, and configured to blow air onto the top surface of the printed circuit board from inside the cover. The substrate is covered with a cover, and while air is blown from inside the cover, only the back surface of the substrate is cleaned, and the cleaning liquid is prevented from penetrating the top surface of the substrate.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 3 to 7.

Figure S (a) is a perspective view of the air blow cover of the present invention, (b) is a sectional view thereof, and Figures 4 and 5 are perspective views showing the air blow cover mounted on a printed circuit board. FIG. 6 is a perspective view showing the overall structure of the present invention, and FIGS. 7(a) to (e) are explanatory diagrams showing a cleaning mechanism by the cleaning apparatus of the present invention.

3 to 7, the single-sided cleaning device 12 for printed circuit boards of the present invention includes a pair of conveyors 4 disposed on both side walls, and a carrier 15 conveyed by the conveyors 4.
, the printed circuit board 6 carried by the carrier 15, the air blow cover 10 covering the printed circuit board, and the cleaning liquid' in the cleaning device 12! II2.

The conveyor 4 is driven by a drive source (not shown),
It is designed to stop and start depending on the signal. A carrier 15 guided by this conveyor 4 has a package, and a printed circuit board 6 is mounted therein with the surface requiring cleaning facing downward.

The air blow cover 10 is supported by a robot hand 13 shown in FIG. 6 and guided into the package. This air blow cover 10 is formed hollow so that the outer periphery of the tip is slightly spaced from the side wall of the package, as shown in FIGS. The narrowing section is connected to a hot air device (not shown). This air blow cover 10 is supported by the robot hand 15 and is configured to start and stop at the same speed as the conveyor 4. Further, the tip of the cover 10 is connected to the carrier 1.
The dry air blown from the warm air device is at a low pressure and a temperature of 50 to 60°C. As shown in FIG. 4, this hot air is blown out from the top surface of the printed circuit board 6 in the direction of the arrow shown by the dotted line, that is, outward. FIG. 5 shows a part of the state in which the washing liquid tank 2 passes above the shown washing liquid tank 2. As shown in this figure, when cleaning the back side of the printed circuit board 6 with the rotating brush 6 immersed in the cleaning liquid 5, hot air from the air blow cover 10 is blown in the direction of the arrow above the printed circuit board B, so that the The cleaning liquid 5 is prevented from coming out upward from the end surface 8 of the substrate 6 or the through hole 9. Note that 14 is an air duct above the cleaning liquid tank 2.

Next, the mechanism of the single-sided cleaning apparatus for flint substrates of the present invention will be explained with reference to FIGS. 7(a) to 7(e).

In FIG. 7, (a) shows a state in which the conveyor 4 is stopped before the carrier 15 carrying the printed circuit board enters the cleaning liquid tank 2. In FIG. Next, as shown in (b), the air blow cover is lowered to cover the upper surface of the printed circuit board 6, and at the same time, the gin pair 4 is activated while dry air is blown out. Next, as shown in (e), the carrier 15 enters the cleaning liquid tank 2, and the rotating brush 6 rotates to clean the back side of the printed circuit board. Next, as shown in (d), the carrier 15
passes over the cleaning liquid tank 2 to stop the conveyor 4 and stop blowing out the dry air. Next, as shown in (e), the air blow cover 10 is removed to complete one-sided cleaning of the printed circuit board.

〔Effect of the invention〕

As described above, according to the single-sided cleaning method and apparatus for printed circuit boards of the present invention, there is no fear that the cleaning liquid will infiltrate the top surface of the printed circuit board, so all electronic components that were conventionally soldered after cleaning can be pre-attached. This has the effect of shortening assembly work time. In addition, new cleaning methods are expected to be introduced in order to ensure the safety of mounted parts against cleaning fluids, and it is not impossible to introduce water-soluble flux etc. in the future.)

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional single-side printed circuit board cleaning device, and FIG. 2 is a sectional view showing the cleaning state in the cleaning device. 3(a) and 3(b) are a perspective view and a sectional view of the air blow cover of the present invention, and FIGS. 4 and 5 are a perspective view and a sectional view showing the air blow cover mounted on a printed circuit board. , FIG. 6 is a perspective view of the entire cleaning device of the present invention, and FIG. 7 is an explanatory view showing the cleaning mechanism by the cleaning device shown in FIG. m6. 2...Cleaning liquid tank 3...Cleaning brush 4...Conveyor 5...Cleaning liquid 6...Printed circuit board 7.
...Mounted parts 8...Edge of board 9...Through hole No. 1 Figure start 2 Figure 3 (α) (b) Figure 5

Claims (1)

[Claims] 1. When cleaning the back side of a printed circuit board after soldering, the entire top surface of the board is covered with a cover, and the cover is cleaned while blowing air from inside to outside. A single-sided cleaning method for printed circuit boards, characterized by the following. 2. In an apparatus for cleaning the back side of a printed circuit board, a cover is provided to cover the entire top surface of the printed circuit board, and
1. A single-sided cleaning device for a printed circuit board, characterized in that the device is configured to blow air onto the top surface of the printed circuit board from inside the cover to prevent cleaning liquid from the back surface of the printed circuit board from entering the top.