JPH05283852A - Surface treating apparatus for printed-circuit board - Google Patents

Abstract

PURPOSE:To completely surface-treat even the inner wall of a slender through hole on a printed circuit board. CONSTITUTION:A plurality of stages of slit type jet nozzles 8 and reflecting plates 9 for generating convection in rust prevention solution 6 in which a printed-circuit board 2 fed by conveyor rollers 1 is dipped are arranged. Ultrasonic vibrators 7 each for generating small cavitation are disposed between the nozzles 8, the solution is well agitated, and bubbles remaining in the through holes on the board 2 are discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a final treatment of a surface of a printed wiring board, and more particularly to a surface treatment apparatus for a printed wiring board which is subjected to imidazole-based and benzotriazole-based rustproofing treatment.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing an example of a conventional surface treatment apparatus for a printed wiring board. As shown in FIG. 3, a conventional surface treatment apparatus for a printed wiring board using an imidazole-based or benzotriazole-based rust-preventive treatment liquid dips the rust-preventive treatment liquid 6 in the printed wiring board 2 conveyed by the conveyance rollers 1. Immersion tank 5 to be treated, chemical solution tank 4 for collecting and storing anticorrosion treatment solution 6 overflowing from immersion tank 5, and this chemical solution tank 4
A pump 3 that pumps up the anticorrosion treatment liquid 6 and pressure-feeds it to the immersion tank.
And have.

In this surface treatment apparatus, the chemical tank is sucked up by the pump 3 into the immersion tank 5 so that the anticorrosive treatment solution 6 always overflows from the immersion tank 5. The printed wiring board 2 is conveyed to the dipping tank 5 by the transport roller 1, the printed wiring board 2 is dipped in the anticorrosion treatment liquid 6, and the through hole and the surface mounting component mounting pad where the copper surface of the printed wiring board 2 is exposed. An imidazole-based and benzotriazole-based rust-preventive coating was deposited on.

[0004]

In this conventional surface treatment apparatus, only the anticorrosive treatment liquid in the dipping tank is convected, so that air bubbles often remain in the through holes of the printed wiring board, and The rust preventive film may not be deposited on the wall surface. In particular, when the thickness of the printed wiring board is larger than 1.6 mm and the hole diameter of the through hole is smaller than 0.6 mm, the bubbles remaining in the through hole are remarkable. Therefore, there is a problem that the rust preventive film does not deposit on the wall surface of the through hole and the wall surface of the through hole is oxidized when mounting the component on the printed wiring board, and the solder cannot adhere to the through hole to mount the component. is there.

It is an object of the present invention to provide a surface treatment device for a printed wiring board, which can sufficiently perform a rust preventive film treatment even on the side surface of such a long through hole.

[0006]

A surface treatment apparatus for a printed wiring board according to the present invention is provided with a dipping tank for storing a chemical liquid for dipping a moving printed wiring board, and the dipping tank is arranged in the dipping tank side by side in the moving direction. A plurality of ejection nozzles that cause convection to the chemical liquid, a reflection plate that reverses the convection, and an ultrasonic oscillator disposed between the ejection nozzles are provided.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a surface treatment apparatus for a printed wiring board according to the present invention. As shown in FIG. 1, this surface treatment apparatus includes a slit-type jet nozzle 8 attached to a pipe outlet for pumping a rust preventive treatment liquid from a pop 3 to a dipping tank 5,
The ultrasonic oscillator 7 is arranged side by side with the slit type jet nozzle 8 and the reflection plate 9 for changing the flow of the rust preventive treatment liquid 6 jetted from the slit type jet nozzle.
Other than that, it is the same as the conventional example.

Next, the operation of this surface treatment apparatus will be described. First, the printed wiring board 2 is sent from the left side of the paper by the transfer port 31 and enters the dipping tank 5. Next, the printed wiring board 2 is bathed by the jet flow of the anticorrosion treatment liquid 6 by the slit type jet nozzle 8 on the left side of the paper surface. Next, when passing through the slit type jet nozzle 8, the jet flow is reflected by the reflecting plate 9 and flows toward the surface of the printed wiring board 2 again. Next, when the printed wiring board 2 is further moved, the printed wiring board 2 is treated with fine bubbles generated by the ultrasonic oscillator 7 arranged on the bottom surface of the immersion tank 5. Further, when the printed wiring board 2 is moved, the rust preventive treatment liquid 6 is sprayed by the slit type jet nozzle 8 arranged at the next position, and the rust preventive treatment liquid 6 is sprayed again by the reflecting plate 9, and the ultrasonic oscillator Through the fine bubbles of the rust preventive treatment liquid 6 generated by 7, the small holes such as through-holes are treated. In this way, the surface of the printed wiring board 2 and the through holes are processed in at least three steps, and the exposed surface is completely rust-proofed.

FIG. 2 is a diagram showing a modification of the surface treatment apparatus for the printed wiring board of FIG. This surface treatment apparatus is provided with the ultrasonic oscillators 7 facing each other in order to further obtain the treatment effect of the above-mentioned surface treatment apparatus.

[0011]

As described above, according to the present invention, the slit type jet nozzle for dividing and stirring the chemical liquid for treating the printed wiring board, the reflecting plate facing the slit jet nozzle, and the ultrasonic oscillation for generating fine cavitation in the chemical liquid. By arranging the child and the child alternately in the dipping tank and dipping them while moving in the dipping tank, the air bubbles remaining on the inner walls of the through holes, which are thin holes in the printed wiring board, are completely discharged, and the printed wiring Since the exposed surface of the board can be processed, there is an effect that it is possible to obtain a surface processing apparatus for a printed wiring board, which is capable of sufficiently performing anticorrosion film processing even on the inner wall of a long through hole.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a surface treatment apparatus for a printed wiring board according to the present invention.

FIG. 2 is a diagram showing a modification of the printed wiring board surface treatment apparatus of FIG.

FIG. 3 is a diagram showing an example of a conventional surface treatment apparatus for a printed wiring board.

[Explanation of symbols]

 1 Conveyor Roller 2 Printed Wiring Board 3 Pump 4 Chemical Solution Tank 5 Immersion Layer 6 Anticorrosion Treatment Device 7 Ultrasonic Oscillator 8 Slit-Type Ejection Nozzle 9 Reflector

Claims (1)

[Claims] 1. A dipping tank for storing a chemical liquid for immersing a moving printed wiring board, a plurality of ejection nozzles arranged in the dipping tank side by side in the moving direction and causing convection to the chemical liquid, and a reflection for inverting the convection. A surface treatment apparatus for a printed wiring board, comprising: a plate; and an ultrasonic oscillator disposed between the ejection nozzles.