JPS6141159B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for efficiently plating terminal portions of a thin printed circuit board.

Conventionally, when continuously plating terminals of printed circuit boards, which are electronic components, the anode was placed in a processing tank in which plating was performed using a processing solution such as nickel sulfate or nickel sulfamate.
A metal that is insoluble in the treatment solution used is titanium coated with platinum.

By the way, since it is an insoluble metal, there is no positive consumption, but naturally the metal ions dissolved in the plating solution become metal and precipitate on the surface of the workpiece, so the metal ion concentration decreases, and as a result, The electrical resistance of the plating solution increases, causing problems such as a decrease in electrolytic efficiency and coarser particles of the plated metal.To prevent the metal ion concentration of the plating solution from decreasing, replenish the plating solution with a concentrated solution of the same type. Operations have been carried out. The present invention solves the above-mentioned problems by employing a soluble metal as the anode disposed in the plating tank. The method and apparatus of the present invention will be described in detail below with reference to the drawings.

Figure 1 is an external view of an apparatus for continuous plating of a thin plate-shaped workpiece 1. In the conventional method, power was supplied by holding the workpiece between rollers or brushes as a power supply means for transporting the workpiece. However, the apparatus shown in the figure is different in that the object to be processed is held and conveyed by a pair of conveyor belts that have a power supply wire 2a embedded in the holding surfaces developed by the applicant. The present invention resides in an improvement of the lower plating tank in which objects to be treated, which are not shown in FIG. 1, are held and conveyed. Please note that the first
The side indicated by the arrow in the figure is called the front.

FIG. 2 is a front view showing a cross section of a plating tank elongated in the conveying direction directly under the conveying belt 2, and is a main part of the present invention. In the figure, 1 is a printed circuit board which is an object to be processed.The lower part of the board is the terminal part 1a of the board to be subjected to the plating process, and the upper part is firmly pressed tightly by a holding part that holds and conveys the board. There is. The holding part is composed of a pair of conveyor belts 2 made of a rubber-like elastic body with a power supply wire 2a embedded all around the outer surface that holds the substrate 1, and the inner surface of the conveyor belt 2 is supported by a guide column 11. Since it is supported by the belt guide 3, it can always maintain a constant position. Note that the surface that holds the substrate is referred to as a longitudinal center surface C. Each of the pair of conveyor belts 2 is endless and rotates under tension by a pulley 18 as shown in FIG. 1 in a conventional manner, and grips and conveys the object 1 to be processed.

In the holding section, that is, below the conveyor belt 2 in the figure, there is disposed an elongated plating tank 6 having slit-like notches (not shown) on the front and back sides through which printed circuit boards enter and exit. It is a front view showing a cross section.
The plating tank 6 is divided into an upper plating chamber 6a and a lower sealed nozzle chamber 4. On the upper surface of the nozzle chamber, a nozzle 5 for spraying plating liquid toward the printed circuit board terminal portion 1a is located on the center surface. They are provided symmetrically at appropriate pitches in the traveling direction of the conveyor belt 2, on both the left and right sides in the figure. In the example, a nozzle with a nozzle diameter of 2 mm and a pitch of 15 mm is used, but a slit of the same capacity may be used instead. An opening 16 is provided on the lower surface of the nozzle chamber 4 through which a plating liquid circulated by a pump and piping described later is fed under pressure. Inside the plating chamber 6a is an anode 10 made of a soluble metal.
are placed horizontally on a plurality of anode pedestals 9, symmetrically and parallel to each other from the front to the back of the plating chamber. The upper end 13 of the anode 10 is fitted into the plating chamber 6a.
It protrudes above the liquid level 17 of. Liquid level adjusting weirs 12 are provided on the left and right side walls of the plating chamber 6a, and are always lower than the liquid level 17' in the side walls so that the plating liquid overflows during operation.
The plating solution used in the examples is nickel sulfate or nickel sulfamylate, and nickel metal is used as the soluble anode.

Next, to outline the operation, the conveyor belt 2 is operated in the usual way, the plating power is turned on, and mask tape is applied in the usual way except for the terminals of the printed circuit board, that is, the part 1a to be plated. When it is held between a pair of conveyor belts 2 on the front side of the plating tank 6, it passes through a slit notch (not shown) in the plating chamber 6a and is conveyed into the plating chamber 6a.
Immerse the terminals in the plating solution. On the other hand, when the pump 14 is operated in a conventional manner, the plating liquid is sucked from the plating liquid management tank 8, the plating liquid is pressurized into the nozzle chamber 4 through the pipe 15, and the plating liquid pumped into the nozzle chamber is The plating liquid is forcibly sprayed from the nozzle 5 toward the board terminal 1a, and the plating liquid in the plating chamber 6a passes through the lower part of the anode 10 as shown by the arrow and flows out from the upper edge of the side wall. In the illustrated example, the water flows out from the upper edge of the adjustment weir 12. The outflowing plating liquid passes through the receiving tank 7 and returns to the management tank 8 via the discharge pipe 15'. From then on, the plating liquid circulates in the same way, and the printed circuit board 1 that has been plated is placed in the plating chamber 6a. It passes through the back slit and then separates from the grip of the conveyor belt.

As described above, according to the present invention, since a soluble metal is used as the anode during plating treatment, the same amount of metal as the metal precipitated from the plating solution is eluted from the anode 10, and the metal ion concentration is stable. So,
Unlike the conventional concentrated liquid replenishment type, the metal is automatically replenished in the same amount as the amount processed, so there is no need for hourly liquid analysis, which greatly contributes to improved productivity by making stable product production possible. It is.

Furthermore, according to this device, the printed circuit board can be securely fixed tightly using the elastic conveyor belt, and the terminal area can be updated with new licking liquid by spraying from the nozzle without damaging the product. The flow rate of liquid circulation can also be adjusted by providing a weir and increasing the difference between the water level and the water level between the electrodes.

Furthermore, as shown in the specification and drawings, due to the organic structure of the present application, the liquid circulation after being ejected from the injection nozzle is as follows:
Since the plating liquid rises toward the center of the plating chamber, descends again, rises again through the bottom of the chamber, and overflows from the side wall, the plating liquid becomes uniform, achieving a marked improvement in both plating ability and plating quality. I can do it.

[Brief explanation of the drawing]

Fig. 1 is an external view of an apparatus for continuous plating by holding and conveying a thin plate-shaped workpiece, and Fig. 2 is a front view showing a cross section of an elongated plating tank, which is the main part of the present invention. It is a longitudinal section along ~. 1... Thin plate-shaped object to be processed (printed circuit board), 1a
... Plated part (terminal part), 2 ... Conveyor belt, 2a ... Power supply part (wire), 4 ... Closed nozzle chamber, 5 ... Nozzle, 6 ... Plating tank, 6a ...
...Plating chamber, 10...Anode, 13...Top end, 1
7, 17'...Liquid level, C...Center plane.

Claims (1)

[Claims] 1. In a continuous plating device, a plate-shaped soluble metal made of the same metal as the metal dissolved in the plating processing solution is used as an anode, and a pair of left and right anode plates, By placing it on the bottom surface of the plating chamber 6a via a plurality of pedestals, a plating liquid flow path is formed on the bottom surface, and the plating liquid is arranged like a weir in the longitudinal direction of the plating tank, and power is supplied to the outer surface. A pair of endless conveyor belts embedded with wires tightly sandwich the workpiece on the plating tank, and transport the lower end covered part of the workpiece over the center plane C between the pair of anodes, and the other The center of the bottom of the plating chamber 6a is formed into an inverted W-shape, and from the pair of V-shaped top slopes, each approximately 45 mm
Spout the plating liquid at an angle of ゜ to cover the covered part 1.
A continuous plating method for printed circuit board terminals, in which both sides of a are plated and the plating liquid is discharged from liquid level adjustment weirs at the upper left and right ends of the plating chamber 6a. 2. A conveying device that includes a holding section that suspends and conveys the object to be processed using a pair of endless conveyor belts that have a power supply section on a holding surface that holds and conveys the upper part of the plated portion 1a of the thin plate-like object 1. An elongated plating tank 6 having slit-like openings on the front and back sides for entering and exiting the thin plate-like material to be processed is arranged below the transport device in the direction of travel of the transport belt, and the plating tank is The nozzle chamber 4 is divided into a sealed nozzle chamber at the bottom and a plating chamber at the top.
The plating liquid is spouted at an angle of 45 degrees from the top of the slope on the center side, and on the bottom of the plating chamber 6a, a space is maintained between the bottom and the bottom symmetrically with the center plane. A pair of left and right soluble plate-shaped anodes that elute the same metal ions as the plating solution are arranged in a weir shape so as to protrude above the plating solution level 17, and the plating device is operated to lower the anode level below the plating solution level. The tamping liquid flowing out from the side wall of the tank is circulated through a pump piping via a receive tank 7 provided on its outer periphery.
A continuous plating device for printed circuit board terminals that pressure feeds into the nozzle chamber and sprays it from the nozzle to process the plating.