JPS61281894A - Plating device for terminal of printed circuit board - Google Patents

Abstract

PURPOSE:To suppress the generation of the variance in plating thickness and to approximate the same to an average thickness by controlling discretely currents to divided anodes in the stage of arranging the plural divided anodes, passing the terminals of a printed circuit board therebetween and injecting a plating liquid thereto. CONSTITUTION:The plural divided anodes 5 are connected to respectively discrete power feed circuits 12 and are made independent. The printed circuit board 1 having the terminals 2 is moved toward an arrow along a moving line A and the plating liquid 6 is ejected from plural nozzles 9 for each of block areas 10 so that each of the terminals 2 positioned in the corresponding positions is subjected to a plating treatment. A current detector 16 detects constantly the current flowing to the circuits 12 and changes over a change-over switch 15 to a resistance circuit 14 side when the current flowing therein attains a set value or above. The switch 15 is again connected to the circuits 14 by a timer 15 upon lapse of the set time. The terminals are plated to the uniform thickness by controlling discretely the plating treatment in the above-mentioned manner.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a plating apparatus for printed circuit board terminals.

<Prior art> A technique is already known in which split anodes are used and the current applied to each split anode is individually controlled to make the amount of plating uniform. plating method disclosed in ).

<Problems to be Solved> However, the above-mentioned conventional techniques are aimed at strips, not printed circuit board terminals. As is generally known, unlike strips, printed circuit board terminals are arranged in various patterns, and it is extremely difficult to plate each terminal with a uniform plating thickness.

For plating printed circuit board terminals (for example, Ni plating, Au plating), methods such as liquid level control (immersion method) and liquid spraying (jet method) are usually used, but in either case, variations occur in the plating thickness. For example, Figures 5 and 6
As shown in the figure, when the terminals 2 of the printed circuit board 1 are grouped together or separated, the plating thickness (μ) is thicker for the terminal group located at the edge (2b) than for the center terminal group (2a). This tends to cause variations in plating thickness (μ). For this reason, Ni plating is about 3 to 4 times the average value, and Au
It is known that in plating, about twice as much of the metal is attached to the terminal group (2b) at the end. Furthermore, the maximum current density is limited at the thick points (2C) at both ends, and this is taken as the upper limit, so it is impossible to increase the current density any further, and there is a large loss in the plating process. Ta.

Means for Solving the Problems> Accordingly, in the present invention, the split anode technology conventionally known for plating strips is improved to suit the plating of printed circuit board terminals.

Specifically, in the printed circuit board terminal plating apparatus according to the present invention, the plurality of divided seven nodes are arranged along the movement line of the printed circuit board terminal, and are arranged at intervals approximately corresponding to the width size of each terminal by the partition wall. Each divided area is combined with a nozzle that applies plating solution to the printed circuit board terminal moving in front of the divided area, and a power supply circuit with a rectifier connected to flow current to each divided anode has a A resistance circuit with a resistance that makes it difficult for current to flow is connected in parallel via a changeover switch, and when the current flowing through the power supply circuit exceeds a set value, it is detected and the changeover switch is connected to the resistance circuit side. The gist is that the detector is combined with a changeover switch.

<Function> When the printed circuit board moves along the path line, the printed circuit board terminals move in front of the sections partitioned by partition walls and sequentially pass in front of each section in the moving direction. In each section, the plating solution is sprayed from the nozzle toward the printed circuit board terminals passing through it.
A large amount of current flows in the power supply circuit through the terminals corresponding to the "end terminal group" and the corresponding split anodes, while the current flows through another split anode corresponding to the other terminals corresponding to the "center terminal group". It does not flow as much as a split anode. If you decide in advance the maximum current value to flow per terminal as the "set value" based on the amount of current for the total terminal area of the printed circuit board to be plated, the current value flowing through the divided anode will exceed the "set value". The current detector detects this, switches the changeover switch to the resistance circuit side, allows less current to flow, and then returns the changeover switch to the original power supply circuit after an arbitrary period of time (can be set arbitrarily with a timer). .

By controlling the terminals made of split anodes in this manner so that overcurrent does not flow, and by individually controlling each split anode, variations in plating thickness will not occur, and the The plating thickness can be brought close to the average thickness, and the maximum current density can be increased.

<Example> Next, an example of this plating apparatus will be described with reference to the drawings (FIGS. 1 to 4). Incidentally, parts common to the conventional one are indicated by the same reference numerals.

A printed circuit board 1 is provided with printed circuit board terminals 2 (hereinafter simply referred to as "terminals") as objects to be plated on both sides thereof, and the terminals 2 move in the direction of the arrow in FIG. 2 along the movement line (A). It is free.

3 is the main part of the plating apparatus, in which a plurality of divided anodes 5 each partitioned by a partition wall 4 are arranged on both sides along the moving line (A).The 0 divided anode 5 is along the moving line (A).
Not only is it divided in the direction, but also in the vertical direction of terminal 2 (
It is also divided into two parts (in the direction of the arrow in Fig. 2). Each of these 7 divided nodes 5 has an injection box 7 for plating solution 6.
The nozzle 9 is attached to the front part 8 of the
are combined in multiple ways. The front part 8 is inclined so that the lower part is farther from the terminal 2 than the upper part, and the lower part is farther from the terminal 2 than the upper part.
Care was taken to ensure that the plating was not thicker on the lower part (2d) than on the upper part (2e). Moreover, as mentioned above, a plurality of nozzles 9,
What is independent of this (see Figure 1) is the upper part of terminal 2 (see Figure 1).
This is to increase the amount of plating solution that hits each part, regardless of whether it is 2e) or the lower part (2d). In the divided areas 10 divided by the partition walls 4, the plating solution 6 can be sprayed onto the terminals 2 moving in front of the divided areas 10.
The width size 0 is predetermined at intervals roughly corresponding to the individual width sizes of each terminal 2.

In this way, adjacent divided anodes 5 are separated from each other in the movement line (A) direction by the partition wall 4, and each divided anode 5 is made independent.

Each of the divided anodes 5 is connected to a constant voltage rectifier 11.
A resistor circuit 14 having a resistor 13 is connected in parallel to each power supply circuit 12 via a changeover switch 15. 16 is a current detector, and the power supply circuit 1
If the current value flowing through 2 exceeds the "set value", a signal is hidden in the changeover switch 15, and the power supply circuit 12 is switched to the resistance circuit 14 side via the changeover switch 15, which always keeps the power supply circuit 12 side in the ON state. OFF, and the resistance circuit 14 can be turned ON.

In the illustrated example, a variable resistor is used as the resistor 13. In addition, the changeover switch 15 that switches and connects the resistance circuit 14 side is configured to return to the power supply circuit 12 side after a set time (T) has elapsed via a timer 17, and the set time (T) is determined by the terminal 2. It can be conveniently adjusted according to the movement speed.

The state of use of such a plating apparatus will be explained next.

Now, suppose that the total number of terminals on one side of one printed circuit board 1 is 1.
00 bin, and the terminal area meter is 0. If the current density is 2OA/dm" and the current amount is 2A, a current of 0.02A will flow through each terminal 2 since it is 2A/100 bins. Accordingly, the current detector 16
Set the “setting value” to 0.022A, which is slightly larger than 0.02A.
I'll leave it as that.

When the terminals 2 move along the movement line (A) in the direction of the arrow in FIG. Terminal 2 approaching the partition area 10 becomes
corresponds to the "terminal group at the end" (2b), a large current (flows easily,
The flow is constantly detected by the current detector 16, and the current value is the fourth
As shown in the figure, if the line of <0.022A is exceeded, the selector switch 15 is switched to the resistor circuit 14 side at the 0 point, the resistor circuit 14 side is turned on, and the current is made difficult to flow [Zone X in Figure 4], and the settings are made. After the time (T) has elapsed, the selector switch 15 is reset to turn on the original power supply circuit 12 side. and another compartment 10 and another split anode 5
``If another terminal 2 corresponding to the central terminal group J (2a) approaches and moves in front of it, the current flowing through another divided anode 5 will not be more than 0.02A, so The changeover switch 15 sets the power supply circuit 12 side to O.
While maintaining the N state (Y zone in FIG. 4), the current is applied to each divided anode 5 individually, and the plating solution 6 is applied to each divided area 10 toward the cathode terminal 2. Each compartment 10 is injected from a plurality of nozzles 9
An independent plating process is performed for each terminal 2 (for each pin), which is moved and positioned accordingly. In the illustrated example, the plating process is individually controlled and performed on both sides (the left and right sides in FIG. 1), but depending on the type of printed circuit board 1, it is also possible to use only one side. It is also possible to shift one of the plating devices on both sides along the movement line (A) so that the plating devices on both sides are not disposed facing each other.

Effects> The plating apparatus for printed circuit board terminals according to the present invention has many excellent effects as described above, and the main ones are listed below. It is.

(b) It is possible to control the thick plating on each individual terminal (for each pin), (b) it is possible to get closer to the average thickness, and (c) this allows the maximum current density to be increased (approx. 2-3 times)
and (d) the plating process time can be shortened accordingly.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of the plating equipment, Figure 2 is a perspective view of the main parts of the plating equipment, Figure 3 is a circuit diagram connected to the split anode, and Figure 4 shows the current flow depending on the terminal (bin). The graph showing the flow direction and FIGS. 5 and 6 are front views of the printed circuit board showing the pattern of the printed circuit board terminals, respectively. Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Tekikugefu Seisho (self-published) Supplementary December 1985 248. Commissioner of the Patent Office
(2) and 26 Name of the invention Printed circuit board terminal plating device 3, Noodles with Hanyu who makes the correction Patent applicant 105 Address No. 1 Okana Building, 2-7-9 Toranomon, Minato-ku, Tokyo Contents (special Application No. 60-123505) Page 6, No. 12 of the specification
Correct ``kono yona'' in the first line to ``kono yona''. In the 17th line of page 6 of the specification, it says ``Upper (26) J is''.
Upper part (2e) Correct as J. Figure 3 of the cylinder in the drawing is corrected as shown in Figure 3 shown in the attached sheet.

Claims (1)

[Scope of Claims] A plating apparatus in which a plurality of divided anodes are disposed on an object to be plated, and a plating solution is applied to the object to be cathodized while controlling the current flowing through each divided anode individually. , the object to be plated is a printed circuit board terminal, the plurality of divided anodes are arranged along the movement line of the printed circuit board terminal, and are partitioned by partition walls at intervals approximately corresponding to the width size of each terminal, Each compartment is equipped with a nozzle that applies plating solution to the printed circuit board terminals moving in front of it, making it difficult for current to flow through the power supply circuit with a constant voltage rectifier connected to each divided anode to allow current to flow. Resistance circuits with resistors are connected in parallel via a changeover switch, and a changeover switch is a current detector that detects when the current flowing through the power supply circuit exceeds a set value and connects the changeover switch to the resistance circuit side. A plating device for printed circuit board terminals, characterized in that it is combined with the following.