JPH0119475B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a liquid flow plating method, and particularly to a liquid flow plating method in which the flow rate of the plating solution can be adjusted.

<Conventional technology> Conventionally, for full-surface plating or stripe-like partial plating of strip-shaped conductors, etc., there have been methods in which most of the material to be plated is immersed in the plating tank, and plating methods have been used in which a slight jet of liquid is applied. Although plating methods have been used, there are still limits to the improvement of plating speed. If the plating current density is increased in an attempt to increase the plating speed, if the plating current density exceeds a certain value, the plating quality deteriorates and is no longer practical, and there is a limit current density.

One method to improve this critical current density is to spray the plating liquid onto the surface to be plated at high speed and stir it, but if the plated surface is larger than a certain extent, it is difficult to stir the plating liquid uniformly over the entire surface. This may result in uneven plating or partial quality defects.

In order to solve this problem, the present applicant proposed a high-speed plating method that can uniformly stir the plating liquid over the entire surface even when the plating area is large, and improves the critical current density without causing uneven plating. Therefore, an application has been filed for a liquid plating method (Patent Application No. 118682, filed June 8, 1982).

However, in this liquid flow down plating method, the plating liquid flow rate is determined by the height difference (head difference) in the plating liquid level between the upper plating liquid tank and the lower plating liquid tank. Although the head difference can be adjusted to a certain extent, if the plating liquid flow rate can be finely adjusted during the plating process according to the material to be plated and the plating conditions, plating can be performed at the optimal flow rate, and even during the process. Since the flow rate can be varied, the optimum plating liquid flow can be used as needed. Development of such a method is desired.

<Problems to be Solved by the Invention> An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a new liquid flow type plating that can control the flow rate of the plating liquid during plating. The purpose is to provide a method.

<Means for Solving the Problems> That is, the present invention provides an upper plating liquid tank having a free surface while the liquid level is maintained at a certain height, and a liquid level lower than the upper plating liquid tank. A lower plating liquid tank having a free surface that is maintained at a certain height that is low, and a liquid pipe that communicates the plating liquid in both plating liquid tanks and is filled with the plating liquid. Plating is performed by placing the object to be plated in the flow of the plating liquid that occurs when the plating liquid flows down due to the difference in height between the liquid levels in both plating liquid tanks. This is a liquid flow plating method characterized by controlling the flow rate of the plating liquid flowing down the liquid pipe.

Here, it is preferable that the flow rate of the plating liquid is controlled by a regulating plate provided in the liquid pipeline.

Further, it is preferable that the plated object is a band-shaped object that moves in the longitudinal direction while maintaining its wide side in a substantially vertical state.

Furthermore, it is preferable to perform electroplating by placing an anode electrode in the plating solution facing the object to be plated.

<Structure of the Invention> The liquid flow plating method of the present invention will be explained in detail with reference to the drawings.

In Fig. 1, 1 is a plating liquid, 2 is an upper plating liquid tank, 3 is a lower plating liquid tank, 4 is an upper plating liquid level, 5 is a lower plating liquid level, 6 is an anode electrode, and 7 is a plated liquid. 8 is a liquid pipe line, 9 is a plating liquid lower flow rate adjustment plate, 10 is a lower plated liquid outlet, and 11 is a pump.

FIG. 1 shows an example in which a plated object 7 is placed in a high-speed flow of a liquid pipe 8. In this example, the plated object 7 made of a strip-shaped conductor is used as a cathode, and the anode is This is a schematic diagram in which electroplating is performed by disposing the object 7 between the electrodes 6 and 6 and moving the object 7 to be plated in a direction perpendicular to the plane of the paper.

The flow rate of the plating liquid flowing down the liquid pipe 8 is high by utilizing the height difference (head difference) between the upper and lower plating liquid levels 4 and 5. In this case, if the plating liquid lower flow rate adjusting plate 9 provided at the bottom of the liquid pipe is moved in the direction of the arrow 12 to completely close the outflow port 10, the high-speed flow due to the plating liquid flowing down is not achieved. The plating liquid overflows from the upper plating liquid tank 2. Conversely, when the plating liquid outflow amount adjustment plate 9 is moved in the direction opposite to the arrow to open the plating liquid lower outlet 10, the plating liquid flows down due to the head difference, so the height difference and the flow A flow velocity commensurate with the outlet area is generated, and the liquid is discharged from the outlet 10 into the lower plating liquid chamber. Therefore, the flow rate can be arbitrarily adjusted by opening and closing the outflow rate adjusting plate 9.

In FIG. 1, a sliding method is illustrated as an opening adjustment method of the plating liquid lower outlet 10 as shown in the drawing to change the flow rate of the plating liquid flowing down the flow pipe, but the present invention is limited to this. Any means may be used as long as it can arbitrarily change the flow rate of the plating liquid flowing down the liquid pipe line without being affected. An opening adjusting means for the plating liquid upper inlet 13 may be used, a valve may be used as well as a slide method, and the opening may be adjusted by changing the rotational speed of a rotating body such as a screw. The opening area may be adjusted accordingly.

In the present invention, there are no particular limitations on the object to be plated, and any object such as a strip, wire, rod, or single object can be used. The method of the present invention is particularly effective when the plated object is a band-like object that moves in the longitudinal direction while keeping its wide side substantially vertical, as shown in FIG. 1.

The lower plating liquid of the present invention is the upper plating liquid level 4,
The lower plating liquid level 5 is maintained at a constant height by a pump 11 and is configured to have a free surface. The height difference between the upper plating liquid level 4 and the lower plating liquid level 5 is called a head difference.

The liquid pipe line 8 communicates the upper plating liquid tank 2 and the lower plating liquid tank 3, and constitutes a flow path for the plating liquid 1 flowing down due to the head difference.

What is important here is to immerse the lower end of the liquid pipe 8 into the plating liquid in the lower plating liquid tank 3, thereby obtaining the lower plating liquid level 5 and allowing air to enter the plating liquid. This allows the plating liquid to flow down the liquid pipe 8 in an even and stable flow even at high speed.

FIG. 1 shows an example in which a plated material 7 is placed in a high-speed flow of a liquid pipe 8. In FIG. In this example, a plated object 7 made of a strip-shaped conductor is placed between the anode electrodes 6 and 6 as a cathode, and electroplating is performed by moving the plated object 7 in a direction perpendicular to the plane of the paper.

Figure 2 shows the plating process material 7 in the upper plating liquid tank 2.
This figure shows an example of the arrangement in the flow. In this example, a wall material 19 is provided so as to extend the liquid pipe line 8 in relation to the above-mentioned arrangement of the object to be plated 7, and this wall material 19 allows the plating liquid to flow to the left and right sides of the object to be plated 7. By suppressing the flow from the bottom and increasing the flow in the vertical direction, the flow rate of the plating liquid to the surface to be plated is improved. is provided, and the flow rate can be arbitrarily adjusted by opening and closing this outflow rate adjusting plate 9.

The reason why the wall material 19 is provided with minute slits is to ensure the electrical conduction state necessary for plating. By providing the wall material 19 with corrugations or irregularities on the side surface as shown in FIG. 7, the downstream flow of the liquid can be disturbed and the effect of stirring the liquid can be increased. Note that FIG. 6 is a partial sectional view of FIG. 2 viewed from the side.

1 and 2, the plating liquid 1 is circulated in the upper plating liquid tank 2 and the lower plating liquid tank 3 by the pump 11, and at the same time the height of the plating liquid levels 4 and 5 is adjusted. However, as a method for easily adjusting the height of the plating liquid levels 4 and 5, there is a method of causing the plating liquid 1 to overflow, as shown in FIG. 3, for example.

4 and 5 show examples in which a band-shaped conductor such as an IC lead frame is used as the plated object 7, and in particular masking when providing striped partial plating 14 on the wide side of the band-shaped conductor. It shows how. That is, in this case, masking tape 1 is placed on both sides of the covered object 7.
5 is pasted, and the flow of the plating liquid flowing down the liquid pipe with the partial plating 11 part exposed is made to be an even and stable flow even at high speed, and the opening of the lower plating liquid outflow port is made. Plating is performed by adjusting the flow rate to arbitrarily control the flow rate. Although FIGS. 4 and 5 are both examples of single-sided partial plating, it goes without saying that the same plating method as described above can be applied to double-sided partial plating.

In FIG. 6, the object to be plated 7 made of a strip is moved in the longitudinal direction, that is, in the horizontal direction, while maintaining its wide side vertically. In contrast, as shown in FIG. At least in the plating area, it is also possible to move the plated object 7 in the vertical direction while maintaining its wide surface in a vertical state. According to FIG. 8, the object to be plated 7 may be moved from either the upper or lower direction by the guide roll 16, and the length of the anode electrode 6 depends on the moving speed of the object to be plated 7, the plating time, etc. It is set taking into account the conditions. In addition, in the plating method shown in Fig. 8, the structure of the plating tank is improved as shown in Fig. 9, and the upper plating liquid tank 2, the lower plating liquid tank 3, and the liquid pipe line 8 are integrated. Furthermore, the flow rate can be arbitrarily controlled by adjusting the opening of the lower plating liquid outflow port with an outflow rate adjusting plate 9.

FIG. 10 shows that a high-speed flow can be obtained by making the shape of the liquid pipe line 8 flare downward and reducing the liquid resistance (pressure loss) downstream of the liquid, and the opening of the lower plating liquid outlet. This shows an example of a plating method in which the flow rate is arbitrarily controlled by adjusting it with the flow rate adjusting plate 9. This method can be applied to each of the above embodiments.

FIG. 12 shows that the main part of the liquid pipe line 8 is extended in the horizontal direction while ensuring a predetermined head difference due to the presence of the upper plating liquid level 4 and the lower plating liquid level 5. An example of the plating direction is shown in which a relatively long anode electrode 6 is arranged in the section and the object to be plated 7 made of a strip-shaped conductor is moved in the horizontal direction, and the opening of the lower plating liquid outlet 10 is adjusted to adjust the outflow amount. The flow rate can be arbitrarily controlled by adjusting with a plate 9. 17 is a sealing device. According to this method, since the length of the anode electrode 6 can be increased, sufficient plating time can be taken in the liquid pipe line 8, so that the moving speed of the plated object 7 can be improved. .

Therefore, this method is suitable for mass production and is industrially very advantageous.

The plating method of the present invention can be applied to pre-treatment tanks and post-treatment tanks other than the plating tank.

<Example> A strip-shaped copper material was silver-plated using the apparatus shown in FIG.

The plating liquid flow velocity near the plating surface has a head difference of 0.8 m.
In this case, it can be arbitrarily varied from 3 m/s to 0.2 m/s.

As a result, it was possible to set plating conditions with the optimum liquid stirring effect, and the limiting current density was also improved to two to three times that of the conventional method.

<Effects of the Invention> According to the method of the present invention, a lower plating tank is provided to form a lower plating liquid level, thereby preventing air from entering and reducing the height difference between the upper and lower liquid levels (head difference).
A high-speed flow can be obtained by using the flow, and a stable and uniform high-speed liquid flow can be obtained over a wide range.
It becomes possible to uniformly and effectively stir the plating liquid over a wide plating area, thereby improving the limiting current density and increasing the speed of plating.

Moreover, the speed of the plating liquid flow can be changed arbitrarily, and the optimum plating liquid flow speed can be selected depending on the material to be plated and the plating conditions. Therefore, the intensity of agitation of the plating solution can be controlled, and plating conditions can be set to ensure quality.

If the speed of the plating liquid flow is adjusted by sliding the adjustment plate, the liquid flow can be easily adjusted by a simple means, and can be done even during the plating process, improving work efficiency.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a liquid flow plating method according to one embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of other embodiments of the present invention, and FIGS. 4 and 5 are respectively 6 is a partial cross-sectional view of FIG. 2 viewed from the side, FIG. 7 is a cross-sectional structure diagram of the wall material, and FIG. FIGS. 9 and 10 are explanatory diagrams of other embodiments of the present invention, FIG. 11 is an explanatory diagram of a reference example of the liquid flow down plating method, and FIG.
FIG. 2 is an explanatory diagram of another embodiment of the present invention;
The figure is a sectional view taken along line A-A' in FIG. Explanation of symbols, 1...Plating liquid, 2...Upper plating liquid tank, 3...Lower plating liquid tank, 4...Upper plating liquid level, 5...Lower plating liquid level, 6... Anode electrode, 7... Covered material, 8... Liquid pipe line, 9...
...outflow adjustment plate, 10...plating liquid lower outflow port,
11...pump, 12...movement direction of plating liquid lower outflow rate adjusting plate, 13...plating liquid upper inlet,
14...Striped portion plating, 15...Masking tape, 16...Guide roll, 17...
Sealing device, 19...Wall material.

Claims (1)

[Claims] 1. An upper plating liquid tank having a free surface with a liquid level maintained at a certain height, and an upper plating liquid tank having a free surface with a liquid level maintained at a certain height lower than the upper plating liquid tank. A lower plating liquid tank having a free surface in a maintained state, and a liquid pipe line that communicates the plating liquid in both of these plating liquid tanks and is filled with the plating liquid. When plating is performed by placing the object to be plated in the flow of plating liquid that occurs when the plating liquid flows down due to the difference in height of the liquid level in the plating liquid tank, the liquid flows down the liquid pipe line. A liquid flow plating method characterized by controlling the flow rate of a lumeting liquid. 2. The liquid flow plating method according to claim 1, wherein the flow rate of the plating liquid is controlled by a regulating plate provided in the liquid line. 3. Liquid flow plating according to claim 1 or 2, wherein the object to be plated is a band-like object that moves in the longitudinal direction while maintaining its wide side in a substantially vertical state. Method. 4. Under liquid flow according to any one of claims 1 to 3, characterized in that electroplating is performed by placing an anode electrode in the plating solution facing the object to be plated. Ceremony plating method.