JPH03275130A - Method and apparatus for agitation of liquid in liquid vessel - Google Patents

Abstract

PURPOSE:To reduce the production of defective goods, to shorten the treatment time, and to save the consumption of chemicals, etc., for instance, in a surface treatment, or in the treatment of washing, etc., by agitating the liquid in a liquid vessel with vibration without vibrating the liquid vessel. CONSTITUTION:There are provided the liquid vessel 1 which is practically in a stationary state, the vibrating agitation means consisting of hanging arms 7 and vibration plate 8, etc., disposed in the liquid vessel 1, and the driving means 11 vibrating the agitation means. By these equipments, the liquid in the liquid vessel is vibrated and agitated practically without vibrating the liquid vessel 1. As a result, the production of defective goods is reduced, for instance, in a surface treatment and in the treatment of washing, etc., and the treatment time is shortened and the consumption of chemicals, etc., is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for stirring a liquid in a liquid tank. The present invention particularly relates to a method and apparatus for stirring a processing liquid or a cleaning liquid in a plating tank, a cleaning tank (for example, a cleaning tank for plating), a surface treatment tank (for example, a treatment tank for electrodeposition coating), and the like.

BACKGROUND OF THE INVENTION As is well known in the art, in operations such as plating, surface treatment, cleaning, etc., it is necessary to bring the object to be treated into proper contact with a liquid such as a processing liquid or a cleaning liquid. Conventionally, aeration means have been used. It is also known to oscillate the object to be treated in the liquid.

There are both electrolytic plating and electroless plating methods, but in either case, it is very important to bring the object to be treated into good contact with the chemical solution to form a homogeneous film. Currently, in the case of products with complex shapes such as bolts and nuts, the product is rocked using a rocking device to make the coating homogeneous, but the occurrence of about 10-20% of defective products is still low. It is said to be unavoidable. Furthermore, extremely high quality is required when performing copper plating for printed circuit boards, which are electronic components, and electroless nickel plating for hard disk drives. It was believed that it was unavoidable that defective products would be produced. Furthermore, since the spacing between the hard disks and the like in the plating bath is narrow, for example, about 20 mm, there is a concern that if aeration is performed using a conventional PVC pipe, the hard disks may easily become glued together due to air bubbles. The cause of the pinholes is that gas is generated during plating and adheres to the surface.

Problems to be Solved by the Invention The present inventor has conducted an inspection with the aim of completely eliminating the occurrence of defective products in processes such as plating, surface treatment, and cleaning, shortening processing time, and reducing the amount of chemicals used. Focusing on the importance of stirring the chemical solution or cleaning solution (hereinafter collectively referred to as "processing solution") in the liquid bath during these operations, we conducted various studies and found that the It has been found that the above objective can be substantially achieved by subjecting the treatment liquid to appropriate vibrational stirring under specific conditions described later.

Components of the Invention The present invention provides a method for stirring a liquid in a liquid tank in a substantially stationary state by vibrating the liquid without substantially vibrating the liquid tank. This relates to a stirring method.

The present invention also provides a substantially stationary liquid tank, a substantially stationary liquid tank (6) disposed in the liquid tank, and a groove rolling means for driving the vibration stirring means. The present invention also relates to an apparatus for stirring a liquid in a liquid tank, characterized in that the apparatus is configured to vibrate and stir the liquid in the liquid tank without substantially vibrating the liquid tank.

DESCRIPTION OF PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view of a copper plating apparatus equipped with a stirring device of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is a side view thereof. The copper plating apparatus includes a plating tank, that is, a liquid tank (1), which is placed stationary on a base (2), and a diaphragm (8) is connected to a connecting rod, for example, a hanging plate, at the bottom of the liquid tank (another place may be used). It is suspended approximately horizontally by arms (7). The upper end of the suspension arm (7) is arranged near the liquid tank (1) (6) and is equipped with a substantial motor (11).
connected to. A vibration motor (11) is fixed on a table (10), and the vibration speed is adjusted by an inverter (13).

When the vibration motor (11) operates, the vibration is transmitted to the diaphragm (8) via the hanging arm (7), and the diaphragm (8)
vibrates, and the vibration stirs the liquid in the liquid tank (1).

According to this stirring method, only the liquid is vibrated and stirred, and the liquid tank (
1) does not vibrate.

As mentioned above, it is an essential condition of the present invention that only the liquid in the liquid tank (1) is vibrated and stirred without vibrating the liquid tank (1). The technique of placing a flask or the like on a diaphragm and vibrating it, that is, the technique of vibrating both the liquid tank and the liquid therein, is known, but this is a technique completely different from the present invention.

The diaphragm (8) may have any size and shape, for example square, polygonal, circular, diamond-shaped, etc. (one or both sides of the diaphragm may have parallel striped irregularities and other It may be formed into a wave shape or the like.

The frequency of the diaphragm (8) can be determined as appropriate in each case, but it is generally 200 to 600 vtm, preferably 300 to 500 vtm (vtm: frequency of 7 minutes). The vibration width is, for example, 8 to 20 mm, preferably 10 to 15n+n+.

The object to be processed (object to be plated) is suspended in the plating solution, that is, the liquid in the liquid tank (1) shown in Figure 1, and the plating electrode (12)
Electricity is applied to the plate, and the plating operation is carried out according to a conventional method while performing the above-mentioned vibration. Since plating itself is well known, detailed explanation thereof will be omitted.

It has been found that when the plating apparatus shown in FIG. 1 is used using the stirring method of the present invention, high-speed plating is possible and the operating efficiency is significantly improved. For example, when a plating operation with a film thickness of 25 bulk meters is performed using conventional technology,
At a temperature of 25°C, the current density was 2.5 A/dm2 and the required time was 55 minutes, but in the case of the present invention, the current density was 3 to 5 A/dm2 and the required time was shortened to 30 to 35 minutes at the same temperature. The quality of the plating layer is very good.

In the case of the above-mentioned plating operation, it is preferable to perform a rocking operation of the object to be treated in addition to a vibration operation.
It is generally preferable to carry out aeration using a porous aeration cylinder having a specific shape as described in Specification No. 204578 (filing date: August 9, 1999), and thereby the time required for plating can be reduced. It can be further shortened.

An example of the porous aeration cylinder described above is shown in FIG. The aeration pipe (16) shown in FIG. 4 has a cylindrical shape and is a high-temperature fired ceramic body made of alundum abrasive grains as an aggregate. The aeration cylinder (16) is supported on an aeration cylinder pedestal (15). Attach the front cover (31) to one end of the aeration pipe (work 6), and attach the N cover (33) to the other end. An air and/or plating solution supply conduit (35) is attached to the back cover (33). Front cover (31) and back cover (33)
) is fixed to the shaft (37). 4 of the diffuser cylinder (16)
The dimensions and physical properties of species A, B, C and D are shown in Table 1. The aeration pipe (16) can be used in the same manner as for conventional PVC pipes.

In the drawings, reference number (3) is the vibration stirring device mount, (4) is the spring seat, (5) is the rubber spring, (6) is the vibration stirring base, (9) is the hanging rod, (14) is the wiring, and (17) is the vibration stirring base.
) is the vibration stirring device motor stand, (18) is the swing device motor for the processed object, (19) is the drive denosk, (20) is the drive pin, (21) is the swing frame, (22) is the swing frame The frame, (23) is a swinging frame supporting roller, and (24) is a workpiece receiving part. A rocking mechanism consisting of a rocking device motor (18), a rocking frame (21), a rocking frame stand (22), a rocking frame support roller (23), a workpiece receiving part (24), etc. This is for swinging the object to be plated in the examples.

The object to be plated may be oscillated by this oscillation mechanism, and the liquid in the liquid layer (1) may be vibrated and stirred by the diaphragm (8).

Next, as an example of the cleaning operation, a cleaning operation for articles after plating will be described. After plating, electrically conductive substances such as acids, bases, or salts remain on the article and must be cleaned to remove them. At the plating factory,
Based on experience, after the plating process, one to four washing tanks were installed to wash the object to be processed, that is, the object to be plated. In order to improve the washing efficiency, the objects to be processed were shaken or washed with water using a shower. However, conventionally,
It took a considerable amount of time to wash thoroughly.

It has been found that if this cleaning is carried out in accordance with the present invention in a cleaning tank equipped with a vibration agitation device for the cleaning liquid, the cleaning time can be considerably shortened and the amount of cleaning liquid used can also be reduced. If the substance to be removed by cleaning is an electrically conductive substance, Japanese Patent Application No. 1-
By measuring the conductivity of the cleaning liquid according to the method disclosed in No. 262951 (filed on October 11, 1999), it is possible to easily know when cleaning has ended. The vibration stirring operation of the liquid in the cleaning tank can be carried out in the same manner as the vibration stirring operation in the case of the plating process described above. Better results are often obtained when the vibration agitation operation is performed in conjunction with other cleaning promotion operations (for example, the above-mentioned shaking of the object to be treated and aeration using an aeration cylinder).

In the case of surface treatment operations such as electrodeposition coating of articles, very good results are obtained by vibratory stirring of the treatment liquid according to the invention, as in the case of the plating described above.

Effects of the Invention As is clear from the foregoing description and the description of the examples below, according to the present invention, in various operations such as plating operations, cleaning operations for plated bodies, surface treatment operations, etc. By vibrating and stirring the liquid under the above conditions, the operation time can be unexpectedly greatly shortened, for example, high-speed plating can be easily carried out, and the number of defective plated products, defective cleaning products, and defective processing products is significantly reduced, and the number of products to be processed is reduced. When things are glued to each other, a remarkable effect can be obtained in that troublesome phenomena such as phenomena do not occur at all. As described above, the present invention has great practical effects.

(Example) Next, Example 1 shows an example of the present invention. Figure 1 shows the copper plating operation of a printed circuit board (size A-1 size: 610 x 800 mm) which is a through-hole board (board with holes). The experiments were carried out in a liquid tank equipped with a vibration stirring device as shown in FIG. The dimensions of the liquid tank are 600mm x 1
000mm x 1000mm, and the diaphragm inside the liquid tank is a rectangular plate with dimensions of 400mm x 850mm x 1.
It was 5 mm. The plating solution was prepared according to a conventional method, and its composition is as follows.

Copper sulfate 100 g/n sulfuric acid
190 g#2 Brightener Appropriate amount of chlorine ion 50mj2/I! .

The plating temperature is 25°C, the current density is 5A/dm2, the vibration plate frequency is 400vtm, and the vibration width is approximately 10m.
It was m. After 30 minutes of current application, a plating layer with a thickness of 25 mm was formed.

Separately, as a comparative experiment, the above plating operation was performed according to the conventional method without performing the vibration stirring operation.

In this case, it took 55 minutes to form a plating layer with a thickness of 25 microns, and the current density was 2.5 A/dm<2>.

The thickness of the resulting plating layer was measured for each part of the sample. FIG. 8 shows data on the thickness (1 chrome) of the plating layer on one side of the through-hole substrate used in the comparative experiment.

FIG. 9 shows data on the thickness of the plating layer on one side of the through-hole substrate when the plating operation was performed while performing the vibration operation according to the present invention.

As is clear from the comparison of the data of the through-hole sample in Figures 8 and 9, the sample from the comparative experiment (Figure 8) had non-uniform thickness in each part, and the occurrence of burns was also observed. Ta. Furthermore, the plating inside the holes was non-uniform and had poor conductivity, and the percentage of defective plating products reached approximately 20%. On the other hand, in the sample according to the present invention (Fig. 9), the thickness of the plating layer is substantially uniform, there is no discoloration, the conductivity through the holes is good, and the quality is very good, with no plating defects. There were no good products.

Yet another experiment was conducted. In this experiment, the aeration cylinder 0ω shown in FIG. 4 was attached to the plating layer equipped with the vibration stirring device shown in FIGS. 1 to 7, and air 3 4 ration was performed. The diffuser pipe 06) is cylindrical and made of alundum, has a length of 500 mm, an inner diameter of 50 mm, a porosity of about 35%, a pore diameter of about 55≧Kron,
Air resistance was approximately 400 kg, bulk specific gravity was approximately 2.4, and air permeation amount was approximately 120012.7 m. The time required for plating was further reduced, and a plating layer with a thickness of 25ξcm was produced in 25 to 30 minutes. The quality of the plating layer was very good.

Example 2 Electroless nickel plating of a 3.5-inch hard disk (thickness: 1.1 mm) was carried out in a plating bath equipped with a vibrating stirrer similar to the plating baths shown in FIGS. 1 to 7. However, in this example, electrodes are of course not used, and a heating steam coil and circulating plating solution discharge pipe are provided according to the usual method, and
The aeration cylinder described in Example 1 was used.

A hard disk frame was provided in the center of the plating tank according to a conventional method, and the frame was rotated around its axis by a motor to swing the object to be plated.

A solution containing 5-6 g of nickel sulfate #2, 150 g of sodium hypophosphite #2, and an appropriate amount of sodium citrate was placed in a plating tank and heated to about 90°C.

The hard disk to be plated is placed in the above-mentioned rocking frame, and after performing preliminary treatments such as water washing, pickling, degreasing, and activation treatment according to conventional methods, the above-mentioned plating solution G is added and the plating solution is vibrated. Plating was performed while Plating time was 45 minutes. A very good plating bath with a thickness of 15 microns was formed.

The thickness of the plating layer was substantially uniform, and there were no defects such as blisters or pinholes.

As a comparative experiment, the plating operation was repeated without performing the vibration stirring operation. In the case of this comparative experiment, a fairly good plating layer was also formed by aeration using the aeration cylinder, but the time required for plating was a little longer, about 1 hour, than when the vibration stirring operation was performed according to the present invention. there were.

As another comparative experiment, plating operation 56 was performed by conventional techniques, omitting the vibration operation and the use of an aeration tube. The plating time became even longer, requiring 1 hour and 30 minutes, and the number of defective products reached approximately 20%.

Example 3 The water washing operation in the electroless nickel plating process of a 3.5-inch hard disk (thickness 1.1 mm) was performed in a washing tank equipped with a vibration device similar to the tanks shown in Figures 1 to 7. Ta.

A predetermined number of hard disks after plating were placed in a frame, shaken, and washed with water. The degree of water washing was determined based on the measured value of the electrical conductivity of the washing liquid. It has been confirmed that when washing with water while performing a vibratory stirring operation according to the present invention, the time required is much shorter than when washing with water according to the conventional method, and the amount of washing water required is also very small. In addition,
If aeration is performed using the above-mentioned aeration pipe together with the vibration stirring device, the cleaning efficiency will be further improved.

[Brief explanation of drawings]

FIG. 1 is a plan view of a liquid tank equipped with a vibration device according to the present invention;
Fig. 2 is a cross-sectional view of a portion taken along the line X-X in Fig. 1, Fig. 3 is a side view of the liquid tank in Fig. 1, and Fig. 4 is a longitudinal cross-sectional view of an example of an aeration cylinder. , FIG. 5 is a plan view of only the liquid tank, FIG. 6 is a longitudinal sectional view taken along line y-y in FIG. 5, FIG. 7 is a right side view of FIG. 5, and FIG. 1. It is a chart showing the measurement results of the thickness of the plating layer of the substrate sample. 1. Liquid tank which is a plating tank; 2. Base of the liquid tank; 3.
- Vibration device mount; 4. Spring seat; 5. Rubber spring; 6. Vibrator; 7. Hanging arm; 8. Vibration plate; 9. Hanging rod; 10. Vibration motor stand; 11・・Vibration morph; 12・・Electrode; 13・
・Inverter; 30... Aeration cylinder;
31. Front cover; 33. Back cover; 35. Air and/or
or plating liquid supply conduit; 37...shaft. (more than that) 7 8 sign spread 3 Z7513υ (°t) Fig. 8 Fig. 9

Claims (8)

[Claims] (1) A method for stirring a liquid in a liquid tank, characterized in that when stirring the liquid in a liquid tank in a substantially stationary state, the liquid is vibrated and stirred without substantially vibrating the liquid tank. (2) The method for stirring a liquid in a liquid tank according to claim 1, wherein the liquid tank is a plating tank, a cleaning tank, or a surface treatment tank. (3) The vibration width of the diaphragm placed in the liquid tank is 8 to 2
2. The method of stirring a liquid in a liquid tank according to claim 1, wherein the vibration frequency is 200 to 600 vtm. (4) The vibration width is 10 to 15 mm and the vibration frequency is 3.
4. The method for stirring a liquid in a liquid tank according to claim 1, wherein the stirring rate is 00 to 500 vtm. (5) The method for stirring a liquid in a liquid tank according to claim 1, 2, 3, or 4, which uses aeration using a diffuser cylinder or a shaking operation of the object to be treated. (6) The liquid tank is equipped with a liquid tank in a substantially stationary state, a stirring means by vibration disposed in the liquid tank, and a driving means for the vibration stirring means, and the liquid tank can be used without substantially vibrating the liquid tank. 1. A stirring device for a liquid in a liquid tank, characterized in that the device is configured to vibrationally stir the liquid therein. (7) The vibrating means is connected to the driving means by a connecting rod, and the driving force from the driving means is transmitted to the vibrating means via the connecting rod, so that the vibrating means vibrates and the liquid is stirred. The device for stirring a liquid in a liquid tank according to claim 6. (8) The device for stirring a liquid in a liquid tank according to claim 6 or 7, further comprising an aeration means using a diffuser cylinder or a means for shaking the object to be treated.