JPH01172590A - Method and device for full plating - Google Patents

Abstract

PURPOSE:To fully plate a material in uniform thickness by providing a shielding plate having an opening for an anode at regular intervals on both sides of a conveyance passage in a plating bath, intermittently conveying the material to be plated between the shielding plates, and stopping the material for specified time when the center of the material reaches the position corresponding to the opening. CONSTITUTION:The electrode in the plating bath 2 is energized, a conveyor means 4 is driven, and short-sized materials 1 to be plated are sent in at regular intervals. The oblong vertical materials 1 are held at regular intervals on an endless cathode contact 7 moving along a holding jig 5 in a conveyance part 6 above the holding jig 5 provided on the periphery of the means 4. The intermittently moving material 1 is stopped by the means 4 for a specified time, when the center of the material 1 reaches the position corresponding to the openings 9 and 9 for an anode. When the material 1 is stopped, a plating film is more thickly formed on the center of the materials 1 corresponding to the anodes 11 and 11 than on the part close to the side edge unlike the case when the material 1 passes between the shielding plates 10 and 10. As a result, a plating film is formed in almost uniform thickness on the center of the material 1 and on the part close to the side edge.

Description

Detailed Description of the Invention A. Purpose of the Invention a. Industrial Field of Application The present invention is applicable to plate-like objects such as IC lead frames and printed circuit boards, or objects to be plated such as rod-like objects.
The present invention relates to a method for fully plating solder, tin-silver, copper, and other materials, and an apparatus therefor.

b. Prior Art As a conventional method for applying full-surface plating to objects to be plated such as plate-like objects and rod-like objects as described above, the 7-king method is generally used. For example, as described on pages 57 to 78 of "Plating Manual" (written by Rihei Tomono, Ohmsha Co., Ltd., published October 25, 1972), the hook is a rack with a peripheral part ( The plate-shaped or rod-shaped object to be plated is suspended from the hook while being in contact with the cathode part, and electrolytically treated in the plating solution. In addition, especially when performing full interior plating on IC lead frames, exterior plating after resin molding, or full copper plating on printed circuit boards, it is often necessary to process a large number of sheets in one rank due to mass production. Common.

C. Problems to be Solved by the Invention When the entire surface of an object to be plated, such as a plate-like object or a rod-like object, is plated by the above-mentioned conventional racking method, the following problems arise.

1) Due to the so-called edge phenomenon in plating, plating tends to stick closer to the side of the object to be plated.

Therefore, if you look at the overall number of objects to be plated that are hooked on the rank, those that are hooked closer to the sides will have a thicker plating, and the ones that are hooked closer to the center will be more likely to be plated. The plating thickness becomes smaller. Furthermore, when looking at a single object to be plated, although it is not the same overall difference as described above, the thickness of the plating is larger near the side edges, and the thickness of the plating becomes smaller closer to the center. Even if a shielding plate is provided between the anode and the anode, this phenomenon still causes a difference in plating n=w in the gap between the shielding plate and the anode. This variation in plating thickness is
In particular, IC lead frames and printed circuit boards that require high precision cannot tolerate the side bottom, and are often rejected.

11) It was necessary to change the size of the rank, the position and shape of the cathode contact, etc. depending on the length and width of the object to be plated, and it took time and effort to prepare a dedicated rack or contact and replace it. Furthermore, it is difficult to automatically rough-size a large number of IC lead frames and printed circuit boards to be plated onto a rack. Furthermore, the structure of the processing tank makes it difficult to exchange and stir the liquid, resulting in a low current density, making it impossible or difficult to increase the speed of plating.

The present invention aims to solve the problems of the conventional full-surface plating means described above. In other words, the purpose of the present invention is to provide full-surface plating that makes the thickness of the plating film uniform on the object to be plated, eliminates the need for a dedicated rack, enables automation of holding the object with a jig, and enables high-speed plating processing. An object of the present invention is to provide a method and apparatus.

Arrangement of the Invention (a) Means for Solving the Problems First of all, the entire surface plating method of the present invention is characterized in that a short object to be plated (1) is plated [(21) provided on a conveying means (4). The holding jig (5) is fed into the upper conveying part (6) at equal intervals and held in a horizontally long vertical shape while contacting the endless cathode contact (7), and the object to be plated (1) is transferred to the holding part (6) on the upper side.
6) Shielding plate QO) (10) with anode openings (9) (9) at regular intervals on both sides and each anode opening f9)
(9) The object to be plated (1) is passed through a feeding path (8) provided with parallel anodes (0υOI) on both sides of the object (1) on the outside, and the central part in the longitudinal direction of the object (1) to be plated is , shielding plate QO
When the anode opening (9) (9) of the IQO) is reached, the movement is stopped for a certain period of time, and the conveyance is carried out intermittently.

Secondly, the entire surface plating apparatus of the present invention has a plating tank (2).
Endless conveyance means (4) that can move horizontally inside the interior.
A holding jig (5) capable of holding the object to be plated (1) in a horizontally long and vertical shape is continuously provided on the outer periphery of the conveying means (4), and the cathode contact (7) is endless. Jig (5)
A shielding plate αωQOI is provided movably in the upper conveying part (6) and has anode openings (9) (9) on both sides of the conveying part (6) at regular intervals in the direction of movement, and each anode. opening (9) (9) Parallel anodes αDOυ are provided on both sides of the object to be plated (1) on the outside, and the conveying means (4) is The shielding plate 00) is provided so as to be able to move intermittently and stop for a certain period of time when it reaches the anode opening (9) (9) position of θω.

The above configuration will be explained in more detail.

The endless conveying means (4) is, for example, a roller chain-type endless conveyor, and forging is carried out horizontally by wheels (rollers) that rotate on horizontal shafts provided at the front and rear of the plating tank (2). A path (8) is formed. The transport means (4) has a shielding plate 001 GO at the longitudinal center of the object to be plated (1).
) The anode opening (9) is designed to be able to move intermittently, stopping for a certain period of time when it reaches the (9) position. In addition, the intermittent movement adjusts the plating film thickness distribution over the entire surface of the object to be plated (1) to a desired state, so that the object to be plated (1)
O) QO) and the opening for the anode (9)
In (9), the time to stop at - can be appropriately adjusted.

The holding jig (5) for the object to be plated (1) holds the object to be plated (1).
The conveying means (
4) Continuously provided on the outer periphery.

The endless cathode contact (7) is, for example, chain-type endless, and is movable together within the transport portion (6) above the holding jig (5).

As mentioned above, the shielding plates QO) QO) are arranged in parallel on both sides with the conveyance path (8) in between, and the shielding plates 00OI on both sides are provided with constant intervals along the conveyance direction, that is, the conveyance path (8). Anode openings (9) (9) are formed therein. The opening (9
) (9) may be set to be larger than at least the width of the object to be plated (1).

The anode aυQl) is connected to each opening (
(9) It is provided on the outside parallel to both side surfaces of the object to be plated (1), for example, as shown in the figure, it may be made into a chip and housed in a titanium-split anode case, or it may be made into a plate. Good too.

Furthermore, depending on the type of the object to be plated (11), the plating film thickness may not be required to be so uniform, so the conveying means (4) may be capable of continuous movement for that case. .

In the figure, (3) is a contact stripping tank, which is placed at the bottom of the plating tank (2) as shown in Figures 1 and 3, and inside the stripping tank (3), an electrolytic stripping solution It is preferable to include a plating solution or a stripping solution that uses some components of the plating solution excluding brighteners and the like.

Further, when the conveying means (4) and the holding jig (5) are returned to the front position of the plating tank (2), the endless cathode contact (7) is inserted into the cathode contact (7) as shown in FIG. further forward to separate it from the holding jig (5), lead it out of the plating tank (2) through the front wall, and pass it through the liquid in the stripping tank (3) via rolls 07). After that, it is desirable to be able to circulate it so that it returns to the plating tank (2) from the rear wall αa.

α is a liquid draining plate, and Q6) as is a circulation pipe for stirring the plating solution between the shielding plates.

b for work The operating state of the present invention is as follows.

Electrodes in a plating bath (2) containing a plating solution are energized, and a conveying means (4) capable of intermittent movement is driven to sequentially feed short objects to be plated (1) at equal intervals. The object to be plated (1) is an endless cathode contact that moves together with the holding jig (5) within the conveyance section (6) above the holding jig (5) provided on the outer periphery of the conveyance means (4). (7) They are held horizontally and vertically at equal intervals on the top.

By moving the conveying means (4), the object to be plated (1) in the conveying part (6) on the upper side of the holding jig (5) is moved along a horizontal conveying path ( 8) The endless cathode contact (7) is also moved together with the holding jig (5) while coming into contact with the object to be plated (1) as described above.

There are -
Shielding plate GO with anode openings (9) (9) at regular intervals
) (10) and each anode opening f9) (9) Anodes aυ0υ are provided in parallel on the outside. Item to be plated (1)
A plating film is formed while moving through the conveyance path (81k), but when passing between the shielding plates θl00, edge plating tends to precipitate on the side edges of the object (1) due to the edge phenomenon. Therefore, the plating film in that area tends to be thick.

However, in the present invention, the conveying means (4) is arranged so that the central part of the object to be plated (1) that has been conveyed is connected to the anode opening (9) (9).
), the robot will move intermittently and stop for a certain period of time. Therefore, during the stoppage, plating is more likely to precipitate at the center of the object to be plated (1) at the position corresponding to the anode αυαυ than at the side edges, contrary to when it passes between the shielding plates 0100. A thick plating film is formed.

Therefore, the object to be plated (1) is in the plating tank (2) as described above.
) while moving through the anode openings (9) f9
) while stopping for a certain period of time, the formation of a plating film is sufficiently repeated on the central part of the object to be plated +1). As a result, at the stage when the object to be plated (1) has finished moving in the plating tank (2), the plating film on the object to be plated (1) has a substantially uniform thickness both in the center and near the side edges. will be formed.

Furthermore, in the present invention, anodes 0υ0υ are provided outside the anode openings (9) (9) on both sides of the withdrawal path (8) in parallel with both side surfaces of the object to be plated (1) in the holding jig (5). It is. Therefore, even when the distance between the anode 000υ and the cathode contact (7) is short, the shortest distance between the object to be plated (1) and the anode αυ0υ is approximated by the height of each part of the object to be plated (1). Therefore, the thickness of the plating film in the height direction of the object to be plated (1) can also be easily made uniform.

In addition, when the endless cathode contact (7) and the contact peeling N (3) are configured as shown in FIGS. 1 and 3 as described above, the cathode contact (7) The transport means (4) near the front of the plating tank (2) separates from the transport means (4) and the holding jig (5) when returning, and the plating tank (
2) Go outside and peel off the contact [pass through f31, plating tank (
Make a circular movement by returning to 2). This contact peeling yM(
31, the electrodeposited plating on the cathode contact (7) is removed by the electrolytic stripping solution in (3).

At that time, what passes through the stripping tank (3) is simply the cathode contact (
7), and the conveying means (4) and holding jig (5) are moved only within the plating tank (2), so the amount of plating solution taken out and brought in is extremely small. Further, the stripping solution in the stripping tank (3) is an electrolytic stripping solution containing a meso-plating solution or a plating solution as a component. Therefore, the plating solution is applied to the peeling M! by the cathode contact (7). (Even if it is brought to 31, the electrolytic stripping solution, which is the same as the plating solution, will not change in quality,
On the other hand, there is no problem if the stripping solution is brought into the plating M(2). Furthermore, it is no longer necessary to wash the cathode contact (7) with water after electrolytic stripping.

C. Example In order to confirm the effects of the present invention, experiments were conducted under the following conditions using the full surface plating apparatus shown in FIGS. 1 to 5 as an example. Plating solution 9:1 solder slot left KB
Bath (manufactured by Max Schroeter, West Germany), current density 5A
/dm2. Bath temperature 20C, set film thickness value 7 μm, distance between electrodes 40 to 50 mm, IC lead frame to be plated (Di
p28 pin 220 x 45mm, F1at84 pin 188
x55mm), shielding plate length 600mm, time 3.5 minutes (
(Stop time: 35 seconds, each movement time: 52.5 seconds), film thickness measuring machine: Fluorescent X-ray film thickness measuring machine (Seiko 5FT-1)
The film thickness of each part of the object to be plated (1) was measured using a model 58. The table below compares this with that of the conventional racking method under the same conditions.

As is clear from the table above, when the entire surface is plated according to the present invention, the difference between the maximum film thickness and the minimum FAPf- becomes extremely small compared to when the conventional racking method is used.

C. Effects of the Invention As is clear from the above, the entire surface plating method and apparatus of the present invention has the following effects.

a. The thickness of the plating film on the object to be plated can be made uniform.

In other words, in the conventional racking method, due to the edge phenomenon, plating tends to precipitate closer to the side edges of the object to be plated. This was not acceptable for IC lead frames and printed circuit boards that required high precision, and the test was often rejected. However, in the present invention, as described above, shielding plates having anode openings are provided at equal intervals on both sides of the dispersion path in the plating tank,
The object to be plated is transported intermittently between the two, stopping for a certain period of time when the center of the object comes to a position corresponding to the opening.

Therefore, plating is likely to precipitate also in the center of the object to be plated, resulting in a plating film thickness similar to that near the side edges. Furthermore, in the present invention, the anodes are provided outside the anode openings on both sides of the mold feeding path, parallel to both sides of the object to be plated in the holding jig, so that when the distance between the anode and the cathode is short, Also, the shortest distance between the object to be plated and the anode is approximated at each height of the object to be plated. Therefore, at each position in the height direction of the object to be plated,
The plating 11 can be easily made uniform. Therefore, in the present invention, it is possible to form a plating film with a substantially uniform thickness over the entire surface of the object to be plated.

b. It is not necessary to change the size of the rank, the position and shape of the cathode contact, etc. depending on the length, width, and other shapes of the object to be plated, and high-speed plating processing can be performed.

In other words, the conventional racking method requires special ranks and contacts depending on the length and width of the object to be plated, and it takes time and effort to replace them depending on the object to be plated, resulting in poor workability. Ta. Due to the structure of the plating tank, it was difficult to stir the liquid at high speed, resulting in a low current density.

In contrast, in the present invention, the object to be plated can be thrown into the holding jig that is intermittently moving and automatically engaged and held.
This can be done regardless of the length, width, etc. of the object to be plated. Furthermore, since the inside of the plating tank can be stirred as a whole parallel to the longitudinal direction of the object to be plated (IM feeding direction), high-speed stirring and high current density are possible, and high-speed plating can be achieved.

C. In addition, as in the plating apparatus shown in the figure, when only the endless cathode contact is taken out from the rear of the plating tank and circulated through the plating solution or an electrolytic stripping solution containing the plating solution as a component, the plating When moving between the tank and the contact/jig stripping tank, the amount of plating solution carried out can be extremely reduced.

That is, in the conventional rough king method, the processing liquid adheres to both the object to be plated and the rack and moves. As a result, the processing liquid is frequently pumped out and brought in between adjacent processing tanks, which is uneconomical, deteriorates the quality of plating, and lengthens the processing time.

In contrast, in the illustrated plating apparatus, only the cathode contact is moved from one plating tank to the next, and the conveyance means and jigs are circulated only within the plating tank. Therefore, the amount of plating solution taken out and brought in is extremely small. In addition, if the stripping solution in the contact stripping tank is a plating solution or an electrolytic stripping solution containing plating solution as a component, even if the plating solution is brought in by the cathode contact, the plating solution will not be removed. There is no deterioration because the liquid and electrolytic stripper are of the same quality. Therefore, there is no need to wash the cathode contact with water after electrolytic stripping, which is economical, improves the quality of plating, and shortens processing time.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; FIG. 1 is a longitudinal sectional front view of the main parts of the plating apparatus, and FIG. 2 is a partial perspective view showing the positional relationship between the shielding plate, the anode opening, and the anode. , Fig. 3 is a sectional view taken along line lll-l11 in Fig. 1, Fig. 4 is a schematic plan view showing the positional relationship with the shield plate when the object to be plated is moving, and Fig. 5 is a schematic plan view when the object to be plated is temporarily stopped. FIG. 3 is a schematic plan view showing the positional relationship with the anode opening at the time. Drawing code (1) - Item to be plated (2) - Plating tank (4) - Mold conveying means (5) - Holding jig (6) - Conveying part (
7) - Cathode contact (8) - Feed path (9) - Opening 00) - Shielding plate QD - Anode

Claims (1)

[Scope of Claims] [1] A short object to be plated (1) is transferred to the upper transport portion (6) of the holding jig (5) provided on the transport means (4) in the plating tank (2), etc. The object to be plated (1
), a shielding plate (10) (10) having anode openings (9) (9) at regular intervals on both sides of the holding part (6), and a shielding plate (10) (10) having anode openings (9) (9) covered on the outside of each anode opening (9) (9). The object to be plated (1) is passed through a conveyance path (8) in which parallel anodes (11) (11) are provided on both sides, and the central part in the longitudinal direction of the object to be plated (1) is connected to a shielding plate. (10) (10) Anode opening (
9) A full surface plating method characterized by intermittent conveyance in which movement is stopped for a certain period of time when the position (9) is reached. [2] In the plating tank (2), an endless conveying means (4) that can move horizontally inside is provided, and the object to be plated (1) is held in a horizontally long vertical shape on the outer periphery of the conveying means (4). The holding jig (5) is provided in a continuous manner, the cathode contact (7) is endless, and the holding jig (5) is provided so as to be movable together in the conveying part (6) above the holding jig (5). 6) A shielding plate (10) (10) having anode openings (9) (9) on both sides at regular intervals in the direction of movement, and an object to be plated on the outside of each anode opening (9) (9). (1) Parallel anodes on both sides (11) (1
1), and when the longitudinal center of the object to be plated (1) is at the anode opening (9) (9) position of the shielding plate (10) (10), the conveying means (4) is moved. A full-surface plating device characterized by being capable of intermittent motion that stops for a certain period of time.