JP2007247003A - Barrel plating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a barrel plating method capable of reconciling the improvement in plating efficiency and the improvement in separation efficiency of materials to be plated from each other. <P>SOLUTION: In the barrel plating method, granular electric insulation members 20 smaller in specific gravity than a plating solution 5 and greater in specific gravity than a cleaning liquid are housed together with electronic components 10 into a barrel 3. The electric insulation members 20 exist so as to cover the upper part of an inner wall of the barrel 3 in electrolytic plating treatment and therefore, the courses of power lines heading toward the upper part of the barrel 3 from an anode electrode 4 are shielded. Accordingly, the power lines concentrate to the lower part of the barrel 3 where the electronic components 10 exist, and the improvement in the plating efficiency is achieved. Also, the electric insulation members 20 sink in the lower part in the barrel 3 and are intermingled with the electronic components 10 in a cleaning treatment. Consequently, when cleaning, the electric insulation members 20 hit the electronic components 10 and even if the adhesion of the electronic components 10 to each other occurs, the separation efficiency is enhanced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a barrel plating method.

  Barrel plating is a method of performing a plating process while stirring an object to be plated in the barrel. In this method, a barrel containing a plurality of objects to be plated is immersed in the plating solution, a pair of anodes are arranged outside the barrel, and a cathode is arranged inside the barrel. Then, the metal in the plating solution is deposited on the surface of the object to be plated by the action of current lines formed between the anode and the cathode while rotating the barrel at a constant speed.

As a technique related to such barrel plating, for example, there is a barrel plating method for electronic components described in Patent Document 1. In this conventional barrel plating method for electronic parts, an agitation assisting member having a specific gravity larger than that of the body to be plated and larger than that of the body to be plated is placed in the barrel together with the conductive medium. By introducing such an agitation auxiliary member, the object to be plated and the conductive medium are taken into the space between the individual agitation auxiliary members in the rotating barrel to improve the agitation efficiency.
JP 2000-256899 A

  An object of this invention is to provide the barrel plating method which can make the improvement of plating efficiency and the improvement of the isolation | separation efficiency of to-be-plated objects compatible.

  In order to solve the above-mentioned problems, the inventors of the present application first conducted intensive research on improving the growth rate (plating efficiency) of plating on an object to be plated in the barrel plating method. In the process, the present inventors paid attention to the density of current lines formed from the anode outside the barrel toward the cathode inside the barrel. And since the object to be plated sinks in the lower part in the barrel, by blocking the current line toward the upper part of the barrel where there is no object to be plated by the electrical insulating member, if the current line can be concentrated at the lower part of the barrel, It has been found that the plating efficiency can be improved. In the above-described barrel plating method for electronic parts, the specific gravity of the auxiliary stirring member is larger than that of the object to be plated, and the technical idea of blocking the current line toward the upper part of the barrel is not disclosed.

  On the other hand, when the improvement of the plating efficiency is pursued, the plating grows between the individual objects to be plated, and adhesion between the objects to be plated easily occurs. Therefore, in the cleaning process after the plating process, the separation efficiency between the objects to be plated may be reduced. On the other hand, the inventors of the present application pay attention to the specific gravity of the above-described electrical insulating member, and in the plating process, the electrical insulating member is present in the upper part in the barrel, and in the cleaning process, the electrical insulating member is in the lower part in the barrel. If it is made to coexist, the knowledge that the improvement of plating efficiency and the improvement of the separation efficiency of to-be-plated objects can be made compatible was acquired, and it came to complete this invention.

  The barrel plating method according to the present invention is a barrel plating method in which a plurality of objects to be plated are agitated while being stirred in a barrel, and is a granular electric material having a specific gravity smaller than a plating solution and larger than a cleaning solution. Preparing a plurality of insulating members, housing a plurality of electrically insulating members and objects to be plated in the barrel, immersing the barrel in a plating solution, energizing, and plating a plurality of objects to be plated while rotating the barrels And a step of immersing the barrel in a cleaning solution after removing the plating solution and cleaning a plurality of objects to be plated while rotating the barrel.

  In this barrel plating method, a plurality of granular electrical insulating members having a specific gravity smaller than that of the plating solution and larger than that of the cleaning solution are prepared and accommodated in the barrel together with the plurality of objects to be plated. When the barrel is immersed in the plating solution in the electrolytic plating process, the electrical insulating member floats on the upper part of the barrel and exists so as to cover the upper part of the inner wall of the barrel. Therefore, the path of the power line from the anode toward the upper part of the barrel is blocked, and the power line is concentrated at the lower part of the barrel where the group of objects to be plated is located, so that the plating efficiency can be improved. On the other hand, when the barrel is immersed in the cleaning liquid in the cleaning process of the object to be plated, the electrical insulating member sinks in the lower part of the barrel and is mixed with the group of objects to be plated. Therefore, if the barrel is rotated in this state, since the electrical insulating member hits the object to be plated when the object flows, even if the objects to be plated adhere to each other during the electrolytic plating process, the separation Efficiency can be increased.

  Moreover, it is preferable that the volume of the several electrical insulation member accommodated in a barrel is 3% or more and 10% or less with respect to the volume of a barrel. When the volume of the electrical insulating member is less than the lower limit of the above range, the effect of improving the plating efficiency and the separation efficiency becomes insufficient. When the volume of the electrical insulating member exceeds the upper limit of the above range, the plating efficiency becomes excessive, and adhesion between the objects to be plated frequently occurs, so that the separation efficiency also decreases. In addition, there is a possibility that an excessive amount of the electrical insulating member hits the object to be plated at the time of cleaning, and the object to be plated is cracked or chipped. Therefore, plating efficiency and separation efficiency can be optimized by setting the volume of the electrical insulating member in the above range.

  As described above, according to the barrel plating method of the present invention, it is possible to achieve both improvement in plating efficiency and improvement in separation efficiency between objects to be plated.

  Hereinafter, a preferred embodiment of a barrel plating method according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration outline of a barrel plating apparatus for realizing an embodiment of a barrel plating method according to the present invention. As shown in FIG. 1, a barrel plating apparatus 1 includes a plating tank 2 that stores a plating solution 5 or a cleaning solution 6 (see FIG. 6), a barrel 3 that houses a plurality of electronic components 10 that are objects to be plated, and 1 The apparatus includes a pair of anode electrodes 4 and 4 and is configured as a device that performs a plating process while stirring the electronic component 10 in the plating solution 5.

  The barrel 3 is formed in a cylindrical shape having a regular hexagonal cross section by metal, for example, and is disposed horizontally at the approximate center of the plating tank 2. The interior of the barrel 3 is a housing space for housing the electronic component 10 and a plurality of electrical insulating members 20 described later. Further, in the barrel 3, a dummy medium (not shown) for electrically connecting the individual electronic components 10 is also accommodated together with the electronic components 10.

  A mesh-shaped window (not shown) is formed on the side wall of the barrel 3. This window portion blocks the electronic component 10 and the like housed in the barrel 3 from passing outside, and allows the plating solution 5 or the cleaning solution 6 to flow from the plating tank 2 into the barrel 3. The barrel 3 is connected to a rectifier (not shown) installed outside the plating tank 2 and functions as a cathode electrode. When performing a plating process and a cleaning process to be described later, the barrel 3 has a predetermined centering on the rotating shaft 7. Rotates at speed.

  The anode electrodes 4 and 4 are disposed on both sides of the barrel 3 in the plating tank 2. Lead wires extending from the upper end portions of the anode electrodes 4 and 4 are drawn out above the plating tank 2 and connected to a rectifier in the same manner as the barrel 3. When the anode electrodes 4, 4 and the barrel 3 are energized, current lines having a predetermined density are formed from the anode electrodes 4, 4 located outside the barrel 3 toward the barrel 3.

  Here, an example of the individual electronic component 10 accommodated in the barrel 3 is shown in FIG. In the example shown in the figure, an electronic component 10 includes an element portion 11 formed by laminating ceramic layers on which conductive patterns are formed, and a pair of terminal electrodes 12 and 12 respectively formed at both ends of the element portion 11. This is a so-called multilayer electronic component. Examples of such an electronic component 10 include a chip capacitor, a chip varistor, a chip inductor, and a chip bead.

  An example of the individual electrical insulating member 20 is shown in FIG. In the example shown in the figure, the electrical insulating member 20 is formed in a spherical shape of about φ5 mm, for example, from polystyrene. The electrical insulating member 20 is a member having a specific gravity smaller than that of the plating solution 5 and larger than that of the cleaning solution 6. Therefore, when the barrel 3 is immersed in the plating solution 5, the electrical insulating member 20 is lifted upward in the barrel 3, and when the barrel 3 is immersed in the cleaning solution 6, the electrical insulating member 20 is lowered in the barrel 3. It is supposed to sink into.

  Next, a barrel plating method using the barrel plating apparatus 1 described above will be described with reference to a flowchart shown in FIG.

  First, a plurality of electronic components 10, which are objects to be plated, a plurality of electrical insulating members 20, and dummy media (not shown) are accommodated in the barrel 3 (step S01). At this time, the volume of the electrical insulating member 20 accommodated in the barrel 3 is in the range of 3% to 10% of the volume of the barrel 3. Next, the barrel 3 is disposed in the plating tank 2, and washing water is allowed to flow into the plating tank 2, whereby the electronic components 10 and the like in the barrel 3 are cleaned in advance. After washing, the washing water is removed from the plating tank 2 and then the plating solution 5 is caused to flow into the plating tank 2. Thereby, the barrel 3 is immersed in the plating solution 5 (step S02).

  After the barrel 3 is immersed in the plating solution 5, the anode electrode 4 and the barrel 3 are energized. Then, by rotating the barrel 3 around the rotation shaft 7 at a predetermined speed, the electroplating process is performed while stirring the electronic component 10 (step S03). In this electrolytic plating process, as shown in FIG. 5, an electrical insulating member 20 having a specific gravity smaller than that of the plating solution 5 is lifted upward in the barrel 3 and covers the upper part of the inner wall of the barrel 3. Therefore, the path of the power line from the anode electrode 4 toward the upper part of the barrel 3 is blocked, and the power line C concentrates on the lower part of the barrel 3 where the electronic component 10 is located. In this state, each electronic component 10 is electrically connected to the barrel 3 via a dummy medium, and the plating metal in the plating solution 5 is deposited on the surface of the terminal electrodes 12 and 12 of the electronic component 10.

  After the electrolytic plating process is completed, the plating solution 5 is removed from the plating tank 2 (step S04). And the washing | cleaning liquid 6 flows into the plating tank 2 instead of the plating liquid 5, and the barrel 3 is immersed in the washing | cleaning liquid 6 (step S05). Then, the cleaning process is performed while the electronic component 10 is being agitated by rotating the barrel 3 around the rotation shaft 7 at a predetermined speed (step S06). For example, pure water is used as the cleaning liquid 6. In this cleaning process, as shown in FIG. 6, the electrical insulating member 20 having a specific gravity greater than that of the cleaning liquid 6 sinks downward in the barrel 3 and is mixed with the electronic component 10. Therefore, by rotating the barrel 3 in this state, the electronic component 10 is cleaned while the electric insulating member hits the electronic component 10.

  After the cleaning step, the barrel 3 is taken out from the plating tank 2 and the electronic component 10 and the electrical insulating member 20 are selected by a sieve or the like. Then, by performing a predetermined drying process, the manufacture of the multilayer electronic component 10 illustrated in FIG. 2 is completed.

  As described above, in the barrel plating method according to the present embodiment, the granular electrical insulating member 20 having a specific gravity smaller than that of the plating solution 5 and larger than that of the cleaning solution 6 is prepared. To house. When the barrel 3 is immersed in the plating solution 5 in the electrolytic plating process, the electrical insulating member 20 floats up to the upper part of the barrel 3 and covers the upper part of the inner wall of the barrel 3. The path of the power line going to the top of will be blocked.

  Therefore, as shown in FIG. 7, when the electrical insulating member 20 is not accommodated in the barrel 3, the power line C is directed from the anode electrode 4 to the barrel 3 with an equal density. As shown, since the power line C is concentrated at the lower part of the barrel 3 where the electronic component 10 is located, the plating efficiency can be improved.

  On the other hand, when the barrel 3 is immersed in the cleaning liquid 6 in the cleaning process of the electronic component 10, the electrical insulating member 20 sinks in the lower portion of the barrel 3 and is mixed with the electronic component 10. Therefore, when the barrel 3 is rotated in this state, the electrical insulating member 20 hits the electronic component 10 when the electronic component 10 flows. Therefore, even if the electronic components 10 adhere to each other during the electrolytic plating process, The separation efficiency can be increased.

  In this barrel plating method, the volume of the electrical insulating member 20 accommodated in the barrel 3 is 3% or more and 10% or less with respect to the volume of the barrel 3. When the volume of the electrical insulating member 20 is less than the lower limit of the above range, the effect of improving the plating efficiency and the separation efficiency becomes insufficient. When the volume of the electrical insulating member 20 exceeds the upper limit of the above range, the plating efficiency becomes excessive, and the electronic components 10 frequently adhere to each other during the electrolytic plating process, so that the separation efficiency also decreases. In addition, the electrical insulating member 20 may hit the electronic component 10 excessively during cleaning, and the electronic component 10 may be cracked or chipped. Therefore, plating efficiency and separation efficiency can be optimized by setting the volume of the electrical insulating member 20 in the above range.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the shape of the electrical insulating member 20 is spherical, but the electrical insulating member 20 may be granular, and may have a cubic shape, a rectangular parallelepiped shape, a cylindrical shape, an ellipsoidal shape, and the like. Also good. Further, the size of the electrical insulating member 20 may be appropriately changed according to the size of the electronic component 10 accommodated in the barrel 3.

It is a figure which shows the structure outline | summary of the barrel plating apparatus for implement | achieving one Embodiment of the barrel plating method which concerns on this invention. It is a perspective view which shows an example of the electronic component accommodated in a barrel. It is a perspective view which shows an example of the electrical insulation member accommodated in a barrel. It is a flowchart which shows the procedure of a barrel plating method. It is a figure which shows the state in the barrel during an electrolytic plating process. It is a figure which shows the state in the barrel under a washing process. It is a figure which shows the state in the barrel during the electroplating process in the case of not accommodating an electrical insulation member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Barrel, 5 ... Plating liquid, 6 ... Cleaning liquid, 10 ... Electronic component (to-be-plated object), 20 ... Electrical insulation member.

Claims (2)

A barrel plating method for performing plating while stirring a plurality of objects to be plated in a barrel,
Preparing a plurality of granular electrical insulating members having a specific gravity smaller than the plating solution and larger than the cleaning solution, and housing the plurality of electrical insulating members and the object to be plated in the barrel;
The step of immersing the barrel in the plating solution and energizing to form plating on the plurality of objects to be plated while rotating the barrel;
And a step of immersing the barrel in the cleaning solution and cleaning the plurality of objects to be plated while rotating the barrel after removing the plating solution. 2. The barrel plating method according to claim 1, wherein a volume of the plurality of electrical insulating members accommodated in the barrel is 3% to 10% with respect to a volume of the barrel.

Images