JP2007270282A - Barrel plating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a barrel plating method by which both of increase of plating efficiency and increase of separation efficiency of work pieces from one another can be satisfied. <P>SOLUTION: In the barrel plating method, a plate-like electric insulating member 20 having a specific gravity which is smaller than that of a plating solution 5 and larger than that of a washing liquid 6 is put in a barrel 3, together with electronic components 10. Since the electric insulating member 20 is present so as to cover an upper part of the inner wall of the barrel 3 in electroplating, electric power lines C concentrate on a lower part of the barrel 3 in which the electronic components 10 are located; accordingly plating efficiency is increased. The electric insulating member 20 goes down to the lower part of the barrel 3 so as to cover the electric components 10 in washing of the electric components 10, whereby the flow range of the electric components 10 is regulated. By this regulation, one electric component 10 hits frequently against other electric components 10 and the lower surface of the electric insulating member 20; accordingly separation efficiency of electric components 10 from one another is increased. <P>COPYRIGHT: (C)2008,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 disposed outside the barrel, and a cathode is disposed in 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 electrical insulating member described above, position the electrical insulating member on the barrel upper part in the plating process to shield the current line, and in the cleaning process, place the electrical insulating member on the lower barrel part. If the efficiency of stirring the flowing object to be plated is increased by using the electrical insulating member as it is, it is possible to achieve both the improvement of the plating efficiency and the improvement of the separation efficiency of the objects to be plated. As a result, the present invention has been completed.

  The barrel plating method according to the present invention is a barrel plating method in which a plurality of objects to be plated are plated while being stirred in a barrel, and has a plate-like shape having a specific gravity smaller than a plating solution and larger than a cleaning solution. An electrical insulating member was prepared, and the electrical insulating member and a plurality of objects to be plated were accommodated in the barrel, the barrel was immersed in the plating solution, and the anode disposed outside the barrel and the barrel were accommodated in the barrel. A process of forming a plating on a plurality of objects to be plated while rotating a barrel and energizing in a state where a part between the objects to be plated is shielded by an electric insulating member, and after removing the plating solution, A step of immersing the substrate in a cleaning solution and cleaning a plurality of objects to be plated while rotating the barrel.

  In this barrel plating method, a plate-shaped electrical insulating member having a specific gravity smaller than that of the plating solution and larger than that of the cleaning solution is prepared and accommodated in the barrel together with a 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 object 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 electric insulating member sinks to the lower part of the barrel so as to cover the object to be plated. Therefore, when the barrel is rotated in this state, the flow range of the object to be plated is restricted by the electric insulating member, and the object to be plated frequently hits other objects to be plated or the electric insulating member. As a result, the objects to be plated are sufficiently agitated in the cleaning process, and even if the objects to be plated adhere to each other during the electrolytic plating process, the separation efficiency can be increased.

  The length of the electrical insulating member is preferably less than 100% based on the inner dimension of the barrel in the rotation axis direction, and the width of the electrical insulating member is 50% or less based on the inner diameter of the barrel. It is preferable. If it carries out like this, since it will become difficult to catch an electric insulation member on the inner wall of a barrel, when changing from an electrolytic plating process to a washing process, an electric insulation member can be reliably moved toward the lower part of a barrel from the upper part of a barrel.

  Moreover, it is preferable that the length dimension of an electrical insulation member is 50% or more on the basis of the internal dimension of the barrel in the rotating shaft direction. In this case, it is possible to suitably perform shielding of the power line path in the electrolytic plating process and restriction of the flow range of the object to be plated in the cleaning process.

  The electrical insulating member is preferably bendable in a direction in which edges along the longitudinal direction of the electrical insulating member face each other. If it carries out like this, in an washing | cleaning process, it will become possible to make an electrical insulation member adhere substantially to the surface of the to-be-plated to-be-plated object, and can control the flow range of to-be-plated object more reliably. As a result, the separation efficiency of the object to be plated can be further increased.

  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. FIG. 2 is a side view of the barrel plating apparatus shown in FIG. As shown in FIGS. 1 and 2, a barrel plating apparatus 1 includes a plating tank 2 that stores a plating solution 5 or a cleaning solution 6 (see FIG. 7), and a barrel 3 that houses a plurality of electronic components 10 that are objects to be plated. And a pair of anode electrodes 4, 4, and configured as a device for performing 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 an electrical insulating member 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 housed 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.

  Next, an example of the electrical insulating member 20 is shown in FIG. In the example shown in the figure, the electrical insulating member 20 is formed in a rectangular plate shape having a thickness of about 5 mm, for example, from polystyrene. The width dimension W1 of the electrical insulating member 20 is about 50% based on the inner diameter W2 of the barrel 3 (see FIG. 1), and the length dimension L1 of the electrical insulating member 20 is the inner dimension of the barrel 3 in the rotation axis direction. It is about 75% based on the dimension L2 (see FIG. 2). The specific gravity of the electrical insulating member 20 is 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.

  Furthermore, as shown in FIG. 4, a groove portion 21 is formed in the central portion of the electrical insulating member 20 along the longitudinal direction. Thereby, the electrical insulating member 20 can be bent so that the edge portions 22 along the longitudinal direction face each other with respect to the direction in which the groove portion 21 is not formed. The electric insulating member 20 is accommodated in the barrel 3 so that the bending direction is directed to the electronic component 10 side.

  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 plate-shaped electrical insulating member 20, and a dummy medium (not shown) are accommodated in the barrel 3 (step S01). 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 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. 6, 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, a part of the path of the power line from the anode electrode 4 to the upper part of the barrel 3 is shielded, 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. 7, an electrical insulating member 20 having a specific gravity greater than that of the cleaning liquid 6 sinks in the lower portion of the barrel 3 so as to cover the electronic component 10. Further, when the electrical insulating member 20 sinks below the barrel 3, the edges 22, 22 along the longitudinal direction of the electrical insulating member 20 are bent so that they face each other, and the electrical insulating member 20 is formed on the surface of the flowing electronic component 10. Close contact. Therefore, when the barrel 3 is rotated in this state, the flow range of the electronic component 10 is regulated by the electrical insulating member 20, and the electronic component 10 frequently hits the other electronic component 10 or the lower surface side of the electrical insulating member 20, The electronic component 10 is cleaned.

  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. 3 is completed.

  As described above, in the barrel plating method according to the present embodiment, the plate-like 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. Housed inside. 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. 8, 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 to the lower part of the barrel 3 so as to cover the electronic component 10. Further, when the electrical insulating member 20 sinks below the barrel 3, the edges 22, 22 along the longitudinal direction of the electrical insulating member 20 are bent so that they face each other, and the electrical insulating member 20 is formed on the surface of the flowing electronic component 10. Close contact. When the barrel 3 is rotated in this state, the flow range of the electronic component 10 is restricted by the electric insulating member 20, and the electronic component 10 frequently hits the other electronic component 10 or the lower surface side of the electric insulating member 20. Ten cleaning processes are performed. Thereby, even if the electronic components 10 are sufficiently stirred in the cleaning process and the electronic components 10 are adhered to each other during the electrolytic plating process, the separation efficiency can be increased. Since the electrical insulating member 20 has a sufficiently large plate shape as compared with the electronic component 10, the electrical insulating member 20 can be easily selected and removed from the electronic component 10 after the cleaning process is completed. it can.

  In this barrel plating method, the width dimension W1 of the electrical insulating member 20 is about 50% with respect to the inner diameter W2 of the barrel 3, and the length dimension L1 of the electrical insulating member 20 is the rotational axis of the barrel 3. It is about 75% based on the inner dimension L2 in the direction. With such a configuration, the electric insulating member 20 is less likely to be caught on the inner wall of the barrel 3, so that when the electroplating process is shifted to the cleaning process, the electric insulating member 20 is moved from the upper part of the barrel 3 toward the lower part of the barrel 3. It can be moved reliably. Furthermore, as described above, since the length dimension L1 of the electrical insulating member 20 is 50% or more based on the inner dimension of the barrel 3 in the rotation axis direction, the path of the power line C in the electrolytic plating process is shielded. The flow range of the electronic component 10 in the cleaning process can be suitably controlled.

  The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the electrical insulating member 20 can be bent by forming the groove portion 21, but such a groove portion 21 is not necessarily formed, and an electrical insulating member that is not bent through the electrolytic plating process and the cleaning process is used. May be. Further, the shape of the electrical insulating member 20 can be appropriately changed according to the size and quantity of the electronic component 10 accommodated in the barrel 3. At this time, the width dimension W1 of the electric insulating member 20 is set to 50% or less with respect to the inner diameter W2 of the barrel 3, and the length dimension L1 of the electric insulating member 20 is set to 100 based on the inner dimension L2 of the barrel 3 in the rotation axis direction. By setting it to less than 50% and less than 50%, it is possible to obtain the same effect as the above-described embodiment.

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 the figure which looked at the barrel plating apparatus shown in FIG. 1 from the side. 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

3 ... Barrel, 5 ... Plating solution, 6 ... Cleaning solution, 10 ... Electronic component (to-be-plated object), 20 ... Electrical insulation member, L1 ... Length dimension of electrical insulation member, L2 ... Internal dimension of barrel in the rotation axis direction, W1 is the width dimension of the electrical insulating member, W2 is the inner diameter of the barrel.

Claims (5)

A barrel plating method for performing plating while stirring a plurality of objects to be plated in a barrel,
Preparing a plate-like electrical insulating member having a specific gravity smaller than the plating solution and larger than the cleaning solution, and storing the electrical insulating member and the plurality of objects to be plated in the barrel;
The barrel is immersed in the plating solution, and a portion between the anode disposed outside the barrel and the plurality of objects to be plated accommodated in the barrel is shielded by the electrical insulating member. Energizing and forming 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.   The barrel plating method according to claim 1, wherein a length dimension of the electrical insulating member is less than 100% based on an inner dimension of the barrel in the rotation axis direction.   3. The barrel plating method according to claim 1, wherein a length dimension of the electrical insulating member is 50% or more based on an inner dimension of the barrel in a rotation axis direction.   4. The barrel plating method according to claim 1, wherein a width dimension of the electrical insulating member is 50% or less based on an inner diameter of the barrel. 5. The barrel plating method according to claim 1, wherein the electrical insulating member is bendable in a direction in which edges along the longitudinal direction of the electrical insulating member face each other.

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