JP2009024242A - Plating device for metal pipe, and plating method for metal pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a plating device where the inside face of a U-shaped or L-shaped waveguide is subjected to uniform electroplating with high quality. <P>SOLUTION: The plating device includes: a plating tank filled with an electrolytic solution; a d.c. power source; a metal electrode as a plating material located in the plating tank and connected to the anode side of the d.c. power source; a waveguide located in the plating tank, connected to the cathode side of the d.c. power source and having a through hole as a work material; and two auxiliary electrodes located in the plating tank, connected to the anode side of the d.c. power source, and respectively inserted from both the edge parts of the waveguide, so as to be arranged at the inside of the waveguide. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a plating apparatus and a plating method for performing uniform electroplating on the inner surface of a metal pipe.

As a method for electroplating the inner surface of a metal pipe, a zinc rod as a plating material connected to the anode side of a DC power source and a bent steel pipe as a work material connected to the cathode side are immersed in this method. In addition, an auxiliary electrode connected to the anode side in which brass rings and synthetic resin rings are alternately fitted to the flexible electrode wire of the auxiliary electrode is disposed, and an electrolytic solution containing zinc ions is disposed inside the steel pipe. A method of plating a steel pipe inner surface by installing a reflux pump for feeding and preventing a short circuit between the auxiliary electrode and the steel pipe inner surface is disclosed (for example, see Patent Document 1).

JP-A-11-12791

The principle of electroplating a metal workpiece is that the plating material (electrode) is connected to the anode, the workpiece is connected to the cathode, the metal of the plating material is ionized at the anode, and supplied to the electrolyte. Electrons are supplied to the metal ions in the electrolytic solution to deposit plated metal. The amount of metal deposited at the cathode, that is, the thickness of the plating is proportional to the amount of electricity passing through the electrolyte.

In general, in an electrode in an electrolytic solution, a voltage at a portion far from a DC power source is lowered by an amount corresponding to the resistance of the electrode as compared with a near portion. That is, the amount of electricity passing through the electrolytic solution is lower in the inner surface portion of the waveguide set in a portion far from the DC power source than in the closer portion.

In the conventional electroplating method for the inner surface of a metal pipe, only one auxiliary electrode is inserted into the inner surface of the metal pipe and the power source is connected to only one side of the corresponding auxiliary electrode. Therefore, there is a problem that a difference occurs in the plating thickness on the inner surface of the waveguide. Further, in the conventional electroplating method of the inner surface of the metal pipe, the auxiliary electrode portion that has been exposed from the inner surface of the metal pipe is exposed, so that the current flowing from this portion does not reach the inner surface of the metal pipe and is close to the distance There is also a problem that the difference in plating thickness between the outer surface and the inner surface of the metal pipe increases as a result of flowing to the outer surface of the pipe. Further, in the conventional electroplating method of the inner surface of the metal pipe, the inner and outer surfaces of the metal pipe are plated at the same time. Therefore, the current flowing on the inner and outer surfaces of the metal pipe changes depending on the shape of the metal pipe and the setting conditions. There was a problem that the film thickness ratios inside and outside were greatly different.

The present invention has been made in order to solve such problems, and in a plating apparatus for plating a metal pipe having a through hole, the thickness ratio between the inside and outside of the metal pipe is set to the same level, and the plating thickness is caused by a voltage drop generated in the auxiliary electrode. An object of the present invention is to provide a plating apparatus that eliminates the non-uniformity and forms a uniform plating thickness on the inner surface of a metal pipe.

The plating apparatus for an inner surface of a waveguide according to the present invention is a plating tank filled with an electrolyte, a DC power supply, and a plating material that is in the plating tank and connected to the first electrode side of the DC power supply. A metal pipe connected to the second electrode side of the DC power source and having a through-hole as a work material, and in the plating tank, The two auxiliary electrodes are connected to the first electrode side, inserted from both ends of the metal pipe, and arranged inside the metal pipe.

According to the present invention, two flexible auxiliary electrodes are inserted from both sides of the waveguide so as to penetrate through the inner surface of the waveguide bent at one or more places. Therefore, the amount of electricity at the part far from the electrode is less decreased by a voltage drop, and therefore, an appropriate current distribution is formed on the inner surface of the waveguide, and plating with a uniform thickness can be applied to the inner surface of the waveguide.

Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same number is attached | subjected mutually to the same structure in each embodiment, and duplication description is abbreviate | omitted.

Embodiment 1 FIG.
In Embodiment 1, a U-shaped waveguide is given as an example of a metal pipe having a through hole, and the U-shaped waveguide is subjected to plating.
FIG. 1 is a configuration diagram of a plating apparatus for plating the inner surface of a U-shaped waveguide according to the first embodiment. The plating tank 1 of this plating apparatus is filled with an electrolytic solution 2, and in this electrolytic solution 2, a metal electrode as a plating material connected to the anode side of a DC power source 3 having a current changeover switch 4. 5 and a U-shaped waveguide 6 as a work material connected to the cathode side are immersed. Examples of the electrolytic solution include silver, gold, copper, and nickel plating.
In the tube of the U-shaped waveguide 6, flexible auxiliary electrodes 7, 8 connected to the anode side and having a flexible bendable structure are inserted from both ends of the waveguide 6. The flexible auxiliary electrodes 7 and 8 are flexible electrode wires. When the flexible auxiliary electrodes 7 and 8 are inserted from the end of the waveguide 6, they enter the tube following the shape of the waveguide 6. Each of the flexible auxiliary electrodes 7 and 8 is inserted from both ends of the waveguide 6 to a position approximately half of the longitudinal direction of the waveguide 6 and overlaps in the vicinity of approximately the center in the longitudinal direction of the waveguide. Note that the two flexible auxiliary electrodes 7 and 8 inserted in the tube are insulated by an insulator ring 14 as an insulator described later, and the tips are not short-circuited.

In this plating apparatus, a reflux pump 9 is installed, and the electrolyte 2 sucked up by the suction side pipe 11 is transferred from the tip of the discharge side pipe 10 inserted into the inner surface of the waveguide 6 to the inner surface of the waveguide 6. Plating metal ions are supplied by supplying. The anode corresponds to the first electrode, and the cathode corresponds to the second electrode.
In FIG. 1, the electrolyte 2 sucked up by the suction side pipe 11 is supplied from the tip of the discharge side pipe 10 inserted into the inner surface of the waveguide 6 to the inner surface of the waveguide 6. The installation positions of the discharge side pipe 10 and the suction side pipe 11 of the pump 9 are switched so that the suction side pipe 11 sucks the electrolyte solution 2 from the inner surface side of the waveguide 6 and discharges it from the tip of the discharge side pipe 10. May be. In any case, the electrolytic solution 2 can circulate through the inside of the waveguide 6.

FIG. 2 is a cross-sectional view when the flexible auxiliary electrodes 7 and 8 are inserted and installed in the waveguide 6 (shown by dotted lines). The flexible auxiliary electrodes 7 and 8 are connected to the anode side, and an insulator ring 14 as an insulator is bonded at a predetermined interval.

As shown in FIGS. 1 and 2, an insulating ring 14 with the flexible auxiliary electrode 7 passed through is bonded to the flexible auxiliary electrodes 7 and 8 at a predetermined interval, for example, about 5 mm. The insulator ring 14 is, for example, a synthetic resin ring or a ceramic ring, and may be a ring made of an insulating material. This insulator ring 14 can prevent a short circuit between the metal parts of the flexible auxiliary electrodes 7 and 8 and the inner surface of the waveguide 6. In particular, in the bent portion that easily contacts the inner surface of the waveguide 6, the insulator ring 14 prevents a short circuit caused by the contact between the inner surface of the waveguide 6 and the metal portions of the flexible auxiliary electrodes 7 and 8. .

As shown in FIG. 1, the flexible auxiliary electrodes 7 and 8 are inserted from both sides of the waveguide 6 bent at one or more places to reduce a decrease in the amount of electricity due to a voltage drop at a site far from the DC power source. An appropriate current distribution is formed on the inner surface of the waveguide 6.

In addition, the flexible auxiliary electrodes 7 and 8 have insulating covers 12 and 13 at portions exposed outside the waveguide 6 and exposed to the electrolytic solution. The insulating covers 12 and 13 are made of a material such as polypropylene, for example, and prevent the current from flowing to the outside of the waveguide 6 which is close to the distance from the flexible auxiliary electrode exposed in the electrolytic solution. As a result, a current loss passing through the electrolyte on the inner surface of the waveguide 6 can be reduced, so that a sufficient amount of metal can be deposited on the inner surface of the waveguide 6 in a short time.
The insulating covers 12 and 13 preferably cover all the flexible auxiliary electrodes 12 and 13 exposed in the electrolytic solution. However, even if the flexible auxiliary electrodes are exposed in the electrolytic solution, the exposed portions are As shown in FIG. 2, it is better to be within about 10 mm from the end of the waveguide 6.

Further, the tips of the flexible auxiliary electrodes 7 and 8 are prevented from contacting the tips of the flexible auxiliary electrodes 7 and 8 and the inner surface of the waveguide 6, and the tips of the flexible auxiliary electrodes 7 and 8 are in contact with each other. In order to prevent this, an insulator ring 15 having a smaller diameter than the insulator ring 14 is provided.
The insulator ring 15 also serves to prevent the insulator ring 14 from falling off the flexible auxiliary electrodes 7 and 8.

As described above, according to the plating apparatus of the first embodiment, the flexible auxiliary electrode on the inner surface of the waveguide 6 is inserted from both sides of the opening of the waveguide 6 as described above. The voltage drop can be suppressed, and the amount of electricity passing through the electrolyte solution on the inner surface of the waveguide 6 can be made uniform.
Furthermore, by supplying the electrolytic solution 2 to the inner surface of the waveguide 6 from the tip of the discharge side pipe 10 inserted into the inner surface of the waveguide 6 by the reflux pump 9, the plating metal ion supply can be activated. .
Thereby, an appropriate current distribution is formed on the inner surface of the waveguide, and plating with a uniform thickness can be applied to the inner surface of the waveguide in a short time.

Next, a plating method using the present plating apparatus will be described with reference to the drawings.
As shown in FIG. 1, a direct current power source 3 having a current changeover switch 4 is disposed in the present plating apparatus, and the application state to the metal electrode 5 or the flexible auxiliary electrodes 7 and 8 is controlled.
FIG. 3 is a flowchart for explaining a plating process by the plating apparatus. First, in the initial stage of starting plating, the metal electrode 5 and the flexible auxiliary electrodes 7 and 8 are simultaneously applied in order to prevent substitution reaction between the metal to be plated on the waveguide 6 and the metal in the electrolytic solution (step S01). The outer surface and inner surface of the waveguide 6 are plated for a predetermined time (step S02).
Thereafter, in order to apply the plating intensively in a short time to the inner surface of the waveguide 6 where the plating thickness is usually reduced, a current is supplied only to the auxiliary electrodes 7 and 8 (step S03). The inner surface of the waveguide 6 is plated for a predetermined time (step S04).
As described above, the current flowing through the metal electrode 5 or the flexible auxiliary electrodes 7, 8 can be individually applied, or simultaneously applied to the metal electrode 5 and the flexible auxiliary electrodes 7, 8, so that the inner surface and the outer surface of the waveguide 6 can be applied. The film thickness ratio can be reduced.
In addition, when it is desired to apply a thick plating to the outside of the waveguide 6, it is only necessary to pass a current only through the metal electrode 5.

Embodiment 2. FIG.
In the second embodiment, an L-shaped waveguide is plated as an example of a waveguide having a through hole. FIG. 4 is a configuration diagram of a plating apparatus for plating the inner surface of the L-shaped waveguide according to the second embodiment.
In the second embodiment, an L-shaped waveguide 16 as a work material connected to the cathode side is immersed. Flexible auxiliary electrodes 7 and 8 connected to the anode side are inserted into the L-shaped waveguide 16 from both ends of the L-shaped waveguide 16. Each of the flexible auxiliary electrodes 7 and 8 inserted from both ends is inserted from one end of the waveguide 16 to a position approximately half the length of the tube of the L-shaped waveguide 16. It overlaps near the center in the longitudinal direction.

Further, in this plating apparatus, a reflux pump 9 is installed, and the electrolytic solution 2 sucked up by the suction side pipe 11 is guided from the tip of the discharge side pipe 10 inserted into the inner surface of the waveguide 6 to the waveguide 16. Plating metal ions are supplied by supplying the inner surface from the lower end. A filtration device (not shown) is installed under the plating apparatus, and the plating solution flows gently from the bottom to the top of the plating tank. The recirculation pump 9 supplies the electrolytic solution from the lower end of the waveguide 16 so as to follow the gentle flow.

As described above, according to the second embodiment, a uniform plating thickness can be formed on the inner surface of the waveguide even if the workpiece material is an L-shaped waveguide.

In the second embodiment, the workpiece material is an L-shaped waveguide, but it may be a workpiece material having a more complex bent structure. The flexible auxiliary electrode is inserted into the workpiece material in the shape of the workpiece material from both ends of the workpiece material, and can be plated with a uniform thickness on the inner surface of the workpiece material in a short time.

Embodiment 3 FIG.
In the first and second embodiments, the insulator ring 14 as shown in FIG. 2 is bonded to the flexible auxiliary electrodes 7 and 8 in the waveguide at predetermined intervals. However, instead of the insulator ring, an insulating material is used. A mesh may be placed around the lexible auxiliary electrode.

FIG. 5 is a cross-sectional view of the flexible auxiliary electrode of the third embodiment.
As shown in FIG. 5, the flexible auxiliary electrode 7 is made of an insulating material around the flexible auxiliary electrode 7 and includes a mesh-like mesh net 30. The mesh net 30 is made of rubber, for example, and has flexibility so that the flexible auxiliary electrode 7 can be inserted along the waveguide 6. A part of the mesh net 30 is fixed to the flexible auxiliary electrode 7 by an adhesive or the like.
Thereby, the short circuit with the metal part of the flexible auxiliary electrodes 7 and 8 and the inner surface of the waveguide 6 can be prevented also at the time of insertion. The mesh net 30 has a mesh shape, and an appropriate current distribution is formed on the inner surface of the waveguide 6 due to the gap.

As described above, according to the third embodiment, a net-like net is provided around the flexible auxiliary electrode 7, and the flexible auxiliary electrode is inserted from both ends of the waveguide, which is a work material, and installed in the waveguide. Thus, an appropriate current distribution is formed on the inner surface of the waveguide, and plating with a uniform thickness can be applied to the inner surface of the waveguide in a short time.

The present invention can be applied to all metal plating. In the first to third embodiments, the metal electrode and the auxiliary electrode as the plating material are connected to the anode side, and the workpiece material is connected to the cathode side. Even when the workpiece is connected to the anode (first electrode) side on the second electrode) side, the same effect is obtained. In the first and second embodiments, the waveguide is used as an example of the metal pipe as the work material. However, the work material is not limited to the waveguide as long as the structure has a through hole. It can also be applied to other metal pipes.

1 is a configuration diagram of a plating apparatus for plating an inner surface of a U-shaped waveguide according to Embodiment 1. FIG. 3 is a cross-sectional view of the flexible auxiliary electrode according to Embodiment 1. FIG. It is a flowchart explaining the plating process by this plating apparatus. FIG. 5 is a configuration diagram of a plating apparatus for plating an inner surface of a U-shaped waveguide according to a second embodiment. 6 is a cross-sectional view of a flexible auxiliary electrode according to Embodiment 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plating tank, 2 Electrolyte, 3 DC power supply, 4 Current changeover switch, 5 Metal electrode, 6 U-shaped waveguide, 7 Flexible auxiliary electrode, 8 Flexible auxiliary electrode, 9 Reflux pump, 10, 11 Metal pipe, 12, 13 Insulation cover, 14 Insulator ring, 15 Insulator ring (for preventing ring dropout), 16 L-shaped waveguide, 30 mesh net

Claims (7)

A plating tank filled with an electrolyte,
DC power supply,
In the plating tank, a metal electrode as a plating material connected to the first electrode side of the DC power supply,
In the plating tank, connected to the second electrode side of the DC power supply, a metal pipe having a through hole as a work material,
In the plating tank, connected to the first electrode side of the DC power supply, two auxiliary electrodes respectively inserted from both ends of the metal pipe and disposed inside the metal pipe,
A metal pipe plating apparatus comprising: 2. The auxiliary electrode according to claim 1, wherein each of the auxiliary electrodes is inserted from both ends of the metal pipe to a position approximately half the length of the pipe of the metal pipe and is disposed inside the metal pipe. Metal pipe plating equipment. The auxiliary electrode has an insulating cover at a portion exposed outside the metal pipe and exposed to the electrolytic solution, and a plurality of insulating rings are provided at predetermined intervals in the portion inside the metal pipe. The metal pipe plating apparatus according to claim 1, wherein: The auxiliary electrode has an insulating cover at a portion exposed outside the metal pipe and exposed to the electrolyte solution, and an insulating mesh-like net is provided at a portion inside the metal pipe. The metal pipe plating apparatus according to claim 1, wherein the apparatus is a metal pipe plating apparatus. The metal pipe plating apparatus according to any one of claims 1 to 4, further comprising a pump for circulating the electrolytic solution on an inner surface of the metal pipe. 6. The metal pipe plating apparatus according to claim 1, further comprising a changeover switch for switching a counterpart to which the DC power source is connected to the auxiliary electrode or both the metal electrode and the auxiliary electrode. A plating tank filled with an electrolytic solution, a DC power source, a metal electrode as a plating material connected to the first electrode side of the DC power source, and a plating electrode in the plating tank. A metal pipe connected to the second electrode side of the DC power source and having a through hole as a work material, and in the plating tank, connected to the first electrode side of the DC power source, Two auxiliary electrodes inserted from both ends and disposed inside the metal pipe, and a changeover switch for switching a partner to which the DC power source is connected to the auxiliary electrode or both the metal electrode and the auxiliary electrode A plating method for plating a metal pipe using a plating apparatus comprising:
A first step of connecting the DC power source to both the metal electrode and the auxiliary electrode, and plating the outer surface and the inner surface of the metal pipe for a predetermined time;
A metal pipe plating method comprising: a second step of connecting the DC power source only to the auxiliary electrode and plating the inner surface of the metal pipe for a predetermined time after the first step.

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