Plating method for cylindrical workpieces

Abstract

To reduce the amount of plating deposition inside a cylindrical work.SOLUTION: In a plating method where a cylindrical work 30 both ends of which in an axial direction open is mounted to a power feeding clip 20 and immersed in a circulating plating solution to electroplate the cylindrical work 30, the mounting of the cylindrical work 30 to the power feeding clip 20 is conducted by inserting the power feeding clip 20 into the interior through one of the openings of the cylindrical work 30. The power feeding clip 20 is made of a folded metal plate and comprises a plurality of elastic contact segments 21, 22 that make an elastic contact with the inner surface of the cylindrical work 30 to hold the cylindrical work 30 and can feed power to the cylindrical work 30 and a restraint part 24 located inside the cylindrical work 30 and that restraints a flow of the plating solution in the axial direction. While restraining the flow of the plating solution inside the cylindrical work 30 by the restraint part 24, the cylindrical work 30 is electroplated.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a method for plating a cylindrical workpiece.

Background Art

[0002] Figs. 17 and 18 show the configuration and operation described in Patent Document 1 as a conventional example of a plating method. Fig. 17 shows a state where a workpiece is attached to an immersion fixture, and Fig. 18 shows the operation of immersing the immersion fixture in a predetermined liquid bath.

[0003] The workpiece is a bag-shaped workpiece in this example, and a bag nut 11 is shown as an example of the bag-shaped workpiece in Figs. 17 and 18. The immersion fixture 12 includes a metal main body shaft portion 13 that extends longitudinally in the lifting direction, and a plurality of support rod portions 14 that are connected in a branched manner at a predetermined interval from the main body shaft portion 13 so as to face obliquely upward. The bag nuts 11 are attached to these support rod portions 14 one by one. An elastic pressing portion 15 is fixed to the main body shaft portion 13 substantially parallel to the support rod portions 14 as shown in Fig. 17B. The bag nut 11 is inserted between these support rod portions 14 and the elastic pressing portion 15, and a large number of bag nuts 11 are held by the immersion fixture 12 in a tree shape as shown in Fig. 17A. Then, as shown in Fig. 18, in this state, it is immersed in a predetermined liquid bath 16 for electrolytic plating, and when the predetermined treatment is completed, the immersion fixture 12 is pulled up together with the treated bag nut 11 from the liquid bath 16.

[0004] Note that Patent Document 1 provides a relief passage for releasing the air trapped inside the bag-shaped workpiece to the outside in the immersion fixture 12, thereby enhancing the plating effect and efficiency on the inner surface of the bag-shaped workpiece.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As described above, in the plating method for the bag-shaped workpiece described in Patent Document 1, the plating on the inner surface of the workpiece can be performed well. However, depending on the workpiece, there may be cases where plating on the inner surface of the workpiece is not particularly required. In such cases, if the deposition amount of plating on the inner surface of the workpiece can be reduced, the plating material can be saved accordingly, and the cost can be reduced.

[0007] In view of such points, an object of the present invention is to provide a plating method that can reduce the deposition amount of plating inside a tubular workpiece, particularly in a tubular workpiece.

Means for Solving the Problems

[0008] According to the present invention, in a plating method for a tubular workpiece in which a tubular workpiece having openings at both ends in the axial direction is attached to a power supply clip and immersed in a circulating plating solution to perform plating on the tubular workpiece, the attachment of the tubular workpiece to the power supply clip is performed by inserting the power supply clip into the inside from one of the openings of the tubular workpiece. The power supply clip is made of a bent metal plate and includes a plurality of elastic contact pieces that can elastically contact the inner surface of the tubular workpiece to hold the tubular workpiece and supply power to the tubular workpiece, and a suppression portion that is located inside the tubular workpiece and suppresses the flow of the plating solution in the axial direction. The method has a step of performing plating on the tubular workpiece while suppressing the flow of the plating solution inside the tubular workpiece by the suppression portion.

Effects of the Invention

[0009] According to the present invention, the deposition amount of plating inside the tubular workpiece can be reduced, and thus the plating material can be saved accordingly.

Brief Description of the Drawings

[0010]

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Embodiments for Carrying Out the Invention

[0011] Embodiments of the present invention will be described by way of examples with reference to the drawings.

[0012] Fig. 1A shows a carrier used in an embodiment of a plating method for a cylindrical workpiece according to the present invention. The carrier 100 is long, and only a part thereof is shown in Fig. 1A. A large number of power supply clips 20 for attaching the cylindrical workpiece are arranged in a row at a predetermined pitch and integrally formed. The carrier 100 is formed, for example, by cutting a single metal plate such as a stainless steel plate into a predetermined shape and bending it. In Fig. 1A, 101 and 102 respectively indicate pilot holes.

[0013] FIG. 2 shows a partially enlarged view of a portion of the carrier 100 where one power supply clip 20 is located. The power supply clip 20 has a shape bent in a U shape in this example, and the portions forming both legs of the U shape function as elastic contact pieces 21 and 22, respectively. Contact portions 21a and 22a are formed on these two elastic contact pieces 21 and 22 so as to project outward from each other. Note that a notch 23 is provided in the portion forming the middle part of the U shape as shown in FIG. 2 in this example, and the middle part of this U shape functions as a suppression portion 24 for suppressing the flow of the plating solution as will be described later.

[0014] Plating of the cylindrical workpiece is performed by attaching the cylindrical workpiece to each power supply clip 20 of the carrier 100 and immersing it in the circulated plating solution. FIG. 1B shows a state where the cylindrical workpiece 30 is attached to each power supply clip 20. In this example, the cylindrical workpiece 30 is a stainless steel shell that is a component of the connector, and Ni plating is to be applied to this shell.

[0015] The attachment of the cylindrical workpiece 30 to the power supply clip 20 is performed by inserting the power supply clip 20 into the inside from one of the openings of the cylindrical workpiece 30 whose both ends in the axial direction are open. As a result, the two elastic contact pieces 21 and 22 of the power supply clip 20 elastically contact the two opposing inner surfaces of the cylindrical workpiece 30 so as to open outward from each other as shown in FIG. 3, and can hold the cylindrical workpiece 30 and supply power to the cylindrical workpiece 30. Note that since the contact portions 21a and 22a are provided so as to project outward from each other on the two elastic contact pieces 21 and 22, stable and good contact with the inner surface of the cylindrical workpiece 30 is enabled by these contact portions 21a and 22a.

[0016] The carrier 100 is operated by a driving device (not shown) to perform the required feeding and lifting operations. As described above, the carrier 100 sequentially experiences at least a mounting process of mounting the cylindrical workpiece 30 on each power supply clip 20, a plating process of passing the cylindrical workpiece 30 mounted on the power supply clip 20 through a plating tank containing a plating solution, and a recovery process of removing the plated cylindrical workpiece 30 from the power supply clip 20. By using such a carrier 100, continuous plating of the cylindrical workpiece 30 can be performed in this example.

[0017] In the plating process, a power supply is connected between the carrier 100 and an anode provided in the plating tank, a positive voltage is applied to the anode, and a negative voltage is applied to the carrier 100 to perform plating. The axial direction of the cylindrical workpiece 30 is, for example, the vertical direction, and it is immersed in the circulated plating solution. Here, as shown in FIG. 3B, the restraining portion 24 of the power supply clip 20 inserted inside the cylindrical workpiece 30 is positioned inside the cylindrical workpiece 30 so as to block a certain amount of space, so the axial flow of the plating solution is restrained by this restraining portion 24. As a result, in this example, the amount of plating deposition inside the cylindrical workpiece 30 is reduced.

[0018] In this way, in the plating process, in order to reduce the amount of plating deposition inside the cylindrical workpiece 30, plating is applied to the cylindrical workpiece 30 while restraining the flow of the plating solution inside the cylindrical workpiece 30 by the restraining portion 24 of the power supply clip 20. As a result, in this example, the plating material can be saved.

[0019] In addition, since the amount of plating deposition on the inner surface of the cylindrical workpiece 30 can be reduced, that is, even if the inner surface is plated, the thickness of the plating film on the inner surface can be made thinner, the amount of variation in film thickness is smaller than when the film thickness is large (thick), that is, the variation in the internal dimensions between each cylindrical workpiece 30 after plating can be reduced. This means that, for example, the assembly work can be performed well in an assembly process or the like after components are inserted into the cylindrical workpiece 30.

[0020] The suppression part 24 of the power supply clip 20 is sized to occupy an area that is 30% or more and 90% or less of the area of one or the other surface of the opening of the cylindrical workpiece 30 when viewed in the axial direction of the cylindrical workpiece 30.

[0021] Before mounting the cylindrical workpiece 30, the carrier 100 is, for example, wound around a reel. The carrier 100 is unwound from the reel, and the cylindrical workpiece 30 is mounted on each power supply clip 20 of the carrier 100, whereby the required plating process is executed.

[0022] FIG. 4A shows the processes in such a case by processes 41 to 47. The processes 41 to 47 are, in order, carrier unwinding from the reel, workpiece mounting, degreasing, plating, drying, workpiece recovery, and winding the carrier onto the reel. These processes 41 to 47 are so-called reel-to-reel plating processes. It is also possible to use an automatic machine for workpiece mounting in process 42 and workpiece recovery in process 46.

[0023] In the process shown in FIG. 4A, the carrier from which the workpiece has been removed is wound onto the reel in the final process 47. However, as in the processes 41 to 45 and 48 shown in FIG. 4B, it is also possible to wind the carrier onto the reel with the workpiece still attached without removing the workpiece in the final process 48. By doing so, it becomes a form suitable for automatically incorporating the plated cylindrical workpiece 30 into the product to be used.

[0024] FIG. 5A shows how the carrier is unwound from the reel in process 41 in FIGS. 4A and B. In the figure, 200 indicates the reel. FIG. 5B shows how the carrier with the workpiece is wound onto the reel in process 48 in FIG. 4B. In the figure, 300 indicates the reel.

[0025] The carrier 100 is in a closed loop shape, and it is also possible to make the carrier 100 circulate to perform continuous plating. FIG. 6 shows the steps in this case in order as steps 42 to 46 and 49. In this example, after the workpiece is recovered in step 46, the plating deposited on the carrier is removed in step 49. After this step 49, it returns to step 42 and the workpiece is mounted on the carrier again. The carrier 100 circulates in this way and repeatedly experiences steps 42 to 46 and 49.

[0026] The removal of the plating deposited on the carrier 100 in step 49 can be performed, for example, by immersing the carrier 100 in an electrolytic solution to cause an electrochemical reaction opposite to that of plating. The plating material removed from the carrier 100 is reused.

[0027] As described above, since the amount of plating deposited inside the cylindrical workpiece 30 is reduced by the suppression portion 24 of the power supply clip 20, it is also difficult for plating to adhere to the power supply clip 20. Therefore, for example, even in the process shown in FIG. 4A, in order to save the plating material, the operation of recovering the plating deposited on the carrier 100 is performed. However, since the amount of plating deposited is small, the operation of removing the plating from the carrier 100 to recover the plating material can also be performed, for example, after several plating steps, and in this regard, the recovery cost can be reduced.

[0028] The shape of the power supply clip provided on the carrier 100 is not limited to the shape shown in FIG. 2, and other shapes can also be adopted. FIGS. 7, 9, 11, 13, and 15 show other shape examples of the power supply clip, and FIGS. 8, 10, 12, 14, and 16 show the states in which the cylindrical workpiece is mounted on the power supply clips shown in FIGS. 7, 9, 11, 13, and 15, respectively.

[0029] The power supply clip 20' shown in FIG. 7 has a shape bent in a U shape, and the same reference numerals are given to the corresponding parts as the power supply clip 20 shown in FIG. 2. In this example, there is no notch in the middle part of the U shape forming the suppression portion 24, and two elastic contact pieces 21 and 22 are formed by both legs of the U shape.

[0030] The power supply clip 50 shown in Fig. 9 is composed of a suppression part 51 and two elastic contact pieces 52 and 53. When the suppression part 51 is inserted into the cylindrical workpiece 30', it is a flat plate part intersecting the axial direction of the cylindrical workpiece 30'. The two elastic contact pieces 52 and 53 are formed by extending in the insertion direction into the cylindrical workpiece 30' at a part where one side of the flat plate part is bent and extended.

[0031] The power supply clip 50' shown in Fig. 11 has the same structure as the power supply clip 50 shown in Fig. 9, including a suppression part 51 composed of a flat plate part and two elastic contact pieces 52 and 53 provided at a part where one side of the flat plate part is bent and extended. However, in this power supply clip 50', after the two elastic contact pieces 52 and 53 are extended in the insertion direction into the cylindrical workpiece as shown in Fig. 11A, they are bent outward and folded back toward the suppression part 51.

[0032] The power supply clip 20'' shown in Fig. 13 has the same U-shaped bent structure as the power supply clip 20 shown in Fig. 2, and two elastic contact pieces 21 and 22 are formed by the two legs of the U-shape. One of the elastic contact pieces 21 is trapezoidal with its width gradually decreasing toward its tip (free end). This trapezoidal part is slightly raised (bent) in a direction away from the other elastic contact piece 22, and a contact part 21a is formed at its tip.

[0033] A contact part 22a is formed on the other elastic contact piece 22 in the same way as the power supply clip 20 shown in Fig. 2. When this power supply clip 20'' is inserted into the cylindrical workpiece 30'', as shown in Figs. 14B and C, the contact part 21a and the edge parts 22b and 22c at both ends in the width direction of the contact part 22a contact the inner surface of the cylindrical workpiece 30''. Note that a notch 23 is provided in the suppression part 24 in the same way as the power supply clip 20.

[0034] The power supply clip 50” shown in Fig. 15 has the same structure as the power supply clip 50 shown in Fig. 9, and includes a suppression part 51 formed of a flat plate part and two elastic contact pieces 52 and 53. Further, this power supply clip 50” has a third elastic contact piece 54. The elastic contact piece 54 is formed between the elastic contact pieces 52 and 53 and is extended in the same manner as the elastic contact pieces 52 and 53. The middle part of the elastic contact piece 54 is bent so that it is slightly above the plate surface of the plate part 55 formed by bending and extending one side of the suppression part 51. This middle part functions as a contact part 54a.

[0035] On the other hand, the elastic contact pieces 52 and 53 are formed by extending obliquely downward from the plate part 55 as shown in Fig. 15, and contact parts 52a and 53a bent in an arc shape are respectively formed at the tips.

[0036] When this power supply clip 50” is inserted into the cylindrical workpiece 30’, the contact parts 52a, 53a and 54a come into contact with the inner surface of the cylindrical workpiece 30’ as shown in Figs. 16B and 16C.

[0037] As described above, other shape examples of the power supply clip have been explained. In any of these power supply clips 20’, 50, 50’, 20” and 50”, as shown in Figs. 8, 10, 12, 14 and 16 respectively, a plurality of elastic contact pieces elastically contact the inner surface of the cylindrical workpiece to hold the cylindrical workpiece and supply power to the cylindrical workpiece. Further, the suppression part is located inside the cylindrical workpiece and can suppress the flow of the plating solution.

Explanation of reference numerals

[0038] 11 Bag nut 12 Immersion holder 13 Main body shaft part 14 Support rod part 15 Elastic pressing part 16 Liquid tank 20, 20’, 20” Power supply clip 21, 22 Elastic contact piece 21a, 22a Contact part 22b, 22c Edge part 23 Notch 24 Suppression part 30, 30’, 30” cylindrical workpieces 50, 50’, 50” power supply clips 51 suppression part 52, 53, 54 elastic contact pieces 52a, 53a, 54a contact parts 55 plate part 100 carrier 101, 102 pilot holes 200, 300 reels

Claims

1. A method for plating a cylindrical workpiece, comprising mounting a cylindrical workpiece having open ends in the axial direction on a power supply clip and immersing the workpiece in a circulating plating solution to apply plating to the cylindrical workpiece, wherein the mounting of the cylindrical workpiece on the power supply clip is performed by inserting the power supply clip into the inside of the cylindrical workpiece from one of the openings of the cylindrical workpiece, the power supply clip is made of a bent metal plate, and includes a plurality of elastic contact pieces that can elastically contact the inner surface of the cylindrical workpiece to hold the cylindrical workpiece and supply power to the cylindrical workpiece, and a restraining portion that is located inside the cylindrical workpiece and suppresses the axial flow of the plating solution, the method having a step of applying plating to the cylindrical workpiece while suppressing the flow of the plating solution inside the cylindrical workpiece by the restraining portion, wherein, in the step, a closed-loop carrier having a plurality of the power supply clips arranged therein is used, and the method includes a mounting step of mounting the cylindrical workpiece on the power supply clip of the carrier, a plating step of passing the carrier with the cylindrical workpiece mounted on the power supply clip through a plating bath containing the circulating plating solution, a recovery step of removing the plated cylindrical workpiece from the power supply clip, and a plating removal step of removing the plating deposited on the carrier, and performing continuous plating in which at least the carrier sequentially experiences these steps as it circulates.

2. In the method for plating a cylindrical workpiece according to Claim 1, the plurality of elastic contact pieces are two elastic contact pieces, the power supply clip has a shape bent in a U shape, the restraining portion is constituted by the middle portion of the U shape, and the two elastic contact pieces are constituted by both legs of the U shape.

3. In the method for plating a cylindrical workpiece according to Claim 1, the plurality of elastic contact pieces are two elastic contact pieces, the power supply clip has a shape bent in a C shape, the restraining portion is constituted by the middle portion of the C shape, and the two elastic contact pieces are constituted by both legs of the C shape.

4. In the method for plating a cylindrical workpiece according to Claim 1, the restraining portion is a flat plate portion intersecting the axial direction, and the plurality of elastic contact pieces are provided at a portion where one side of the flat plate portion is bent and extended.

5. In the method for plating a cylindrical workpiece according to any one of claims 1 to 4, The plating method of a cylindrical workpiece, characterized in that the suppression portion has a size occupying an area of 30% or more and 90% or less of the area of one or the other of the openings when viewed in the axial direction.

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