Plating equipment

Abstract

Provided is a plating apparatus with which the time required for plating is improved and unevenness in the thickness of the obtained plating film is minimized.　This plating apparatus comprises a plating tank storing a plating liquid, a cylindrical metal tube having a hollow part, a cylindrical mesh tube having a hollow part, and a second electrode, wherein: the metal tube is a first electrode; the mesh tube is produced from an insulating material; the metal tube, the mesh tube, and the second electrode are housed in the plating tank; the metal tube is disposed inside the hollow part of the mesh tube; a plating forming part is formed between the inner side of the mesh tube and the outer side of the metal tube; the second electrode is disposed on the outer side of the mesh tube; an upward flow lifting the plating liquid is generated inside the hollow part of the metal tube; and an object to be plated is lifted inside the hollow part of the metal tube by the upward flow of the plating liquid, is discharged to the outside of the metal tube, is stirred, then falls inside the plating forming part, and is plated through application of a current between the metal tube, i.e. the first electrode, and the second electrode during the descent of the object. There is an auxiliary electrode inside the plating part, the auxiliary electrode being electrically connected to the metal tube, i.e. the first electrode.

Description

Technical Field

[0001] The present invention relates to a plating apparatus.

Background Art

[0002] So-called jet plating apparatuses are widely used for forming external electrodes of electronic components and the like. Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2021-138999) discloses a jet plating apparatus.

[0003] The plating apparatus disclosed in Patent Document 1 includes a plating tank. Inside the plating tank, a metal tube (cathode) as a first electrode, a mesh tube (partition wall) made of an insulating material, and a second electrode (anode) are accommodated.

[0004] The metal tube is disposed inside the mesh tube, and a plating formation part is formed between the inside of the mesh tube and the outside of the metal tube. The plating formation part refers to a region (space) where plating is applied to the object to be plated. The second electrode is disposed outside the mesh tube.

[0005] An injection part is provided under the metal tube. The injection part is for generating an upward flow of the plating solution inside the metal tube. That is, in the apparatus disclosed in Patent Document 1, the injection part is a source for generating a jet flow in the plating solution.

[0006] The plating apparatus disclosed in Patent Document 1 accommodates a plating solution, an object to be plated (for example, a body of an electronic component, etc.), and a conductive medium in the plating tank. Further, insulating balls are accommodated as necessary to enhance the fluidity of the object to be plated.

[0007] The object to be plated, the medium, and the insulating balls ride on the upward flow of the plating solution generated inside the metal tube, rise inside the metal tube, are ejected outward from the upper end of the metal tube, and are agitated.

[0008] The agitated material to be plated, media, and insulating balls then accumulate on the upper side of the plating formation section. At this time, the plating formation section is already filled (accumulated) with other material to be plated, media, and insulating balls. The material to be plated, media, and insulating balls accumulated on the upper side of the plating formation section then gradually descend through the plating formation section. At this time, a current is applied between the metal tube, which is the first electrode, and the second electrode, causing a plating film to form on the plating formation region (the region where the base electrode, etc., is formed) on the surface of the material to be plated.

[0009] The object to be plated, along with the media and insulating balls, are extruded from the lower end of the plating section, then carried again by the rising flow of the plating solution generated inside the metal tube, rising through the metal tube, and ejected out from the upper end of the metal tube, where they are agitated. The object to be plated is circulated through the plating apparatus several to several thousand times until the desired plating film thickness is reached.

[0010] The media plays a role in electrically connecting the metal tube, which is the first electrode, and the plating area on the surface of the object to be plated during the plating process in the plating formation section. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2021-138999 [Overview of the project] [Problems that the invention aims to solve]

[0012] In the plating process, the quantity (volume) and dimensions of the media are adjusted as appropriate according to the desired state of the plated film.

[0013] When the quantity of media is small, the diameter of the media is small, or the plating area on the surface of the object to be plated is small, the electrical connection between the metal tube, which is the first electrode, and the plating area of ​​the object to be plated may not be sufficient. If the electrical connection between the metal tube, which is the first electrode, and the plating area of ​​the object to be plated is not sufficient, it may take a long time to reach the planned plating film thickness, or the thickness of the deposited plating film may vary among the objects to be plated.

[0014] Therefore, increasing the quantity of media is considered, but increasing the quantity of media may cause the electric field to be shielded by the media, which could lead to longer film deposition times or variations in plating thickness.

[0015] Therefore, the present invention aims to solve the above-mentioned conventional problems and provide a plating apparatus that improves the time required for plating and suppresses variations in the thickness of the formed plating film. [Means for solving the problem]

[0016] A plating apparatus according to one embodiment of the present invention, in order to solve the above-mentioned conventional problems, comprises a plating tank for storing a plating solution, a cylindrical metal tube having a hollow portion which is a first electrode, a cylindrical mesh tube having a hollow portion made of an insulating material, and a second electrode, wherein the metal tube, the mesh tube, and the second electrode are each housed in the plating tank, the metal tube is placed inside the hollow portion of the mesh tube, a plating forming section is formed between the inside and outside of the mesh tube, the second electrode is placed outside the mesh tube, an upward flow is generated in the hollow portion of the metal tube to raise the plating solution, the object to be plated rises through the hollow portion of the metal tube on the upward flow of the plating solution, is discharged to the outside of the metal tube, is stirred, and then descends through the plating forming section, and is plated by applying an electric current between the metal tube, which is the first electrode, and the second electrode during the descent, wherein an auxiliary electrode electrically connected to the metal tube, which is the first electrode, is provided in the plating form section.

Advantages of the Invention

[0017] In the plating apparatus according to one embodiment of the present invention, since the auxiliary electrode assists the electrical connection between the metal tube as the first electrode and the plating formation region of the object to be plated, the time until the desired plating thickness is reached is improved.

[0018] Also, in the plating apparatus according to one embodiment of the present invention, since the auxiliary electrode assists the electrical connection between the metal tube as the first electrode and the plating formation region of the object to be plated, and a uniform current is supplied to the plating formation region, the thickness variation of the formed plating film is suppressed.

Brief Description of the Drawings

[0019] [Figure 1] It is a cross-sectional view of the plating apparatus 100 according to the first embodiment. [Figure 2] It is a cross-sectional view of the plating apparatus 100, showing the portion indicated by the dashed-dotted arrow A-A in FIG. 1. [Figure 3] FIG. 3(A) is a front view of the main part of the metal tube 2 and the auxiliary electrode 15 of the plating apparatus 100. FIG. 3(B) is a cross-sectional view of the main part of the metal tube 2 and the auxiliary electrode 15 of the plating apparatus 100. FIG. 3(C) is a plan view of the main part of the metal tube 2 and the auxiliary electrode 15 of the plating apparatus 100. [Figure 4] FIG. 4(A) is a front view of the main part of the metal tube 2 of the plating apparatus 1100 according to the comparative example. FIG. 4(B) is a cross-sectional view of the main part of the metal tube 2 of the plating apparatus 1100. FIG. 4(C) is a plan view of the main part of the metal tube 2 of the plating apparatus 1100. [Figure 5] FIG. 5(A) is a graph showing the distribution (frequency) of the thickness of the plating film of Example 1 in Experiment 1. FIG. 5(B) is a graph showing the distribution (frequency) of the thickness of the plating film of Comparative Example 1 in Experiment 1. [Figure 6] It is a graph showing the thickness variation of the plating films of Example 1 and Comparative Example 1 in Experiment 1. [Figure 7] It is a front view of the main part of the plating apparatus 200 according to the second embodiment. [Figure 8] FIG. 8(A) is a cross-sectional view of the main part of the plating apparatus 200A. FIG. 8(B) is a cross-sectional view of the main part of the plating apparatus 200B. FIG. 8(C) is a cross-sectional view of the main part of the plating apparatus 200C. [Figure 9] It is a graph showing the variation in the thickness of the plating films of Example 21, Example 22, and Example 23 in Experiment 2.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0021] Each embodiment illustratively shows an embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Also, it is possible to combine the contents described in different embodiments and implement them, and the implementation content in that case is also included in the present invention. Further, the drawings are for assisting in understanding the specification, and may be drawn schematically, and the ratio of the drawn components or the dimensions between the components may not match the ratio of those dimensions described in the specification. Also, there may be cases where the components described in the specification are omitted in the drawings or the number is omitted in the drawing.

[0022] [First Embodiment] FIGS. 1, 2, and 3(A) to (C) show the plating apparatus 100 according to the present embodiment. However, FIG. 1 is a cross-sectional view of the plating apparatus 100. FIG. 2 is also a cross-sectional view of the plating apparatus 100 and shows the A-A portion indicated by the dashed-dotted arrow in FIG. 1. FIG. 3(A) is a front view of the main part showing the metal tube 2 and the auxiliary electrode 15, which will be described later, of the plating apparatus 100. FIG. 3(B) is a cross-sectional view of the main part of the metal tube 2 and the auxiliary electrode 15. FIG. 3(C) is a plan view of the main part of the metal tube 2 and the auxiliary electrode 15.

[0023] The plating apparatus 100 includes a plating tank 1. The plating tank 1 is open at the top. The plating tank 1 is for storing a mixture 16 of the plating solution, the object to be plated, and the media, which will be described later. Insulating balls may be added to the mixture 16 as needed to increase the fluidity of the object to be plated.

[0024] The plating apparatus 100 includes a cylindrical metal tube 2 inside the plating tank 1. The metal tube 2 has a hollow section 2a. The metal tube 2 is the first electrode, and in this embodiment, it is the cathode electrode. In this embodiment, the metal tube 2 is cylindrical. However, the metal tube 2 may be a polygonal tube. The material of the metal tube 2 is arbitrary, and various metals can be used. The dimensions of the metal tube 2, such as the outer diameter, inner diameter, and length, are arbitrary and can be set as appropriate.

[0025] In this embodiment, as shown in Figure 3, two conductive, rod-shaped support portions 2b are formed integrally with the upper part of the metal tube 2. However, the number of support portions 2b is arbitrary; there may be one or more than two.

[0026] The plating apparatus 100 includes a mesh tube 3 made of an insulating material inside the plating tank 1. The mesh tube 3 has a hollow section 3a. In this embodiment, the mesh tube 3 is cylindrical. However, the mesh tube 3 may be polygonal. The mesh tube 3 is formed in a mesh (network) shape that allows the plating solution to pass through but prevents the object to be plated, the media, and the insulating ball from passing through. The material of the mesh tube 3 is arbitrary; for example, various resins can be used. The dimensions of the mesh tube 3, such as the outer diameter, inner diameter, and length, are arbitrary and can be set as appropriate.

[0027] The inner diameter of the mesh tube 3 is larger than the outer diameter of the metal tube 2. The metal tube 2 is positioned within the hollow portion 3a of the mesh tube 3. A plating area 4 is formed between the inside of the mesh tube 3 and the outside of the metal tube 2. The plating area 4 is the region (space) where plating is applied to the object to be plated. In Figures 1 and 2, the plating area 4 is depicted as a shaded area. The area between the outer diameter of the metal tube 2 and the inner diameter of the mesh tube 3 is the plating area 4. The dimensions of the plating area 4, such as its length, are arbitrary and can be set as appropriate.

[0028] The object to be plated, the media, and the insulating balls accumulate inside the plating forming section 4 and gradually descend downwards. During this descent, the surface of the object to be plated is plated.

[0029] The plating apparatus 100 includes a second electrode 5 inside the plating tank 1. In this embodiment, the second electrode 5 is an anode electrode. In this embodiment, the second electrode 5 is made of a cylindrical metal. The second electrode 5 is located outside the mesh tube 3. The material of the second electrode 5 is arbitrary, and various metals can be used.

[0030] As shown in Figure 2, the plating apparatus 100 is arranged concentrically such that, when viewed in a planar direction, the metal tube 2, the mesh tube 3, and the second electrode 5 coincide with their respective central axes. Therefore, in the plating apparatus 100, a uniform current is applied between the first electrode, the metal tube 2, and the second electrode 5 in any region of the plating formation section 4, thereby suppressing variations in the thickness of the formed plating film.

[0031] The plating apparatus 100 is equipped with a spray unit 6 below the metal pipe 2. The spray unit 6 is equipped with a spray nozzle 6a. The spray nozzle 6a sprays the plating solution toward the hollow section 2a of the metal pipe 2, generating an upward flow of the plating solution inside the hollow section 2a.

[0032] The plating apparatus 100 is equipped with a circulation line 7 formed of pipes. One end of the circulation line 7 is connected to a liquid intake port 8 formed in the plating tank 1. The other end of the circulation line 7 is connected to the nozzle 6a of the spray unit 6. A pump 9 and a filter 10 are provided in the middle of the circulation line 7. When the pump 9 is driven, the circulation line 7 draws in the plating solution from the liquid intake port 8 and sprays the plating solution from the nozzle 6a.

[0033] The plating apparatus 100 is equipped with a mixing section 11 below the metal pipe 2 and mesh pipe 3, and above the spray section 6. The mixing section 11 is the region where the plating solution sprayed from the nozzle 6a of the spray section 6 is mixed with the object to be plated, media, and insulating balls that have descended from the plating forming section 4. In this embodiment, the mixing section 11 is made of an insulating material, and an inverted frustoconical recess is formed on its upper surface. An inverted frustoconical is a frustoconical shape in which the upper base is larger than the lower base. However, the shape of the recess is arbitrary, and instead of an inverted frustoconical shape, it may be mortar-shaped or the like. The spray section 6 is formed on the bottom surface of the recess of the mixing section 11.

[0034] The plating apparatus 100 is equipped with a guide section 12 above the metal tube 2 and the mesh tube 3. The guide section 12 is a region where the workpiece, media, and insulating balls, which are agitated and then guided to the plating forming section 4 after rising on the upward flow of the plating solution formed inside the hollow section 2a of the metal tube 2 by the injection from the nozzle 6a of the injection section 6 and discharged (ejected) from the upper opening of the hollow section 2a of the metal tube 2, are agitated. The guide section 12 is made of an insulating material and has an inverted truncated cone shape. The upper end of the metal tube 2 protrudes from the bottom surface of the guide section 12. The upper end of the hollow section 2a of the metal tube 2 opens to the bottom surface of the guide section 12. The bottom surface of the guide section 12 is connected to the mesh tube 3.

[0035] The plating apparatus 100 is equipped with an insulating reflector 13 above the opening of the plating tank 1. The reflector 13 is sometimes called a deflector. The reflector 13 plays a role in suppressing the scattering of the plating solution. A support portion 2b for the metal pipe 2 is attached to the lower surface of the reflector 13. A cylindrical suppression plate 13a is also formed on the lower surface of the reflector 13. The suppression plate 13a is located inside the guide section 12. The plating solution may overflow from the upper edge of the guide section 12, but the suppression plate 13a prevents only the plating solution from overflowing from the guide section 12, thus preventing the workpiece, media, and insulating balls from overflowing.

[0036] The plating apparatus 100 is equipped with a power supply 14. One line of the power supply 14 is connected to the support portion 2b of the metal tube 2, which is the first electrode, and the other line is connected to the second electrode 5. The power supply 14 applies current between the metal tube 2, which is the first electrode, and the second electrode 5.

[0037] The plating apparatus 100 is provided with an auxiliary electrode 15, which is an important component in the present invention, within the plating forming section 4. The auxiliary electrode 15 is electrically connected to the metal tube 2, which is the first electrode. The auxiliary electrode 15 plays a role in assisting the metal tube 2, which is the first electrode, when plating is applied to the object to be plated in the plating forming section 4. More specifically, when plating is applied to the object to be plated in the plating forming section 4, the metal tube 2, which is the first electrode, and the plating forming area of ​​the object to be plated are electrically connected via a conductive path formed by multiple media. However, since the plating apparatus 100 is equipped with an auxiliary electrode 15 electrically connected to the metal tube 2, which is the first electrode, the number of power supply points is increased, and the electrical connection between the metal tube 2, which is the first electrode, and the plating forming area of ​​the object to be plated is made more reliable.

[0038] In this embodiment, the auxiliary electrode 15 is plate-shaped. However, the shape of the auxiliary electrode 15 is arbitrary and not limited to a plate shape. The auxiliary electrode 15 may be, for example, rod-shaped, block-shaped, or the like.

[0039] In this embodiment, the auxiliary electrode 15 is triangular in shape. However, the auxiliary electrode 15 is not limited to a triangular shape; for example, it may be rectangular in shape.

[0040] In this embodiment, the auxiliary electrode 15 is attached to the outside of the metal tube 2, which is the first electrode, and is electrically connected to the metal tube 2. The triangular plate-shaped auxiliary electrode 15 is attached to the outside of the metal tube 2 with one side facing upwards and the vertex opposite that side facing downwards. Therefore, the auxiliary electrode 15 does not easily obstruct the passage of the object to be plated, the media, and the insulating balls through the plating formation section 4. That is, as you go from the top to the bottom of the plating formation section 4, the cross-sectional area of ​​the space excluding the part where the auxiliary electrode 15 is located increases, allowing the object to be plated, the media, and the insulating balls to pass through smoothly. Note that the auxiliary electrode 15 may not be attached to the metal tube 2, but may be suspended independently from, for example, a reflector 13.

[0041] In this embodiment, when viewed in a planar direction, four auxiliary electrodes 15 are arranged radially around the metal tube 2. Therefore, the auxiliary electrodes 15 can supply current evenly within the plating formation section 4. Note that the number of auxiliary electrodes 15 is not limited to four; it may be less than four or more than four.

[0042] In the first embodiment of the plating apparatus 100 having the above structure, the auxiliary electrode 15 assists in the electrical connection between the metal tube 2, which is the first electrode, and the plating formation area of ​​the object to be plated, thereby shortening (improving) the time required to reach the desired plating thickness.

[0043] Furthermore, in the plating apparatus 100 according to the first embodiment, the auxiliary electrode 15 assists in the electrical connection between the metal tube 2, which is the first electrode, and the plating formation area of ​​the object to be plated, and a uniform current is supplied to the plating formation section 4, thereby suppressing variations in the thickness of the formed plating film.

[0044] (Example of use of plating apparatus 100) The following is an example of a plating process using the plating apparatus 100.

[0045] First, the desired plating solution is poured into plating tank 1.

[0046] Next, the objects to be plated, media, and insulating balls, each with a desired shape, dimensions, and quantity, are placed into the guide section 12 within the plating tank 1. The order in which the plating solution is added and the objects to be plated, media, and insulating balls are added may be reversed. The added objects to be plated, media, and insulating balls accumulate in the plating forming section 4.

[0047] Next, the pump 9 is activated to spray the plating solution from the nozzle 6a of the spray unit 6. As a result, an upward flow of the plating solution is generated inside the metal tube 2. Then, some of the material to be plated, media, and insulating balls that had accumulated inside the plating forming unit 4 are taken out from the lower end of the plating forming unit 4 to the mixing unit 11, mix with the sprayed plating solution, and rise up the inside of the metal tube 2 carried by the upward flow.

[0048] The plated material, media, and insulating balls that have risen inside the metal tube 2 are ejected out from the upper end of the metal tube 2 and agitated.

[0049] The stirred material to be plated, media, and insulating balls are deposited on top of other material to be plated, media, and insulating balls that have already been deposited in the plating forming section 4.

[0050] The newly deposited material to be plated, media, and insulating balls gradually descend as a portion of the material to be plated, media, and insulating balls that had accumulated in the plating forming section 4 are taken out from the lower end of the plating forming section 4 and mixed in the mixing section 11. In this way, the material to be plated, media, and insulating balls circulate inside the plating apparatus 100.

[0051] Next, the power supply 14 is activated, and current is applied between the metal tube 2, which is the first electrode, and the second electrode 5. As a result, plating of the object to be plated is started in the plating forming section 4.

[0052] After a predetermined time has elapsed and a plating film of the desired thickness has been formed on the object to be plated, the power supply 14 is stopped, and the plating of the object to be plated is stopped. Subsequently, the pump 9 is stopped, and the circulation of the object to be plated, media, and insulating balls inside the plating apparatus 100 is stopped.

[0053] The plating process is completed by removing the objects to be plated, media, and insulating balls from plating tank 1, and then sorting the objects to be plated.

[0054] (Experiment 1) To confirm the effectiveness of the present invention, the following Experiment 1 was conducted.

[0055] For Example 1, the plating apparatus 100 described above was prepared.

[0056] In addition, a plating apparatus 1100 was prepared for Comparative Example 1. As shown in Figures 4(A) to (C), the auxiliary electrode 15 that was attached to the metal tube 2 of the plating apparatus 100 was omitted from the plating apparatus 1100 (it was designed without the auxiliary electrode 15). The other structures of the plating apparatus 1100 were the same as those of the plating apparatus 100.

[0057] In addition, the length of the plating forming section 4 was set to 220 mm in both the plating apparatus 100 and the plating apparatus 1100.

[0058] Mixtures of the object to be plated, media, and insulating balls were prepared for Example 1 and Comparative Example 1, respectively. The composition and mixing amounts of the mixtures for Example 1 and Comparative Example 1 were the same.

[0059] The total volume of the material to be plated, media, and insulating balls was 1720 cc. The mixing ratio was 1376 cc (80 vol%) for the material to be plated, 86 cc (5 vol%) for the media, and 258 cc (15 vol%) for the insulating balls.

[0060] The same plating solution was prepared for both Example 1 and Comparative Example 1.

[0061] In Example 1, plating was performed on an object to be plated for 210 minutes using the plating apparatus 100, the above mixture, and the above plating solution. The magnitude of the applied current was 0.17 A / dm 2 The plating solution flow rate was set to 85 L / min. However, the plating apparatus 1100 was stopped 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes, and 210 minutes after the start of plating, and 30 objects to be plated were removed and the thickness of the formed plating film was measured.

[0062] In Comparative Example 1, the plating apparatus 1100, the above mixture, and the above plating solution were similarly used to perform plating on the object to be plated for 210 minutes. The magnitude of the applied current was 0.17 A / dm 2 The plating solution flow rate was set to 85 L / min. Similarly, the plating apparatus 1100 was stopped 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes, and 210 minutes after the start of plating. Thirty objects to be plated were removed at each of these times, and the thickness of the formed plating film was measured.

[0063] Details of Example 1 and Comparative Example 1 are shown in Table 1. [Table 1]

[0064] Figure 5(A) shows the distribution (frequency) of the thickness of the plating film deposited on 30 objects to be plated 60 minutes after the start of plating in Example 1. Figure 5(B) shows the distribution (frequency) of the thickness of the plating film deposited on 30 objects to be plated 60 minutes after the start of plating in Comparative Example 1.

[0065] As can be seen by comparing Figure 5(A) and Figure 5(B), the plating film thickness in Example 1 tends to be generally larger than that in Comparative Example 1.

[0066] Thus, it was confirmed that by attaching the auxiliary electrode 15 to the metal tube 2 of the plating apparatus 100, the electrical connection between the metal tube 2 and the plating formation area of ​​the object to be plated is assisted by the auxiliary electrode 15, and the rate of film formation of the plating film is improved.

[0067] Figure 6 shows the variation (CV(%)) in the thickness of the plated film for Example 1 and Comparative Example 1, respectively, after 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes, and 210 minutes from the start of plating.

[0068] As can be seen from Figure 6, Example 1 shows less variation overall. At 60 minutes, 90 minutes, 120 minutes, and 150 minutes after the start of plating, Example 1 shows less variation than Comparative Example 1. Comparative Example 1 shows particularly large variation at 60 minutes after the start of plating. At 180 minutes and 210 minutes, Example 1 and Comparative Example 1 show similar levels of variation.

[0069] Thus, it was confirmed that by attaching the auxiliary electrode 15 to the metal tube 2 of the plating apparatus 100, the auxiliary electrode 15 assists in the electrical connection between the metal tube 2 and the plating formation region of the object to be plated, a uniform current is supplied to the plating formation region, and variations in the thickness of the deposited plating film are suppressed.

[0070] As described above, the present invention exhibits unique and excellent effects.

[0071] [Second Embodiment] A plating apparatus 200 according to the second embodiment was fabricated. The plating apparatus 200 is a modified version of the plating apparatus 100 according to the first embodiment.

[0072] Specifically, in the plating apparatus 100, four triangular auxiliary electrodes 15 were attached to the outside of the metal tube 2, which was the first electrode. The plating apparatus 200 modified this, and as shown in Figure 7, removed the four auxiliary electrodes 25 from the metal tube 2 and independently suspended them into the plating forming section 4 by conductive, rod-shaped support parts 25b. In addition, the shape of the auxiliary electrodes 25 was changed from triangular plates to rectangular plates. The tips of the support parts 25b of the auxiliary electrodes 25 are each attached, for example, to the lower surface of the reflector 13.

[0073] The auxiliary electrode 25 is electrically connected to the metal tube 2, which is the first electrode, via the support portion 25b. The auxiliary electrode 25 assists the metal tube 2, which is the first electrode, and plays a role in increasing the number of power supply points.

[0074] The arrangement of the four auxiliary electrodes 15 was determined in three ways, as shown in Figures 8(A), (B), and (C). Figures 8(A), (B), and (C) are cross-sectional views of the main parts of the plating apparatus 200, respectively. The one shown in Figure 8(A) is the plating apparatus 200A, the one shown in Figure 8(B) is the plating apparatus 200B, and the one shown in Figure 8(C) is the plating apparatus 200C. The plating apparatus 200 shown in Figure 7 corresponds to the plating apparatus 200B.

[0075] The plating apparatus 200A has four auxiliary electrodes 25 positioned on the metal tube 2 side. The four auxiliary electrodes 25 are arranged radially around the metal tube 2. The auxiliary electrodes 25 may be in contact with the metal tube 2, or they may be separated by a small gap.

[0076] In the plating apparatus 200B, four auxiliary electrodes 25 are positioned between the metal tube 2 and the mesh tube 3. The four auxiliary electrodes 25 are arranged radially with the metal tube 2 as the center.

[0077] The plating apparatus 200C has four auxiliary electrodes 25 positioned on the mesh tube 3 side. Each of the four auxiliary electrodes 25 is positioned parallel to the mesh surface of the mesh tube 3.

[0078] (Experiment 2) Experiment 2, described below, was conducted to compare the performance of plating equipment 200A, 200B, and 200C.

[0079] Plating apparatus 200A was used in Example 21. Plating apparatus 200B was used in Example 22. Plating apparatus 200C was used in Example 23.

[0080] For Example 21, Example 22, and Example 23, the same mixtures of the object to be plated, media, and insulating balls used in Experiment 1 (Example 1 and Comparative Example 1) were prepared, respectively. The mixing ratios and quantities for Example 21, Example 22, and Example 23 were all the same.

[0081] For Example 21, Example 22, and Example 23, the same plating solution used in Experiment 1 was prepared for each.

[0082] In Examples 21, 22, and 23, the above mixture and the above plating solution were used to plate the object to be plated for 210 minutes. The magnitude of the applied current was 0.17 A / dm 2 The plating solution flow rate was set to 85 L / min. Then, as in Experiment 1, the plating apparatus 1100 was stopped 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes, and 210 minutes after the start of plating. Thirty objects to be plated were removed at each of these times, and the thickness of the deposited plating film was measured.

[0083] Details of Examples 21, 22, and 23 are shown in Table 2, respectively.

[0084] [Table 2]

[0085] Figure 9 shows the variation in plating film thickness (CV(%)) for Examples 21, 22, and 23 after 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes, and 210 minutes from the start of plating.

[0086] As can be seen from Figure 9, the variation in Example 21, in which the four auxiliary electrodes 25 are placed on the metal tube 2 side, is generally smaller. Example 21 shows less variation at 60 minutes, 90 minutes, 120 minutes, and 150 minutes after the start of plating than Example 22, in which the four auxiliary electrodes 25 are placed between the metal tube 2 and the mesh tube 3, and Example 23, in which the four auxiliary electrodes 25 are placed on the mesh tube 3 side. Furthermore, Example 22, in which the four auxiliary electrodes 25 are placed between the metal tube 2 and the mesh tube 3, shows less variation overall than Example 23, in which the four auxiliary electrodes 25 are placed on the mesh tube 3 side. Example 22 shows less variation at 60 minutes, 90 minutes, 120 minutes, and 180 minutes after the start of plating than Example 23.

[0087] Based on the above, it was found that when the auxiliary electrode 25 is placed in the plating forming section 4, placing it as close as possible to the metal tube 2, which is the first electrode, rather than the mesh tube 3, can suppress variations in the thickness of the plating film.

[0088] The plating apparatus 100 and plating apparatus 200 (plating apparatus 200A, 200B, and 200C) according to the embodiment have been described above. However, the present invention is not limited to the above-described content, and various modifications can be made in accordance with the spirit of the invention.

[0089] For example, in the above embodiment, the number of auxiliary electrodes 15 and 25 was set to 4, but the number of auxiliary electrodes 15 and 25 is arbitrary and may be less than 4 or more than 4.

[0090] Furthermore, in the above embodiment, the auxiliary electrodes 15 and 25 were made into triangular or rectangular plates, but the shape of the auxiliary electrodes 15 and 25 is arbitrary and may be other shapes.

[0091] The plating apparatus according to one embodiment of the present invention is as described in the "Means for Solving the Problem" section.

[0092] In this plating apparatus, it is also preferable that the first electrode is the cathode electrode and the second electrode is the anode electrode.

[0093] Furthermore, it is preferable that the auxiliary electrode is attached to the outside of the metal tube and electrically connected to the metal tube. In this case, the auxiliary electrode can be easily provided.

[0094] It is also preferable that the auxiliary electrode hangs down within the plating formation area. In this case, the auxiliary electrode can be placed at any position in the plating formation area.

[0095] It is also preferable that the auxiliary electrodes consist of multiple electrodes. In this case, the current can be supplied more uniformly to the plating area.

[0096] It is also preferable to have four auxiliary electrodes. In this case, the current can be supplied more uniformly to the plating area.

[0097] When viewed in a planar direction, it is also preferable that the auxiliary electrodes be arranged radially around the metal tube. In this case, current can be supplied more uniformly to the plating formation area.

[0098] It is also preferable that the auxiliary electrode be a metal plate. In this case, it is possible to suppress the auxiliary electrode from obstructing the passage of the plated object, media, insulating ball, or other plating-forming parts.

[0099] In this case, it is also preferable that the metal plate is triangular, with one side of the triangle facing upwards and the vertex opposite that side facing downwards, and that it is placed within the plating formation area. In this case, the auxiliary electrode can be less likely to obstruct the passage of the object to be plated, media, insulating balls, etc., through the plating formation area. However, the shape of the metal plate is arbitrary; for example, it may be a rectangular plate. [Explanation of Symbols]

[0100] 1. Plating tank 2. Metal tube (first electrode; cathode) 2a...Hollow part 2b...Support part 3. Mesh tube 3a...Hollow part 4. Plating formation section 5. Second electrode (anode) 6...Injection part 6a...Injection port 7. Circulation Line 8...Liquid suction port 9. Pump 10.. Filter 11...Mixing section 12...Guiding part 13. Reflector (deflector) 13a...Suppression plate 14...Power supply 15, 25...Auxiliary electrode 25a...Support part

Claims

1. A plating tank for storing the plating solution, The first electrode is a cylindrical metal tube having a hollow section, A cylindrical mesh tube having a hollow section, made of an insulating material, A second electrode is provided, The metal tube, the mesh tube, and the second electrode are each housed in the plating bath. The metal tube is placed inside the hollow portion of the mesh tube, and a plating portion is formed between the inside of the mesh tube and the outside of the metal tube. The second electrode is positioned on the outside of the mesh tube. An upward flow is generated within the hollow portion of the metal tube, causing the plating solution to rise. The object to be plated is, The metal tube rises through the hollow portion, carried by the upward flow of the plating solution. After being discharged outside the metal pipe and stirred, Descending through the aforementioned plating forming section, A plating apparatus in which, during the aforementioned descent, a current is applied between the metal tube which is the first electrode and the second electrode, thereby plating, Within the plating forming portion, an auxiliary electrode is provided, which is electrically connected to the metal tube that is the first electrode. Plating equipment.

2. The first electrode is a cathode electrode, The second electrode is the anode electrode. A plating apparatus as described in claim 1.

3. The auxiliary electrode is attached to the outside of the metal tube and electrically connected to the metal tube. A plating apparatus according to claim 1 or 2.

4. The auxiliary electrode is suspended within the plating formation portion. A plating apparatus according to claim 1 or 2.

5. The auxiliary electrode consists of a plurality of, A plating apparatus according to claim 1 or 2.

6. There are four auxiliary electrodes. A plating apparatus as described in claim 5.

7. When viewed in a planar direction, The auxiliary electrodes are arranged radially around the metal tube, A plating apparatus according to claim 1 or 2.

8. The auxiliary electrode is a metal plate. A plating apparatus according to claim 1 or 2.

9. The aforementioned metal plate is a triangular plate, With one side of the aforementioned triangle facing upwards and the vertex opposite to that side facing downwards, the following is placed within the plating forming section: A plating apparatus as described in claim 8.

10. The aforementioned metal plate is a rectangular plate. A plating apparatus as described in claim 8.

Images