Plating apparatus

Abstract

Provided is a plating apparatus with which, even when the flow amount of a plating solution sprayed from a spray unit is increased, there is no excessive rising of a material subject to plating to a high position within retained plating solution, and defects in the material subject to plating are inhibited from occurring.　This plating apparatus comprises a plating bath that retains a plating solution containing a material subject to plating, and a spray unit that is formed on the plating bath and that sprays the plating solution, the material subject to plating contained in the plating solution being stirred by the plating solution sprayed from the spray unit. The spray unit has an inner cylindrical shape having a bottom surface that expands in the horizontal direction, an inner wall that extends in the height direction from the bottom surface, and an opening formed at the upper end of the inner wall. The opening is a first spray port through which the plating solution is sprayed into the plating bath. A mesh member is provided to the first spray port. A second spray port through which the plating solution is sprayed into the spray unit is provided to the bottom surface. A flow rate control plate in which a plurality of holes are formed is provided, parallel to the bottom surface, at a location partway along the height direction of the spray unit. When viewed in a planar direction, the flow rate control plate has a center part and a periphery part provided to the outer side of the center part. The respective opening areas of the holes formed in the center part is less than the respective opening areas of the holes formed in the periphery part. A cylindrical member having a hollow part is provided between the flow rate control plate and the mesh member of the first spray port.

Description

Plating Equipment

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

[0002] So-called jet-type plating apparatuses are widely used for forming external electrodes of electronic components, etc. Patent Document 1 (JP 2021-138999 A) discloses a jet-type plating apparatus.

[0003] The plating apparatus disclosed in Patent Document 1 includes a plating tank. The plating tank contains a metal tube (cathode) that serves as a first electrode, a partition tube made of an insulating material, and a second electrode (anode). The partition tube has multiple small holes that allow the plating solution to pass through but not the object to be plated or media.

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

[0005] An injection unit having an injection port for injecting plating solution is provided below the metal pipe. The injection unit is for generating an upward flow of plating solution inside the metal pipe. Although not disclosed in the plating apparatus of Patent Document 1, the injection port of the injection unit is usually provided with a mesh member to prevent the object to be plated or media from falling into the injection unit when injection is stopped.

[0006] In the plating apparatus disclosed in Patent Document 1, a plating solution is contained in a plating tank. Subsequently, the object to be plated, conductive media, and, if necessary, insulating balls are added to the plating tank containing the plating solution. However, the plating solution may be added to the plating tank after the object to be plated, media, and insulating balls are added to the plating tank. The media serves to electrically connect the metal tube, which is the first electrode, to the plating formation region on the surface of the object to be plated (the region where the base electrode, etc., is formed) when plating the object to be plated in the plating formation section. The insulating balls serve to increase the fluidity of the object to be plated as it circulates through the plating apparatus.

[0007] The workpiece, media, and insulating balls are carried up inside the metal tube by the upward flow of plating solution generated by the injection from the injection section, and are ejected from the top end of the metal tube and agitated in the plating solution.

[0008] The stirred object to be plated, media, and insulating balls are then deposited on the upper side of the plating formation section. At this time, other object to be plated, media, and insulating balls are already deposited in the plating formation section. The object to be plated, media, and insulating balls that have deposited on the upper side of the plating formation section then gradually descend within the plating formation section. At this time, a current is applied between the metal tube, which is the first electrode, and the second electrode, forming a plating film in the plating formation region on the surface of the object to be plated.

[0009] The object to be plated, media, and insulating balls with the plating film formed thereon are pushed out from the bottom end of the plating formation section, and again ride the rising current of plating solution generated inside the metal pipe, rise inside the metal pipe, and are ejected from the top end of the metal pipe and stirred.Then, just like last time, the stirred object to be plated, media, and insulating balls are deposited on the top of the plating formation section, and then gradually descend inside the plating formation section, and during the descent, a plating film is formed on the object to be plated.

[0010] The object to be plated may be circulated through the plating apparatus several to several thousand times until the plating film reaches a predetermined thickness and the plating process is completed.

[0011] Japanese Patent Application Laid-Open No. 2021-138999

[0012] Plating on objects to be plated must satisfy the following (a) and (b): (a) A plating film having a thickness equal to or greater than a predetermined thickness must be formed on each object to be plated. (b) The thickness of the plating film formed among multiple objects plated simultaneously must have little variation (within a predetermined tolerance).

[0013] When the "total plating time" is defined as the time from the start of plating to the end of plating in one plating process (one lot), if the total plating time is constant, the thickness of the plating film formed on each object to be plated will be approximately the same even if the time required for the object to be plated to pass through the plating formation section once and the number of times the object to be plated passes through the plating formation section are changed. This is because the thickness of the plating film formed on each object to be plated depends on the total time each object to be plated passes through the plating formation section (the time required for one pass through the plating formation section multiplied by the number of passes). Naturally, when the total plating time is constant, if the time required for the object to be plated to pass through the plating formation section once is increased, the number of times the object to be plated passes through the plating formation section will decrease, and if the time required for the object to be plated to pass through the plating formation section once is decreased, the number of times the object to be plated passes through the plating formation section will increase.

[0014] On the other hand, when the total plating time is constant, shortening the time required for the objects to be plated to pass through the plating formation section once and increasing the number of times the objects to be plated circulate through the plating apparatus results in smaller variations in the thickness of the plating film formed among multiple objects to be plated than lengthening the time required for the objects to be plated to pass through the plating formation section once and decreasing the number of times the objects to be plated circulate through the plating apparatus. In other words, since the thickness of the plating film formed (grown) on the objects to be plated each time the objects to be plated pass through the plating formation section varies depending on conditions such as whether the objects to be plated pass near the metal pipe, near the partition pipe, or near the middle between the metal pipe and the partition pipe, increasing the number of passes to level out the thickness can reduce variations in the thickness of the plating film formed.

[0015] Considering the productivity of the plating process, it is preferable that the total plating time is short. In order to increase the number of times that the object to be plated passes through the plating formation section within the limited total plating time, it is sufficient to increase the flow rate of the plating solution sprayed from the spray section, and the flow rate of the plating solution sprayed from the spray section can be increased, for example, by increasing the output of the pump connected to the spray section.

[0016] However, increasing the flow rate of the plating solution sprayed from the spray unit can result in defects, such as cracks or chips on the object or peeling of the plating film formed on the object. This is thought to be because increasing the flow rate of the plating solution sprayed from the spray unit causes the object to rise too quickly up the metal tube (the first electrode), causing the object to rise to a high position in the plating solution stored in the plating tank and collide with a reflector called a deflector, or to collide with the inner wall of the plating tank or other objects as it descends (sinks) from a high position in the plating solution. Specifically, the object is discharged from the top of the metal tube along with the media and insulating balls to agitate them. However, if the force of the discharge is too great and the object rises to a high position in the plating solution, defects may occur.

[0017] Therefore, the present invention aims to provide a plating apparatus in which, even if the flow rate of plating solution sprayed from the spray section is increased, the object to be plated does not rise too high in the stored plating solution, thereby suppressing the occurrence of defects in the object to be plated.

[0018] In order to solve the above-mentioned conventional problems, one embodiment of the present invention provides a plating apparatus comprising: a plating tank for storing a plating solution containing an object to be plated; and an injection unit formed in the plating tank for injecting the plating solution, wherein the object to be plated is agitated by the plating solution sprayed from the injection unit. The injection unit has an inner cylindrical shape having a bottom surface extending horizontally, an inner wall extending vertically from the bottom surface, and an opening formed at the upper end of the inner wall. The opening is a first injection port for injecting the plating solution into the plating tank, a mesh member is provided at the first injection port, and a second injection port is provided at the bottom surface for injecting the plating solution into the injection unit. A flow rate control plate having a plurality of holes formed therein is provided midway along the height of the injection unit and parallel to the bottom surface, and the flow rate control plate has, when viewed in a plan view, a central portion and a peripheral portion provided outside the central portion, and a plurality of holes are formed in each of the central portion and the peripheral portion, and a cylindrical member having a hollow portion is provided between the flow rate control plate and the mesh member of the first injection port.

[0019] A plating apparatus according to one embodiment of the present invention can reduce the speed of plating solution passing through the central portion compared to the speed of plating solution passing through the peripheral portion by adjusting the size of each opening area of ​​the holes formed in the central portion and the holes formed in the peripheral portion, the total opening area per unit area of ​​multiple holes, and the number of holes per unit area.

[0020] As a result, in the plating apparatus according to one embodiment of the present invention, for example, when a cylindrical metal tube having a hollow portion is placed directly above the injection portion, the speed of the plating solution passing through the center of the metal tube is suppressed, so that even if the flow rate of the plating solution injected from the injection portion is increased, the object to be plated does not rise too high in the stored plating solution, and the occurrence of defects in the object to be plated is suppressed.

[0021] For example, the speed at which the plating solution passes (rises) inside the metal tube, which is the first electrode, is not uniform across the entire cross section of the metal tube, but is faster in the center of the metal tube and slower in the peripheral area closer to the inner wall of the metal tube. This is because resistance (frictional resistance) occurs in the peripheral area close to the inner wall of the metal tube, suppressing the speed of the plating solution.

[0022] Furthermore, in a case where an inner cylindrical injection part is provided on the bottom surface of the plating tank of the plating equipment, a first injection port is provided above the injection part, and a second injection port that injects plating solution into the injection part is provided on the bottom surface of the injection part, and the diameter of the second injection port is smaller than the inner diameter of the metal pipe, this may also cause the plating solution to move faster towards the center of the metal pipe and slower towards the periphery closer to the inner wall of the metal pipe.

[0023] On the other hand, when the flow rate of the plating solution sprayed from the spraying part is increased, not all of the objects to be plated sprayed out from the upper end of the metal pipe rise to a high position in the plating solution stored in the plating tank. The objects to be plated that rise to a high position in the plating solution stored in the plating tank are thought to be mainly objects that pass (rise) through the center of the metal pipe in one go, where the plating solution flows at a high speed.

[0024] In a plating apparatus according to one embodiment of the present invention, the speed of the plating solution passing through the center of the flow rate control plate is suppressed. For example, when a cylindrical metal tube with a hollow section is placed directly above the injection section, the speed of the plating solution passing through the interior of the metal tube is suppressed at the center of the metal tube. Therefore, even if the flow rate of the plating solution injected from the injection section is increased, the object to be plated does not rise too high in the stored plating solution, thereby suppressing the occurrence of defects in the object to be plated.

[0025] 5A is a cross-sectional view of the plating apparatus 100 according to the first embodiment. FIG. 5B is a plan view of the flow rate control plate 8′, which is a modified example of the flow rate control plate 8 of the plating apparatus 100, and the cylindrical member 10. FIG. 6A is a plan view of a mesh member 7′, which is a modified example of the mesh member 7 of the plating apparatus 100. FIG. 6B is a plan view of a mesh member 7″, which is a modified example of the mesh member 7 of the plating apparatus 100. FIG. 6B is a plan view of a mesh member 7″, which is a modified example of the mesh member 7 of the plating apparatus 100. FIG. 6C is a plan view of a main part of a plating apparatus 200 according to a second embodiment.

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] It should be noted that each embodiment exemplifies an embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Furthermore, it is possible to combine the contents described in different embodiments, and such combinations are also included in the present invention. Furthermore, the drawings are intended to facilitate understanding of the specification and may be drawn schematically, and the dimensional ratios of the depicted components or between the components may not match the dimensional ratios of those components described in the specification. Furthermore, components described in the specification may be omitted in the drawings, or the number of components may be omitted.

[0028] [First Embodiment] Figures 1, 2, 3, 4A, and 4B show a plating apparatus 100 according to a first embodiment. FIG. 1 is a cross-sectional view of the plating apparatus 100. Figure 2 is also a cross-sectional view of the plating apparatus 100, showing the A-A portion indicated by the dashed-dotted arrow in Figure 1. Figure 3 is a cross-sectional view of the main parts of the plating apparatus 100. Figure 4 is a perspective view of the main parts of the plating apparatus 100, showing the injection unit 6. Figure 5A is a plan view of the flow rate control plate 8 and the cylindrical member 10 of the plating apparatus 100. Figure 5B is a plan view of the cylindrical member 10 and a flow rate control plate 8', which is a modified version of the flow rate control plate 8.

[0029] The plating apparatus 100 includes a plating tank 1. The plating tank 1 is open at the top. The plating tank 1 is used to store a mixture 19 of a plating solution, an object to be plated, media, and insulating balls, which will be described later. However, the insulating balls can be omitted if not necessary.

[0030] The plating apparatus 100 includes a cylindrical metal tube 2 inside a plating tank 1. The metal tube 2 has a hollow portion 2a. The metal tube 2 is a first electrode, and in this embodiment, it is a cathode electrode. In this embodiment, the metal tube 2 is cylindrical. However, the metal tube 2 may also be polygonal cylindrical. 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.

[0031] In this embodiment, two rod-shaped conductive support parts 2b are formed integrally with the metal tube 2 on the upper part of the metal tube 2. However, the number of support parts 2b is arbitrary and is not limited to two.

[0032] The plating apparatus 100 includes a partition wall tube 3 made of an insulating material inside the plating tank 1. The partition wall tube 3 has a hollow portion 3a. In this embodiment, the partition wall tube 3 is cylindrical. However, the partition wall tube 3 may also be a polygonal cylindrical tube. The partition wall tube 3 has a plurality of small holes 3b formed therein that allow the plating solution to pass through but not the workpiece, media, or insulating balls. When a current is applied between the metal tube 2, which serves as the first electrode, and the second electrode 5, the holes 3b pass the current through the plating solution. The partition wall tube 3 may be made of any material, and may be made of, for example, various resins. The dimensions of the partition wall tube 3, such as the outer diameter, inner diameter, and length, may be any desired size and can be set appropriately.

[0033] The inner diameter of the partition wall pipe 3 is larger than the outer diameter of the metal pipe 2. The metal pipe 2 is disposed in the hollow portion 3a of the partition wall pipe 3. A plating-forming portion 4 is formed between the inside of the partition wall pipe 3 and the outside of the metal pipe 2. The plating-forming portion 4 is a region (space) where plating is applied to an object to be plated. Note that in Figures 1, 2, and 3, the plating-forming portion 4 is depicted as a crosshatched portion. The plating-forming portion 4 is the area between the outer diameter of the metal pipe 2 and the inner diameter of the partition wall pipe 3. The dimensions of the plating-forming portion 4, such as its length, are arbitrary and can be set as appropriate.

[0034] The object to be plated, the media, and the insulating balls are accumulated inside the plating forming section 4 and gradually descend downward. During this descent, the surface of the object to be plated is plated.

[0035] 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 disposed outside the partition tube 3. The second electrode 5 may be made of any material, and various metals may be used.

[0036] 2, in the plating apparatus 100, the metal tube 2, the partition tube 3, and the second electrode 5 are concentrically arranged so that their central axes coincide when viewed in a plan view. Therefore, in the plating apparatus 100, a current is applied uniformly between the metal tube 2, which is the first electrode, and the second electrode 5 in any region of the plating formation section 4, thereby suppressing variations in the thickness of the plating film that is formed.

[0037] The plating apparatus 100 includes a jet unit 6 below the metal tube 2. The jet unit 6 is used to generate an upward flow of plating solution inside the metal tube 2. In this embodiment, the jet unit 6 has an inner tubular shape with a bottom surface extending horizontally, an inner wall extending vertically from the bottom surface, and an opening formed at the upper end of the inner wall. In this embodiment, the inner tubular shape of the jet unit 6 is an inner cylinder. However, the inner tubular shape of the jet unit 6 is not limited to an inner cylinder and may be other shapes. The dimensions of the jet unit 6, such as the inner diameter and depth, are arbitrary and can be set as appropriate. The inner diameter of the jet unit 6 is preferably the same as the inner diameter of the metal tube 2, but there is no problem if they are different.

[0038] A first injection port 6a is formed in an opening formed at the upper end of the injection portion 6. The shape and dimensions of the first injection port 6a are arbitrary, but in this embodiment it is a circle with a diameter of 28 mm.

[0039] A second injection port 6b is formed on the bottom surface of the injection unit 6. The plating solution is injected from the second injection port 6b into the injection unit 6. The plating solution is injected from the first injection port 6a into the plating tank 1. In this embodiment, the opening area of ​​the second injection port 6b is smaller than the opening area of ​​the first injection port 6a.

[0040] Furthermore, when the inner diameter of the metal tube 2 is compared with the diameter of the second jet nozzle 6b, the diameter of the second jet nozzle 6b is smaller than the inner diameter of the metal tube 2. This also causes the plating solution to flow faster at the center of the metal tube 2, so measures to suppress the plating solution flow speed at the center of the metal tube 2 are required.

[0041] A mesh member 7 is provided at the first injection port 6a of the injection unit 6. The mesh member 7 is provided to prevent the object to be plated, media, insulating balls, etc. from falling into the injection unit 6 when the injection of the injection unit 6 is stopped. In this embodiment, since the first injection port 6a of the injection unit 6 is circular, the mesh member 7 is also circular when viewed in a planar direction.

[0042] In this embodiment, the mesh member 7 is entirely made up of a single layer of mesh with a mesh opening of 900 μm. However, as in mesh member 7' shown in FIG. 6(A) and mesh member 7" shown in FIG. 6(B), the mesh member may be made up of a mesh central portion 7a and a mesh peripheral portion 7b provided on the outside of the mesh central portion 7a, with the mesh central portion 7a made up of multiple layers (for example, two layers) of mesh and the mesh peripheral portion 7b made up of a single layer of mesh. In this case, the shape and dimensions of the mesh central portion 7a are preferably the same as the shape and dimensions of the central portion 8a of a flow velocity control plate 8 described later and the shape and dimensions of the inner diameter of a tubular member 10 described later, but there is no problem if they are different. The mesh central portion 7a of mesh member 7' is circular, while the mesh central portion 7a of mesh member 7" is rectangular.

[0043] The "opening" of a mesh is the distance between adjacent lines in a mesh where vertical and horizontal lines intersect (not including the wire diameter). The opening is sometimes called the opening (OP) or opening dimension. Generally, the opening refers to the opening of a single layer of mesh, but in the present application documents, when multiple meshes are stacked, it may refer to the overall opening of the multiple meshes. When comparing the opening of a single layer of mesh with the opening of two layers of that mesh stacked together (or the opening of that mesh stacked with another mesh), the latter is smaller (finer) than the former.

[0044] In the mesh members 7' and 7", the mesh openings in the central mesh portion 7a are smaller than those in the peripheral mesh portion 7b. Therefore, in the mesh members 7' and 7", the speed of the plating solution passing through the central mesh portion 7a is slower than the speed of the plating solution passing through the peripheral mesh portion 7b.

[0045] The mesh constituting the mesh members 7, 7', 7" may be made of any material, for example nylon. When using a plurality of overlapping mesh layers, the meshes may be joined together, for example with an adhesive, or may be overlapped and then the ends may be fixed.

[0046] In the plating apparatus 100, a flow rate control plate 8 is provided midway in the height direction of the spray unit 6, parallel to the bottom surface of the spray unit 6. As can be seen particularly from Figure 5(A), when viewed in a planar direction, the flow rate control plate 8 has a central portion 8a and a peripheral portion 8b provided outside the central portion 8a.

[0047] The shape and dimensions of the flow velocity control plate 8 are arbitrary, but in this embodiment it is a disk shape with a diameter of 28 mm. The shape and dimensions of the central portion 8a are also arbitrary, but in this embodiment it is a circle with a diameter of 20 mm.

[0048] The flow velocity control plate 8 may be made of any material, for example, vinyl chloride.

[0049] A plurality of holes 9 (9a, 9b) are formed in the flow velocity control plate 8, penetrating between both main surfaces. The holes 9 (9a, 9b) may have any shape, but in this embodiment, they are circular when viewed in a planar direction. If the holes 9 (9a, 9b) are circular, they can be easily formed by irradiating them with laser light or by drilling them.

[0050] In this embodiment, the opening area of ​​each of the holes 9 a formed in the central portion 8 a is smaller than the opening area of ​​each of the holes 9 b formed in the peripheral portion 8 b. Specifically, the diameter of each of the holes 9 a formed in the central portion 8 a is 1.2 mm, and the diameter of each of the holes 9 b formed in the peripheral portion 8 b is 3.0 mm.

[0051] In this embodiment, the pattern shape of the central portion 8a where the holes 9a are formed and the pattern shape of the peripheral portion 8b where the holes 9b are formed are similar. More specifically, multiple holes 9a with a diameter of 1.2 mm were formed in the central portion 8a in a matrix (checkerboard pattern) at predetermined intervals. Then, while maintaining this shape, the hole diameter, including the spacing between the holes, was enlarged until it reached a diameter of 3.0 mm. Holes 9b were then formed in the peripheral portion 8b using the enlarged spacing and diameter of the holes. Therefore, in this embodiment, the total opening area of ​​the multiple holes 9a per unit area in the central portion 8a is equal to the total opening area of ​​the multiple holes 9b per unit area in the peripheral portion 8b.

[0052] However, the total opening area of ​​the multiple holes 9a per unit area does not necessarily have to be equal to the total opening area of ​​the multiple holes 9b per unit area in the peripheral portion 8b. In order to more effectively suppress the speed of the plating solution passing through the central portion 8a, it is preferable that the total opening area of ​​the multiple holes 9a per unit area in the central portion 8a be smaller than the total opening area of ​​the multiple holes 9b per unit area in the peripheral portion 8b. However, conversely, even if the total opening area of ​​the multiple holes 9a per unit area in the central portion 8a is larger than the total opening area of ​​the multiple holes 9b per unit area in the peripheral portion 8b, the speed of the plating solution passing through the central portion 8a can be suppressed compared to the speed of the plating solution passing through the peripheral portion 8b as long as the opening area of ​​each hole 9a formed in the central portion 8a is sufficiently smaller than the opening area of ​​each hole 9b formed in the peripheral portion 8b.

[0053] In the flow rate control plate 8 of the plating apparatus 100 of this embodiment, the opening area of ​​each of the holes 9a formed in the central portion 8a is smaller than the opening area of ​​each of the holes 9b formed in the peripheral portion 8b. Therefore, the resistance to the plating solution passing through the central portion 8a is greater than the resistance to the plating solution passing through the peripheral portion 8b. Therefore, the speed of the plating solution passing through the central portion 8a is suppressed. That is, when a fluid such as plating solution passes through a hole, the smaller the opening area of ​​the hole, the greater the resistance to the fluid, and the larger the opening area of ​​the hole, the less the resistance to the fluid. By making the opening area of ​​each of the holes 9b formed in the peripheral portion 8b as large as possible and the opening area of ​​each of the holes 9a formed in the central portion 8a as small as possible, the speed of the plating solution passing through the central portion 8a can be suppressed compared to the speed of the plating solution passing through the peripheral portion 8b.

[0054] In the flow rate control plate 8 of the plating apparatus 100 shown in Fig. 5(A), the total opening area of ​​the plurality of holes 9a per unit area in the central portion 8a is equal to the total opening area of ​​the plurality of holes 9b per unit area in the peripheral portion 8b, but the total opening area of ​​the plurality of holes 9a per unit area in the central portion 8a may be smaller than the total opening area of ​​the plurality of holes 9b per unit area in the peripheral portion 8b, as in a modified flow rate control plate 8' shown in Fig. 5(B). That is, in the modified flow rate control plate 8', the distance between the centers of the plurality of holes 9a formed in the central portion 8a is the same as the distance between the centers of the plurality of holes 9b formed in the peripheral portion 8b, and the diameters of the holes 9a are 1.2 mm and the diameters of the holes 9b are 3.0 mm.

[0055] In the flow rate control plate 8′ of the modified example shown in FIG. 5(B), the speed of the plating solution passing through the central portion 8a is further suppressed by the synergistic effect of: (I) the opening area of ​​each of the holes 9a formed in the central portion 8a is smaller than the opening area of ​​each of the holes 9b formed in the peripheral portion 8b; and (II) the total opening area of ​​the plurality of holes 9a per unit area in the central portion 8a is smaller than the total opening area of ​​the plurality of holes 9b per unit area in the peripheral portion 8b.

[0056] However, to reiterate, it is not essential that the total opening area of ​​the plurality of holes 9 a per unit area in the central portion 8 a be equal to or smaller than the total opening area of ​​the plurality of holes 9 b per unit area in the peripheral portion 8 b. Even if the total opening area of ​​the plurality of holes 9 a per unit area in the central portion 8 a is larger than the total opening area of ​​the plurality of holes 9 b per unit area in the peripheral portion 8 b, as long as the opening area of ​​each of the holes 9 a formed in the central portion 8 a is sufficiently smaller than the opening area of ​​each of the holes 9 b formed in the peripheral portion 8 b, the speed of the plating solution passing through the central portion 8 a can be suppressed compared to the speed of the plating solution passing through the peripheral portion 8 b.

[0057] The plating apparatus 100 includes a hollow cylindrical member 10 between the flow rate control plate 8 and the mesh member 7 of the first injection port 6a. The cylindrical member 10 may have any shape and dimensions, but it is preferable that they be the same as the shape and dimensions of the central portion 8a of the flow rate control plate 8. However, differences do not pose any problems. In this embodiment, the cylindrical member 10 has a cylindrical shape with an inner diameter of 20 mm. In this embodiment, as shown in FIG. 5A , when the flow rate control plate 8 and the cylindrical member 10 are viewed in a planar direction, the central portion 8a of the flow rate control plate 8 is located inside the cylindrical member 10, and the peripheral portion 8b of the flow rate control plate 8 is located outside the cylindrical member 10.

[0058] The cylindrical member 10 is provided to maintain the difference between the velocity (slow) of the plating solution passing through the central portion 8a and the velocity (fast) of the plating solution passing through the peripheral portion 8b, which is generated by the flow velocity control plate 8, up to the first injection port 6a of the injection unit 6 provided with the mesh member 7. In other words, without the cylindrical member 10, the plating solution passing through the central portion 8a at a slower velocity and the plating solution passing through the peripheral portion 8b at a faster velocity would mix along the way, weakening the effect of slowing the velocity of the plating solution injected from the central portion of the first injection port 6a of the injection unit 6 provided with the mesh member 7 compared to the velocity of the plating solution injected from the peripheral portion of the first injection port 6a.

[0059] It is preferable that the lower end of the cylindrical member 10 contacts the flow rate control plate 8. However, there is no problem if a gap is formed between the lower end of the cylindrical member 10 and the flow rate control plate 8. It is also preferable that the upper end of the cylindrical member 10 contacts the mesh member 7. However, there is no problem if a gap is formed between the upper end of the cylindrical member 10 and the mesh member 7.

[0060] The plating apparatus 100 includes a circulation line 11 formed of a pipe. One end of the circulation line 11 is connected to a suction port 12 formed in the plating tank 1. The other end of the circulation line 11 is connected to a second injection port 6b of the injection unit 6. A pump 13 and a filter 14 are provided midway along the circulation line 11. When the pump 13 is driven, the circulation line 11 sucks up plating solution through the suction port 12 and injects the plating solution from the second injection port 6b.

[0061] The plating apparatus 100 includes a mixing section 15 below the metal tube 2 and the partition tube 3 and above the injection section 6. The mixing section 15 is an area where the plating solution injected from the first injection port 6a of the injection section 6 is mixed with the workpiece, media, and insulating balls that have descended through the plating formation section 4. In this embodiment, the mixing section 15 is made of an insulating material, and has an inverted truncated cone-shaped recess formed on the upper surface. The inverted truncated cone refers to a truncated cone whose upper base is larger than its lower base. However, the shape of the recess is arbitrary, and it may be a mortar-like shape instead of an inverted truncated cone.

[0062] The first injection nozzle 6a of the injection unit 6 is disposed on the bottom surface of the mixing unit 15. As described above, the mesh member 7 is provided at the first injection nozzle 6a of the injection unit 6. Because the mesh member 7 is provided at the first injection nozzle 6a, the object to be plated, media, insulating balls, etc. do not fall into the injection unit 6 even when the injection of the injection unit 6 is stopped.

[0063] The plating apparatus 100 includes a guide section 16 above the metal tube 2 and the partition tube 3. The guide section 16 is a region where the workpiece, media, and insulating balls, which rise on the upward flow of plating solution formed inside the hollow section 2a of the metal tube 2 by the injection from the first injection port 6a of the injection section 6 and are ejected (discharged) from the upper opening of the hollow section 2a of the metal tube 2, are agitated and then guided to the plating formation section 4. The guide section 16 is made of an insulating material and has an inverted truncated cone shape in this embodiment. The upper end of the metal tube 2 protrudes from the bottom surface of the guide section 16. The upper end of the hollow section 2a of the metal tube 2 opens at the bottom surface of the guide section 16. The bottom surface of the guide section 16 is connected to the partition tube 3.

[0064] The plating apparatus 100 is equipped with an insulating reflector 17 above the opening of the plating tank 1. The reflector 17 is sometimes called a deflector. The reflector 17 serves to prevent plating solution from scattering. The support portion 2b of the metal tube 2 is attached to the underside of the reflector 17. A cylindrical suppression plate 17a is also formed on the underside of the reflector 17. The suppression plate 17a is disposed within the guide portion 16. Although the plating solution may overflow from the upper edge of the guide portion 16, the suppression plate 17a ensures that only the plating solution overflows from the guide portion 16, preventing the plating workpiece, media, and insulating balls from overflowing.

[0065] The plating apparatus 100 includes a power supply 18. One line of the power supply 18 is connected to the support portion 2 b of the metal tube 2, which serves as the first electrode, and the other line is connected to the second electrode 5. The power supply 18 applies a current between the metal tube 2, which serves as the first electrode, and the second electrode 5.

[0066] In the plating apparatus 100 according to the first embodiment having the above structure, the flow rate control plate 8 and the cylindrical member 10 are provided, thereby controlling (adjusting) the speed of the plating solution sprayed from the first jet nozzle 6a of the spray unit 6. Specifically, the speed of the plating solution that passes through the central portion 8a of the flow rate control plate 8, then passes inside the cylindrical member 10, and is sprayed from the first jet nozzle 6a of the spray unit 6 is suppressed (decelerated) compared to the speed of the plating solution that passes through the peripheral portion 8b of the flow rate control plate 8, then passes outside the cylindrical member 10, and is sprayed from the first jet nozzle 6a of the spray unit 6.

[0067] As described above, the speed at which the plating solution rises inside the metal tube 2, which is the first electrode, is faster in the center of the metal tube 2 and slower in the peripheral areas closer to the inner wall of the metal tube 2. Furthermore, when the flow rate of the plating solution sprayed from the spray unit 6 is increased, of the objects to be plated that are sprayed out from the upper end of the metal tube 2, those that rise to a high position in the plating solution stored in the plating tank are thought to be mainly objects that rise rapidly through the center of the metal tube 2, where the plating solution moves at a faster rate.

[0068] In the plating apparatus 100, the speed of the plating solution passing through the inside of the cylindrical member 10 and sprayed from the first jet nozzle 6a of the spray unit 6 is slower than the speed of the plating solution passing through the outside of the cylindrical member 10 and sprayed from the first jet nozzle 6a of the spray unit 6, thereby suppressing the speed of the plating solution rising in the center of the metal tube 2. More specifically, when the amount of plating solution sprayed from the spray unit 6 is constant, the plating apparatus 100 can reduce the speed of the plating solution rising in the center of the metal tube 2 compared to when the flow rate control plate 8 and the cylindrical member 10 are not provided.

[0069] Therefore, the plating apparatus 100 increases the amount of plating solution sprayed from the spray unit 6, shortens the time required for the object to pass through the plating formation unit 4 once, and prevents the object from rising too high in the stored plating solution even if the number of times the object circulates through the plating apparatus is increased. Therefore, the plating apparatus 100 prevents defects such as cracks, chips, and peeling of the plating film on the object to be plated caused by the object rising to a high position in the stored plating solution.

[0070] (Example of Use of Plating Apparatus 100) An example of a plating process using the plating apparatus 100 will be described below.

[0071] First, a desired plating solution is charged into the plating tank 1 .

[0072] Next, the object to be plated, media, and insulating balls, each of the desired shape, size, and number, are introduced into the induction section 16 in the plating tank 1. The order of introducing the plating solution and the object to be plated, media, and insulating balls may be reversed. The introduced object to be plated, media, and insulating balls are deposited in the plating formation section 4.

[0073] Next, the pump 13 is driven to spray the plating solution from the first spray nozzle 6a of the spray unit 6. As a result, an upward flow of plating solution is generated inside the metal tube 2. Then, some of the objects to be plated, media, and insulating balls that had accumulated inside the plating formation unit 4 are taken out from the lower end of the plating formation unit 4 to the mixing unit 15, where they mix with the sprayed plating solution and rise inside the metal tube 2 on the upward flow.

[0074] The object to be plated, media, and insulating balls that have risen inside the metal tube 2 are ejected from the upper end of the metal tube 2 and stirred.

[0075] The stirred objects to be plated, media, and insulating balls are deposited on top of other objects to be plated, media, and insulating balls that have already been deposited in the plating formation section 4.

[0076] The newly deposited objects to be plated, media, and insulating balls gradually descend as some of the objects to be plated, media, and insulating balls that had been deposited in the plating formation section 4 are removed from the lower end of the plating formation section 4 to the mixing section 15. In this way, the objects to be plated, media, and insulating balls circulate inside the plating apparatus 100.

[0077] Next, the power supply 18 is driven to apply a current 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 begins in the plating forming section 4.

[0078] After a predetermined time has passed and a plating film of the desired thickness has been formed on the object to be plated, the power supply 18 is turned off to stop plating on the object to be plated. Then, the pump 13 is turned off to stop the object to be plated, the media, and the insulating balls from circulating inside the plating apparatus 100.

[0079] The plating process is completed by removing the objects to be plated, media, and insulating balls from the plating tank 1 and sorting the objects to be plated.

[0080] (Experiment) The following experiment was conducted to confirm the effectiveness of the present invention. Specifically, Examples 1 and 2 were conducted using the plating apparatus 100 described above, and Comparative Example 1 was conducted using a plating apparatus other than the plating apparatus of the present invention. In this experiment, any plating apparatus that includes a flow rate control plate 8 and a cylindrical member 10 is considered to belong to the plating apparatus 100, even if the diameter of the central portion 8a of the flow rate control plate 8 or the inner diameter of the cylindrical member 10 is different.

[0081] The plating apparatus 100 used in Example 1 and the plating apparatus 100 used in Example 2 differ in the diameter of the central portion 8a of the flow rate control plate 8 and the inner diameter of the tubular member 10. Furthermore, unlike the plating apparatus 100, the plating apparatus other than the plating apparatus of the present invention used in Comparative Example 1 does not include the flow rate control plate 8 and the tubular member 10.

[0082] The plating apparatus 100 of Example 1, the plating apparatus 100 of Example 2, and the plating apparatus of Comparative Example 1 have a common configuration except for the flow rate control plate 8 and the tubular member 10, and for example, the length of the plating formation section 4 is 220 mm in all cases.

[0083] First, Example 1 was carried out. In the plating apparatus 100 used in Example 1, the flow rate control plate 8 was circular with a diameter of 28 mm, and the central portion 8a of the flow rate control plate 8 was circular with a diameter of 15 mm. In addition, in the plating apparatus 100 used in Example 1, the tubular member 10 was cylindrical with an inner diameter of 15 mm.

[0084] Furthermore, in the plating apparatus 100 used in Example 1, a plurality of holes 9a with a diameter of 1.2 mm were formed in the central portion 8a of the flow rate control plate 8, and a plurality of holes 9b with a diameter of 3.0 mm were formed in the peripheral portion 8b of the flow rate control plate 8. The pattern shape of the central portion 8a where the holes 9a are formed and the pattern shape of the peripheral portion 8b where the holes 9b are formed are similar in shape. In other words, the pattern shape of the peripheral portion 8b where the holes 9b are formed is obtained by enlarging the pattern shape of the central portion 8a where the holes 9a are formed until the diameter of the holes, including the spacing between the holes, becomes 3.0 mm.

[0085] A plating solution was contained in the plating tank 1 of the plating apparatus 100 .

[0086] The workpiece, media, and insulating balls were placed in the induction section 16 in the plating tank 1 of the plating apparatus 100. The total amount of the workpiece, media, and insulating balls was 1720 cc. The mixing ratio was 1376 cc (80% by volume) of the workpiece, 86 cc (5% by volume) of the media, and 258 cc (15% by volume) of the insulating balls.

[0087] The pump 13 was driven at low power to spray the plating solution from the first nozzle 6a of the spray section 6, and the workpieces, media, and insulating balls were circulated through the mixing section 15, the hollow section 2a of the metal tube 2, the guide section 16, the plating formation section 4, and the mixing section 15, in that order. The power of the pump 13 was gradually increased to increase the circulation speed of the workpieces, media, and insulating balls. Then, when the workpieces discharged from the upper end of the hollow section 2a of the metal tube 2 and those rising relatively high (spouting up) in the stored plating solution reached a predetermined height, the power of the pump 13 was stopped from increasing and the power of the pump 13 was made constant. Specifically, the power of the pump 13 was made constant when the workpieces discharged from the upper end of the hollow section 2a of the metal tube 2 and those rising relatively high in the stored plating solution reached a height half the height between the upper end of the metal tube 2 and the level of the plating solution contained in the plating tank 1.

[0088] Next, the power supply 18 was driven to apply a current between the metal tube 2 serving as the first electrode and the second electrode 5, and plating of the object to be plated was started in the plating forming section 4.

[0089] In this state, the amount of plating solution sprayed from the first injection port 6a of the injection unit 6 (flow rate of plating solution) was measured. Also, in this state, the time required for each object to pass through the plating formation unit 4 once was measured.

[0090] In Example 1, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 was 39 L / min. The time required for each object to pass through the plating formation unit 4 once was 10.5 seconds.

[0091] Next, Example 2 was carried out. In the plating apparatus 100 used in Example 2, the flow rate control plate 8 was circular with a diameter of 28 mm, the central portion 8a of the flow rate control plate 8 was circular with a diameter of 20 mm, and the tubular member 10 was cylindrical with an inner diameter of 20 mm.

[0092] Similarly to Example 1, the plating apparatus 100 used in Example 2 also had a plurality of holes 9a with a diameter of 1.2 mm formed in the central portion 8a of the flow velocity control plate 8, and a plurality of holes 9b with a diameter of 3.0 mm formed in the peripheral portion 8b of the flow velocity control plate 8. The pattern shape of the central portion 8a where the holes 9a are formed and the pattern shape of the peripheral portion 8b where the holes 9b are formed were similar to each other, similar to Example 1.

[0093] In Example 2, the plating solution was placed in the plating tank 1 of the plating apparatus 100 under the same conditions as in Example 1.

[0094] In Example 2, the object to be plated, media, and insulating balls were also placed in the induction section 16 in the plating tank 1 of the plating apparatus 100 under the same conditions as in Example 1.

[0095] In Example 2, under the same conditions as in Example 1, the pump 13 was driven at low power, and then the power of the pump 13 was gradually increased until the part of the workpiece discharged from the upper end of the hollow portion 2a of the metal tube 2 that rose relatively high in the plating solution reached half the height between the upper end of the metal tube 2 and the surface of the plating solution contained in the plating tank 1. Next, the power source 18 was driven, and a current was applied between the metal tube 2, which was the first electrode, and the second electrode 5, and plating of the workpiece began in the plating formation section 4.

[0096] In Example 2, the amount of plating solution sprayed from the first injection port 6a of the injection unit 6 (flow rate of plating solution) was measured in this state. Also, the time required for each object to pass through the plating formation unit 4 once was measured in this state.

[0097] In Example 2, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 was 40 L / min. The time required for each object to pass through the plating formation unit 4 once was 6.1 seconds.

[0098] Next, Comparative Example 1 was carried out. As described above, the plating apparatus used in Comparative Example 1 did not include the flow rate control plate 8 and the cylindrical member 10. The other configurations of the plating apparatus used in Comparative Example 1 were the same as those of the plating apparatus 100.

[0099] In Comparative Example 1, the plating solution was placed in the plating tank 1 of the plating apparatus 100 under the same conditions as in Examples 1 and 2.

[0100] In Comparative Example 1, the object to be plated, media, and insulating balls were also placed in the induction section 16 in the plating tank 1 of the plating apparatus 100 under the same conditions as in Examples 1 and 2.

[0101] In Comparative Example 1, under the same conditions as in Examples 1 and 2, the pump 13 was driven at low power, and then the power of the pump 13 was gradually increased until the part of the workpiece discharged from the upper end of the hollow portion 2a of the metal tube 2 that rose relatively high in the plating solution reached half the height between the upper end of the metal tube 2 and the surface of the plating solution contained in the plating tank 1. Next, the power source 18 was driven, and a current was applied between the metal tube 2, which was the first electrode, and the second electrode 5, and plating of the workpiece began in the plating formation section 4.

[0102] In Comparative Example 1, the amount of plating solution sprayed from the first injection port 6a of the injection unit 6 (flow rate of plating solution) was measured under this condition. Also, under this condition, the time required for each object to pass through the plating formation unit 4 once was measured.

[0103] In Comparative Example 1, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 was 34 L / min. The time required for each object to pass through the plating formation unit 4 once was 16.7 seconds.

[0104] The details and experimental results of Examples 1, 2, and Comparative Example 1 are shown in Table 1.

[0105] As can be seen from Table 1, under the condition that the output of the pump 13 was made constant (maintained) when the part of the object to be plated that was discharged from the upper end of the hollow portion 2 a of the metal pipe 2 and rose relatively high in the plating solution stored therein reached half the height between the upper end of the metal pipe 2 and the surface of the plating solution contained in the plating tank 1, both Example 1 and Example 2 had a higher flow rate of the plating solution and a shorter time required for the object to be plated to pass through the plating formation portion 4 once than Comparative Example 1.

[0106] Furthermore, when Example 1 and Example 2 are compared, Example 2, in which the diameter of the central portion 8a of the flow rate control plate 8 and the inner diameter of the tubular member 10 are larger, has a higher flow rate of plating solution and a shorter time required for the object to be plated to pass once through the plating formation section 4 than Example 1, in which the diameter of the central portion 8a of the flow rate control plate 8 and the inner diameter of the tubular member 10 are smaller. When practicing the present invention, it is thought that the flow rate of plating solution can be increased and the time required for the object to be plated to pass once through the plating formation section 4 can be shortened by relatively increasing the diameter of the central portion 8a of the flow rate control plate 8 and the inner diameter of the tubular member 10, which suppress the speed of the plating solution.

[0107] From the above, it has been found that according to the present invention, it is possible to suppress the occurrence of defects in the plated object while increasing the flow rate of the plating solution and the number of times the plated object circulates through the plating device, thereby suppressing the variation in the thickness of the plated film formed.

[0108] Second Embodiment Fig. 7 shows a plating apparatus 200 according to a second embodiment. Fig. 7 is a plan view of a main portion of the plating apparatus 200. Specifically, Fig. 7 is a plan view of the flow rate control plate 28 and the cylindrical member 10 of the plating apparatus 200.

[0109] The plating apparatus 200 according to the second embodiment is obtained by adding some modifications to the configuration of the plating apparatus 100 according to the first embodiment described above. The modifications will be described below.

[0110] In the flow rate control plate 8 of the plating apparatus 100 according to the first embodiment, the opening area of ​​each of the holes 9a formed in the central portion 8a is smaller than the opening area of ​​each of the holes 9b formed in the peripheral portion 8b. In contrast, in the flow rate control plate 28 of the plating apparatus 200 according to the second embodiment, the opening area of ​​each of the holes 29a formed in the central portion 28a is the same as the opening area of ​​each of the holes 29b formed in the peripheral portion 28b. However, in the flow rate control plate 28 of the plating apparatus 200, the number of holes 29a formed per unit area in the central portion 28a is smaller than the number of holes 29b formed per unit area in the peripheral portion 28b. The other configurations of the plating apparatus are the same as those of the plating apparatus 100.

[0111] In the flow rate control plate 28 of the plating apparatus 200 according to the second embodiment, the total opening area per unit area of ​​the plurality of holes 29a formed in the central portion 28a is smaller than the total opening area per unit area of ​​the plurality of holes 29b formed in the peripheral portion 28b.

[0112] In the plating apparatus 200 according to the second embodiment, the velocity of the plating solution passing through the central portion 28a of the flow rate control plate 28, passing further inside the cylindrical member 10, and sprayed from the first jet nozzle 6a of the spray unit 6 is also suppressed (decelerated) compared to the velocity of the plating solution passing through the peripheral portion 28b of the flow rate control plate 28, passing further outside the cylindrical member 10, and sprayed from the first jet nozzle 6a of the spray unit 6. Therefore, in the plating apparatus 200, for the purpose of suppressing variations in the thickness of the plating film, the amount of plating solution sprayed from the spray unit 6 is increased, the time required for the object to pass through the plating formation unit 4 once is shortened, and the number of times the object to be plated circulates through the plating apparatus is increased, making it less likely that defects will occur in the object to be plated.

[0113] The plating apparatus according to the first and second embodiments has been described above. However, the present invention is not limited to the above-described contents, and various modifications can be made in accordance with the spirit of the invention.

[0114] For example, in the above embodiment, the mesh member 7 is configured as a single layer of mesh throughout, but as shown in Fig. 6(A), the mesh member 7' may be configured as follows: a central mesh portion 7a and a peripheral mesh portion 7b provided outside the central mesh portion 7a; the central mesh portion 7a may be configured as multiple layers of mesh; and the peripheral mesh portion 7b may be configured as a single layer of mesh. In this case, the speed of the plating solution passing through the central mesh portion 7a can be reduced more than the speed of the plating solution passing through the peripheral mesh portion 7b, even in the mesh member 7', thereby further enhancing the effects of the present invention.

[0115] A plating apparatus according to one embodiment of the present invention is as described in the section "Means for Solving the Problems."

[0116] In this plating apparatus, it is also preferable that the opening area of ​​each of the holes formed in the central portion is smaller than the opening area of ​​each of the holes formed in the peripheral portion. In this case, the resistance to the plating solution passing through each of the holes formed in the central portion is greater than the resistance to the plating solution passing through each of the holes formed in the peripheral portion, so the speed of the plating solution passing through the central portion can be reduced compared to the speed of the plating solution passing through the peripheral portion. In this case, it is also preferable that the total opening area per unit area of ​​the multiple holes formed in the central portion is the same as or smaller than the total opening area per unit area of ​​the multiple holes formed in the peripheral portion. In this case, the speed of the plating solution passing through the central portion can be further reduced.

[0117] It is also preferable that the opening area of ​​each of the holes formed in the central portion is the same as that of each of the holes formed in the peripheral portion, but the number of holes formed in the central portion per unit area is smaller than the number of holes formed in the peripheral portion per unit area, in which case the speed of the plating solution passing through the central portion can be reduced compared to the speed of the plating solution passing through the peripheral portion.

[0118] It is also preferable that the total opening area per unit area of ​​the plurality of holes formed in the central portion is smaller than the total opening area per unit area of ​​the plurality of holes formed in the peripheral portion, in which case the speed of the plating solution passing through the central portion can be reduced compared to the speed of the plating solution passing through the peripheral portion.

[0119] In these plating apparatuses, when the flow rate control plate and the cylindrical member are viewed in a planar direction, it is also preferable that the central portion of the flow rate control plate is disposed inside the cylindrical member and the peripheral portion of the flow rate control plate is disposed outside the cylindrical member. In this case, the difference in velocity of the plating solution passing through the central portion and the peripheral portion, which is generated by the flow rate control plate, can be maintained as is up to the first injection port of the injection unit.

[0120] It is also preferable that the holes formed in the central portion and the holes formed in the peripheral portion are each circular when the flow velocity control plate is viewed in a planar direction, which makes it easier to form holes in the flow velocity control plate.

[0121] It is also preferable that the mesh member has, when viewed in a planar direction, a mesh central portion and a mesh peripheral portion provided outside the mesh central portion, and the mesh central portion has a smaller mesh opening than the mesh peripheral portion. In this case, the speed of the plating solution passing through the mesh central portion can be reduced more than the speed of the plating solution passing through the mesh peripheral portion. In this case, it is also preferable that the mesh member in the mesh peripheral portion consists of a single layer of mesh and the mesh member in the mesh central portion consists of multiple layers of mesh.

[0122] It is also preferable to provide a cylindrical metal tube having a hollow portion directly above the injection portion, which makes it possible to control the speed at which the plating solution rises inside the metal tube, and in particular to suppress (slow down) the flow of plating solution that rises quickly in the center of the metal tube.

[0123] It is also preferable that the plating apparatus comprises a partition wall tube made of an insulating material, having a hollow cylindrical shape, and having a plurality of holes formed therein that allow the plating solution to pass through but not the object to be plated, and a second electrode, the metal tube being the first electrode, the metal tube, the partition wall tube, and the second electrode being each contained in a plating tank, the metal tube being disposed within the hollow part of the partition wall tube, a plating formation part being formed between the inside of the partition wall tube and the outside of the metal tube, the second electrode being disposed on the outside of the partition wall tube, the spray part being provided below the metal tube, the object to be plated being carried by the ascending flow of plating solution sprayed by the spray part and rising within the hollow part of the metal tube, being discharged from the upper end of the hollow part of the metal tube, being agitated in the plating solution, and then descending within the plating formation part, and during the descent, a current is applied between the metal tube, which is the first electrode, and the second electrode, thereby being plated. In this case, the speed at which the plating solution rises inside the metal tube can be controlled, and in particular, the flow of plating solution that rises quickly in the center of the metal tube can be suppressed (decelerated). Note that the first electrode is, for example, a cathode electrode, and the second electrode is, for example, an anode electrode.

[0124] DESCRIPTION OF SYMBOLS 1: Plating tank 2: Metal tube (first electrode; cathode) 2a: Hollow portion 2b: Support portion 3: Partition tube 3a: Hollow portion 3b: Hole 4: Plating formation portion 5: Second electrode (anode) 6: Injection portion 6a: First injection port 6b: Second injection port 7, 7', 7": Mesh member 7a: Mesh central portion 7b: Mesh peripheral portion 8, 28: Flow rate control plate 8a, 28a: Central portion 8b, 28b: Peripheral portion 9, 29: Hole 9a, 29a: Hole (formed in central portion 8a) 9b, 29b: Hole (formed in peripheral portion 8b) 10: Cylindrical member 11: Circulation line 12: Liquid suction port 13: Pump 14: Filter 15: Mixing portion 16: Guiding portion 17: Reflector (deflector) 17a: Suppression plate 18...Power supply

Claims

1. A plating tank for storing a plating solution containing an object to be plated; An injection unit that is formed in the plating tank and injects the plating solution, The plating solution jetted from the jetting unit stirs the object to be plated contained in the plating solution, The injection portion has an inner cylindrical shape having a bottom surface extending in a horizontal direction, an inner wall extending in a height direction from the bottom surface, and an opening formed at an upper end of the inner wall, the opening is a first injection port that injects the plating solution into the plating tank, A mesh member is provided at the first injection port, a second injection port is provided on the bottom surface to inject the plating solution into the injection portion; A flow velocity control plate having a plurality of holes formed therein is provided in the middle of the height direction of the injection part and parallel to the bottom surface, The flow velocity control plate has a central portion and a peripheral portion provided outside the central portion when viewed in a planar direction, A plurality of the holes are formed in the central portion and the peripheral portion, A cylindrical member having a hollow portion is provided between the flow velocity control plate and the mesh member of the first injection port. Plating equipment.

2. an opening area of ​​each of the holes formed in the central portion is smaller than an opening area of ​​each of the holes formed in the peripheral portion; 2. The plating apparatus according to claim 1.

3. A total opening area per unit area of ​​the plurality of holes formed in the central portion is equal to or smaller than a total opening area per unit area of ​​the plurality of holes formed in the peripheral portion.

3. The plating apparatus according to claim 2.

4. an opening area of ​​each of the holes formed in the central portion is equal to an opening area of ​​each of the holes formed in the peripheral portion, but the number of the holes formed in the central portion per unit area is smaller than the number of the holes formed in the peripheral portion per unit area; 2. The plating apparatus according to claim 1.

5. a total opening area per unit area of ​​the plurality of holes formed in the central portion is smaller than a total opening area per unit area of ​​the plurality of holes formed in the peripheral portion; 2. The plating apparatus according to claim 1.

6. When the flow rate control plate and the cylindrical member are viewed in a planar direction, The central portion of the flow rate control plate is disposed inside the cylindrical member, The peripheral portion of the flow rate control plate is disposed on the outside of the cylindrical member.

6. A plating apparatus according to claim 1.

7. When the flow rate control plate is viewed in a planar direction, The hole formed in the central portion and the hole formed in the peripheral portion are each circular.

6. A plating apparatus according to claim 1.

8. When viewed in a planar direction, the mesh member has a mesh central portion and a mesh peripheral portion provided outside the mesh central portion, The mesh opening in the central portion of the mesh is smaller than the mesh opening in the peripheral portion of the mesh.

6. A plating apparatus according to claim 1.

9. The mesh member in the mesh periphery is made of one layer of mesh, The mesh member in the central portion of the mesh is made of a plurality of layers of mesh.

9. The plating apparatus according to claim 8.

10. A cylindrical metal tube having a hollow portion is provided directly above the injection portion.

6. A plating apparatus according to claim 1.

11. a partition tube made of an insulating material, having a hollow cylindrical shape, and having a plurality of holes formed therein that allow the plating solution to pass but not the object to be plated to pass therethrough; A second electrode, the metal tube is a first electrode; the metal tube, the partition tube, and the second electrode are each contained in the plating tank, The metal pipe is disposed in the hollow portion of the partition pipe, and a plating formation portion is formed between an inside of the partition pipe and an outside of the metal pipe, The second electrode is disposed on the outside of the partition tube, The ejection portion is provided below the metal tube, The object to be plated is The plating solution is carried by the upward flow of the plating solution sprayed by the spray unit and rises in the hollow portion of the metal pipe, The metal is discharged from the upper end of the hollow portion of the metal tube and stirred in the plating solution, Descending through the plating formation section, During the descent, a current is applied between the metal tube, which is the first electrode, and the second electrode, thereby plating.

11. The plating apparatus according to claim 10.

12. The first electrode is a cathode electrode, The second electrode is an anode electrode.

12. The plating apparatus according to claim 11.