Plating equipment

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

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 the first electrode, a partition tube made of an insulating material, and a second electrode (anode) are accommodated. A plurality of small holes are formed in the partition tube through which the plating solution passes but the object to be plated, media, etc. do not pass.

[0004] The metal tube is disposed inside the partition tube, and a plating formation part is formed between the inside of the partition 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 partition tube.

[0005] Below the metal tube, an injection part having an injection port for injecting the plating solution is provided. The injection part is for generating an upward flow of the plating solution inside the metal tube. Although not disclosed in the plating apparatus of Patent Document 1, usually, a mesh member is provided at the injection port of the injection part so that the object to be plated and media do not fall into the injection part when the injection stops.

[0006] The plating apparatus disclosed in Patent Document 1 contains a plating tank containing a plating solution. Subsequently, the object to be plated, conductive media, and insulating balls, if necessary, are placed into the plating tank containing the plating solution. However, the plating solution may be placed into the plating tank after the object to be plated, media, and insulating balls have been placed in the plating tank. The media is used 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) during plating of the object to be plated in the plating formation section. The insulating balls are used to improve the fluidity of the object to be plated as it circulates within the plating apparatus.

[0007] The objects to be plated, media, and insulating balls are carried by the upward flow of the plating solution inside the metal tube, generated by the spray from the nozzle, and rise through the metal tube before being ejected from the top end of the metal tube and agitated in the plating solution.

[0008] The stirred material to be plated, media, and insulating balls then accumulate on the upper side of the plating formation area. At this time, other material to be plated, media, and insulating balls have already accumulated inside the plating formation area. The material to be plated, media, and insulating balls accumulated on the upper side of the plating formation area then gradually descend within the plating formation area. 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 area of ​​the surface of the material to be plated.

[0009] The plated object, media, and insulating balls, on which the plating film has been formed, are extruded from the lower end of the plating section, and again, carried by the rising flow of the plating solution generated inside the metal tube, they rise through the metal tube and are ejected out from the upper end of the metal tube, where they are agitated. The agitated object, media, and insulating balls then accumulate on the upper side of the plating section, as before, and subsequently gradually descend through the plating section, during which time the plating film is formed on the object.

[0010] The object to be plated may be circulated through the plating apparatus several to several thousand times before the plating film reaches a predetermined thickness and the plating process is completed. [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] Plating of an object to be plated must satisfy the following conditions (a) and (b). (a) A plating film with a thickness equal to or greater than a predetermined thickness is formed on each object to be plated. (b) The variation in the thickness of the plated film formed among multiple plated objects plated simultaneously is small (within a predetermined tolerance).

[0013] When the total plating time is defined as the time from the start to the end of a single plating process (one lot), if the total plating time is constant, the thickness of the plating film formed on each object will be approximately the same, even if the time required for the object to pass through the plating area once and the number of times the object passes through the plating area are changed. This is because the thickness of the plating film formed on an object depends on the total time each object spends passing through the plating area (time required to pass through the plating area once × number of times). Naturally, when the total plating time is constant, increasing the time required for the object to pass through the plating area once will decrease the number of times the object passes through the plating area, and decreasing the time required for the object to pass through the plating area once will increase the number of times the object passes through the plating area.

[0014] On the other hand, when the total plating time is constant, shortening the time required for the object to be plated to pass through the plating formation section once and increasing the number of times the object circulates through the plating apparatus results in less variation in the thickness of the formed plating film among multiple objects than lengthening the time required for the object to pass through the plating formation section once and decreasing the number of times the object circulates through the plating apparatus. In other words, the thickness of the plating film formed (grown) on the object each time it passes through the plating formation section varies depending on conditions such as whether the object passes near the metal pipe, near the partition pipe, or near the middle of the metal pipe and the partition pipe. By increasing the number of passes and leveling the process, the variation in the thickness of the formed plating film can be reduced.

[0015] Considering the productivity of the plating process, a short total plating time is preferable. In order to increase the number of times the object to be plated passes through the plating formation area within a limited total plating time, the flow rate of the plating solution sprayed from the spray unit should be increased. To increase the flow rate of the plating solution sprayed from the spray unit, for example, the output of the pump connected to the spray unit should be increased.

[0016] However, increasing the flow rate of the plating solution sprayed from the nozzle can sometimes cause defects in the plated object, such as cracks or chips, 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 nozzle causes the speed of the object being plated rising up the metal tube, which is the first electrode, to become too fast. The object being ejected from the top of the metal tube rises to a high position in the plating solution stored in the plating tank, where it may collide with a reflector called a deflector, or, as it descends (sediments) from a high position in the plating solution, it may collide with the inner wall of the plating tank or with other objects being plated. In other words, the object being plated, along with the media and insulating balls, is discharged from the top of the metal tube to agitate them, but if the force is too strong and the object is ejected to a high position in the stored plating solution, defects in the plated object can occur.

[0017] Therefore, the present invention aims to provide a plating apparatus that prevents the object to be plated from rising too high in the stored plating solution even when the flow rate of the plating solution sprayed from the spray unit is increased, thereby suppressing defects in the object to be plated. [Means for solving the problem]

[0018] 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 containing an object to be plated, and a spray unit formed in the plating tank for spraying the plating solution, wherein the object to be plated contained in the plating solution is agitated by the plating solution sprayed from the spray unit, wherein the spray unit is an inner cylindrical shape having a bottom surface that extends horizontally, 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 for spraying the plating solution into the plating tank, a mesh member is provided in the first spray port, a second spray port for spraying the plating solution into the spray unit is provided on the bottom surface, a flow velocity control plate is provided in the middle of the height direction of the spray unit and parallel to the bottom surface, a flow velocity control plate having a plurality of holes formed therein is provided in the middle of the height direction of the spray unit, the flow velocity control plate has a central part and a peripheral part provided outside the central part when viewed in the planar direction, a plurality of holes are formed in the central part and the peripheral part, respectively, and a cylindrical member having a hollow part is provided between the flow velocity control plate and the mesh member of the first spray port. [Effects of the Invention]

[0019] In one embodiment of the present invention, the plating apparatus can suppress the speed of the plating solution passing through the central part to that of the plating solution passing through the peripheral part by adjusting the size of each opening area, the total opening area per unit area of ​​the multiple openings, and the number of openings per unit area in the holes formed in the central part and the holes formed in the peripheral part.

[0020] As a result, in one embodiment of the present invention, when a cylindrical metal tube having a hollow section is placed directly above the spray section, the velocity of the plating solution passing through the center of the metal tube is suppressed. Therefore, even if the flow rate of the plating solution sprayed from the spray section is increased, the object to be plated does not rise too high into the stored plating solution, thus suppressing defects in the object to be plated. Further explanation follows.

[0021] For example, the speed of the plating solution passing through (rising) inside the metal tube, which is the first electrode, is not uniform across the entire cross-section of the metal tube. It is faster at the center of the metal tube and slower near the inner wall of the metal tube. This is because resistance (frictional resistance) occurs in the flow of the plating solution near the inner wall of the metal tube, suppressing the speed of the plating solution.

[0022] Also, in the case where an inner cylindrical injection part is provided on the bottom surface of the plating tank of the plating apparatus, a first injection port is provided above the injection part, and a second injection port for injecting the plating solution into the injection part is provided on the bottom surface of the injection part, and when the diameter of the second injection port is smaller than the inner diameter of the metal tube, it may cause the plating solution to be faster at the center of the metal tube and slower near the inner wall of the metal tube.

[0023] On the other hand, when increasing the flow rate of the plating solution injected from the injection part, not all the workpieces ejected outward from the upper end of the metal tube will rise to a high position in the plating solution stored in the plating tank. The workpieces that rise to a high position in the plating solution stored in the plating tank are mainly considered to be the workpieces that have passed (risen) through the center of the metal tube where the speed of the plating solution is fast in one go.

[0024] In the plating apparatus according to an embodiment of the present invention, the speed of the plating solution passing through the central part of the flow rate control plate is suppressed. For example, when a cylindrical metal tube having a hollow part is arranged directly above the injection part, since the speed of the plating solution passing through the inside of the metal tube is suppressed at the center of the metal tube, even if the flow rate of the plating solution injected from the injection part is increased, the workpiece will not rise too high in the plating solution in which the workpiece is stored, and the occurrence of defects in the workpiece is suppressed.

Brief Description of the Drawings

[0025] [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 partial cross-section along the dash-dotted arrow A-A in FIG. 1. [Figure 3]This is a cross-sectional view of the main part of the plating apparatus 100. [Figure 4] This is a perspective view of the main part of the plating apparatus 100. [Figure 5] Figure 5(A) is a plan view of the flow velocity control plate 8 and cylindrical member 10 of the plating apparatus 100. Figure 5(B) is a plan view of the flow velocity control plate 8', which is a modified example of the flow velocity control plate 8 of the plating apparatus 100, and the cylindrical member 10. [Figure 6] Figure 6(A) is a plan view showing a modified mesh member 7' of the mesh member 7 of the plating apparatus 100. Figure 6(B) is a plan view showing a modified mesh member 7'' of the mesh member 7 of the plating apparatus 100. [Figure 7] This is a plan view of the main part of the plating apparatus 200 according to the second embodiment. [Modes for carrying out the invention]

[0026] The embodiments for carrying out the present invention will be described below with reference to the drawings.

[0027] Each embodiment is illustrative of an embodiment of the present invention, and the present invention is not limited to the contents of the embodiments. It is also possible to combine the contents described in different embodiments, and the contents of such implementations are also included in the present invention. Furthermore, the drawings are for the purpose of aiding the understanding of the specification and may be schematically drawn, and the proportions of the dimensions of the drawn components or the dimensions between components may not match the proportions of those dimensions described in the specification. In addition, components described in the specification may be omitted in the drawings, or their quantities may be omitted.

[0028] [First Embodiment] Figures 1, 2, 3, 4(A), and 4(B) show a plating apparatus 100 according to the first embodiment. However, Figure 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 part AA indicated by the dashed arrow in Figure 1. Figure 3 is a cross-sectional view of the main part of the plating apparatus 100. Figure 4 is a perspective view of the main part of the plating apparatus 100, showing the spray unit 6. Figure 5(A) is a plan view of the flow velocity control plate 8 and cylindrical member 10 of the plating apparatus 100. Figure 5(B) is a plan view of the flow velocity control plate 8', which is a modified example of the flow velocity control plate 8, and the cylindrical member 10.

[0029] 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 19 of the plating solution, the object to be plated, the media, and insulating balls, which will be described later. However, the insulating balls can be omitted if they are not needed.

[0030] 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.

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

[0032] The plating apparatus 100 includes a partition tube 3 made of an insulating material inside the plating tank 1. The partition tube 3 has a hollow section 3a. In this embodiment, the partition tube 3 is cylindrical. However, the partition tube 3 may be polygonal. The partition tube 3 has a plurality of small holes 3b that allow the plating solution to pass through, but not the object to be plated, the media, or the insulating balls. The holes 3b allow current to pass through via the plating solution when current is applied between the metal tube 2, which is the first electrode, and the second electrode 5. The material of the partition tube 3 is arbitrary, and various resins can be used, for example. The dimensions of the partition tube 3, such as the outer diameter, inner diameter, and length, are arbitrary and can be set as appropriate.

[0033] The inner diameter of the partition pipe 3 is larger than the outer diameter of the metal pipe 2. The metal pipe 2 is positioned within the hollow portion 3a of the partition pipe 3. A plating area 4 is formed between the inside of the partition pipe 3 and the outside of the metal pipe 2. The plating area 4 is the region (space) where plating is applied to the object to be plated. In Figures 1, 2, and 3, the plating area 4 is depicted as a shaded area. The area between the outer diameter of the metal pipe 2 and the inner diameter of the partition pipe 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.

[0034] 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.

[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 located outside the partition pipe 3. The material of the second electrode 5 is arbitrary, and various metals can be used.

[0036] 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 partition 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.

[0037] The plating apparatus 100 is equipped with a spray unit 6 below the metal pipe 2. The spray unit 6 is for generating an upward flow of plating solution inside the metal pipe 2. In this embodiment, the spray unit 6 is an inner cylinder having a bottom surface that expands horizontally, an inner wall that extends vertically from the bottom surface, and an opening formed at the upper end of the inner wall. In this embodiment, the inner cylinder of the spray unit 6 is an inner cylindrical shape. However, the inner cylinder of the spray unit 6 is not limited to an inner cylindrical shape and may be of other shapes. The dimensions of the spray unit 6, such as the inner diameter and depth, are arbitrary and can be set as appropriate. It is preferable that the inner diameter of the spray unit 6 be the same as the inner diameter of the metal pipe 2, but it is not a problem if they are different.

[0038] A first injection port 6a is formed in an opening at the upper end of the injection section 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 nozzle 6b is formed on the bottom surface of the injection unit 6. The plating solution is injected into the injection unit 6 from the second nozzle 6b. The plating solution is injected into the plating tank 1 from the first nozzle 6a. In this embodiment, the opening area of ​​the second nozzle 6b is smaller than the opening area of ​​the first nozzle 6a.

[0040] Furthermore, when comparing the inner diameter of the metal tube 2 with the diameter of the second nozzle 6b, the diameter of the second nozzle 6b is smaller than the inner diameter of the metal tube 2. This also causes the plating solution velocity in the center of the metal tube 2 to increase, so measures are needed to suppress the velocity of the plating solution in the center of the metal tube 2.

[0041] A mesh member 7 is provided at the first nozzle 6a of the injection unit 6. The mesh member 7 is provided to prevent objects 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 nozzle 6a of the injection unit 6 is circular, the mesh member 7 is also circular when viewed in the planar direction.

[0042] In this embodiment, the mesh member 7 is composed entirely of a single layer of mesh with an opening of 900 μm. However, as shown in the mesh member 7' in Figure 6(A) and the mesh member 7'' in Figure 6(B), the mesh member may be composed of a mesh central portion 7a and a mesh peripheral portion 7b provided outside the mesh central portion 7a, with the mesh central portion 7a being composed of multiple layers (for example, two layers) of mesh and the mesh peripheral portion 7b being composed 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 the flow velocity control plate 8 described later, and the shape and dimensions of the inner diameter of the cylindrical member 10 described later, but it is not a problem if they are different. In the mesh member 7', the mesh central portion 7a is circular, and in the mesh member 7'', the mesh central portion 7a is rectangular.

[0043] The "mesh opening" refers to the distance between adjacent lines in a mesh where vertical and horizontal lines intersect (excluding the wire diameter). The mesh opening is sometimes called the opening (OP) or opening dimension. Generally, the term "mesh opening" refers to the opening of a single layer of mesh; however, in this application, it may refer to the combined opening of multiple meshes when multiple meshes are layered. When comparing the mesh opening of a single layer of mesh with the mesh opening of two layers of that mesh (or the mesh opening when that mesh is layered with another mesh), the latter will be smaller (finer) than the former.

[0044] In the mesh members 7' and 7'', the mesh opening in the central part 7a is smaller than the mesh opening in the peripheral part 7b. Therefore, in the mesh members 7' and 7'', the speed of the plating solution passing through the central part 7a is suppressed compared to the speed of the plating solution passing through the peripheral part 7b.

[0045] The material of the mesh constituting the mesh members 7, 7', and 7'' can be arbitrary, but nylon can be used, for example. When using multiple layers of mesh, the meshes can be joined together, for example, with adhesive, or the edges can be fixed after overlapping them.

[0046] The plating apparatus 100 has a flow velocity control plate 8 located midway along the height of the injection section 6, parallel to the bottom surface of the injection section 6. As can be seen particularly in Figure 5(A), when viewed in the planar direction, the flow velocity control plate 8 has a central section 8a and a peripheral section 8b located outside the central section 8a.

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

[0048] The material of the flow velocity control plate 8 can be arbitrary, but for example, polyvinyl chloride can be used.

[0049] The flow velocity control plate 8 has multiple holes 9(9a, 9b) formed through the two main surfaces. The shape of the holes 9(9a, 9b) can be arbitrary, but in this embodiment, they are circular when viewed in the planar direction. If the holes 9(9a, 9b) are circular, they can be easily formed by laser irradiation or drilling.

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

[0051] In this embodiment, the pattern shape of the central portion 8a where holes 9a are formed and the pattern shape of the peripheral portion 8b where holes 9b are formed are similar. More specifically, multiple holes 9a with a diameter of 1.2 mm are formed in the central portion 8a in a matrix-like (grid-like) pattern at predetermined intervals. Then, while maintaining this shape, the holes are enlarged, including the spacing between them, until the diameter of the holes reaches 3.0 mm. Using the enlarged spacing between the holes and the enlarged diameter of the holes, holes 9b are formed in the peripheral portion 8b. 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 and the total opening area of ​​the multiple holes 9b per unit area in the peripheral area 8b do not necessarily have to be equal. In order to more effectively suppress the speed of the plating solution passing through the central area 8a, it is preferable that the total opening area of ​​the multiple holes 9a per unit area in the central area 8a is smaller than the total opening area of ​​the multiple holes 9b per unit area in the peripheral area 8b. However, conversely, even if the total opening area of ​​the multiple holes 9a per unit area in the central area 8a is larger than the total opening area of ​​the multiple holes 9b per unit area in the peripheral area 8b, if the opening area of ​​each hole 9a formed in the central area 8a is sufficiently smaller than the opening area of ​​each hole 9b formed in the peripheral area 8b, the speed of the plating solution passing through the central area 8a can be suppressed compared to the speed of the plating solution passing through the peripheral area 8b.

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

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

[0055] In the modified flow velocity control plate 8' shown in Figure 5(B), the velocity of the plating solution passing through the central part 8a is further suppressed due to the synergistic effect of (I) the opening area of ​​each hole 9a formed in the central part 8a being smaller than the opening area of ​​each hole 9b formed in the peripheral part 8b, and (II) the total opening area of ​​the multiple holes 9a per unit area in the central part 8a being smaller than the total opening area of ​​the multiple holes 9b per unit area in the peripheral part 8b.

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

[0057] The plating apparatus 100 is provided with a cylindrical member 10 having a hollow portion between the flow velocity control plate 8 and the mesh member 7 of the first injection port 6a. The shape and dimensions of the cylindrical member 10 are arbitrary, but it is preferable that they be the same as the shape and dimensions of the central portion 8a of the flow velocity control plate 8. However, it is not a problem if they are different. In this embodiment, the cylindrical member 10 is a cylinder with an inner diameter of 20 mm. In this embodiment, as shown in Figure 5(A), when the flow velocity control plate 8 and the cylindrical member 10 are viewed in the planar direction, the central portion 8a of the flow velocity control plate 8 is located inside the cylindrical member 10, and the peripheral portion 8b of the flow velocity control plate 8 is located outside the cylindrical member 10.

[0058] The cylindrical member 10 is provided to maintain the difference between the velocity of the plating solution passing through the central part 8a (slow) and the velocity of the plating solution passing through the peripheral part 8b (fast), which is generated by the flow velocity control plate 8, all the way to the first nozzle 6a of the spray unit 6 equipped with the mesh member 7. In other words, without the cylindrical member 10, the slow-moving plating solution that passed through the central part 8a and the fast-moving plating solution that passed through the peripheral part 8b would mix along the way, weakening the effect of making the velocity of the plating solution sprayed from the center of the first nozzle 6a slower than the velocity of the plating solution sprayed from the peripheral part of the first nozzle 6a of the spray unit 6 equipped with the mesh member 7.

[0059] It is preferable that the lower end of the cylindrical member 10 is in contact with the flow velocity control plate 8. However, it is not a problem if there is a gap between the lower end of the cylindrical member 10 and the flow velocity control plate 8. Also, it is preferable that the upper end of the cylindrical member 10 is in contact with the mesh member 7. However, it is not a problem if there is a gap between the upper end of the cylindrical member 10 and the mesh member 7.

[0060] The plating apparatus 100 is equipped with a circulation line 11 formed of pipes. One end of the circulation line 11 is connected to a liquid intake port 12 formed in the plating tank 1. The other end of the circulation line 11 is connected to a second nozzle 6b of the spray unit 6. A pump 13 and a filter 14 are provided in the middle of the circulation line 11. When the pump 13 is driven, the circulation line 11 draws in the plating solution from the liquid intake port 12 and sprays the plating solution from the second nozzle 6b.

[0061] The plating apparatus 100 is equipped with a mixing section 15 below the metal pipe 2 and the partition pipe 3, and above the spray section 6. The mixing section 15 is the region where the plating solution sprayed from the first 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 15 is made of an insulating material and has an inverted frustoconical recess formed on its upper surface. An inverted frustoconical is a frustoconical cone 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.

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

[0063] The plating apparatus 100 is equipped with 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 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 first injection port 6a of the injection section 6 and ejected (discharged) from the upper opening of the hollow section 2a of the metal tube 2, are agitated. The guide section 16 is made of an insulating material and, in this embodiment, has the shape of an inverted frustocone. 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 is open to 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 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 17. A cylindrical suppression plate 17a is also formed on the lower surface of the reflector 17. The suppression plate 17a is located inside the guide section 16. The plating solution may overflow from the upper edge of the guide section 16, but the suppression plate 17a prevents only the plating solution from overflowing from the guide section 16, thus preventing the workpiece, media, and insulating balls from overflowing.

[0065] The plating apparatus 100 is equipped with a power supply 18. One line of the power supply 18 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 18 applies current between the metal tube 2, which is the first electrode, and the second electrode 5.

[0066] In the first embodiment of the plating apparatus 100 having the above structure, the velocity of the plating solution sprayed from the first nozzle 6a of the spray unit 6 is controlled (adjusted) by providing a flow velocity control plate 8 and a cylindrical member 10. Specifically, the velocity of the plating solution sprayed from the first nozzle 6a of the spray unit 6 after passing through the central part 8a of the flow velocity control plate 8 and then the inside of the cylindrical member 10 is suppressed (decelerated) compared to the velocity of the plating solution sprayed from the first nozzle 6a of the spray unit 6 after passing through the peripheral part 8b of the flow velocity control plate 8 and then the outside of the cylindrical member 10.

[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, it is thought that the objects to be plated that are ejected from the upper end of the metal tube 2 and rise to a high position in the plating solution stored in the plating tank are mainly those that rose rapidly through the center of the metal tube 2 where the plating solution speed is faster.

[0068] In the plating apparatus 100, the velocity of the plating solution that passes inside the cylindrical member 10 and is ejected from the first nozzle 6a of the ejection unit 6 is slower than the velocity of the plating solution that passes outside the cylindrical member 10 and is ejected from the first nozzle 6a of the ejection unit 6. Therefore, the velocity of the plating solution rising in the center of the metal tube 2 is suppressed. More specifically, when the amount of plating solution ejected from the ejection unit 6 is constant, the plating apparatus 100 can reduce the velocity of the plating solution rising in the center of the metal tube 2 compared to when the flow velocity control plate 8 and the cylindrical member 10 are not provided.

[0069] Therefore, even if the plating apparatus 100 increases the amount of plating solution sprayed from the spray unit 6, shortens the time required for the object to be plated to pass through the plating forming unit 4 once, and increases the number of times the object to be plated circulates through the plating apparatus, the object to be plated will not rise too high in the stored plating solution. As a result, the plating apparatus 100 suppresses defects such as cracks, chips, and peeling of the plating film on the object to be plated that would otherwise occur due to the object to rise too high in the stored plating solution.

[0070] (Example of use of plating apparatus 100) The following is an example of a plating process using the plating apparatus 100.

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

[0072] Next, the objects to be plated, media, and insulating balls, each with a desired shape, dimensions, and quantity, are placed into the guide section 16 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.

[0073] Next, the pump 13 is activated to spray the plating solution from the first 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 objects 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 15, mix with the sprayed plating solution, and rise up the inside of the metal tube 2 carried by the upward flow.

[0074] 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.

[0075] 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.

[0076] 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 15. In this way, the material to be plated, media, and insulating balls circulate inside the plating apparatus 100.

[0077] Next, the power supply 18 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.

[0078] 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 18 is stopped to stop the plating process on the object. Subsequently, the pump 13 is stopped 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 plating tank 1, and then sorting the objects to be plated.

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

[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 velocity control plate 8 and the inner diameter of the cylindrical member 10. Furthermore, the plating apparatus other than the plating apparatus of the present invention used in Comparative Example 1 differs from the plating apparatus 100 in that it does not have a flow velocity control plate 8 and a cylindrical 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 are common to all except for the flow rate control plate 8 and the cylindrical member 10. For example, the length of the plating forming 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 made circular with a diameter of 28 mm, and the central part 8a of the flow rate control plate 8 was made circular with a diameter of 15 mm. In addition, the tubular member 10 of the plating apparatus 100 used in Example 1 was made cylindrical with an inner diameter of 15 mm.

[0084] Furthermore, the plating apparatus 100 used in Example 1 had multiple holes 9a with a diameter of 1.2 mm formed in the central part 8a of the flow velocity control plate 8, and multiple holes 9b with a diameter of 3.0 mm formed in the peripheral part 8b of the flow velocity control plate 8. The pattern shape of the central part 8a where the holes 9a are formed and the pattern shape of the peripheral part 8b where the holes 9b are formed are similar in shape. That is, the pattern shape of the peripheral part 8b where the holes 9b are formed is the same as the pattern shape of the central part 8a where the holes 9a are formed, but enlarged until the diameter of the holes is 3.0 mm, including the spacing between the holes.

[0085] The plating solution was placed in the plating tank 1 of the plating apparatus 100.

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

[0087] Pump 13 was driven at low output to spray the plating solution from the first nozzle 6a of the injection unit 6, circulating the workpiece, media, and insulating balls in the following order: mixing unit 15, hollow section 2a of metal pipe 2, guide unit 16, plating forming unit 4, and mixing unit 15. The output of pump 13 was gradually increased to increase the circulation speed of the workpiece, media, and insulating balls. When the workpiece discharged from the upper end of the hollow section 2a of metal pipe 2 that rose relatively high (sprayed up) in the stored plating solution reached a predetermined height, the output of pump 13 was stopped and the output of pump 13 was kept constant. Specifically, when the workpiece discharged from the upper end of the hollow section 2a of metal pipe 2 that rose relatively high in the stored plating solution reached half the height between the upper end of metal pipe 2 and the liquid surface of the plating solution contained in the plating tank 1, the output of pump 13 was kept constant.

[0088] Next, the power supply 18 was activated, and current was applied between the metal tube 2, which is the first electrode, and the second electrode 5, and the 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 nozzle 6a of the spray unit 6 (the flow rate of the plating solution) was measured. Also in this state, the time required for each object to be plated to pass through the plating forming 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 be plated to pass through the plating forming 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 velocity control plate 8 was made circular with a diameter of 28 mm, the central part 8a of the flow velocity control plate 8 was made circular with a diameter of 20 mm, and the cylindrical member 10 was made cylindrical with an inner diameter of 20 mm.

[0092] Furthermore, the plating apparatus 100 used in Example 2 also had multiple holes 9a with a diameter of 1.2 mm formed in the central part 8a of the flow velocity control plate 8, and multiple holes 9b with a diameter of 3.0 mm formed in the peripheral part 8b of the flow velocity control plate 8, similar to Example 1. The pattern shape of the central part 8a where the holes 9a are formed and the pattern shape of the peripheral part 8b where the holes 9b are formed are similar, 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, under the same conditions as in Example 1, the object to be plated, media, and insulating balls were placed in the guide section 16 inside the plating tank 1 of the plating apparatus 100.

[0095] In Example 2, under the same conditions as in Example 1, the pump 13 was driven at a low output, and then the output of the pump 13 was gradually increased. When the amount of material to be plated that rose relatively high in the stored plating solution, among the material to be plated discharged from the upper end of the hollow portion 2a of the metal pipe 2, reached half the height between the upper end of the metal pipe 2 and the liquid level of the plating solution contained in the plating tank 1, the output of the pump 13 was set to a constant value. Subsequently, the power supply 18 was driven, and current was applied between the metal pipe 2, which is the first electrode, and the second electrode 5, and plating of the material to be plated was started in the plating forming section 4.

[0096] In Example 2, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 (the flow rate of the plating solution) was measured in this state. In addition, the time required for each object to be plated to pass through the plating forming 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 be plated to pass through the plating forming 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 does not have a flow rate control plate 8 and a 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, under the same conditions as in Examples 1 and 2, the object to be plated, media, and insulating balls were placed in the guide section 16 of the plating tank 1 of the plating apparatus 100.

[0101] In Comparative Example 1, under the same conditions as in Examples 1 and 2, the pump 13 was driven at a low output, and then the output of the pump 13 was gradually increased. When the amount of material to be plated that rose relatively high in the stored plating solution, among the material to be plated discharged from the upper end of the hollow portion 2a of the metal tube 2, reached half the height between the upper end of the metal tube 2 and the liquid level of the plating solution contained in the plating tank 1, the output of the pump 13 was set to a constant value. Subsequently, the power supply 18 was driven, and current was applied between the metal tube 2, which is the first electrode, and the second electrode 5, and plating of the material to be plated was started in the plating forming section 4.

[0102] In Comparative Example 1, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 (the flow rate of the plating solution) was measured in this state. In addition, the time required for each object to be plated to pass through the plating forming unit 4 once was measured in this state.

[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 be plated to pass through the plating forming unit 4 once was 16.7 seconds.

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

[0105] As can be seen from Table 1, under the condition that the output of the pump 13 is kept constant (maintained) when the material to be plated, which is discharged from the upper end of the hollow section 2a of the metal pipe 2 and rises relatively high in the stored plating solution, reaches half the height between the upper end of the metal pipe 2 and the liquid level 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 material to be plated to pass through the plating forming section 4 once, compared to Comparative Example 1.

[0106] Furthermore, when comparing Example 1 and Example 2, Example 2, in which the diameter of the central portion 8a of the flow velocity control plate 8 and the inner diameter of the cylindrical member 10 are larger, 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 section 4 once, compared to Example 1, in which the diameter of the central portion 8a of the flow velocity control plate 8 and the inner diameter of the cylindrical member 10 are smaller. When implementing the present invention, it is considered that making the diameter of the central portion 8a of the flow velocity control plate 8 and the inner diameter of the cylindrical member 10 relatively larger, which suppresses the speed of the plating solution, will allow for 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 section 4 once.

[0107] From the above, it has been found that, according to the present invention, while suppressing the occurrence of defects in the plated object, variations in the thickness of the formed plating film can be suppressed by increasing the flow rate of the plating solution and increasing the number of times the object to be plated circulates through the plating apparatus.

[0108] [Second Embodiment] Figure 7 shows a plating apparatus 200 according to the second embodiment. However, Figure 7 is a plan view of the main part of the plating apparatus 200. Specifically, Figure 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 has been modified in part from the plating apparatus 100 according to the first embodiment described above. The modifications are described below.

[0110] In the first embodiment, the flow velocity control plate 8 of the plating apparatus 100 had an opening area of ​​each hole 9a formed in the central part 8a that was smaller than the opening area of ​​each hole 9b formed in the peripheral part 8b. In contrast, in the second embodiment, the flow velocity control plate 28 of the plating apparatus 200 had an opening area of ​​each hole 29a formed in the central part 28a that was the same as the opening area of ​​each hole 29b formed in the peripheral part 28b. However, in the flow velocity control plate 28 of the plating apparatus 200, the number of holes 29a per unit area formed in the central part 28a was less than the number of holes 29b per unit area formed in the peripheral part 28b. The other configurations of the plating apparatus were 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 that passes through the central part 28a of the flow velocity control plate 28, then passes inside the cylindrical member 10, and is sprayed from the first nozzle 6a of the spray unit 6 is suppressed (decelerated) compared to the velocity of the plating solution that passes through the peripheral part 28b of the flow velocity control plate 28, then passes outside the cylindrical member 10, and is sprayed from the first nozzle 6a of the spray unit 6. Therefore, even in the plating apparatus 200, even if the amount of plating solution sprayed from the spray unit 6 is increased for purposes such as suppressing variations in the thickness of the plating film, and the time required for the object to be plated to pass through the plating forming part 4 once is shortened, and the number of times the object to be plated circulates through the plating apparatus is increased, defects in the object to be plated are less likely to occur.

[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 content, 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 was composed of a single layer of mesh throughout. However, as shown in Figure 6(A), for example, the mesh member 7' may be composed of a central mesh portion 7a and a peripheral mesh portion 7b provided outside the central mesh portion 7a, with the central mesh portion 7a being composed of multiple layers of mesh and the peripheral mesh portion 7b being composed of a single layer of mesh. In this case, even in the mesh member 7', the speed of the plating solution passing through the central mesh portion 7a can be suppressed more than the speed of the plating solution passing through the peripheral mesh portion 7b, further enhancing the effects of the present invention.

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

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

[0117] Furthermore, it is preferable that the opening area of ​​each hole formed in the central part is the same as the opening area of ​​each hole formed in the peripheral part, but the number of holes per unit area formed in the central part is less than the number of holes per unit area formed in the peripheral part. In this case, the speed of the plating solution passing through the central part can be suppressed compared to the speed of the plating solution passing through the peripheral part.

[0118] It is also preferable that the total opening area per unit area of ​​the multiple holes formed in the central part is smaller than the total opening area per unit area of ​​the multiple holes formed in the peripheral part. In this case, the speed of the plating solution passing through the central part can be suppressed compared to the speed of the plating solution passing through the peripheral part.

[0119] In these plating apparatuses, when the flow velocity control plate and the cylindrical member are viewed in a planar direction, it is also preferable that the central part of the flow velocity control plate is positioned inside the cylindrical member, and the peripheral part of the flow velocity control plate is positioned outside the cylindrical member. In this case, the difference between the velocity of the plating solution passing through the central part and the velocity of the plating solution passing through the peripheral part, generated by the flow velocity control plate, can be maintained until it reaches the first nozzle of the injection unit.

[0120] When the flow velocity control plate is viewed in a planar direction, it is also preferable that the holes formed in the center and the holes formed around the periphery are circular. In this case, it becomes easier to form holes in the flow velocity control plate.

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

[0122] It is also preferable to provide a cylindrical metal tube with a hollow section directly above the injection section. In this case, the speed of the plating solution rising inside the metal tube can be controlled, and in particular, the flow of the plating solution rising at a high speed in the center of the metal tube can be suppressed (decelerated).

[0123] The plating system comprises a cylindrical partition tube made of an insulating material, having a hollow section and multiple 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 is the first electrode, and the metal tube, partition tube, and second electrode are each housed in a plating tank. The metal tube is placed inside the hollow section of the partition tube, and a plating formation section is formed between the inside of the partition tube and the outside of the metal tube. The second electrode is placed outside the partition tube, and the spraying section is provided below the metal tube. The object to be plated is carried upward by the rising flow of the plating solution sprayed by the spraying section, rises through the hollow section of the metal tube, is discharged to the outside from the upper end of the hollow section of the metal tube, is stirred in the plating solution, and then descends through the plating formation section. It is also preferable that a current is applied between the metal tube, which is the first electrode, and the second electrode during the descent to plate the object. In this case, the speed at which the plating solution rises inside the metal tube can be controlled, and in particular, the flow of the plating solution rising at a high speed in the center of the metal tube can be suppressed (decelerated). The first electrode is, for example, a cathode electrode, and the second electrode is, for example, an anode electrode. [Explanation of Symbols]

[0124] 1. Plating tank 2. Metal tube (first electrode; cathode) 2a...Hollow part 2b...Support part 3...Bulkhead pipe 3a...Hollow part 3b...hole 4. Plating formation section 5. Second electrode (anode) 6...Injection part 6a...1st injection port 6b...Second injection port 7, 7', 7"... Mesh components 7a...Center of the mesh 7b... Mesh periphery 8, 28... Flow velocity control plate 8a, 28a...Central part 8b, 28b... Peripheral area 9, 29...hole 9a, 29a... Holes (formed in the central part 8a) 9b, 29b... Holes (formed in the peripheral area 8b) 10. Cylindrical member 11. Circulation Line 12...Liquid suction port 13... Pump 14.. Filter 15...Mixing section 16...guiding section 17. Reflector (deflector) 17a...Suppression plate 18...Power supply

Claims

1. A plating tank for storing the plating solution containing the object to be plated, The plating tank comprises an injection unit formed therein for spraying the plating solution, A plating apparatus wherein the object to be plated, contained in the plating solution, is agitated by the plating solution sprayed from the spraying unit, The injection section is shaped like an inner cylinder, having a bottom surface that extends horizontally, an inner wall that extends 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 spraying the plating solution into the plating tank. A mesh member is provided at the first injection nozzle. A second nozzle for spraying the plating solution into the injection section is provided on the bottom surface. A flow velocity control plate with multiple holes formed parallel to the bottom surface is provided in the middle of the height direction of the injection section. The flow velocity control plate, when viewed in a planar direction, has a central portion and a peripheral portion provided outside the central portion. Multiple holes are formed in the central portion and the peripheral portion, respectively. A cylindrical member having a hollow portion is provided between the flow velocity control plate and the mesh member of the first injection port. 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. Plating equipment.

2. The opening area of ​​each hole formed in the central part is smaller than the opening area of ​​each hole formed in the peripheral part. A plating apparatus as described in claim 1.

3. The opening area of ​​each hole formed in the central part and the opening area of ​​each hole formed in the peripheral part are the same, but the number of holes per unit area formed in the central part is less than the number of holes per unit area formed in the peripheral part. A plating apparatus as described in claim 1.

4. When the flow velocity control plate and the cylindrical member are viewed in the planar direction, The central portion of the flow velocity control plate is positioned inside the cylindrical member. The peripheral portion of the flow velocity control plate is positioned on the outside of the cylindrical member. A plating apparatus according to any one of claims 1 to 3.

5. When the flow velocity control plate is viewed in the planar direction, The hole formed in the central part and the hole formed in the peripheral part are both circular. A plating apparatus according to any one of claims 1 to 3.

6. The mesh member, when viewed in a planar direction, has a mesh center portion and a mesh peripheral portion provided outside the mesh center portion. The opening of the mesh in the center is smaller than the opening of the mesh around the periphery. A plating apparatus according to any one of claims 1 to 3.

7. The mesh member in the peripheral part of the mesh consists of one layer of mesh. The mesh member in the central part of the mesh consists of multiple layers of mesh. The plating apparatus according to claim 6.

8. A cylindrical metal tube having a hollow section is provided directly above the aforementioned injection section. A plating apparatus according to any one of claims 1 to 3.

9. A partition tube made of an insulating material, having a hollow section, and having multiple holes formed therein that allow the plating solution to pass through but prevent the object to be plated from passing through, A second electrode is provided, The metal tube is the first electrode, The metal tube, the partition tube, and the second electrode are each housed in the plating tank. The metal pipe is placed within the hollow portion of the partition pipe, and a plating portion is formed between the inside of the partition pipe and the outside of the metal pipe. The second electrode is positioned on the outside of the partition tube. The injection unit is provided below the metal pipe, The plated object is, The plating solution sprayed by the injection unit rises through the hollow portion of the metal tube, carried by the upward flow of the plating solution. After being discharged from the upper end of the hollow portion of the metal tube and stirred in the plating solution, Descending through the aforementioned plating forming section, During the aforementioned descent, a current is applied between the metal tube, which is the first electrode, and the second electrode, thereby causing plating. A plating apparatus as described in claim 8.

10. The first electrode is a cathode electrode, The second electrode is the anode electrode. A plating apparatus as described in claim 9.

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