Plating equipment

Abstract

Provided is a plating apparatus that suppresses the occurrence of defects in a plated object without the plated object rising excessively to a high position in a plating solution in which the plated object is contained, even if the flow rate of the plating solution sprayed from a spraying unit is increased.　The plating apparatus according to the present invention comprises: a plating tank that stores the plating solution and contains the plated object; and the spraying unit, which includes a first spraying port that is formed in the plating tank and sprays the plating solution, the plated object in the plating solution being agitated by the plating solution sprayed from the spraying unit. A mesh member is provided to the first spraying port of the spraying unit. The mesh member is formed by overlapping at least two meshes, and, when viewed in a planar direction, the mesh member includes a center portion and a peripheral portion provided to the outside of the center portion. The peripheral portion is formed using a layer of one mesh or a layer of a plurality of meshes. The center portion is formed in a layer of a plurality of meshes, and the number of layers of the mesh in the center portion is greater than the number of layers of the mesh in the peripheral portion.

Description

Technical Field

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

Background Art

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

[0003] The plating apparatus disclosed in Patent Document 1 includes a plating tank. Inside the plating tank, a metal tube (cathode) as a first electrode, a partition tube made of an insulating material, and a second electrode (anode) are accommodated. Note that 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 portion is formed between the inner side of the partition tube and the outer side of the metal tube. The plating formation portion 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 portion having an injection port for injecting the plating solution is provided. The injection portion 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 portion so that the object to be plated and media do not fall into the injection portion 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 having a first spray nozzle 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 a mesh member is provided at the first spray nozzle of the spray unit, the mesh member is formed by overlapping at least two meshes, and when viewed in a planar direction, the mesh member has a central part and a peripheral part provided outside the central part, the peripheral part is formed of one mesh layer or multiple mesh layers, and the central part is formed of multiple mesh layers, the number of mesh layers in the central part is greater than the number of mesh layers in the peripheral part.

Advantages of the Invention

[0019] Even if the flow rate of the plating solution jetted from the jetting section is increased, the object to be plated does not rise too high in the plating solution in which the object to be plated is stored, and the occurrence of defects in the object to be plated is suppressed. The following provides supplementary explanations.

[0020] 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. The speed is higher at the center of the metal tube and lower at the peripheral part closer to the inner wall of the metal tube. This is because resistance occurs in the flow of the plating solution at the peripheral part closer to the inner wall of the metal tube, suppressing the speed of the plating solution.

[0021] Also, in the case where an inner cylindrical jetting section is provided on the bottom surface of the plating tank of the plating apparatus, a first jetting port is provided above the jetting section, and a second jetting port for jetting the plating solution into the jetting section is provided on the bottom surface of the jetting section, even when the diameter of the second jetting 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 at the peripheral part closer to the inner wall of the metal tube.

[0022] On the other hand, when the flow rate of the plating solution jetted from the jetting section is increased, not all the objects to be plated 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 objects to be plated that rise to a high position in the plating solution stored in the plating tank are mainly considered to be the objects to be plated that have passed through (risen) through the center of the metal tube where the speed of the plating solution is fast in one go.

[0023] The plating apparatus according to an embodiment of the present invention suppresses the speed of the plating solution passing through (rising) inside the metal tube at the center of the metal tube. Therefore, even if the flow rate of the plating solution jetted from the jetting section is increased, the object to be plated does not rise too high in the plating solution in which the object to be plated is stored, and the occurrence of defects in the object to be plated is suppressed.

Brief Description of the Drawings

[0024] [Figure 1] It is a cross-sectional view of the plating apparatus 100 according to the embodiment. [Figure 2] It is a cross-sectional view of the plating apparatus 100, showing the partial cross-section along the dashed-dotted arrow A-A in FIG. 1. [Figure 3] It is a cross-sectional view of the main part of the plating apparatus 100. [Figure 4] FIG. 4(A) is a plan view of the mesh member 7 of the plating apparatus 100. FIG. 4(B) is a plan view of a mesh member 7' which is a modified example of the mesh member 7.

Embodiments for Carrying Out the Invention

[0025] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0026] Each embodiment exemplarily shows an embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Also, it is possible to combine the content described in different embodiments and implement it, and the implementation content in that case is also included in the present invention. Further, the drawings are for assisting the understanding of the specification and may be drawn schematically, and the ratio of the drawn components or the dimensions between the components may not match the ratio of those dimensions described in the specification. Also, there may be cases where the components described in the specification are omitted in the drawings or the number is omitted in the drawing.

[0027] FIGS. 1, 2, 3, 4(A), and (B) show the plating apparatus 100 according to the embodiment. However, FIG. 1 is a cross-sectional view of the plating apparatus 100. FIG. 2 is also a cross-sectional view of the plating apparatus 100, showing the partial cross-section along the dashed-dotted arrow A-A in FIG. 1. FIG. 3 is a cross-sectional view of the main part of the plating apparatus 100. FIG. 4(A) is a plan view of the mesh member 7 of the plating apparatus 100. FIG. 4(B) is a plan view of a mesh member 7' which is a modified example of the mesh member 7.

[0028] The plating apparatus 100 includes a plating tank 1. The plating tank 1 is open at the top. The plating tank 1 is for storing a mixture 16 of the plating solution, the object to be plated, the media, and insulating balls, which will be described later. However, the insulating balls can be omitted if they are not needed.

[0029] 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.

[0030] 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.

[0031] 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 ball. 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; for example, various resins can be used.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The plating apparatus 100 is equipped with a spray unit 6 below the metal tube 2. The spray unit 6 is for generating an upward flow of plating solution inside the metal tube 2. In this embodiment, the spray unit 6 is an inner cylinder having a bottom surface and an 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 have other shapes.

[0037] A first nozzle 6a is formed at the upper end of the injection unit 6. 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.

[0038] 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.

[0039] 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.

[0040] In this embodiment, the mesh member 7 is formed by overlapping two meshes (mesh-like members). However, the mesh member 7 only needs to be formed by overlapping at least two meshes, and may be formed by overlapping three or more meshes. In this embodiment, as shown in Figures 1 and 3, the mesh member 7 is formed of a first mesh layer 7a and a second mesh layer 7b.

[0041] The first mesh layer 7a and the second mesh layer 7b are each composed of mesh. Preferably, the first mesh layer 7a and the second mesh layer 7b are insulating. The material of the first mesh layer 7a and the second mesh layer 7b is arbitrary, but nylon can be used, for example. The first mesh layer 7a and the second mesh layer 7b can be joined together, for example, with an adhesive, or they can be simply overlapped and their ends fixed.

[0042] When viewed in a planar direction, the mesh member 7 has a central portion 7c formed by a first mesh layer 7a and a second mesh layer 7b, as shown in Figure 4(A), and a peripheral portion 7d provided outside the central portion 7c, which is formed only by the first mesh layer 7a.

[0043] In this embodiment, as shown in Figure 4(A), the second mesh layer 7b of the central portion 7c is circular. However, the shape of the central portion 7c is arbitrary. For example, as shown in the modified example in Figure 4(B), the second mesh layer 7b' of the central portion 7c may be square (rectangle) or the like.

[0044] The mesh opening of the first mesh layer 7a and the mesh opening of the second mesh layer 7b may be the same or different. In this embodiment, a mesh with a mesh opening of 900 μm was used for both the first mesh layer 7a and the second mesh layer 7b. 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.

[0045] When we refer to mesh opening, it generally means the opening of a single layer of mesh. However, in the present application documents, when multiple meshes are layered, 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 (or the opening of that mesh layered with another mesh), the latter will be smaller (finer) than the former.

[0046] In this embodiment, when viewed in a planar direction, the mesh member 7 has a smaller opening in the central portion 7c, which consists of two layers of mesh, than in the peripheral portion 7d, which consists of one layer of mesh. Note that if the vertical and horizontal lines of the first mesh layer 7a in the central portion 7c completely overlap with the vertical and horizontal lines of the second mesh layer 7b, the openings of the central portion 7c and the peripheral portion 7d will be the same; however, this does not usually occur.

[0047] The central portion 7c of the mesh member 7 is not limited to a double mesh structure consisting of two layers of mesh. For example, the central portion 7c may be a triple mesh structure consisting of three layers of mesh, and the peripheral portion 7d may be a single mesh structure consisting of one layer of mesh. Alternatively, an intermediate portion (not shown) may be provided between the central portion 7c and the peripheral portion 7d, with the central portion 7c being a triple mesh structure, the intermediate portion a double mesh structure, and the peripheral portion 7d a single mesh structure. In other words, in the mesh member 7, the number of mesh layers should be increased in the area where the passage of the plating solution is to be suppressed. The peripheral portion 7d is basically sufficient as a single mesh structure consisting of one layer of mesh, but it may also be a multi-mesh structure consisting of multiple layers of mesh. Thus, various variations can be adopted in the structure of the mesh member 7.

[0048] In this embodiment, as shown in Figures 1 and 3, the mesh member 7 is constructed with a first mesh layer 7a covering the entire area of ​​the mesh member 7 on top and a second mesh layer 7b covering a portion of the mesh member 7 on the bottom. The outer edge of the mesh member 7 is attached to the first injection nozzle 6a. Since the plating solution is sprayed from bottom to top at the first injection nozzle 6a, this structure prevents the second mesh layer 7b from peeling off from the first mesh layer 7a.

[0049] In the plating apparatus 100, the force of the plating solution passing through the mesh member 7 is suppressed in the central section 7c, which has a double mesh structure. In addition, in the plating apparatus 100, the force of the plating solution sprayed from the second nozzle 6b is suppressed by the central section 7c, which has a double mesh structure.

[0050] The plating apparatus 100 is equipped with a circulation line 8 formed of pipes. One end of the circulation line 8 is connected to a liquid intake port 9 formed in the plating tank 1. The other end of the circulation line 8 is connected to the second nozzle 6b of the spray unit 6. A pump 10 and a filter 11 are provided in the middle of the circulation line 8. When the pump 10 is driven, the circulation line 8 draws in the plating solution from the liquid intake port 9 and sprays the plating solution from the second nozzle 6b.

[0051] The plating apparatus 100 is equipped with a mixing section 12 below the metal pipe 2 and the partition pipe 3, and above the spray section 6. The mixing section 12 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 12 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.

[0052] The first nozzle 6a of the spray unit 6 is located on the bottom surface of the mixing unit 12. 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.

[0053] The plating apparatus 100 is equipped with a guide section 13 above the metal tube 2 and the partition tube 3. The guide section 13 is a region where the workpiece to be plated, media, and insulating balls, which are stirred 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 13 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 13. The upper end of the hollow section 2a of the metal tube 2 opens to the bottom surface of the guide section 13. The bottom surface of the guide section 13 is connected to the partition tube 3.

[0054] The plating apparatus 100 is equipped with an insulating reflector 14 above the opening of the plating tank 1. The reflector 14 is sometimes called a deflector. The reflector 14 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 14. A cylindrical suppression plate 14a is also formed on the lower surface of the reflector 14. The suppression plate 14a is located inside the guide section 13. The plating solution may overflow from the upper edge of the guide section 13, but the suppression plate 14a prevents only the plating solution from overflowing from the guide section 13, thus preventing the workpiece, media, and insulating balls from overflowing.

[0055] The plating apparatus 100 is equipped with a power supply 15. One line of the power supply 15 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 15 applies current between the metal tube 2, which is the first electrode, and the second electrode 5.

[0056] In the first embodiment of the plating apparatus 100 having the above structure, the force of the plating solution sprayed from the first nozzle 6a of the spray unit 6 is controlled (adjusted) by the mesh member 7. Specifically, the force of the plating solution sprayed from the first nozzle 6a of the spray unit 6 and passing through the mesh member 7 is suppressed in the central part 7c, where the first mesh layer 7a and the second mesh layer 7b are formed in overlapping form, compared to the peripheral part 7d, which is formed only by the first mesh layer 7a.

[0057] 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.

[0058] In the plating apparatus 100, the force of the plating solution sprayed from the first nozzle 6a of the spray unit 6 is suppressed in the central part 7c, where the first mesh layer 7a and the second mesh layer 7b are superimposed, compared to the peripheral part 7d, which is formed only by the first mesh layer 7a. Therefore, the force of the plating solution rising up the center of the metal pipe 2 can be suppressed. 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 up the center of the metal pipe 2 compared to the case where a mesh member consisting of a single mesh layer is provided at the first nozzle 6a of the spray unit 6, as in the conventional case.

[0059] 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.

[0060] The plating apparatus 100 increases the amount of plating solution sprayed from the spray unit 6 to suppress variations in the thickness of the plating film, 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, making it less likely for defects to occur in the object to be plated.

[0061] (Example of use of plating apparatus 100) The following is an example of a plating process using the plating apparatus 100.

[0062] First, the desired plating solution is poured into plating tank 1.

[0063] Next, the objects to be plated, media, and insulating balls, each with a desired shape, dimensions, and quantity, are placed into the guide section 13 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 are deposited in the plating forming section 4.

[0064] Next, the pump 10 is driven 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 12, mix with the sprayed plating solution, and rise up the inside of the metal tube 2 carried by the upward flow.

[0065] 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.

[0066] 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.

[0067] 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 12. In this way, the material to be plated, media, and insulating balls circulate inside the plating apparatus 100.

[0068] Next, the power supply 15 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.

[0069] 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 15 is stopped to stop the plating process on the object. Subsequently, the pump 10 is stopped to stop the object to be plated, the media, and the insulating balls from circulating inside the plating apparatus 100.

[0070] 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.

[0071] (experiment) To confirm the effectiveness of the present invention, the following experiments were conducted. Specifically, Example 1 was carried out using the plating apparatus of the present invention, and Comparative Examples 1 and 2 were carried out using plating apparatus other than the plating apparatus of the present invention.

[0072] First, Example 1 was carried out. Example 1 used the plating apparatus 100 of the embodiment described above. In the plating apparatus 100 of Example 1, the first nozzle 6a of the spraying section 6 was made circular with a diameter of 28 mm. Also, in the plating apparatus 100 of Example 1, the length of the plating forming section 4 was made 220 mm.

[0073] The first nozzle 6a of the spray section 6 of the plating apparatus 100 is provided with a mesh member 7 as shown in Figure 4(A). The mesh member 7 is circular with a diameter of 28 mm, just like the first nozzle 6a. The central part 7c of the mesh member 7 is circular with a diameter of 20 mm. The central part 7c of the mesh member 7 has a double mesh structure, consisting of a first mesh layer 7a with an opening of 900 μm and a second mesh layer 7b with an opening of 900 μm. The peripheral part 7d of the mesh member 7 has a single mesh structure, consisting only of the first mesh layer 7a with an opening of 900 μm.

[0074] The plating solution was placed in the plating tank 1 of the plating apparatus 100. Ni plating solution was used as the plating solution.

[0075] The workpiece, media, and insulating balls were placed into the guide section 13 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.

[0076] Pump 10 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 12, hollow section 2a of metal tube 2, guide unit 13, plating forming unit 4, and mixing unit 12. The output of pump 10 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 tube 2 that rose relatively high (sprayed up) in the stored plating solution reached a predetermined height, the output of pump 10 was stopped and the output of pump 10 was kept constant. Specifically, when the workpiece discharged from the upper end of the hollow section 2a of metal tube 2 that rose relatively high in the stored plating solution reached half the height between the upper end of metal tube 2 and the liquid surface of the plating solution contained in the plating tank 1, the output of pump 10 was kept constant.

[0077] Next, the power supply 15 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.

[0078] 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.

[0079] 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 10.8 seconds.

[0080] Next, Comparative Example 1 was carried out. Comparative Example 1 used a plating apparatus 1100 (not shown) which was a modified version of the plating apparatus 100 used in Example 1.

[0081] The plating apparatus 1100 differs from the mesh member 7 of Example 1 in that the mesh member 17 (not shown) is modified. Specifically, the mesh member 17 of Comparative Example 1 has a single-mesh structure, consisting of a single layer of mesh with an opening of 900 μm across its entire surface.

[0082] In Comparative Example 1, under the same conditions as in Example 1, the plating solution was placed in the plating tank 1, and the object to be plated, media, and insulating balls were placed in the guide section 13 inside the plating tank 1.

[0083] In Comparative Example 1, under the same conditions as in Example 1, the pump 10 was driven at a low output, and then the output of the pump 10 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 10 was set to a constant value. Subsequently, the power supply 15 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.

[0084] In Comparative Example 1, under these conditions, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 and the time required for each object to be plated to pass through the plating forming unit 4 once were measured.

[0085] In Comparative Example 1, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 was 35 L / min. Also, in Comparative Example 1, the time required for each object to be plated to pass through the plating forming unit 4 once was 18.4 seconds.

[0086] Next, Comparative Example 2 was carried out. Comparative Example 2 used a plating apparatus 1200 (not shown) which was a modified version of the plating apparatus 100 used in Example 1.

[0087] The plating apparatus 1200 differs from the mesh member 7 of Example 1 in that the mesh member 27 (not shown) is modified. Specifically, the mesh member 27 of Comparative Example 2 has a double-mesh structure in which two layers of mesh with an opening of 900 μm are stacked on top of each other across its entire surface.

[0088] In Comparative Example 2, under the same conditions as in Example 1 and Comparative Example 1, the plating solution was placed in the plating tank 1, and the object to be plated, media, and insulating balls were placed in the guide section 13 inside the plating tank 1.

[0089] In Comparative Example 1, under the same conditions as in Example 1 and Comparative Example 1, the pump 10 was driven at a low output, and then the output of the pump 10 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 10 was set to a constant value. Subsequently, the power supply 15 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.

[0090] In Comparative Example 1, under these conditions, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 and the time required for each object to be plated to pass through the plating forming unit 4 once were measured.

[0091] In Comparative Example 2, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 was 32 L / min. Also in Comparative Example 2, the time required for each object to be plated to pass through the plating forming unit 4 once was 11.2 seconds.

[0092] Table 1 shows the details and experimental results of Example 1, Comparative Example 1, and Comparative Example 2. [Table 1]

[0093] As can be seen from Table 1, under the condition that the output of the pump 10 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, 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, Example 1 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 Examples 1 and 2.

[0094] From the above, it has been found that, according to the present invention, it is possible to suppress defects such as cracks, chips, and peeling of the plating film in the object to be plated, and to increase the flow rate of the plating solution and shorten the time required for the object to be plated to pass through the plating forming section 4 once, compared to a structure in which the mesh member is a single mesh over the entire surface (Comparative Example 1) or a structure in which the mesh member is a double mesh over the entire surface (Comparative Example 2).

[0095] 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, increasing the number of times the object to be plated circulates through the plating apparatus, and suppressing variations in the thickness of the formed plating film.

[0096] The plating apparatus according to the embodiment 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.

[0097] For example, in the above embodiment, the central part 7c of the mesh member 7 has a double mesh structure and the peripheral part 7d of the mesh member 7 has a single mesh structure, but the present invention is not limited to this structure. For example, if it is desired to further suppress the amount of plating solution passing through the central part 7c of the mesh member 7, the central part 7c may have a triple mesh structure, a quadruple mesh structure, or even more multi-mesh structures.

[0098] Furthermore, when viewed in a planar direction, the mesh member 7 does not necessarily have to consist only of a central portion 7c and a peripheral portion 7d; for example, an intermediate portion may be provided between the central portion 7c and the peripheral portion 7d. For example, the central portion 7c may have a triple mesh structure, the intermediate portion a double mesh structure, and the peripheral portion 7d a single mesh structure.

[0099] The plating apparatus according to one embodiment of the present invention is as described in the "Means for Solving the Problem" section.

[0100] In this plating apparatus, it is also preferable to provide a cylindrical metal tube having a hollow section directly above the spray section. In this case, the flow of the fast-moving plating solution rising in the center of the metal tube can be suppressed (decelerated).

[0101] Furthermore, it is preferable that the mesh in the peripheral area has one layer and the mesh in the central area has two layers. In this case, the mesh member can be easily manufactured.

[0102] When viewed in a planar direction, it is preferable that the mesh opening in the center of the mesh member is smaller than the mesh opening in the periphery. In this case, the mesh member can suppress the amount of plating solution passing through the center compared to the amount passing through the periphery.

[0103] When viewed in a planar direction, it is also preferable that the central part is circular. In this case, the plating solution can be passed uniformly through the mesh member in all radial directions from the center of the mesh member.

[0104] When viewed in a planar direction, it is also preferable that the central part is polygonal. In particular, it is also preferable that the central part is quadrilateral when viewed in a planar direction. In this case, the mesh member can be easily manufactured.

[0105] Preferably, the injection unit is an inner cylinder having a bottom surface and an inner wall, with a first injection port at its upper end, and a second injection port on the bottom surface, the opening area of ​​the second injection port being smaller than the opening area of ​​the first injection port, and the plating solution being injected into the injection unit from the second injection port. In this case, the diameter of the first injection port that injects the plating solution from the injection unit into the plating tank can be made larger than the diameter of the pipe connected to the second injection port, and the velocity of the plating solution injected from the first injection port can be made more uniform as it passes through the injection unit (the difference between fast and slow parts can be reduced).

[0106] The plating system comprises a first electrode, a cylindrical metal tube having a hollow section; a partition tube made of an insulating material, which is cylindrical and has a hollow section, and has multiple holes that allow the plating solution to pass through but not the object to be plated; and a second electrode. 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, a plating formation section is formed between the inside and outside of the partition tube, the second electrode is placed outside the partition tube, the spraying section is provided below the metal tube, the object to be plated rises through the hollow section of the metal tube on the upward flow of the plating solution sprayed by the spraying section, 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 first electrode (metal tube) 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]

[0107] 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. Mesh component 7a...First mesh layer 7b...Second mesh layer 7c...Central part 7d... Peripheral area 8. Circulation Line 9...Liquid suction port 10... pump 11.. Filter 12...Mixing section 13...Induction part 14. Reflector (deflector) 14a...Suppression plate 15...Power supply

Claims

1. A plating tank for storing the plating solution containing the object to be plated, The plating tank comprises a spray section having a first spray nozzle 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, A mesh member is provided at the first nozzle of the injection unit. The aforementioned mesh member is formed by overlapping at least two meshes, The mesh member, when viewed in a planar direction, has a central portion and a peripheral portion provided outside the central portion. The peripheral portion is formed by one layer of the mesh or multiple layers of the mesh. The central portion is formed by multiple layers of the mesh, The number of mesh layers in the central portion is greater than the number of mesh layers in the peripheral portion. When viewed in the aforementioned planar direction, the opening of the central part is smaller than the opening of the peripheral part. Plating equipment.

2. A cylindrical metal tube having a hollow section is provided directly above the aforementioned injection section. A plating apparatus as described in claim 1.

3. The number of layers of the mesh in the peripheral area is one layer. The number of layers of the mesh in the central part is two. A plating apparatus according to claim 1 or 2.

4. When viewed in a planar direction, The central part is circular. A plating apparatus according to claim 1 or 2.

5. When viewed in a planar direction, The aforementioned central part is polygonal. A plating apparatus according to claim 1 or 2.

6. When viewed in a planar direction, The central part is rectangular. A plating apparatus as described in claim 5.

7. The aforementioned injection unit, It has a bottom surface and an inner wall, and the first injection port is provided at the upper end, A second injection port is provided on the bottom surface. The opening area of ​​the second injection port is smaller than the opening area of ​​the first injection port. The plating solution is sprayed from the second nozzle into the spray section. A plating apparatus according to claim 1 or 2.

8. The first electrode is a cylindrical metal tube having a hollow section, 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, the partition tube, and the second electrode are each housed in the plating bath. 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 according to claim 1 or 2.

9. The first electrode is a cathode electrode, The second electrode is the anode electrode. A plating apparatus as described in claim 8.

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