Plating apparatus

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

Plating Equipment

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0018] In order to solve the above-mentioned conventional problems, one embodiment of the plating apparatus of the present invention comprises a plating tank for storing a plating solution containing an object to be plated, and an injection unit formed in the plating tank and having a first injection port for injecting the plating solution, wherein the object to be plated contained in the plating solution is agitated by the plating solution sprayed from the injection unit, and a mesh member is provided at the first injection port of the injection unit, and the mesh member is formed by stacking at least two meshes, and when viewed in a planar direction, the mesh member has a central portion and a peripheral portion provided outside the central portion, and the peripheral portion is formed of one mesh layer or multiple mesh layers, and the central portion is formed of multiple mesh layers, and the number of mesh layers in the central portion is greater than the number of mesh layers in the peripheral portion.

[0019] In a plating apparatus according to an embodiment of the present invention, even if the flow rate of the plating solution sprayed from the spraying part is increased, the object to be plated does not rise too high in the stored plating solution, thereby suppressing the occurrence of defects in the object to be plated.

[0020] The speed at which the plating solution passes (rises) inside the metal tube, which is the first electrode, is not uniform across the entire cross section of the metal tube, but is faster in the center of the metal tube and slower in the peripheral area closer to the inner wall of the metal tube. This is because resistance to the flow of the plating solution occurs in the peripheral area closer to the inner wall of the metal tube, suppressing the speed of the plating solution.

[0021] Furthermore, in a case where an inner cylindrical injection part is provided on the bottom surface of the plating tank of the plating equipment, a first injection port is provided above the injection part, and a second injection port that injects plating solution into the injection part is provided on the bottom surface of the injection part, and the diameter of the second injection port is smaller than the inner diameter of the metal pipe, this may also cause the plating solution to move faster towards the center of the metal pipe and slower towards the periphery closer to the inner wall of the metal pipe.

[0022] On the other hand, when the flow rate of the plating solution sprayed from the spraying part is increased, not all of the objects to be plated sprayed out from the upper end of the metal pipe rise to a high position in the plating solution stored in the plating tank. The objects to be plated that rise to a high position in the plating solution stored in the plating tank are thought to be mainly objects that pass (rise) through the center of the metal pipe in one go, where the plating solution flows at a high speed.

[0023] In a plating apparatus according to one embodiment of the present invention, the speed at which the plating solution passes (rises) inside the metal tube is suppressed at the center of the metal tube. 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 in the stored plating solution, thereby suppressing the occurrence of defects in the object to be plated.

[0024] 4A is a cross-sectional view of a plating apparatus 100 according to an embodiment. FIG. 4B is a cross-sectional view of the plating apparatus 100, showing the portion indicated by the dashed-dotted arrow A-A in FIG. 1. FIG. 4C is a cross-sectional view of a main part of the plating apparatus 100. FIG. 4A is a plan view of a mesh member 7 of the plating apparatus 100. FIG. 4B is a plan view of a mesh member 7', which is a modified example of the mesh member 7.

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0026] It should be noted that each embodiment exemplifies an embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Furthermore, it is possible to combine the contents described in different embodiments, and such combinations are also included in the present invention. Furthermore, the drawings are intended to facilitate understanding of the specification and may be drawn schematically, and the dimensional ratios of the depicted components or between the components may not match the dimensional ratios of those components described in the specification. Furthermore, components described in the specification may be omitted in the drawings, or the number of components may be omitted.

[0027] 1, 2, 3, 4A, and 4B show a plating apparatus 100 according to an embodiment. 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 portion A-A indicated by the dashed-dotted arrow in FIG. 1. FIG. 3 is a cross-sectional view of a main part of the plating apparatus 100. FIG. 4A is a plan view of the mesh member 7 of the plating apparatus 100. FIG. 4B 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 used to store a mixture 16 of a plating solution, an object to be plated, media, and insulating balls, which will be described later. However, the insulating balls can be omitted if not necessary.

[0029] The plating apparatus 100 includes a cylindrical metal tube 2 inside a plating tank 1. The metal tube 2 has a hollow portion 2a. The metal tube 2 is a first electrode, which is a cathode electrode in this embodiment. In this embodiment, the metal tube 2 is cylindrical. However, the metal tube 2 may also be polygonal cylindrical. The material of the metal tube 2 is arbitrary, and various metals can be used.

[0030] In this embodiment, two rod-shaped conductive support parts 2b are formed integrally with the metal tube 2 on the upper part of the metal tube 2. However, the number of support parts 2b is arbitrary and is not limited to two.

[0031] The plating apparatus 100 includes a partition wall tube 3 made of an insulating material inside the plating tank 1. The partition wall tube 3 has a hollow portion 3a. In this embodiment, the partition wall tube 3 is cylindrical. However, the partition wall tube 3 may also be a polygonal cylindrical tube. The partition wall tube 3 has a plurality of small holes 3b formed therein that allow the plating solution to pass through but not the object to be plated, the media, or the insulating balls. When a current is applied between the metal tube 2, which is the first electrode, and the second electrode 5, the current passes through the holes 3b via the plating solution. The partition wall tube 3 may be made of any material; for example, various resins may be used.

[0032] The inner diameter of the partition wall pipe 3 is larger than the outer diameter of the metal pipe 2. The metal pipe 2 is disposed in the hollow portion 3a of the partition wall pipe 3. A plating formation portion 4 is formed between the inside of the partition wall pipe 3 and the outside of the metal pipe 2. The plating formation portion 4 is a region (space) where plating is applied to an object to be plated. Note that in Figures 1, 2 and 3, the plating formation portion 4 is depicted as a hatched area.

[0033] The object to be plated, the media, and the insulating balls are accumulated inside the plating forming section 4 and gradually descend downward. During this descent, the surface of the object to be plated is plated.

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

[0035] 2, in the plating apparatus 100, the metal tube 2, the partition tube 3, and the second electrode 5 are concentrically arranged so that their central axes coincide when viewed in a plan view. Therefore, in the plating apparatus 100, a current is applied uniformly between the metal tube 2, which is the first electrode, and the second electrode 5 in any region of the plating formation section 4, thereby suppressing variations in the thickness of the plating film that is formed.

[0036] The plating apparatus 100 is provided 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 has an inner tubular shape having a bottom surface and an inner wall. In this embodiment, the inner tubular shape of the spray unit 6 is an inner cylindrical shape. However, the inner tubular shape of the spray unit 6 is not limited to an inner cylindrical shape and may be another shape.

[0037] A first injection port 6a is formed at the upper end of the injection unit 6. A second injection port 6b is formed at the bottom surface of the injection unit 6. The plating solution is injected into the injection unit 6 from the second injection port 6b. The plating solution is injected into the plating tank 1 from the first injection port 6a. In this embodiment, the opening area of ​​the second injection port 6b is smaller than the opening area of ​​the first injection port 6a.

[0038] Furthermore, when the inner diameter of the metal tube 2 is compared with the diameter of the second jet nozzle 6b, the diameter of the second jet nozzle 6b is smaller than the inner diameter of the metal tube 2. This also causes the plating solution to flow faster at the center of the metal tube 2, so measures to suppress the plating solution flow speed at the center of the metal tube 2 are required.

[0039] A mesh member 7 is provided at the first injection port 6a of the injection unit 6. The mesh member 7 is provided to prevent the object to be plated, media, insulating balls, etc. from falling into the injection unit 6 when the injection of the injection unit 6 is stopped. In this embodiment, since the first injection port 6a of the injection unit 6 is circular, the mesh member 7 is also circular when viewed in a planar direction.

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

[0041] The first mesh layer 7a and the second mesh layer 7b are each made of a mesh. The first mesh layer 7a and the second mesh layer 7b are preferably insulating. The first mesh layer 7a and the second mesh layer 7b may be made of any material, such as nylon. The first mesh layer 7a and the second mesh layer 7b may be bonded together with an adhesive, or may be simply overlapped with each other so that their ends are fixed.

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

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

[0044] The mesh size of the first mesh layer 7a and the mesh size of the second mesh layer 7b may be the same or different. In this embodiment, meshes with a mesh size of 900 μm were used for the first mesh layer 7a and the second mesh layer 7b. The "mesh size" of a mesh is the distance between adjacent lines in a mesh in which vertical and horizontal lines intersect (not including the wire diameter). The mesh size may also be called the opening (OP) or opening dimension.

[0045] Generally, the term "opening size" refers to the opening size of one layer of mesh, but in the present application documents, when multiple meshes are stacked, it may refer to the overall opening size of the multiple meshes. When comparing the opening size of one layer of mesh with the opening size of two layers of that mesh stacked together (or the opening size of that mesh stacked with another mesh), the latter will be smaller (finer) than the former.

[0046] In this embodiment, when viewed in a plan view, the mesh member 7 has a central portion 7c made of two layers of mesh with a smaller mesh opening than a peripheral portion 7d made of a single layer of mesh. Note that if the vertical and horizontal lines of the first mesh layer 7a in the central portion 7c were to completely overlap with the vertical and horizontal lines of the second mesh layer 7b, the mesh openings in the central portion 7c and the peripheral portion 7d would be the same, but 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 have a triple mesh structure consisting of three layers of mesh, and the peripheral portion 7d may have 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, such that the central portion 7c has a triple mesh structure, the intermediate portion has a double mesh structure, and the peripheral portion 7d has a single mesh structure. In other words, the number of mesh layers in the mesh member 7 may be increased particularly in areas where it is desired to prevent the passage of the plating solution. Note that, although a single mesh structure consisting of a single layer of mesh is basically sufficient for the peripheral portion 7d, a multi-mesh structure consisting of multiple layers of mesh may also be used. As such, various variations in the structure of the mesh member 7 can be adopted.

[0048] 1 and 3, the mesh member 7 is stacked with the first mesh layer 7a, which occupies the entire area of ​​the mesh member 7, on top and the second mesh layer 7b, which occupies 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. Because the plating solution is injected from the bottom to the top through the first injection nozzle 6a, this structure can prevent the second mesh layer 7b from peeling off from the first mesh layer 7a.

[0049] In the plating apparatus 100, the central portion 7c having a double mesh structure suppresses the momentum of the plating solution passing through the mesh member 7. Furthermore, in the plating apparatus 100, the central portion 7c having a double mesh structure suppresses the momentum of the plating solution sprayed from the second spray nozzle 6b.

[0050] The plating apparatus 100 is equipped with a circulation line 8 formed of a pipe. One end of the circulation line 8 is connected to a suction port 9 formed in the plating tank 1. The other end of the circulation line 8 is connected to the second injection port 6b of the injection unit 6. A pump 10 and a filter 11 are provided midway along the circulation line 8. When the pump 10 is driven, the circulation line 8 sucks up the plating solution through the suction port 9 and injects the plating solution from the second injection port 6b.

[0051] The plating apparatus 100 includes a mixing section 12 below the metal tube 2 and the partition tube 3 and above the injection section 6. The mixing section 12 is an area where the plating solution injected from the first injection port 6a of the injection section 6 is mixed with the workpiece, media, and insulating balls that have descended through the plating formation section 4. In this embodiment, the mixing section 12 is made of an insulating material, and has an inverted truncated cone-shaped recess formed on the upper surface. The inverted truncated cone refers to a truncated cone whose upper base is larger than its lower base. However, the shape of the recess is arbitrary, and it may be a mortar-like shape instead of an inverted truncated cone.

[0052] The first injection nozzle 6a of the injection unit 6 is disposed on the bottom surface of the mixing unit 12. As described above, the mesh member 7 is provided at the first injection nozzle 6a of the injection unit 6. Because the mesh member 7 is provided at the first injection nozzle 6a, the object to be plated, media, insulating balls, etc. do not fall into the injection unit 6 even when the injection of the injection unit 6 is stopped.

[0053] The plating apparatus 100 includes a guide section 13 above the metal tube 2 and the partition tube 3. The guide section 13 is a region where the workpiece, media, and insulating balls, which rise on the upward flow of plating solution formed inside the hollow portion 2a of the metal tube 2 by the injection from the first injection port 6a of the injection section 6 and are ejected (discharged) from the upper opening of the hollow portion 2a of the metal tube 2, are agitated and then guided to the plating formation section 4. The guide section 13 is made of an insulating material and has an inverted truncated cone shape in this embodiment. The upper end of the metal tube 2 protrudes from the bottom surface of the guide section 13. The upper end of the hollow portion 2a of the metal tube 2 opens at 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 preventing the plating solution from scattering. The support portion 2b of the metal tube 2 is attached to the underside of the reflector 14. A cylindrical suppression plate 14a is also formed on the underside of the reflector 14. The suppression plate 14a is disposed within the guide portion 13. The plating solution may overflow from the upper edge of the guide portion 13, but the suppression plate 14a ensures that only the plating solution overflows from the guide portion 13, preventing the plating workpiece, media, and insulating balls from overflowing.

[0055] The plating apparatus 100 includes a power supply 15. One line of the power supply 15 is connected to the support portion 2 b of the metal tube 2, which serves as the first electrode, and the other line is connected to the second electrode 5. The power supply 15 applies a current between the metal tube 2, which serves as the first electrode, and the second electrode 5.

[0056] In the plating apparatus 100 according to the first embodiment having the above-described structure, the momentum 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 momentum of the plating solution sprayed from the first nozzle 6a of the spray unit 6 and passing through the mesh member 7 is suppressed more in the central portion 7c formed by overlapping the first mesh layer 7a and the second mesh layer 7b than in the peripheral portion 7d formed by only 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, of the objects to be plated that are sprayed out from the upper end of the metal tube 2, those that rise to a high position in the plating solution stored in the plating tank are thought to be mainly objects that rise rapidly through the center of the metal tube 2, where the plating solution moves at a faster rate.

[0058] In the plating apparatus 100, the momentum of the plating solution sprayed from the first nozzle 6a of the spray unit 6 is suppressed in the central portion 7c formed by the overlapping first mesh layer 7a and second mesh layer 7b, compared to the peripheral portion 7d formed by only the first mesh layer 7a, and therefore it is possible to suppress the momentum of the plating solution rising in the center of the metal tube 2. More specifically, when the amount of plating solution sprayed from the spray unit 6 is constant, the plating apparatus 100 can reduce the speed of the plating solution rising in the center of the metal tube 2, compared to when the first nozzle 6a of the spray unit 6 is provided with a mesh member made of a single layer of mesh as in the prior art.

[0059] Therefore, the plating apparatus 100 increases the amount of plating solution sprayed from the spray unit 6, shortens the time required for the object to pass through the plating formation unit 4 once, and prevents the object from rising too high in the stored plating solution even if the number of times the object circulates through the plating apparatus is increased. Therefore, the plating apparatus 100 prevents defects such as cracks, chips, and peeling of the plating film on the object to be plated caused by the object rising to a high position in the stored plating solution.

[0060] The plating apparatus 100 increases the amount of plating solution sprayed from the spray section 6 in order 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 formation section 4 once, and is less likely to produce defects in the object to be plated even if the number of times the object to be plated circulates through the plating apparatus is increased.

[0061] (Example of Use of Plating Apparatus 100) An example of a plating process using the plating apparatus 100 will be described below.

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

[0063] Next, the object to be plated, media, and insulating balls, each having the desired shape, dimensions, and number, are introduced into the induction section 13 in the plating tank 1. The order of introducing the plating solution and the object to be plated, media, and insulating balls may be reversed. The introduced object to be plated, media, and insulating balls are deposited in the plating formation section 4.

[0064] Next, the pump 10 is driven to spray the plating solution from the first spray nozzle 6a of the spray unit 6. As a result, an upward flow of plating solution is generated inside the metal tube 2. Then, some of the objects to be plated, media, and insulating balls that have accumulated inside the plating formation unit 4 are taken out from the lower end of the plating formation unit 4 to the mixing unit 12, where they mix with the sprayed plating solution and rise inside the metal tube 2 on the upward flow.

[0065] The object to be plated, media, and insulating balls that have risen inside the metal tube 2 are ejected from the upper end of the metal tube 2 and stirred.

[0066] The stirred objects to be plated, media, and insulating balls are deposited on top of other objects to be plated, media, and insulating balls that have already been deposited in the plating formation section 4.

[0067] The newly deposited objects to be plated, media, and insulating balls gradually descend as some of the objects to be plated, media, and insulating balls deposited in the plating formation section 4 are removed from the lower end of the plating formation section 4 to the mixing section 12. In this way, the objects to be plated, media, and insulating balls circulate inside the plating apparatus 100.

[0068] Next, the power supply 15 is driven to apply a current between the metal tube 2, which is the first electrode, and the second electrode 5. As a result, plating of the object to be plated begins in the plating forming section 4.

[0069] After a predetermined time has passed and a plating film of the desired thickness has been formed on the object to be plated, the power supply 15 is turned off to stop plating on the object to be plated. Then, the pump 10 is turned off 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 the plating tank 1 and sorting the objects to be plated.

[0071] (Experiment) In order to confirm the effectiveness of the present invention, the following experiment was carried out. 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 apparatuses other than the plating apparatus of the present invention.

[0072] First, Example 1 was carried out. In Example 1, the plating apparatus 100 of the above-described embodiment was used. In the plating apparatus 100 of Example 1, the first injection port 6a of the injection unit 6 was circular and had a diameter of 28 mm. In addition, in the plating apparatus 100 of Example 1, the length of the plating formation unit 4 was 220 mm.

[0073] The mesh member 7 shown in FIG. 4A is provided in the first injection nozzle 6a of the injection unit 6 of the plating apparatus 100. The mesh member 7, like the first injection nozzle 6a, is circular and has a diameter of 28 mm. The central portion 7c of the mesh member 7 is circular and has a diameter of 20 mm. The central portion 7c of the mesh member 7 has a double mesh structure in which a first mesh layer 7a with a mesh size of 900 μm and a second mesh layer 7b with a mesh size of 900 μm are stacked one on top of the other. The peripheral portion 7d of the mesh member 7 has a single mesh structure consisting only of the first mesh layer 7a with a mesh size of 900 μm.

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

[0075] The workpiece, media, and insulating balls were placed in the induction section 13 in the plating tank 1 of the plating apparatus 100. The total amount of the workpiece, media, and insulating balls was 1720 cc. The mixing ratio was 1376 cc (80% by volume) of the workpiece, 86 cc (5% by volume) of the media, and 258 cc (15% by volume) of the insulating balls.

[0076] The pump 10 was driven at low power to spray the plating solution from the first nozzle 6a of the spray section 6, and the workpieces, media, and insulating balls were circulated through the mixing section 12, the hollow section 2a of the metal tube 2, the guide section 13, the plating formation section 4, and the mixing section 12 in that order. The output of the pump 10 was gradually increased to increase the circulation speed of the workpieces, media, and insulating balls. Then, when the workpieces discharged from the upper end of the hollow section 2a of the metal tube 2 and rising relatively high (spurting up) in the stored plating solution reached a predetermined height, the increase in the output of the pump 10 was stopped and the output of the pump 10 was made constant. Specifically, the output of the pump 10 was made constant when the workpieces discharged from the upper end of the hollow section 2a of the metal tube 2 and rising relatively high in the stored plating solution reached half the height between the upper end of the metal tube 2 and the level of the plating solution contained in the plating tank 1.

[0077] Next, the power supply 15 was driven to apply a current between the metal tube 2 serving as the first electrode and the second electrode 5, and plating of the object to be plated was started in the plating forming section 4.

[0078] In this state, the amount of plating solution sprayed from the first injection port 6a of the injection unit 6 (flow rate of plating solution) was measured. Also, in this state, the time required for each object to pass through the plating formation unit 4 once was measured.

[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 pass through the plating formation unit 4 once was 10.8 seconds.

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

[0081] In plating apparatus 1100, mesh member 17 (not shown) was changed from mesh member 7 in Example 1. Specifically, mesh member 17 in Comparative Example 1 had a single mesh structure consisting of a single layer of mesh with a mesh opening of 900 μm over the entire surface.

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

[0083] In Comparative Example 1, the pump 10 was driven at low power under the same conditions as in Example 1, and then the power of the pump 10 was gradually increased until the part of the workpiece discharged from the upper end of the hollow portion 2a of the metal tube 2 that rose relatively high in the stored plating solution reached half the height between the upper end of the metal tube 2 and the surface of the plating solution contained in the plating tank 1. Next, the power source 15 was driven to apply a current between the metal tube 2, which was the first electrode, and the second electrode 5, and plating of the workpiece began in the plating formation section 4.

[0084] In Comparative Example 1, in this state, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 and the time required for each object to pass through the plating formation 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 workpiece to pass through the plating formation unit 4 once was 18.4 seconds.

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

[0087] In plating apparatus 1200, mesh member 27 (not shown) was changed from mesh member 7 in Example 1. Specifically, mesh member 27 in Comparative Example 2 had a double mesh structure in which two layers of mesh with openings of 900 μm were stacked on top of each other on the entire surface.

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

[0089] In Comparative Example 1, the pump 10 was driven at low power under the same conditions as in Example 1 and Comparative Example 1, and then the power of the pump 10 was gradually increased until the part of the workpiece discharged from the upper end of the hollow portion 2a of the metal tube 2 that rose relatively high in the plating solution reached half the height between the upper end of the metal tube 2 and the surface of the plating solution contained in the plating tank 1. Next, the power source 15 was driven, and a current was applied between the metal tube 2, which was the first electrode, and the second electrode 5, and plating of the workpiece began in the plating formation section 4.

[0090] In Comparative Example 1, in this state, the amount of plating solution sprayed from the first nozzle 6a of the spray unit 6 and the time required for each object to pass through the plating formation 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 pass through the plating formation unit 4 once was 11.2 seconds.

[0092] The details and experimental results of Example 1, Comparative Example 1, and Comparative Example 2 are shown in Table 1.

[0093] As can be seen from Table 1, under the condition that the output of the pump 10 was made constant (maintained) when the part of the object to be plated that was discharged from the upper end of the hollow portion 2 a of the metal pipe 2 and rose relatively high in the plating solution reached half the height between the upper end of the metal pipe 2 and the surface of the plating solution contained in the plating tank 1, Example 1 had a higher flow rate of the plating solution and the time required for the object to be plated to pass through the plating formation portion 4 once was shorter than Comparative Examples 1 and 2.

[0094] From the above, it has been found that according to the present invention, it is possible to suppress the occurrence of defects such as cracks, chips, and peeling of the plating film on the object to be plated, while increasing the flow rate of the plating solution and shortening the time required for the object to be plated to pass through the plating formation 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 increase the flow rate of the plating solution, increase the number of times the object to be plated circulates through the plating device, and suppress variations in the thickness of the plating film formed, while suppressing the occurrence of defects in the object to be plated.

[0096] The plating apparatus according to the embodiment has been described above, but 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 portion 7c of the mesh member 7 has a double mesh structure and the peripheral portion 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 portion 7c of the mesh member 7, the central portion 7c may have a triple mesh structure, a quadruple mesh structure, or a more multiple mesh structure.

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

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

[0100] In this plating apparatus, it is also preferable that a cylindrical metal tube having a hollow portion is provided immediately above the injection portion, in which case the flow of plating solution that rises rapidly through the center of the interior of the metal tube can be suppressed (slowed down).

[0101] It is also preferable that the number of mesh layers in the peripheral portion is 1 and the number of mesh layers in the central portion is 2. In this case, the mesh member can be easily produced.

[0102] It is also preferable that the mesh member has a smaller mesh size in the central portion than in the peripheral portion when viewed in a planar direction, so that the mesh member can suppress the amount of plating solution passing through the central portion more than the amount of plating solution passing through the peripheral portion.

[0103] It is also preferable that the central portion is circular when viewed in a planar direction, in which case the mesh member allows the plating solution to pass uniformly from the center of the mesh member in all radial directions.

[0104] It is also preferable that the central portion is polygonal when viewed in a planar direction. In particular, it is also preferable that the central portion is quadrangular when viewed in a planar direction. In this case, the mesh member can be easily produced.

[0105] It is also preferable that the injection part is an inner cylindrical shape having a bottom surface and an inner wall, and a first injection port provided at the upper end, and a second injection port provided at 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 is injected from the second injection port into the injection part. In this case, the diameter of the first injection port that injects the plating solution from the injection part into the plating tank can be made larger than the diameter of the pipe connected to the second injection port, and the speed of the plating solution injected from the first injection port can be made uniform (the difference between fast and slow parts can be reduced) while passing through the injection part.

[0106] It is also preferable that the plating apparatus comprises a cylindrical metal tube having a hollow portion as a first electrode, a partition tube made of an insulating material, having a hollow portion, and having a plurality of holes formed therein that allow the plating solution to pass through but not the object to be plated, and a second electrode, wherein the metal tube, partition tube, and second electrode are each housed in a plating tank, the metal tube is disposed within the hollow portion of the partition tube, a plating formation portion is formed between the inside of the partition tube and the outside of the metal tube, the second electrode is disposed on the outside of the partition tube, an injection portion is provided below the metal tube, the object to be plated rides on the ascending flow of plating solution injected by the injection portion and rises within the hollow portion of the metal tube, is discharged from the upper end of the hollow portion of the metal tube, is agitated in the plating solution, and then descends within the plating formation portion, and is plated by applying a current between the metal tube as the first electrode and the second electrode during the descent. In this case, the speed at which the plating solution rises inside the metal tube can be controlled, and in particular, the flow of plating solution that rises quickly through the center of the metal tube can be suppressed (slowed down). Note that the first electrode is, for example, a cathode electrode, and the second electrode is, for example, an anode electrode.

[0107] DESCRIPTION OF SYMBOLS 1: Plating tank 2: Metal tube (first electrode; cathode) 2a: Hollow portion 2b: Support portion 3: Partition tube 3a: Hollow portion 3b: Hole 4: Plating formation portion 5: Second electrode (anode) 6: Injection portion 6a: First injection nozzle 6b: Second injection nozzle 7: Mesh member 7a: First mesh layer 7b: Second mesh layer 7c: Central portion 7d: Peripheral portion 8: Circulation line 9: Liquid suction port 10: Pump 11: Filter 12: Mixing portion 13: Guidance portion 14: Reflector (deflector) 14a: Suppression plate 15: Power source

Claims

1. A plating tank for storing a plating solution containing an object to be plated; an injection unit having a first injection port formed in the plating tank for injecting the plating solution; The plating solution jetted from the jetting unit stirs the object to be plated contained in the plating solution, A mesh member is provided at the first injection port of the injection part, The mesh member is formed by overlapping at least two meshes, When viewed in a planar direction, the mesh member has a central portion and a peripheral portion provided outside the central portion, The periphery is formed of one layer of the mesh or a plurality of layers of the mesh, the central portion is formed of a plurality of layers of the mesh, The number of layers of the mesh in the central portion is greater than the number of layers of the mesh in the peripheral portion. Plating equipment.

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

2. The plating apparatus according to claim 1.

3. The number of layers of the mesh in the peripheral portion is one, The number of layers of the mesh in the central portion is two.

3. The plating apparatus according to claim 1 or 2.

4. When viewed in a planar direction, the mesh member has a smaller mesh size in the central portion than in the peripheral portion.

3. The plating apparatus according to claim 1 or 2.

5. When viewed in the planar direction, The central portion is circular.

3. The plating apparatus according to claim 1 or 2.

6. When viewed in the planar direction, The central portion is polygonal.

3. The plating apparatus according to claim 1 or 2.

7. When viewed in the planar direction, The central portion is rectangular.

7. The plating apparatus according to claim 6.

8. The injection unit is The nozzle has a bottom surface and an inner wall, and is formed in an inner cylindrical shape with the first injection port provided at an upper end thereof. 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 injected from the second injection port into the injection part.

3. The plating apparatus according to claim 1 or 2.

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

3. The plating apparatus according to claim 1 or 2.

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

10. The plating apparatus according to claim 9.