Electroplating device and method therefor, production method for plated article, and plating tank

Abstract

An electroplating device (100) includes: a plating tank (10) in which an insulating coating (12) is formed at least on an upper surface (15a) of a bottom part (15) of a conductive tank body (11); and a magnetic polishing unit (5) that uses a group of magnetic polishing materials (2) to stir and polish a group of articles (1) to be plated in an electrolytic solution retained in the plating tank (10). A thin linear slit (31) that is deep enough to reach the upper surface (15a) of the bottom part (15) is formed in the coating (12), and one or more of the magnetic polishing materials (2) included in the group of magnetic polishing materials (2) can electrically connect to the tank body (11) via an exposed surface (15b) of the upper surface (15a) of the bottom part (15) that is exposed by the slit (31).

Description

Electroplating apparatus and method, method for producing plated object, and plating tank

[0001] The present disclosure relates to an electroplating apparatus and method, a method for producing a plated object, and a plating tank.

[0002] Patent Document 1 discloses a method for improving adhesion of a plating layer to a substrate by simultaneously performing an agitation process during an electroplating process. Patent Document 1 also discloses forming a low-friction material (e.g., a resin sheet) on the bottom surface of a plating tank to promote the flow of the object to be plated (see paragraph 0100 and Figures 21 and 22 of the specification of the same document). Patent Document 2 discloses moving a magnetic rotor that generates an alternating magnetic field in a lateral direction that intersects with its rotation axis. Patent Document 3 discloses an electroplating system.

[0003] International Publication No. 2018 / 189916 International Publication No. 2021 / 130874 International Publication No. 2021 / 130873

[0004] In Patent Documents 1 to 3, it is required to connect the object to be plated to the negative pole (i.e., cathode potential) of the power supply with a high probability to efficiently electroplat the object. For this purpose, Patent Document 2 connects the metal plating tank itself to the negative pole of the power supply. However, according to the inventor's investigations, in such a case, a plating film grows not only on the surface of the object to be plated but also on the inner surface of the plating tank, and the plating film may peel off, particularly due to impacts from a magnetic abrasive. If this peeled plating film adheres to the object to be plated in the electrolyte, it may lead to poor appearance. For example, the peeled plating film or fine particles may adhere to the surface of the object to be plated and become fixed there as microprotrusions. Alternatively, the peeled plating film or fine particles may serve as nuclei for plating film growth.

[0005] The same applies to Patent Document 1. In Figures 21 and 22 of Patent Document 1, a resin sheet is attached to the upper surface of the bottom of the plating tank to promote the flow of the object to be plated. In Example 1 described in paragraph 0120 of the same document, a polyethylene friction material is attached to the bottom of the plating tank.

[0006] As can be seen from the non-limiting description above, when electroplating and polishing are performed in the same plating tank under the condition that the plating tank itself is connected to the cathode of the power supply, defects in the plated object (i.e., the plated product) may occur. Defects in the plated object include, but are not limited to, defects in appearance.

[0007] According to one aspect of the present disclosure, there is provided an electroplating apparatus comprising: a plating tank having an electrically conductive tank body with an insulating coating formed on an upper surface of the bottom thereof; and a magnetic polishing unit for stirring and polishing a group of workpieces to be plated in an electrolytic solution stored in the plating tank using a group of magnetic abrasives. The coating unit has thin slits formed therein, the slits having a depth reaching the upper surface of the bottom thereof, and one or more magnetic abrasives included in the group of magnetic abrasives are electrically connectable to the tank body via the exposed surface of the upper surface of the bottom thereof.

[0008] A method for manufacturing a plated object according to another aspect of the present disclosure includes agitating and polishing a group of objects to be plated using a group of magnetic abrasives in an electrolyte stored in a plating tank having an insulating coating formed on at least the upper surface of the bottom of a conductive tank body, and electroplating one or more of the objects to be plated included in the group of objects to be plated by electrically connecting the objects to the tank body via one or more magnetic abrasives included in the group of magnetic abrasives, the one or more magnetic abrasives being electrically connected to the tank body by contacting an exposed surface of the upper surface of the bottom that is exposed by a thin slit formed in the coating to a depth reaching the upper surface of the bottom. In some embodiments, all of the objects to be plated included in the group of objects to be plated are electroplated without direct contact with the exposed surface.

[0009] An electroplating method according to yet another aspect of the present disclosure includes stirring and polishing a group of objects to be plated using a group of magnetic abrasives in an electrolyte stored in a plating tank having an insulating coating formed on at least the upper surface of the bottom of a conductive tank body, and electroplating one or more objects to be plated included in the group of objects to be plated by electrically connecting them to the tank body via one or more magnetic abrasives included in the group of magnetic abrasives, wherein the one or more magnetic abrasives are electrically connected to the tank body by contacting an exposed surface of the upper surface of the bottom exposed by thin slits formed in the coating at a depth reaching the upper surface of the bottom.

[0010] A plating tank according to yet another aspect of the present disclosure is a plating tank for electroplating in which magnetic polishing using a magnetic abrasive is performed in the same tank as electroplating, the plating tank comprising a conductive tank body having a bottom and a sidewall, and an insulating covering portion formed on at least an upper surface of the bottom. The covering portion has thin slits formed therein, the slits having a depth reaching the upper surface of the bottom, and the magnetic abrasive can be electrically connected to the tank body via the exposed surface of the upper surface of the bottom.

[0011] In some embodiments, the slits are formed at a location other than directly below one or more anodes immersed in the electrolyte or the mesh cage that receives them.

[0012] In some embodiments, the magnetic polishing unit includes at least one magnetic rotating body rotatably mounted below the bottom of the plating tank, the magnetic rotating body having a plurality of permanent magnets configured to generate an alternating magnetic field, and the exposed surface is formed at a position where magnetic flux between the plurality of permanent magnets can interlink.

[0013] In some embodiments, the at least one magnetic rotating body is movable in a lateral direction intersecting its rotation axis, and magnetic flux between the plurality of permanent magnets interlinks with the exposed surface regardless of the position of the magnetic rotating body in the lateral direction.

[0014] In some embodiments, the entire top surface of the bottom portion is covered by the covering portion except for the exposed surface.

[0015] In some embodiments, the slit has a length / width aspect ratio of 50 or greater, or 60 or greater, or 100 or greater.

[0016] In some embodiments, the slit width of the slit is 0.5 mm or more, 0.8 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 4 mm or more, or 5 mm or more, and / or 10 mm or less, 5 mm or less, or 3 mm or less.

[0017] In some embodiments, the coverage of the exposed surface of the top surface of the bottom portion is 5% or less.

[0018] In some embodiments, the magnetic polishing unit includes at least one magnetic rotating body rotatably mounted below the bottom of the plating tank, the magnetic rotating body being movable in a lateral direction intersecting its rotation axis, and the slits include one or more slits extending linearly or non-linearly longitudinally along the lateral direction.

[0019] In some embodiments, the covering portion is formed on the inner surface of the side wall of the tank body, and a groove is formed in the covering portion that is deep enough to reach the inner surface and is wider than the slit, and the one or more magnetic abrasives can be electrically connected to the tank body via the exposed surface of the inner surface exposed by the groove.

[0020] In some embodiments, each magnetic abrasive in the group of magnetic abrasives is an abrasive pin.

[0021] In some embodiments, the coating comprises nylon.

[0022] The magnetic polishing unit may be disposed below the plating tank. The upper surface of the bottom of the plating tank may be disposed on a plane perpendicular to the rotation axis of the magnetic rotating body. The rotation axis of the magnetic rotating body may coincide with the vertical direction. The object to be plated may be a fastening part.

[0023] According to one aspect of the present disclosure, the occurrence of defects in plated products can be suppressed.

[0024] FIG. 1 is a schematic diagram of an electroplating apparatus according to an embodiment of the present disclosure, in which the magnetic rotating body is positioned at a first end position directly below the first end of the plating tank. FIG. 2 is a schematic diagram of an electroplating apparatus according to an embodiment of the present disclosure, in which the magnetic rotating body is positioned at a second end position directly below the second end of the plating tank. The power supply, electrical wiring, and the like are omitted from the illustration. FIG. 3 is a schematic top view showing the positional relationship between the plating tank and the magnetic rotating body, with both the magnetic rotating body at the first end position and the magnetic rotating body at the second end position indicated by dotted lines. FIG. 4 is a schematic top view of the plating tank taken along line VV of FIG. 3, enlarging the view showing that the object to be plated is electrically connected to the negative pole of the power supply via a polishing pin inserted into the slit. FIG. 5 is a schematic top view of a plating tank according to a first modified example. FIG. 6 is a schematic top view of a plating tank according to a second modified example. FIG. 7 is a schematic top view of a plating tank according to a third modified example. FIG. 8 is a schematic top view of a plating tank according to a fourth modified example. 10 is a schematic top view of a plating tank according to a fifth modified example. 11 is a schematic partial cross-sectional view of a plating tank according to a sixth modified example. 12 is a schematic view of a plating tank according to a seventh modified example, in which the flange of the tank body is electrically connected to the cathode of the power source. 13 is a photograph of an example of a product with a defective appearance, in which a minute protrusion is formed at the location indicated by the arrow.

[0025] Various embodiments and features will be described below with reference to the drawings. Those skilled in the art will be able to combine the embodiments and / or features without excessive explanation and will be able to understand the synergistic effects of such combinations. Duplicate descriptions between embodiments will be omitted as a general rule. The reference drawings are primarily intended to describe the invention and are simplified for ease of illustration. Each feature is not only applicable to the apparatus and method disclosed in this application, but is also understood as a general feature applicable to apparatuses and methods not disclosed in this specification.

[0026] 1 , the electroplating apparatus 100 includes a plating tank 10, a magnetic polishing unit 5 that uses a group of magnetic abrasives 2 to stir and polish a group of objects 1 to be plated in an electrolyte stored in the plating tank 10, and a movement mechanism M1 configured to laterally move the magnetic polishing unit 5. In some cases, the magnetic polishing unit 5 includes at least one magnetic rotating body 6 and a rotational force supply unit 65 that supplies a rotational force to the magnetic rotating body 6. The movement mechanism M1 is configured to laterally move the rotational force supply unit 65. Other configurations of the magnetic polishing unit 5 and the movement mechanism M1 are also possible.

[0027] The plating tank 10 has a conductive (e.g., metallic) tank body 11. The tank body 11 is connected to the cathode of a DC power source E1, and an anode 23 in the electrolytic solution is connected to the anode of the DC power source E1. Metal ions are dissolved from the anode 23 into the electrolytic solution and precipitate on the surface of the workpiece 1, which is electrically connected to the tank body 11 via the magnetic abrasive 2. The inner surface 11p of the conductive tank body 11 is covered with an insulating coating 12, which has slits 31 and grooves 32 formed therein, as described below. Therefore, the workpiece 1 in the electrolytic solution can be electrically connected to the tank body 11 via the magnetic abrasive 2. The anode 23 is, for example, a metal lump (e.g., a metal lump of tin, tin-nickel alloy, etc.) placed in a conductive mesh basket 22 immersed in the electrolytic solution. The electrolytic solution stored in the plating tank 10 is a cyanide-based electrolytic solution, but other types of electrolytic solutions can also be used.

[0028] Both the object to be plated 1 and the magnetic abrasive 2 are conductive. The object to be plated 1 has a size (e.g., a maximum width, length, or height of 5 cm or less, 4 cm or less, or 3 cm or less) that allows it to be stirred in the electrolyte by the magnetic abrasive 2, and is typically, but not limited to, a metal fastening part in the fastening field, such as a button or a slider of a slide fastener. In one example, the object to be plated 1 is the shell of a button attached to clothing or the like (see Figure 13). Note that Figure 13 shows an example of a defective appearance in which numerous small protrusions (see arrows) are formed on the shell surface for the reasons explained at the beginning.

[0029] The magnetic abrasive 2 is shaped to physically polish the object 1 to be plated, and is typically a fine needle-shaped polishing pin. The magnetic abrasive 2 is smaller than the object 1 to be plated, for example, having a (maximum) width or diameter of 3 mm or less or 2 mm or less and a (maximum) length of 2 cm or less or 1 cm or less. The polishing pin has, for example, but is not limited to, the shape of a cylinder, a rectangular prism, or a triangular prism. For convenience of illustration, the polishing pin is shown by a single line in Figures 1 and 2, etc. The polishing pin may not have a sharp tip. By using such a polishing pin without a sharp tip, excessive polishing of the object 1 to be plated is avoided or suppressed.

[0030] The tank body 11 is typically made of metal such as stainless steel and has a bottom 15, sidewalls 16, and a flange 17. The bottom 15 and sidewalls 16 form a storage space for the electrolyte. The bottom 15 is typically a flat plate with a predetermined thickness. The sidewalls 16 are also flat plate with a predetermined thickness. The sidewalls 16 are inclined relative to the bottom 15 so that the tank body 11 tapers slightly toward the bottom. The sidewalls 16 form a cylindrical portion whose opening width increases with increasing distance from the bottom 15. The flange 17 extends from the upper end of the sidewalls 16 outward from the tank body 11 and can be used as a gripping part when lifting the plating tank 10 or for contacting a DC power source E1.

[0031] In a configuration in which the magnetic polishing unit 5 (the magnetic rotor 6 and the rotational force supply unit 65) moves laterally, the tank body 11 can be shaped to be elongated in the direction of movement. The tank body 11 has a center line AX1 extending in the direction of movement of the magnetic polishing unit 5 and is configured symmetrically about this center line. The tank body 11 has a first end 11m, a second end 11n, and a body portion 11j therebetween, all of which are located on the center line AX1. The bottom portion 15 has an arc-shaped or semicircular contour at the first end 11m of the tank body 11, an arc-shaped or semicircular contour at the second end 11n of the tank body 11, and a contour of parallel lines connecting the two arc-shaped or semicircular contours at the body portion 11j of the tank body 11.

[0032] The tank body 11 has an inner surface 11p and an outer surface 11q. A covering portion 12 is formed on the inner surface 11p of the tank body 11. Typically, the inner surface 11p of the tank body 11 is covered with the covering portion 12 except for slits 31 and grooves 32 described below, but this is not limited to this. The bottom 15 has an upper surface 15a and a lower surface 15c. The covering portion 12 is formed on the upper surface 15a of the bottom 15. Typically, the upper surface 15a of the bottom 15 is covered with the covering portion 12 except for slits 31 described below, but this is not limited to this. The sidewall 16 has an inner surface 16a and an outer surface 16c. The covering portion 12 is formed on the inner surface 16a of the sidewall 16. Typically, the inner surface 16a of the sidewall 16 is covered with the covering portion 12 except for grooves 32 described below, but this is not limited to this. The inner surface 11 p of the tank body 11 includes the upper surface 15 a of the bottom 15 and the inner surface 16 a of the side wall 16 .

[0033] A configuration is also envisioned in which the outer surface 11q of the tank body 11 is (typically partially) covered with the covering portion 12. For example, the outer surface 11q of the tank body 11 is covered with the covering portion 12 except for the contact portion with the cathode of the DC power supply E1. In this manner, the risk of electric shock due to contact with the tank body 11 is reduced. This also improves the quality and coating efficiency of the covering portion 12. Preferably, the entire tank body 11 is immersed in an uncured resin liquid, and the resin liquid is cured to form the covering portion 12. By partially removing this covering portion 12, electrical connection to the tank body 11 can be ensured where necessary.

[0034] The covering portion 12 is made of an insulating (non-conductive) resin and is typically formed as a covering layer or coating layer. The covering layer optionally has a smooth upper surface, which promotes smooth flow of the workpiece 1 and / or the magnetic abrasive 2. The covering portion 12 does not need to be formed as a single layer of a single material, but may be formed as multiple layers made of different materials. The covering portion 12 should preferably have a color (e.g., white) that is distinguishable from the metal of the tank body 11. This makes it easy to determine whether the outer surface 11q of the tank body 11 is exposed by partial removal of the covering portion 12. There are no particular limitations on the material of the covering portion 12, but (white) nylon is preferred.

[0035] The magnetic rotating body 6 is rotatably provided below the bottom 15 of the plating tank 10 so as to stir and polish a group of objects 1 to be plated in the electrolyte stored in the plating tank 10 using a group of magnetic abrasives 2. The magnetic rotating body 6 moves the magnetic abrasives 2 in the electrolyte based on magnetic attraction and / or repulsion. The objects 1 to be plated flow upon collision with the magnetic abrasives 2, and are then struck and polished. The magnetic rotating body 6 can be configured in various ways. In the illustrated example, the magnetic rotating body 6 has a rotating disk 68 and a plurality of permanent magnets 7 provided on the rotating disk 68. The permanent magnets 7 are arranged offset radially outward from the rotation axis AX6 of the magnetic rotating body 6. An electromagnet or a magnetic circuit can also be used in place of the permanent magnets 7.

[0036] The permanent magnet 7 may include multiple permanent magnets, i.e., first and second permanent magnets 71 and 72, arranged to generate an alternating magnetic field. The first permanent magnet 71 is arranged with its north pole facing upward, and the second permanent magnet 72 is arranged with its south pole facing upward. In FIG. 3 , two first permanent magnets 71 and two second permanent magnets 72 are provided, and in particular, the first and second permanent magnets 71 and 72 are arranged alternately in the circumferential direction. When the magnetic rotating body 6 rotates in response to the operation of the rotational force supply unit 65, the first and second permanent magnets 71 and 72 orbit in the circumferential direction. With respect to the fixed point FP1 of the plating tank 10 (see FIGS. 3 and 4 ), downward magnetic flux is linked at the time of FIG. 3 , and upward magnetic flux is linked at the time of FIG. 4 . In other words, an alternating magnetic field is generated in which the direction and magnitude of the magnetic flux change over time. The number of permanent magnets arranged on the magnetic rotating body 6 is arbitrary, and a configuration in which only two or three permanent magnets are arranged in total is also envisioned.

[0037] The rotation of the magnetic rotating body 6 allows the magnetic abrasive 2 (e.g., a polishing pin) to transition between the first and second magnetization states at any timing. In the first magnetization state, the first end of the magnetic abrasive 2 is the north pole, and the opposite second end is the south pole. In the second magnetization state, the first end of the magnetic abrasive 2 is the south pole, and the opposite second end is the north pole. The magnetic abrasive 2 is magnetically attracted to the permanent magnet 7 and flows in the circumferential direction, and can also rotate irregularly due to the reversal of its magnetization state. The magnetic abrasive 2 collides with the object 1 to be plated, causing the object 1 to flow in the rotation direction of the magnetic rotating body 6. The irregular rotation of the magnetic abrasive 2 caused by the reversal of the magnetization state hits and polishes the object 1 more randomly. The rotation direction of the magnetic rotating body 6 can also be reversed at any period.

[0038] The rotational force supply unit 65 is configured to supply rotational force to the magnetic rotating body 6. The rotational force supply unit 65 includes, for example, an electric motor 66, and the magnetic rotating body 6 is non-rotatably mounted on its rotation shaft 67. The rotational force generated by the electric motor 66 is transmitted to the magnetic rotating body 6, causing the magnetic rotating body 6 to rotate around its rotation axis AX6. The rotational speed of the magnetic rotating body 6 is appropriately adjusted. A mechanism for transmitting the rotational force generated by the electric motor to the magnetic rotating body 6 via an endless belt is also envisioned.

[0039] The magnetic rotating body 6 moves laterally, intersecting (perpendicular to) its rotation axis AX6, based on the operation of the moving mechanism M1. The moving mechanism M1 is configured to move the rotational force supply unit 65 (and the magnetic rotating body 6 via the rotational force supply unit 65) laterally. In the illustrated example, the moving mechanism M1 includes an electric motor 61 and a crank mechanism for converting the rotational force generated by the electric motor 61 into lateral movement of the rotational force supply unit 65. The crank mechanism includes first and second links 62, 63 pivotally connected to each other. The first link 62 has a first end non-rotatably connected to the rotation shaft 61 a of the electric motor 61 and a second end rotatably connected to the second link 63. The second link 63 has a first end rotatably connected to the first link 62 and a second end rotatably connected to the rotational force supply unit 65. The crank mechanism continuously reverses the traveling direction of the rotational force supply unit 65. The rotational force supply unit 65 is mounted on and supported by a guide rail G1 that runs in parallel in the horizontal direction.

[0040] The first link 62 rotates clockwise or counterclockwise in response to the rotation of the rotation shaft 61a of the electric motor 61. The posture of the second link 63 changes in response to the rotation of the first link 62, and the rotational force supply unit 65 moves along the guide rail G1. The magnetic rotating body 6 moves laterally together with the rotational force supply unit 65. By rotating the rotation shaft 61a of the electric motor 61 by 180°, the rotational force supply unit 65 (and the magnetic rotating body 6) moves from a first end position P1 (see FIGS. 1 and 3) directly below the first end 11m of the tank body 11 to a second end position P2 (see FIGS. 2 and 3) directly below the second end 11n of the tank body 11. By further rotating the rotation shaft 61a of the electric motor 61 by 180°, the rotational force supply unit 65 (and the magnetic rotating body 6) moves from a second end position P2 directly below the second end 11n of the tank body 11 to a first end position P1 directly below the first end 11m. As the rotation shaft 61a continues in this manner, the rotational force supply unit 65 (and the magnetic rotating body 6) reciprocates between the first end position P1 and the second end position P2.

[0041] When the magnetic rotor 6 is disposed below the plating tank 10, the interior space of the plating tank 10 is divided into a first space SP1, which occupies the space above the magnetic rotor 6, and a second space SP2, which occupies the space other than the first space SP1. As the magnetic rotor 6 moves laterally, the first space SP1 moves in unison. The second space SP2 is the total volume of the interior space of the plating tank 10 minus the first space SP1, and its position and / or range within the interior space of the plating tank 10 changes in unison with the movement of the first space SP1. Needless to say, the size of the first space SP1 depends on the shape of the interior space of the plating tank 10, the shape of the magnetic rotor 6, and the relative positional relationship between the interior space of the plating tank 10 and the magnetic rotor 6, and is not limited to that shown in the figure.

[0042] In the configuration in which the magnetic rotating body 6 moves laterally as described above, the object 1 to be plated can be switched between a state in which it is in the electrolytic solution in the first space SP1 and a state in which it is in the electrolytic solution in the second space SP2. In the electrolytic solution in the first space SP1, polishing is more prevalent than electroplating. On the other hand, in the electrolytic solution in the second space SP2, electroplating is more prevalent than polishing. The lateral movement of the magnetic rotating body 6 allows both electroplating and polishing of the object 1 to be successfully achieved. For example, excessive polishing that would excessively inhibit the growth of the plating layer is avoided or suppressed. Allocating the first and second spaces SP1 and SP2 within the tank space of the plating tank 10 also facilitates electroplating of a larger amount of object 1 to be plated.

[0043] In this embodiment, a covering portion 12 is formed on the upper surface 15a of the bottom 15 of the tank body 11, and thin slits 31 are formed in this covering portion 12 so as to reach the upper surface 15a of the bottom 15. Furthermore, one or more magnetic abrasives 2 included in the group of magnetic abrasives 2 can be electrically connected to the tank body 11 via the exposed surface 15b of the upper surface 15a of the bottom 15 exposed by the slits 31. This prevents poor appearance of the plated product from occurring due to an excessively large exposed area of ​​the upper surface 15a of the bottom 15 of the plating tank 10.

[0044] There is also concern that if the exposed area of ​​the upper surface 15a of the bottom 15 of the plating tank 10 is too small, the supply of electrons to the object 1 to be plated may be insufficient. Contrary to this concern, it has been confirmed that electroplating proceeds sufficiently even when the slits 31 are formed in the covering portion 12 in the shape of thin lines. This is presumably due in part to the fact that the formation of the slits 31 determines the path of electrons flowing in the tank body 11, making it possible to supply electrons at a high density.

[0045] The slit width W31 of the slit 31 is defined by a pair of side walls 12p, 12q formed on the covering portion 12 (see the enlarged view in FIG. 5 ). The illustrated side walls 12p, 12q are substantially vertical, but this is not limited thereto. By making the side walls 12p, 12q inclined, the impact applied to the side walls 12p, 12q by the rotating magnetic abrasive 2 can be reduced, thereby preventing the covering portion 12 from peeling off. The depth of the slit 31 depends on the thickness of the covering portion 12 and can be 100 μm or more. A form in which the slit width W31 of the slit 31 varies in the depth direction of the slit 31 is also conceivable.

[0046] When forming the slits 31 by cutting the covering portion 12 using a cutter or metal saw, the side walls 12p, 12q may be inclined rather than vertical, and / or the slit width W31 may vary rather than be constant along the length of the slit 31. The slit width W31 depends on the blade width of the cutter or metal saw, but is not necessarily limited to this. For example, the slit 31 may be formed with a V-shaped or trapezoidal cross section by inserting the blade of the cutter obliquely into the covering portion 12 and pulling it back twice. Additionally or alternatively, masking or lift-off may be utilized.

[0047] The slit width W31 of the slit 31 is larger than the width or diameter of the magnetic abrasive material 2 (see the enlarged view in Figure 5). If the magnetic abrasive material 2 is a polishing pin with a circular cross section, it has a diameter and a length. If the magnetic abrasive material 2 is a polishing pin with an elliptical cross section, it has a minor diameter, a major diameter, and a length. If the magnetic abrasive material 2 is a cuboid polishing block, the widths of each side are equal. If the magnetic abrasive material 2 is a rectangular polishing block, it has a length defined between one end and the other end and two different or identical widths that define its cross section. The slit width W31 is set according to the three-dimensional shape or dimensions of such magnetic abrasive material 2.

[0048] When the magnetic abrasive material 2 is a polishing pin, the slit width W31 is larger than the diameter of the polishing pin. Using polishing pins of a predetermined size increases the uniformity of polishing, but polishing pins of different diameters and / or lengths can also be used. For example, a first subset of first polishing pins with diameters less than the slit width W31 and a second subset of second polishing pins with diameters slightly larger than the slit width W31 can be used together. The first polishing pins are connected to the cathode potential more frequently (by colliding with the upper surface 15a of the bottom portion 15 exposed by the slit 31) than the second polishing pins. Magnetic abrasive materials 2 of different shapes (e.g., pins and blocks) can also be used together.

[0049] Optionally, the slit width W31 of the slit 31 may be set to be equal to or smaller than the smallest dimension of the three-dimensional object 1 to be plated. Setting the slit width W31 of the slit 31 to be equal to or smaller than the smallest dimension of the three-dimensional object 1 to be plated reduces the possibility or frequency of the object 1 to be plated entering and engaging with the slit 31. If the object 1 to be plated is a male part of a snap button having a central portion shaped like a male protrusion and a thin outer periphery, the central portion will not enter the slit 31, but the outer periphery may enter the slit 31 (the same applies to female parts and other types of fastening parts). While this contributes to connecting the part to the cathode potential, it creates a risk of engagement with the slit 31, which may result in uneven electroplating. To address this issue, the slit width W31 may be set to be equal to or smaller than the thickness of the outer periphery of the part. Similar solutions can be applied to other types of objects to be plated, not just snap button parts.

[0050] The fact that the slit 31 is thin can mean that the length / width aspect ratio is large. Typically, the length / width aspect ratio of the slit 31 is 50 or more, or 60 or more, and preferably 100 or more. If the slit 31 is formed endlessly (e.g., annular), the length of the slit 31 can be considered to be ∞, and the aspect ratio can also be considered to be ∞. To give a specific example, if the width of the slit 31 is 1 mm and the length is 500 mm, the aspect ratio is 500. If the width of the slit 31 is 2 mm and the length is 500 mm, the aspect ratio is 250. If the width of the slit 31 is 4 mm and the length is 500 mm, the aspect ratio is 125. If the width of the slit 31 is 1 mm and the length is 250 mm, the aspect ratio is 250. If the width of the slit 31 is 2 mm and the length is 250 mm, the aspect ratio is 125. If the width of the slit 31 is 4 mm and the length is 250 mm, the aspect ratio is 62.5. If the slit 31 extends non-linearly, for example, meandering, the aspect ratio increases compared to when the slit 31 extends linearly.

[0051] The slits 31 have a different aspect ratio of slit width / slit depth. This different aspect ratio depends on the thickness of the covering portion 12, as a result of the slit width being set in light of the above-mentioned points. The thickness of the covering portion 12 is set to 0.1 mm or more to ensure coverage of the upper surface 15 a of the bottom portion 15. If the covering portion 12 is too thick, the probability of the magnetic abrasive material 2 coming into contact with the exposed surface 15 b may decrease. Therefore, the thickness of the covering portion 12 is preferably 5 mm or less.

[0052] When the magnetic rotor 6 is placed below the plating tank 10, the magnetic abrasive 2 may rub against the exposed surface 15b, causing the exposed surface 15b to wear away. Although this is not necessarily the case, when the bottom 15 of the tank body 11 is formed thin (for example, 20 mm or less) to allow the magnetic field lines to pass through, the wear described above may result in a shortened life of the plating tank 10. From this perspective, the area of ​​the slit 31 is set to 10,000 mm 2 or less than 5,000 mm 2 or less than 3,000 mm 2 or less, or 2,000 mm 2 The area of ​​the slit 31 is calculated by multiplying the length and width of the slit 31. For example, if the width of the slit 31 is 1 mm and the length is 500 mm, the area is 500 mm. 2 If the width of the slit 31 is 2 mm and its length is 500 mm, the area is 1000 mm. 2 If the width of the slit 31 is 4 mm and its length is 500 mm, the area is 2000 mm. 2 If the width of the slit 31 is 1 mm and its length is 800 mm, the area is 800 mm. 2 If the width of the slit 31 is 2 mm and its length is 800 mm, the area is 1600 mm. 2 If the width of the slit 31 is 4 mm and its length is 800 mm, the area is 3200 mm. 2 The area of ​​the slit 31 is equal to the area of ​​the exposed surface 15b.

[0053] In light of one or any combination of the above considerations, the slit width W31 of the slit 31 may be set to 0.5 mm or more, 0.8 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 4 mm or more, or 5 mm or more. Additionally or alternatively, the slit width W31 of the slit 31 may be set to 10 mm or less, 5 mm or less, or 3 mm or less.

[0054] Additional exposed surfaces may be formed for the purpose of improving power supply efficiency or for other purposes. In Figures 1 to 4, a covering portion 12 is formed on the inner surface 16a of the sidewall 16 of the tank body 11. A groove 32 is formed in this covering portion 12, reaching the inner surface 16a and wider than the slit 31. The groove 32 may be formed to a predetermined width from the upper surface 15a of the bottom portion 15 or from a position spaced apart therefrom. The width of the groove 32 is determined in a direction along the rotation axis AX6 of the magnetic rotating body 6. One or more magnetic abrasives 2 can be electrically connected to the tank body 11 via the exposed surface 16b of the inner surface 16a exposed by the groove 32. Preferably, the groove 32 is formed continuously in the circumferential direction of the tank body 11, i.e., annularly. Depending on the width of the exposed surface 16b, the object to be plated 1 can come into direct contact with the exposed surface 16b, which sufficiently promotes connection of the object to be plated 1 to the cathode potential and the supply of electrons thereto. The width of the groove 32 is typically 1 cm or more, or 2 cm or more, and / or 5 cm or less.

[0055] Although some of the explanations given with respect to the slit 31 may also be applicable to the groove 32, there are differences. Specifically, when the magnetic rotating body 6 is disposed below the plating bath 10, the exposed surface 15b is disposed in a plane perpendicular to the rotation axis AX6 of the magnetic rotating body 6, and the exposed surface 16b is disposed in a plane oriented along the rotation axis AX6 of the magnetic rotating body 6 (e.g., parallel to the magnetic rotating body 6 or obliquely oriented so as to form an acute angle of 30° or less). As a result, the exposed surface 16b is cut by the magnetic abrasive 2 to a lesser extent than the exposed surface 15b, or is hardly cut at all. Therefore, the exposed surface 16b can be made wider than the exposed surface 15b, thereby improving power supply efficiency. In some cases, the following relationship is satisfied: (width of groove 32 / width of slit 31) > 3, (width of groove 32 / width of slit 31) > 4, or (width of groove 32 / width of slit 31) > 5. Preferably, the width of the groove 32 is greater than 10 mm. This can be advantageous from the viewpoint of preventing the object 1 to be plated, which is a three-dimensional object, from fitting into the groove 32. If the groove 32 is formed endlessly, its aspect ratio (length / width) can be regarded as ∞.

[0056] As described above, the slits 31 are formed in a thin line shape, and therefore the exposed surface 15b of the inner surface 11p of the tank body 11 is also narrow. Therefore, even if a plating film accumulates on the exposed surface 15b and peels off due to impact with the magnetic abrasive 2, it is unlikely that this will result in a poor appearance of the plated product. The grooves 32 are located farther from the mesh basket 22 and / or the anode 23 than the slits 31. A large amount of the object 1 to be plated is present between the exposed surface 16b and the anode 23, and therefore the growth of the plating film on the exposed surface 16b is slow or negligible.

[0057] Advantageously, the entire upper surface 15a of the bottom 15 of the tank body 11 is covered with the covering portion 12 except for the exposed surface 15b, and / or the entire inner surface 16a of the side wall 16 of the tank body 11 is covered with the covering portion 12 except for the exposed surface 16b. Additionally or alternatively, the occupancy rate of the exposed surface 15b on the upper surface 15a of the bottom 15 is 5% or less, and / or the occupancy rate of the exposed surface 16b on the inner surface 16a of the side wall 16 is 5% or less. This effectively prevents poor appearance of the plated product.

[0058] As shown in Figures 3 and 4, the slits 31 and / or exposed surface 15b are formed at a position other than directly below the mesh basket 22 and / or anode 23, which are immersed in the electrolyte. In other words, the slits 31 and / or exposed surface 15b are formed so as not to overlap the projection area (see Figure 3) of the mesh basket 22 and / or anode 23 onto the bottom side of the plating tank 10. The slits 31 and / or exposed surface 15b are positioned farther away from the source of metal ions in the electrolyte (i.e., the mesh basket 22 and / or the anode 23), suppressing the growth of a plating film on the exposed surface 15b. Conversely, a plating film is more likely to grow on the object 1 to be plated between the anode 23 and the exposed surface 15b.

[0059] Advantageously, the exposed surface 15b is positioned so that the magnetic flux FX formed between the multiple permanent magnets 7 (e.g., the first permanent magnet 71 and the second permanent magnet 72) on the magnetic rotating body 6 can interlink with the exposed surface 15b. Even more advantageously, regardless of the lateral position of the magnetic rotating body 6, the magnetic flux FX formed between the permanent magnets 7 on the magnetic rotating body 6 interlinks with the exposed surface 15b. This ensures a reliable supply of electrons to the workpiece 1 in the submerged space where polishing is dominant, thereby preventing over-polishing. For this purpose, it is advantageous for the slit 31 to include at least two slits or slit portions extending linearly or non-linearly in the lateral direction. While the magnetic flux FX is schematically represented by arrows in FIGS. 3 and 4, in reality, an arch-shaped magnetic flux flow is formed. As shown in FIGS. 3 and 4, it is advantageous for magnetic fluxes of alternating magnetic fields with different directions to interlink with the exposed surface 15b.

[0060] The operation of the electroplating apparatus 100 will be described with reference to FIGS. 1 and 2 . When the switch SW is turned on, the DC power supply E1 is connected between the anode 23 and the tank body 11. When the rotational force supply unit 65 is activated, the magnetic rotor 6 rotates (spins), generating an alternating magnetic field in the electrolyte stored in the plating tank 10. As an option, the movement mechanism M1 is activated to move the magnetic rotor 6 laterally. In this case, the magnetic rotor 6 moves laterally while rotating (spinning), specifically, reciprocating between the first and second end positions P1 and P2. The switch SW is turned on and the magnetic rotor 6 rotates simultaneously, so that the workpiece 1 is electroplated and polished with the magnetic abrasive 2 simultaneously. It is also possible to perform electroplating and polishing alternately or complementarily without overlapping on the time axis.

[0061] This will be explained with reference to FIG. 5 . As shown in FIG. 5 , the slit width W31 of the slit 31 is too narrow for the object 1 to be plated. Therefore, the object 1 cannot enter the slit 31 and, as a result, cannot contact the exposed surface 15b. In contrast, the magnetic abrasive 2 can easily enter the slit 31 and contact the exposed surface 15b. When the magnetic abrasive 2 is in contact with the exposed surface 15b, it is electrically connected to the negative pole of the DC power supply E1, set to a cathode potential, and can receive electrons. The object 1 to be plated, which is in direct contact with the magnetic abrasive 2, is also connected to a cathode potential and can receive electrons. Metal ions in the electrolyte receive electrons from the object 1 to be plated and are deposited as metal on the object 1 to be plated. This metal deposition process continues, and a plating film grows on the object 1 to be plated. During this process, the plating film is polished by the magnetic abrasive 2, thereby forming a plating film with high adhesion to the substrate of the object 1 to be plated. As is clear from Figure 5, the object 1 to be electroplated is not limited to being electrically connected to the exposed surface 15b via one magnetic abrasive 2, but can be electrically connected to the exposed surface 15b via multiple magnetic abrasives 2 and, in addition, one or more other objects 1 to be plated.

[0062] To reiterate, the slits 31 are formed in a thin line shape, which prevents the occurrence of poor appearance of the plated object due to an excessively large exposed area on the upper surface 15a of the bottom 15 of the plating tank 10. The thin line-shaped slits 31 also form the exposed surface 15b in a thin line shape. The growth of the plating film on the exposed surface 15b is slow or negligible due to high frequency impacts by the magnetic abrasive material 2. The growth of the plating film on the magnetic abrasive material 2 is slow or negligible due to collisions with other magnetic abrasive materials 2 and / or the object 1 to be plated.

[0063] 3 and 4, the slit 31 is formed linearly, specifically, extending linearly from the first end 11m of the tank body 11 to the second end 11n of the tank body 11. The slit 31 includes two slits 31a and 31b, which extend parallel to each other with a distance W5 greater than the width W22 of the mesh basket 22. The distance W5 is smaller than the diameter of the magnetic rotor 6 (or the diameter of an imaginary circle based on the orbit of the radially outer end of the permanent magnet 7). The slits 31a and 31b extend in the longitudinal direction of the plating tank 10 and are spaced equal distances from a center line AX1 located at the center of the narrow width of the plating tank 10. The length L31 of the slits 31a and 31b is greater than the length L22 of the mesh basket 22 and greater than the diameter of the magnetic rotor 6 (or the diameter of an imaginary circle based on the orbit of the radially outer end of the permanent magnet 7).

[0064] The slits 31 are not limited to the linear slits 31a and 31b described above, but can also be arranged nonlinearly, and the number and position of the slits can be changed in various ways. In FIG. 6, the slits 31 are formed as a rectangular frame. This rectangular frame is constructed from two long slits extending in the horizontal direction in which the magnetic rotating body 6 moves, and two short slits perpendicular to these. In such a case, the same effect can be obtained as long as it does not contradict the above explanation. In addition to the rectangular frame, an elliptical frame, a circular frame, or a triangular frame can also be used.

[0065] 7, the slit 31 may include one or more slits 31c, 31d formed in a wave shape along the lateral movement direction of the magnetic rotating body 6. In such a case, the same effect can be obtained as long as it does not contradict the above description. The minimum spacing W1 and maximum spacing W2 of the slits 31c, 31d are greater than the width W22 of the mesh cage 22 and smaller than the diameter of the magnetic rotating body 6 (or the diameter of an imaginary circle based on the rotation locus of the radially outer end of the permanent magnet 7).

[0066] 8, the slit 31 may include one or more slits 31e, 31f, 31g, 31h, 31i, 31j, 31k, and 31l extending in a direction intersecting or perpendicular to the lateral movement direction of the magnetic rotating body 6. In such a case, the same effect can be obtained as long as it does not contradict the above description. All of the slits 31e, 31f, 31g, 31h, 31i, 31j, 31k, and 31l are formed in positions other than directly below the mesh cage 22 and the anode 23.

[0067] 9, two mesh baskets 22 each having a shorter length may be immersed in the electrolyte. Each of the slits 31m, 31n, and 31o may be formed at a position other than the position directly below the mesh basket 22.

[0068] 10, the slit 31 may include one or more slits 31p, 31q including a portion located directly below the mesh cage 22. Two slits 31p, 31q are formed as the slit 31, and the minimum distance W1 between them is smaller than the width W22 of the mesh cage 22, and the maximum distance W2 between them is larger than the width W22 of the mesh cage 22 and smaller than the diameter of the magnetic rotating body 6 (or the diameter of an imaginary circle based on the rotation locus of the radially outer end of the permanent magnet 7).

[0069] 11 , the slit width of the slit 31 may gradually decrease toward the upper surface 15a of the bottom portion 15. The slit width of the slit 31 is defined between the side walls 12p, 12q of the covering portion 12 that approach each other toward the upper surface 15a of the bottom portion 15, and gradually decreases from a maximum width W4 to a minimum width W3 toward the upper surface 15a of the bottom portion 15. In this way, the probability of the magnetic abrasive 2 (e.g., a polishing pin) coming into contact with the exposed surface 15b can be increased without enlarging the exposed surface 15b.

[0070] 12, the entire surface of the tank body 11 may be covered with the covering portion 12, except for the slit 31, the groove 32, and the contact portion C2. The contact portion C2 is preferably formed on the flange 17 (e.g., on its lower surface), and the electrical connection is more reliably ensured due to the weight of the plating tank 10.

[0071] As is clear from the above description, the following method for producing a plated object is also disclosed. The method includes agitating and polishing a group of objects to be plated (1) using a group of magnetic abrasives (2) in an electrolyte stored in a plating tank (10) having an insulating coating (12) formed on the upper surface (15a) of the bottom (15) of a conductive tank body (11), and electroplating one or more of the objects to be plated (1) by electrically connecting them to the tank body (11) via one or more magnetic abrasives (2) included in the group of objects to be plated. The one or more magnetic abrasives (2) are electrically connected to the tank body (11) by contacting the exposed surface (15b) of the upper surface (15a) of the bottom (15) exposed by the slit (31) described above. Advantageously, all of the objects to be plated (1) included in the group of objects to be plated (1) are electroplated without directly contacting the exposed surface (15b). The features described with respect to the electroplating apparatus (100) are also applicable to the method for producing a plated object.

[0072] In light of the above disclosure, those skilled in the art can make various modifications to each embodiment and each feature. The magnetic polishing unit can also be constructed using a magnetic circuit.

[0073] The present disclosure also discloses the following invention: [1] An electroplating apparatus (100) including: a plating tank (10) having an insulating coating (12) formed on an upper surface (15a) of a bottom (15) of a conductive tank body (11); and a magnetic polishing unit (5) that stirs and polishes a group of objects to be plated (1) in an electrolyte stored in the plating tank (10) using a group of magnetic abrasives (2), wherein the coating (12) has thin slits (31) formed therein that have a depth that reaches the upper surface (15a) of the bottom (15), and the entire upper surface (15a) of the bottom (15) is covered with the coating (12) except for an exposed surface (15b) of the upper surface (15a) that is exposed by the slits (31). [2] The electroplating apparatus according to [1], wherein the slit (31) is formed at a position other than a position directly below one or more anodes (23) immersed in the electrolytic solution or a mesh cage (22) that receives the anodes. [3] The electroplating apparatus according to [1] or [2], wherein the magnetic polishing unit (5) includes at least one magnetic rotating body (6) rotatably provided below the bottom (15) of the plating tank (10), the magnetic rotating body (6) having a plurality of permanent magnets (71, 72) provided to generate an alternating magnetic field, and the exposed surface (15b) is formed at a position where magnetic flux between the plurality of permanent magnets (71, 72) can interlink. [4] The electroplating apparatus according to [3], wherein the at least one magnetic rotating body (6) is provided so as to be movable in a lateral direction intersecting its rotation axis (AX6), and the magnetic flux between the plurality of permanent magnets (71, 72) intersects with the exposed surface (15 b) regardless of the position of the magnetic rotating body (6) in the lateral direction. [5] The electroplating apparatus according to any one of [1] to [4], wherein the slit width (W31) of the slit (31) is set so that one or more magnetic abrasive materials (2) included in the group of magnetic abrasive materials (2) can contact the exposed surface (15 b), but each of the objects to be plated (1) in the group of objects to be plated (1) cannot contact the exposed surface (15 b).

[0074] REFERENCE SIGNS LIST 1: Object to be plated 2: Magnetic abrasive material 5: Magnetic abrasive portion 6: Magnetic rotating body 7: Permanent magnet 10: Plating tank 11: Tank body 15: Bottom 15a: Top surface 15b: Exposed surface 16: Side wall 16a: Inner surface 16b: Exposed surface 22: Mesh cage 23: Anode 31: Slit 32: Groove

Claims

1. An electroplating apparatus (100) comprising: a plating tank (10) having an insulating coating portion (12) formed on at least an upper surface (15a) of a bottom portion (15) of a conductive tank body (11); and a magnetic polishing portion (5) for stirring and polishing a group of objects to be plated (1) in an electrolyte stored in the plating tank (10) using a group of magnetic abrasives (2), wherein a slit (31) having a depth reaching the upper surface (15a) of the bottom portion (15) is formed in the coating portion (12) in the form of a thin line, and one or more magnetic abrasives (2) included in the group of magnetic abrasives (2) can be electrically connected to the tank body (11) via an exposed surface (15b) of the upper surface (15a) of the bottom portion (15) exposed by the slit (31).

2. The electroplating apparatus according to claim 1, wherein the slit (31) is formed at a position other than a position directly below one or more anodes (23) immersed in the electrolyte or a mesh cage (22) receiving the anodes.

3. An electroplating apparatus as described in claim 1 or 2, wherein the magnetic polishing section (5) includes at least one magnetic rotating body (6) rotatably mounted below the bottom (15) of the plating tank (10), the magnetic rotating body (6) has a plurality of permanent magnets (71, 72) arranged to generate an alternating magnetic field, and the exposed surface (15b) is formed at a position where magnetic flux between the plurality of permanent magnets (71, 72) can interlink.

4. The electroplating apparatus of claim 3, wherein the at least one magnetic rotating body (6) is arranged to be movable in a lateral direction intersecting its rotation axis (AX6), and the magnetic flux between the plurality of permanent magnets (71, 72) interlinks with the exposed surface (15b) regardless of the position of the magnetic rotating body (6) in the lateral direction.

5. An electroplating apparatus according to any one of claims 1 to 4, wherein the entire area of ​​the top surface (15a) of the bottom portion (15) is covered by the covering portion (12) except for the exposed surface (15b).

6. An electroplating apparatus according to any one of claims 1 to 5, wherein the length / width aspect ratio of the slit (31) is 50 or more, or 60 or more, or 100 or more.

7. An electroplating apparatus as claimed in any one of claims 1 to 6, wherein the slit width (W31) of the slit (31) is 0.5 mm or more, 0.8 mm or more, 1 mm or more, 1.5 mm or more, 2 mm or more, 4 mm or more, or 5 mm or more, and / or 10 mm or less, 5 mm or less, or 3 mm or less.

8. An electroplating apparatus according to any one of claims 1 to 7, wherein the occupancy rate of the exposed surface (15b) on the upper surface (15a) of the bottom portion (15) is 5% or less.

9. An electroplating apparatus as claimed in any one of claims 1 to 8, wherein the magnetic polishing section (5) includes at least one magnetic rotating body (6) rotatably mounted below the bottom (15) of the plating tank (10), the magnetic rotating body (6) being movably mounted in a lateral direction intersecting its rotation axis (AX6), and the slit (31) includes one or more slits (31a) extending linearly or non-linearly in a long length along the lateral direction.

10. An electroplating apparatus as described in any one of claims 1 to 9, wherein the covering portion (12) is formed on the inner surface (16a) of the side wall (16) of the tank body (11), and a groove (32) having a depth reaching the inner surface (16a) and wider than the slit (31) is formed in the covering portion (12), and the one or more magnetic abrasives (2) can be electrically connected to the tank body (11) via the exposed surface (16b) of the inner surface (16a) exposed by the groove (32).

11. An electroplating apparatus according to any one of claims 1 to 10, wherein each magnetic abrasive (2) of the group of magnetic abrasives (2) is an abrasive pin.

12. The electroplating apparatus of any one of claims 1 to 11, wherein the coating (12) comprises nylon.

13. A method for producing a plated object, comprising: stirring and polishing a group of objects to be plated (1) using a group of magnetic abrasives (2) in an electrolyte stored in a plating tank (10) in which an insulating coating portion (12) is formed on at least an upper surface (15a) of a bottom portion (15) of a conductive tank body (11); and electrically connecting one or more objects to be plated (1) included in the group of objects to be plated (1) to the tank body (11) via one or more magnetic abrasives (2) included in the group of magnetic abrasives (2) and electroplating the objects, wherein the one or more magnetic abrasives (2) are in contact with an exposed surface (15b) of the upper surface (15a) of the bottom portion (15) exposed by a slit (31) formed in the coating portion (12) in the form of a thin line at a depth reaching the upper surface (15a) of the bottom portion (15), and electrically connecting the one or more magnetic abrasives (2) to the tank body (11).

14. A method for producing a plated object as described in claim 13, wherein all of the objects to be plated (1) included in the group of objects to be plated (1) are electroplated without direct contact with the exposed surface (15b).

15. An electroplating method comprising: stirring and polishing a group of objects to be plated (1) using a group of magnetic abrasives (2) in an electrolyte stored in a plating tank (10) in which an insulating coating portion (12) is formed on at least an upper surface (15a) of a bottom portion (15) of a conductive tank body (11); and electrically connecting one or more objects to be plated (1) included in the group of objects to be plated (1) to the tank body (11) via one or more magnetic abrasives (2) included in the group of magnetic abrasives (2) to perform electroplating, wherein the one or more magnetic abrasives (2) are in contact with an exposed surface (15b) of the upper surface (15a) of the bottom (15) exposed by a slit (31) formed in the coating portion (12) in the form of a thin line at a depth reaching the upper surface (15a) of the bottom (15), and are electrically connected to the tank body (11).

16. A plating tank (10) for electroplating in which magnetic polishing using a magnetic abrasive (2) is performed in the same tank as electroplating, comprising: a conductive tank body (11) having a bottom (15) and a side wall (16); and an insulating covering portion (12) formed on at least an upper surface (15a) of the bottom (15), wherein a slit (31) having a depth reaching the upper surface (15a) of the bottom (15) is formed in the covering portion (12) in the form of a thin line, and the magnetic abrasive (2) can be electrically connected to the tank body (11) via an exposed surface (15b) of the upper surface (15a) of the bottom (15) exposed by the slit (31).

Images