Electroplating method capable of accurately controlling thicknesses of inner and outer films

Abstract

The invention discloses an electroplating method capable of achieving accurate control over the thickness of an inner film and the thickness of an outer film, the electroplating method comprises the steps of preparing a special hanging tool, hanging a workpiece, electroplating the workpiece and the like, the electroplating method is reasonable in design, the specially-made hanging tool and the dual-power-source power supply design are adopted, and the main negative electrode of the hanging tool can make contact with the workpiece; the auxiliary positive pole of the hanger can extend into an inner hole of the workpiece, the positive pole of the main control power supply is connected with the positive pole of the electroplating bath, the negative pole of the main control power supply is connected with the main negative pole of the hanger, the positive pole of the auxiliary power supply is connected with the auxiliary positive pole of the hanger, and the negative pole of the auxiliary power supply is connected with the main negative pole of the hanger; the main control power supply and the auxiliary power supply can supply power at the same time, the main control power supply can play a role in ions in the electroplating bath so that metal electroplating materials in the electroplating bath can be electroplated on the outer surface and the inner hole surface of a workpiece, and the auxiliary power supply can accelerate ion reduction to the inner hole surface of the workpiece through discharge of the auxiliary positive electrode. Therefore, accurate proportion control of the inner and outer film thicknesses of the workpiece can be realized.

Description

Technical Field

[0001] The present invention relates to the field of electroplating technology, and more specifically, to an electroplating method capable of achieving precise control of inner and outer film thickness. Background Art

[0002] In the processing of some metal workpieces, it is often necessary to electroplate the surface to meet the corresponding conductive performance requirements, such as Figure 1 The connector female head 2 with inner hole 21 shown or other various pipes with inner cavity or inner hole.

[0003] In the current electroplating process, the workpiece to be electroplated can be placed in the electroplating tank for electroplating by means of a hanger. An ordinary hanger has only one negative pole (i.e., cathode). When connecting, the negative pole of the power supply can be connected to the negative pole of the hanger, and the positive pole of the power supply can be connected to the positive pole (i.e., anode) of the electroplating tank. During the electroplating process, the flow direction and time of ions are limited by the direction and distance of the single positive and negative poles, which will cause the ions to be uneven on the outer surface and inner hole surface of the workpiece, resulting in uneven film thickness of the inner and outer coatings of the workpiece, with a large difference. However, the current electroplating process can generally only well control the external film thickness of the workpiece. If you want to make the internal and external film thickness consistent or control the internal and external film thickness proportionally, it is difficult to do so. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide an electroplating method that can achieve precise control of the inner and outer film thickness.

[0005] To achieve the above object, the present invention provides an electroplating method capable of realizing precise control of inner and outer film thickness, comprising the following steps:

[0006] (1) preparing a special hanger; wherein the hanger is provided with a main negative electrode in contact with the workpiece to be electroplated, an auxiliary positive electrode not in contact with the workpiece to be electroplated, and an insulating hanging bar for hanging the workpiece to be electroplated and insulated from the workpiece, and an insulation arrangement is adopted between the main negative electrode and the auxiliary positive electrode of the hanger to avoid short circuit between the positive and negative electrodes on the hanger;

[0007] (2) Workpiece hanging: insert the insulating hanging bar of the hanger into the inner hole of the workpiece to be electroplated, so that the workpiece to be electroplated is hung on the insulating hanging bar of the hanger, and at the same time, insert the auxiliary positive electrode of the hanger into the inner hole of the workpiece to be electroplated without contacting the workpiece to be electroplated, and make the main negative electrode of the hanger contact with the workpiece to be electroplated;

[0008] (3) Workpiece electroplating: placing the mounted workpiece to be electroplated and the hanger together into the electroplating tank, connecting the positive electrode of the main control power supply to the positive electrode of the electroplating tank, connecting the negative electrode of the main control power supply to the main negative electrode of the hanger, connecting the positive electrode of the auxiliary power supply to the auxiliary positive electrode of the hanger, and connecting the negative electrode of the auxiliary power supply to the main negative electrode of the hanger, and then controlling the main control power supply and the auxiliary power supply to supply power simultaneously, so that the metal plating material in the electroplating tank is electroplated on the outer surface and inner hole surface of the workpiece according to a preset film thickness;

[0009] During the electroplating process of the workpiece, the current of the main power supply is greater than the output current of the auxiliary power supply.

[0010] Preferably, the hanger is configured as a cage-hanging hanger or a row-hanging hanger.

[0011] Preferably, when the hanger is set as a cage-hanging hanger, the cage-hanging hanger includes a top outer ring, a bottom outer ring, an outer ring column, an inner ring, an inner ring column, an insulating connecting column, a negative electrode power connection hook, an auxiliary positive electrode power connection piece, a main negative electrode, an auxiliary positive electrode and an insulating hanging bar. The bottom outer ring is located below the top outer ring and is connected to the top outer ring through a plurality of evenly arranged outer ring columns. The bottom outer ring and the top outer ring are both located outside the inner ring. The inner ring is provided with a plurality of columns that are arranged in sequence from top to bottom. All inner rings are connected through evenly arranged inner ring columns. The top outer ring is connected through an insulating connecting column. The bottom outer ring is connected to the inner ring at the top, the bottom outer ring is connected to the inner ring at the bottom through an insulating connecting column, the negative pole power hook is installed on the inner ring at the top, the negative pole power hook is connected to the negative pole of the main control power supply and the negative pole of the auxiliary power supply, the auxiliary positive pole power connection piece is installed on the top outer ring, the auxiliary positive pole power connection piece is connected to the positive pole of the auxiliary power supply, the auxiliary positive pole and the insulating hanging strip are respectively installed on the same side of each outer ring column, the main negative pole is evenly installed on the outer edge of the inner ring, and the end of each main negative pole extends to one side of the end of the corresponding auxiliary positive pole and the insulating hanging strip.

[0012] Preferably, the insulating connecting column is configured as a ceramic rod.

[0013] Preferably, the outside of the top outer ring, the bottom outer ring, the outer ring column, the inner ring, the inner ring column, the insulating connecting column and the insulating hanging bar are all provided with insulating resin, the end of the main negative electrode is exposed and the remaining external positions are provided with insulating resin, and the end of the auxiliary positive electrode is exposed and the remaining external positions are provided with insulating resin.

[0014] Preferably, the output current of the main power supply is 2 to 4 times the output current of the auxiliary power supply.

[0015] Preferably, during the workpiece electroplating process, the hanger needs to be lifted and the power needs to be turned off 2 to 4 times, each time for 3 to 5 seconds.

[0016] Preferably, the on-off current of the main power supply and the on-off current of the auxiliary power supply are controlled by respectively connected relays.

[0017] Preferably, the auxiliary positive electrode is pre-electroplated with a metal that is the same as the plating material of the workpiece.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The electroplating method of the present invention is reasonably designed. It adopts a special hanger and a dual power supply design. The main negative pole of the hanger can contact the workpiece, and the auxiliary positive pole of the hanger can extend into the inner hole of the workpiece. The positive pole of the main power supply is connected to the positive pole of the electroplating tank, the negative pole of the main power supply is connected to the main negative pole of the hanger, the positive pole of the auxiliary power supply is connected to the auxiliary positive pole of the hanger, and the negative pole of the auxiliary power supply is connected to the main negative pole of the hanger. The main power supply and the auxiliary power supply can supply power at the same time. The main power supply can act on the ions in the electroplating tank, so that the metal plating material in the electroplating tank is electroplated on the outer surface and the inner hole surface of the workpiece. The auxiliary power supply can accelerate the reduction of ions to the inner hole surface of the workpiece through the discharge of the auxiliary positive pole, so that the precise proportional control of the inner and outer film thickness of the workpiece can be achieved.

[0020] 2. The main negative electrode and the auxiliary positive electrode of the present invention are both integrated on one hanger, but a clever insulation design is used between the two, which can avoid short circuit between the positive and negative electrodes on the same hanger.

[0021] 3. In the process of electroplating the workpiece, the hanger needs to be lifted several times, so that the electroplating solution can be fully exchanged and the ions can be maintained at a balanced abundance.

[0022] 4. In the present invention, the auxiliary positive electrode is pre-electroplated with a metal having the same material as the coating of the workpiece, which can speed up the electroplating speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 is a schematic structural diagram of a female connector provided by an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of the structure of a hanger provided by an embodiment of the present invention;

[0026] Figure 3is a top view of a hanger provided by an embodiment of the present invention;

[0027] Figure 4 is an enlarged view of a partial structure of a hanger provided in an embodiment of the present invention;

[0028] Figure 5 It is a schematic diagram of the mounting of the connector female head and the mounting device provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] An embodiment of the present invention provides an electroplating method capable of achieving precise control of inner and outer film thickness, comprising the following steps:

[0031] (1) Preparation of special hangers;

[0032] The hanger of this embodiment can be preferably configured as a cage-hanging metal hanger, such as Figure 2 , Figure 3 and Figure 4 As shown, the hanger may include a top outer ring 11, a bottom outer ring 12, an outer ring column 13, an inner ring 14, an inner ring column 15, an insulating connecting column 16, a negative electrode power connection hook 17, an auxiliary positive electrode power connection piece 18, a main negative electrode 19, an auxiliary positive electrode 110 and an insulating hanging bar 111. The bottom outer ring 12 is located below the top outer ring 11 and is connected to the top outer ring 11 through a plurality of evenly arranged outer ring columns 13. The bottom outer ring 12 and the top outer ring 11 are both located outside the inner ring 14. The inner ring 14 is provided with a plurality of inner ring columns 13 that are arranged in sequence from top to bottom. All inner rings 14 are connected through evenly arranged inner ring columns 13. 5, the top outer ring 11 is connected to the inner ring 14 at the top through the insulating connecting column 16, the bottom outer ring 12 is connected to the inner ring 14 at the bottom through the insulating connecting column 16, the negative electrode connecting hook 17 is installed on the inner ring 14 at the top, the auxiliary positive electrode connecting piece 18 is installed on the top outer ring 11, the auxiliary positive electrode 110 and the insulating hanging bar 111 are respectively installed on the same side of each outer ring column 13 in parallel, the main negative electrode 19 is evenly installed on the outer edge of the inner ring 14, and the end of each main negative electrode 19 extends to one side of the end of the corresponding auxiliary positive electrode 110 and the insulating hanging bar 111.

[0033] In this embodiment, the insulating connecting column 16 can be preferably set as a ceramic rod, which has a good insulation effect. The main negative electrode and the auxiliary positive electrode of this embodiment are integrated on a hanger, but the two are insulated by the insulating connecting column 16, which can avoid short circuit between the positive and negative electrodes on the same hanger.

[0034] In this embodiment, the top outer ring 11, the bottom outer ring 12, the outer ring column 13, the inner ring 14, the inner ring column 15, the negative electrode connection hook 17, the auxiliary positive electrode connection piece 18, the main negative electrode 19, and the auxiliary positive electrode 110 are all made of conductive metal materials, and the top outer ring 11, the bottom outer ring 12, the outer ring column 13, the inner ring 14, the inner ring column 15, the insulating connection column 16, and the insulating hanging bar 111 can be provided with insulating resin on the outside, the end of the main negative electrode 19 is exposed and the other external positions can be provided with insulating resin, and the end of the auxiliary positive electrode 110 is exposed and the other external positions can be provided with insulating resin. In specific implementation, the insulating resin can be preferably set to epoxy resin or other insulating coatings.

[0035] (2) Workpiece mounting: Insert the insulating hanging bar 111 of the rack into the inner hole 21 of the workpiece 2 to be electroplated, so that the workpiece to be electroplated is mounted on the insulating hanging bar of the rack, and at the same time, insert the auxiliary positive electrode 110 of the rack into the inner hole 21 of the workpiece 2 to be electroplated without contacting the workpiece to be electroplated, and make the main negative electrode 19 of the rack contact with the workpiece 2 to be electroplated (see Figure 5 );

[0036] (3) Workpiece electroplating: The mounted workpiece to be electroplated and the hanger are placed together in the electroplating tank, the positive electrode of the main control power supply is connected to the positive electrode of the electroplating tank, the negative electrode of the main control power supply is connected to the main negative electrode 19 of the hanger, the positive electrode of the auxiliary power supply is connected to the auxiliary positive electrode 110 of the hanger, and the negative electrode of the auxiliary power supply is connected to the main negative electrode 19 of the hanger, and then the main control power supply and the auxiliary power supply are controlled to supply power simultaneously, so that the metal plating material in the electroplating tank is electroplated on the outer surface and inner hole surface of the workpiece according to the preset film thickness;

[0037] When connecting the power, the negative pole power hook 17 of the hanger is connected to the negative pole of the main power supply and the negative pole of the auxiliary power supply, the negative pole power hook 17 is connected to the main negative pole 19 through the inner ring 14 and the inner ring column 15, the auxiliary positive pole power connection piece 18 is connected to the positive pole of the auxiliary power supply, and the auxiliary positive pole power connection piece 18 is connected to the auxiliary positive pole 110 through the top outer ring 11 and the outer ring column 13.

[0038] During the workpiece electroplating process, the current of the main power supply needs to be greater than the output current of the auxiliary power supply. Preferably, the output current of the main power supply is 2 to 4 times the output current of the auxiliary power supply.

[0039] During the workpiece electroplating process, the hanger needs to be lifted and the power needs to be turned off 2 to 4 times (preferably 3 times), each time for 3 to 5 seconds. Lifting the hanger multiple times allows the electroplating solution to be fully exchanged, so that the ions are maintained at a balanced abundance.

[0040] In this embodiment, the current on and off of the main power supply and the current on and off of the auxiliary power supply can be controlled by the relays connected to them respectively. Through the control of the two relays, the current and time can be distributed and compensated.

[0041] During electroplating, the main power supply and auxiliary power supply can effectively control the current density, potential difference, and ion exchange time during the electroplating process. Among them, different electroplating times can be set according to different plating materials (such as nickel, silver, gold, etc.).

[0042] As a further improvement of the electroplating method, preferably, the auxiliary positive electrode may be pre-electroplated with a metal that is the same as the plating material of the workpiece, which can speed up the electroplating speed.

[0043] It should be noted here that, according to actual needs, the electroplating method can also adopt a row-hanging hanger, which can also be provided with a main negative electrode in contact with the workpiece to be electroplated, an auxiliary positive electrode that does not contact the workpiece to be electroplated, and an insulating hanging bar for hanging the workpiece to be electroplated and insulating it from the workpiece, and insulation is also required between the main negative electrode and the auxiliary positive electrode.

[0044] In summary, the electroplating method of the present invention is reasonably designed. It adopts a special hanger and a dual power supply design, which can achieve precise proportional control of the inner and outer film thickness of the workpiece (such as a thickness ratio of 1:1 or 1:3). It can solve the problem that the inner and outer film thickness of the electroplated workpiece cannot be controlled, thereby affecting the conductive properties of the electroplated workpiece. The electroplating method of the present invention is suitable for all electroplating industries.

[0045] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An electroplating method capable of achieving precise control of inner and outer film thickness, characterized in that: The following steps are involved: (1) preparing a special hanger; wherein the hanger is provided with a main negative electrode in contact with the workpiece to be electroplated, an auxiliary positive electrode not in contact with the workpiece to be electroplated, and an insulating hanging bar for hanging the workpiece to be electroplated and insulated from the workpiece, and an insulation arrangement is adopted between the main negative electrode and the auxiliary positive electrode of the hanger to avoid short circuit between the positive and negative electrodes on the hanger; (2) Workpiece hanging: insert the insulating hanging bar of the hanger into the inner hole of the workpiece to be electroplated, so that the workpiece to be electroplated is hung on the insulating hanging bar of the hanger, and at the same time, insert the auxiliary positive electrode of the hanger into the inner hole of the workpiece to be electroplated without contacting the workpiece to be electroplated, and make the main negative electrode of the hanger contact with the workpiece to be electroplated; (3) Workpiece electroplating: placing the mounted workpiece to be electroplated and the hanger together into the electroplating tank, connecting the positive electrode of the main control power supply to the positive electrode of the electroplating tank, connecting the negative electrode of the main control power supply to the main negative electrode of the hanger, connecting the positive electrode of the auxiliary power supply to the auxiliary positive electrode of the hanger, and connecting the negative electrode of the auxiliary power supply to the main negative electrode of the hanger, and then controlling the main control power supply and the auxiliary power supply to supply power simultaneously, so that the metal plating material in the electroplating tank is electroplated on the outer surface and inner hole surface of the workpiece according to a preset film thickness; During the electroplating process of the workpiece, the current of the main power supply is greater than the output current of the auxiliary power supply.

2. The electroplating method capable of realizing precise control of inner and outer film thickness according to claim 1, characterized in that: The hanger is configured as a cage-hanging hanger or a row-hanging hanger.

3. The electroplating method capable of realizing precise control of inner and outer film thickness according to claim 2, characterized in that: When the hanger is set as a cage-hanging hanger, the cage-hanging hanger includes a top outer ring, a bottom outer ring, an outer ring column, an inner ring, an inner ring column, an insulating connecting column, a negative electrode power connection hook, an auxiliary positive electrode power connection piece, a main negative electrode, an auxiliary positive electrode and an insulating hanging bar. The bottom outer ring is located below the top outer ring and is connected to the top outer ring through a plurality of evenly arranged outer ring columns. The bottom outer ring and the top outer ring are both located outside the inner ring. The inner ring is provided with a plurality of columns that are spaced from top to bottom. All inner rings are connected through evenly arranged inner ring columns. The top outer ring is connected to the inner ring through an insulating connecting column. The inner ring at the top is connected, the bottom outer ring is connected to the inner ring at the bottom through an insulating connecting column, the negative pole power hook is installed on the inner ring at the top, the negative pole power hook is connected to the negative pole of the main control power supply and the negative pole of the auxiliary power supply, the auxiliary positive pole connecting piece is installed on the top outer ring, the auxiliary positive pole connecting piece is connected to the positive pole of the auxiliary power supply, the auxiliary positive pole and the insulating hanging strip are respectively installed on the same side of each outer ring column, the main negative pole is evenly installed on the outer edge of the inner ring, and the end of each main negative pole extends to one side of the end of the corresponding auxiliary positive pole and the insulating hanging strip.

4. The electroplating method capable of realizing precise control of inner and outer film thickness according to claim 3, characterized in that: The insulating connecting column is configured as a ceramic rod.

5. The electroplating method capable of realizing precise control of inner and outer film thickness according to claim 3, characterized in that: The outside of the top outer ring, the bottom outer ring, the outer ring column, the inner ring, the inner ring column, the insulating connecting column and the insulating hanging bar are all provided with insulating resin, the end of the main negative electrode is exposed and the other external positions are provided with insulating resin, and the end of the auxiliary positive electrode is exposed and the other external positions are provided with insulating resin.

6. The electroplating method capable of realizing precise control of inner and outer film thickness according to claim 1, characterized in that: The output current of the main control power supply is 2 to 4 times the output current of the auxiliary power supply.

7. The electroplating method capable of achieving precise control of inner and outer film thickness according to claim 1, characterized in that: During the workpiece electroplating process, the hanger needs to be lifted and the power needs to be turned off 2 to 4 times, each time for 3 to 5 seconds.

8. The electroplating method capable of achieving precise control of inner and outer film thickness according to claim 1, characterized in that: The on-off current of the main power supply and the on-off current of the auxiliary power supply are controlled by the relays connected to them respectively.

9. The electroplating method capable of realizing precise control of inner and outer film thickness according to claim 1, characterized in that: The auxiliary positive electrode is pre-electroplated with a metal that is the same as the plating material of the workpiece.

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