Uniform electroplating equipment for precision hardware and method of use thereof

Abstract

The application discloses a kind of uniform electroplating equipment of precision hardware's use method, comprising the following steps: S1, workpiece placement: hardware with inner angle is clamped between positioning rod and anode, while ensuring the inner angle side of hardware towards anode, drive component tends to anode center movement, cathode is pushed by cylinder and is attached to hardware, and the midline of arc inner angle of hardware coincides with the vertical edge of anode;S2, discharge plating layer: current density is 10-15mA / cm 2 It is applied to workpiece, and plating duration is kept for 2-10s;S3, periodic discharge: cylinder is retracted to adhere to device away from cathode while drive component moves along track away from anode center, cathode also moves away from workpiece at this time, rotate gear at the speed of 40-50 degrees / s, drive cathode to rotate 119-121 degrees around anode center, repeat step S1 and step S2, and gear rotation is 3 times as a cycle;S4: repeat step S1-S3, and plating is completed after two cycles;In the application, by setting periodic plating device, the problem of uneven coating on workpiece surface caused by hydrogen evolution reaction is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of metal surface treatment, and in particular to a uniform electroplating device for precision hardware parts and its method of use. Background Technology

[0002] Electroplating is a surface finishing method in which the substrate metal is used as the cathode in a salt solution containing the metal to be plated. Through electrolysis, the cations of the metal to be plated are deposited on the surface of the substrate metal, forming a coating. The properties of the coating differ from those of the substrate metal, exhibiting new characteristics. Based on function, coatings are classified into protective coatings, decorative coatings, and other functional coatings. Electroplating technology has evolved into a crucial modern processing technique, far beyond simply protecting and decorating metal surfaces, although protective and decorative electroplating still constitute a significant portion of electroplating processes. The functional applications of electroplating are becoming increasingly widespread, particularly in the electronics, communications, military, and aerospace industries, where functional electroplating technologies are extensively used.

[0003] The existing electroplating equipment has the following problems: 1. During the conventional electrolyte electrodeposition process, hydrogen evolution reaction usually occurs on the cathode surface. The generated bubbles continuously rise and produce a strong stirring effect, which causes changes in the cathode polarization resistance and electrolyte resistance in the longitudinal direction. This results in differences in current efficiency at the upper and lower ends of the pipe, ultimately leading to uneven coating thickness; 2. For hardware parts with bends, the electric field lines at and near the inner corners are usually sparse, resulting in a thinner deposited coating or even incomplete plating; 3. The anode surface is prone to passivation during the electroplating process and needs to be replaced frequently. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and provides a uniform electroplating device and its usage method for precision hardware parts. It aims to solve the problem that hydrogen evolution reaction easily occurs on the cathode surface in the prior art, resulting in uneven electroplating coating thickness, and at the same time improve the electroplating effect at the inner corners of tight hardware parts with inner corners.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a uniform electroplating device for precision hardware parts and a method for using the same, comprising: a worktable and a plurality of cathodes and anodes disposed on the worktable.

[0006] The workbench has a circular groove, several insertion holes and a positioning rod in the center. The anode is installed in the circular groove, and the bottom of the circular groove is connected to several drainage grooves.

[0007] The positioning rod is installed in the insertion hole, and the installation position of the positioning rod can be adjusted according to the size of the workpiece. The drain channel is used to guide the electroplating solution on the worktable into the liquid pool when the worktable is raised from the electroplating solution.

[0008] The cathode includes several mounting strips and several ejector rods mounted on the mounting strips by several springs, and the cathodes are linearly arranged and mounted on several racks; the racks are connected to several driving devices, the driving devices include several gears and a moving part connected by a U-shaped frame, and the moving part is mounted in a guide rail on the worktable;

[0009] The side of the cathode facing away from the anode is also connected to a bonding device. The bonding device includes a cylinder and an X-shaped support plate connected to the output shaft of the cylinder. The X-shaped support plate is provided with several fixed columns, and several horizontally arranged push plates are installed on the several fixed columns.

[0010] In a preferred embodiment of the present invention, the anode is a triangular prism with an equilateral triangle shape in top view, and the surface of the anode is provided with a number of protrusions. The triangular prism shape of the anode facilitates symmetry with the cathode and allows the workpiece to be placed symmetrically between the anode and cathode, which is beneficial to the uniform formation of the coating. The protrusions can increase the surface area of ​​the anode.

[0011] In a preferred embodiment of the present invention, the anode and the cathode are respectively connected to the positive and negative terminals of the power supply, and the power supply can also rotate as the rack moves to ensure that the polarities correspond.

[0012] In a preferred embodiment of the present invention, the end of the ejector rod facing the anode is a spherical body, and the end facing away from the anode is a locking block. When the spherical body contacts the workpiece, it will not cause deep scratches on the workpiece surface and has a large contact area. The locking block is used to limit the orientation of the cathode on the mounting strip and control the position of the ejector rod with the spring.

[0013] In a preferred embodiment of the present invention, the U-shaped frame is further provided with a plurality of clamping plates, which are used to engage with the gear and the rack.

[0014] In a preferred embodiment of the present invention, the elastic force of the plurality of springs gradually increases from the center to both ends along the direction of the rack, thereby conforming to the curvature of the hardware, ensuring that both sides of the hardware can contact the anode and cathode, while preventing the tip of the anode from forming a deep indentation on the surface of the hardware.

[0015] In a preferred embodiment of the present invention, the spring and the ejector rod are in clearance fit, and the inner diameter of the spring is smaller than the diameter of the spherical body.

[0016] In a preferred embodiment of the present invention, the cathode is symmetrical about the axis of symmetry of the anode in the horizontal plane, ensuring that the distance from both ends of the workpiece to the tip of the anode is the same, thereby improving the electroplating effect.

[0017] This invention also provides a method for using a uniform electroplating device for precision hardware parts, based on the uniform electroplating device for precision hardware parts according to any one of claims 1-8, characterized by comprising the following steps:

[0018] S1. Workpiece placement: The hardware with an inner angle is placed between the positioning rod and the anode, while ensuring that one side of the inner angle of the hardware faces the anode. The driving component moves toward the center of the anode, and the cylinder pushes the cathode to fit with the hardware. The center line of the arc-shaped inner angle of the hardware coincides with the vertical edge of the anode.

[0019] S2, Discharge plating: Applying a discharge plating layer to the workpiece with a density of 10-15 mA / cm². 2 The current is applied, and the electroplating time is maintained at 2-10 seconds;

[0020] S3, Periodic Discharge: As the cylinder retracts to the bonding device and moves away from the cathode, the driving component moves along the track away from the anode center. At this time, the cathode also moves away from the workpiece. The gear rotates at a speed of 40-50 degrees / s, driving the cathode to rotate around the anode center by 119°-121°. Then, steps S1 and S2 are repeated, and the gear rotates 3 times as one cycle.

[0021] S4: Repeat steps S1-S3 and complete the electroplating after two cycles.

[0022] In a preferred embodiment of the present invention, when step S1 is repeated after step S3, the movement of the cathode will cause the electroplating solution to slosh. Therefore, it is only necessary to keep the center line of the arc-shaped inner corner of the hardware as coincident as possible with the vertical edge of the anode. The electroplating solution is composed of a variety of components, mainly including solvents (such as water, organic solutions, molten salts, etc.), main salts, additives and impurities.

[0023] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0024] (1) This invention provides a periodic electroplating apparatus in which a driving device controls the periodic rotation of the cathode plate. At the same time, a gear is installed on a U-shaped frame so that the rack and cathode plate can pass through it without affecting the rotation of the cathode. The driving device and the bonding device cooperate with each other. When the cathode rotates, the driving device moves to the farthest end, opens the rack and then rotates. When electroplating, the driving device moves towards the center, so that the rack and cathode are flexible and will not fall off due to the action of the gear and the clamping plate. The bonding device pushes the cathode to bond to the surface of the workpiece. Since the entire electroplating apparatus and the placement method are symmetrical, the distance from both ends of the workpiece to the anode and cathode is equal during electroplating, avoiding the impact on the uniformity and overall performance of the coating due to uneven current density distribution.

[0025] (2) In conventional electroplating, when the curvature of the inner corner of the workpiece is small, the electric field lines are difficult to reach, resulting in a small current density. This can easily cause the coating to be thin and uneven near the inner corner, or even lead to plating failure. In this invention, a symmetrical and pointed anode is provided, and the tip of the anode is always aligned with the cathode. By utilizing the tip discharge effect, the current density at the inner corner is increased, thereby improving the overall uniformity of the coating. At the same time, several protrusions are provided on the surface of the anode to increase the surface area of ​​the anode and prevent the anode from becoming passivated.

[0026] (3) In the electroplating process, the cathode is attached to the workpiece and then moved away from the workpiece to form a periodic electroplating method. During the periodic rotation of the cathode, the bubbles (hydrogen) generated on the cathode surface will move upward, which avoids the problem that the bubbles generated in the conventional electroplating process continuously overflow and generate a strong stirring effect, causing the cathode polarization resistance and electrolyte resistance to change in the longitudinal direction, resulting in the difference in current efficiency at the upper and lower ends of the workpiece, and ultimately leading to the problem of uneven coating thickness.

[0027] (4) Simultaneously, the periodic switching on and off of DC electroplating allows the instantaneous high current density during conduction to reduce metal ions at high overpotential, thereby improving electroplating efficiency and refining the grain size of the deposited layer. At the same time, the relaxation characteristics of the periodic switching current are beneficial to increasing the cathode electrochemical polarization and reducing the concentration polarization, improving the distribution of the deposited layer, and having advantages such as reducing the porosity of the coating, enhancing the coating adhesion, improving the deep plating ability and dispersion ability, reducing the internal stress of the coating, and improving the appearance and mechanical and physical properties of the coating. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a top view of a preferred embodiment of the present invention;

[0030] Figure 2 This is a structural diagram of the driving device according to a preferred embodiment of the present invention;

[0031] Figure 3 This is a cathode structure diagram of a preferred embodiment of the present invention;

[0032] Figure 4 This is a structural diagram of the bonding device according to a preferred embodiment of the present invention.

[0033] In the diagram: 1. Workbench; 2. Drive unit; 3. Rack; 4. Circular groove; 5. Cathode; 6. Insertion hole; 7. Positioning rod; 8. Guide rail; 9. Drainage channel; 10. Bonding device; 11. Anode; 12. Workpiece; 13. Gear; 14. U-shaped frame; 15. Moving part; 16. Clamping plate; 17. Mounting strip; 18. Spring; 19. Ejector rod; 20. Spherical body; 21. Cylinder; 22. X-shaped support plate; 23. Fixed column; 24. Push plate. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0036] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0037] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0038] like Figure 1 As shown, a top view of a uniform electroplating device for precision hardware parts is provided, including: a worktable and several cathodes 5 and anodes 11 disposed on the worktable. The anode is a triangular prism with an equilateral triangle shape in the top view, and the anode surface is provided with several protrusions. The anode and cathode are respectively connected to the positive and negative terminals of the power supply. The cathode is symmetrical about the axis of symmetry of the anode in the horizontal plane.

[0039] The workbench 1 has a circular groove 4, several insertion holes 6 and a positioning rod 7 in the center. The workpiece 12 is placed between the positioning rod 7 and the anode 11. The anode 11 is installed in the circular groove 4, and the bottom of the circular groove 4 is connected to several drainage grooves 9.

[0040] like Figure 2 As shown, a structural diagram of a drive device for a uniform electroplating equipment for precision hardware parts is provided. The drive device 2 includes several gears 13 and a moving part 15 connected by a U-shaped frame 14. The moving part 15 is installed in the guide rail 8 on the worktable 1. Several clamping plates 16 are also provided on the U-shaped frame 14. The clamping plates 16 are used to engage with the gears 13 and the rack 3.

[0041] like Figure 3 The diagram shows the cathode structure of a uniform electroplating device for precision hardware parts. The cathode 5 includes several mounting strips 17 and several ejector rods 19 mounted on the mounting strips 17 via several springs 18. The cathodes 5 are linearly arranged on several racks 3. The end of the ejector rod 19 facing the anode 11 is a spherical body 20, and the end facing away from the anode 11 is a locking block. The racks 3 are connected to several driving devices 2. The springs 18 and ejector rods 19 are in clearance fit, and the inner diameter of the springs 18 is smaller than the diameter of the spherical body 20. The elastic force of the springs gradually increases from the center to both ends along the rack direction.

[0042] like Figure 4 As shown, a bonding device structure diagram of a uniform electroplating equipment for precision hardware parts is provided. The side of the cathode 5 facing away from the anode 11 is also connected to a bonding device 10. The bonding device 10 includes a cylinder 21 and an X-shaped support plate 22 connected to the output shaft of the cylinder 21. Several fixed columns 23 are provided on the X-shaped support plate 22, and several horizontally arranged push plates 24 are installed on the several fixed columns 23.

[0043] This invention also provides a method for using a uniform electroplating device for precision hardware parts, comprising the following steps:

[0044] S1. Workpiece placement: The hardware with an inner angle is placed between the positioning rod and the anode, while ensuring that one side of the inner angle of the hardware faces the anode. The driving component moves toward the center of the anode, and the cylinder pushes the cathode to fit with the hardware. The center line of the arc-shaped inner angle of the hardware coincides with the vertical edge of the anode.

[0045] S2, Discharge plating: Applying a discharge plating layer with a density of 10 mA / cm² to the workpiece. 2 The current is applied, and the electroplating time is maintained at 3 seconds;

[0046] S3, Periodic Discharge: As the cylinder retracts to the bonding device and moves away from the cathode, the driving component moves along the track away from the anode center. At this time, the cathode also moves away from the workpiece. The gear rotates at a speed of 40 degrees / s, driving the cathode to rotate 120° around the anode center. Then, steps S1 and S2 are repeated, and the gear rotates 3 times as one cycle.

[0047] S4: Repeat steps S1-S3 and complete the electroplating after two cycles.

[0048] It should be noted that when repeating step S1 after step S3, the movement of the cathode will cause the electroplating solution to slosh. Therefore, it is only necessary to keep the center line of the arc-shaped inner corner of the hardware as coincident as possible with the vertical edge of the anode. The electroplating solution is composed of a variety of components, mainly including solvents (such as water, organic solutions, molten salts, etc.), main salts, additives and impurities.

[0049] This invention provides a periodic electroplating apparatus. A driving device controls the periodic rotation of a cathode plate, while a gear is mounted on a U-shaped frame, allowing the rack and cathode plate to pass through without affecting the cathode's rotation. The driving device and a bonding device work together: during cathode rotation, the driving device moves to its furthest point, opening the rack before it rotates; during electroplating, the driving device moves towards the center, ensuring the rack and cathode are flexible while preventing them from falling off due to the gear and clamping plate. The bonding device then pushes the cathode to adhere to the workpiece surface. Because the entire electroplating apparatus and placement method are symmetrical, the distances from both ends of the workpiece to the anode and cathode are equal during electroplating, avoiding uneven current density distribution that could affect the uniformity and overall performance of the coating.

[0050] In conventional electroplating, when the curvature of the inner corner of the workpiece is small, the electric field lines are difficult to reach, resulting in a low current density. This can easily lead to a thin and uneven coating near the inner corner, or even plating defects. In this invention, a symmetrical and pointed anode is provided, and the tip of the anode is always aligned with the cathode. By utilizing the tip discharge effect, the current density at the inner corner is increased, thereby improving the overall uniformity of the coating. At the same time, several protrusions are provided on the surface of the anode to increase the surface area of ​​the anode and prevent passivation.

[0051] In this invention, the cathode is brought into contact with the workpiece and then moved away from it during the electroplating process, forming a periodic electroplating method. During the periodic rotation of the cathode, the bubbles (hydrogen) generated on the cathode surface move upward, avoiding the problem of the bubbles continuously overflowing and generating a strong stirring effect during conventional electroplating process. This causes changes in the cathode polarization resistance and electrolyte resistance in the longitudinal direction, resulting in differences in current efficiency at the upper and lower ends of the workpiece, and ultimately leading to uneven coating thickness.

[0052] Simultaneously, the periodic switching on and off of DC electroplating allows for the reduction of metal ions at high overpotentials during the on-time flow, thereby improving electroplating efficiency and refining the grain size of the deposited layer. Furthermore, the relaxation characteristics of the periodic on-off current are beneficial for increasing cathode electrochemical polarization and reducing concentration polarization, improving the distribution of the deposited layer. This results in advantages such as reduced coating porosity, enhanced coating adhesion, improved deep plating and dispersion capabilities, reduced internal stress in the coating, and improved coating appearance and mechanical and physical properties.

[0053] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A uniform electroplating apparatus for precision hardware parts, comprising: The worktable and a plurality of cathodes and anodes disposed on the worktable are characterized in that, The workbench has a circular groove, several insertion holes and a positioning rod in the center. The anode is installed in the circular groove, and the bottom of the circular groove is connected to several drainage grooves. The cathode includes several mounting strips and several ejector rods mounted on the mounting strips by several springs, and the cathodes are linearly arranged and mounted on several racks; the racks are connected to several driving devices, the driving devices include several gears and a moving part connected by a U-shaped frame, and the moving part is mounted in a guide rail on the worktable, the driving devices are used to control the cathodes to make periodic rotations. The side of the cathode facing away from the anode is also connected to a bonding device. The bonding device includes a cylinder and an X-shaped support plate connected to the output shaft of the cylinder. The X-shaped support plate is provided with a plurality of fixed columns, and a plurality of horizontally arranged push plates are installed on the plurality of fixed columns. The cathode is symmetrical about the axis of symmetry of the anode in the horizontal plane.

2. The uniform electroplating equipment for precision hardware parts according to claim 1, characterized in that: The anode is a triangular prism that is an equilateral triangle in top view, and the surface of the anode is provided with several protrusions.

3. The uniform electroplating equipment for precision hardware parts according to claim 1, characterized in that: The anode and the cathode are respectively connected to the positive and negative terminals of the power supply.

4. The uniform electroplating equipment for precision hardware parts according to claim 1, characterized in that: The end of the ejector rod facing the anode is spherical, and the end facing away from the anode is a locking block.

5. The uniform electroplating equipment for precision hardware parts according to claim 1, characterized in that: The U-shaped frame is also provided with several clamping plates, which are used to engage with the gear and the rack.

6. The uniform electroplating equipment for precision hardware parts according to claim 1, characterized in that: Along the rack direction, the elastic force of several springs gradually increases from the center to both ends.

7. The uniform electroplating equipment for precision hardware parts according to claim 4, characterized in that: The spring and the ejector rod are in clearance fit, and the inner diameter of the spring is smaller than the diameter of the spherical body.

8. A method of using a uniform electroplating equipment for precision hardware parts, based on the uniform electroplating equipment for precision hardware parts according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Workpiece placement: The hardware with an inner angle is placed between the positioning rod and the anode, while ensuring that one side of the inner angle of the hardware faces the anode. The driving component moves toward the center of the anode, and the cylinder pushes the cathode to fit with the hardware. The center line of the arc-shaped inner angle of the hardware coincides with the vertical edge of the anode. S2, Discharge plating: Applying a discharge plating layer to the workpiece with a density of 10-15 mA / cm². 2 The current is applied, and the electroplating time is maintained at 2-10 seconds; S3, Periodic Discharge: As the cylinder retracts to the bonding device and moves away from the cathode, the driving component moves along the track away from the anode center. At this time, the cathode also moves away from the workpiece. The gear rotates at a speed of 40-50 degrees / s, driving the cathode to rotate around the anode center by 119°-121°. Then, steps S1 and S2 are repeated, and the gear rotates 3 times as one cycle. S4: Repeat steps S1-S3 and complete the electroplating after two cycles.

9. The method of using a uniform electroplating equipment for precision hardware parts according to claim 8, characterized in that: When repeating step S1 after step S3, the movement of the cathode will cause the electroplating solution to slosh. Therefore, it is only necessary to keep the center line of the arc-shaped inner corner of the hardware as coincident as possible with the vertical edge of the anode.

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