Diverter electroplating method

Abstract

The invention provides a current divider electroplating method which is suitable for a current divider formed by welding a manganese-copper plate body and red copper plate bodies on the two sides, and aims to form a silver or nickel coating on the surface of red copper and ensure that the manganese-copper plate body is free of plating layer residues at the same time. The method comprises two technical schemes: 1, a pre-shielding electroplating method: after ultrasonic cleaning and acid pickling activation pretreatment, wrapping and shielding a manganese-copper area by adopting a high-temperature-resistant insulating tape or a strippable coating, then electroplating, and finally removing a shielding object; and the other method is a polishing method after integral electroplating, specifically, after the shunt is integrally electroplated, a plating layer in a manganese-copper area is directionally removed by utilizing numerical control grinding machine equipment, a red copper plating layer is reserved, and surface finishing is carried out. According to the two methods, the coating area is accurately controlled, so that the manganese-copper resistance characteristic is prevented from being influenced by the coating. The method is high in process compatibility, is suitable for high-efficiency production of the shunt in the field of current measurement, and has the advantages of low cost and high precision.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology for electronic components, specifically to an electroplating method for a shunt for current detection, which is particularly suitable for a shunt composed of a welded structure of a manganese copper plate and a copper plate. Background Technology

[0002] A shunt is a precision resistive device used to measure current. It is typically constructed by welding a low-resistivity manganese-copper alloy plate (as the resistor body) to a highly conductive copper plate (as the conductive terminal). In the electroplating process, the copper plate needs to be electroplated to form a protective layer (such as nickel or tin plating) to prevent oxidation, while the manganese-copper plate, due to its resistive characteristics, must maintain its original surface condition. In traditional electroplating processes, because the manganese-copper and copper are directly welded, the plating solution easily penetrates to the surface of the manganese-copper plate, causing it to be covered by the plating layer, thus affecting the resistance stability and measurement accuracy of the shunt.

[0003] Therefore, there is an urgent need for an electroplating method that can selectively protect manganese copper plates. Summary of the Invention

[0004] The purpose of this invention is to provide a shunt electroplating method to solve the problems mentioned in the background art above:

[0005] (1) How to ensure the electroplating quality of copper plate while avoiding the formation of a coating on the surface of manganese copper plate and forming a coating on the outside of copper plate to enhance its corrosion resistance through physical isolation or post-processing.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A shunt electroplating method includes the following steps:

[0008] a) Smooth and seamlessly weld the manganese copper plate body and the copper plates on both sides of the shunt.

[0009] b) Prepare the electroplating solution and perform electroplating on the distributor;

[0010] c) Clean the surface residue of the distributor, perform hot water cleaning, drying and anti-discoloration treatment on the distributor, and complete the electroplating process of the distributor.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] Furthermore, in step b), a wrapping layer is first provided on the outer side of the manganese copper plate of the distributor. The wrapping layer is tightly attached to the entire outer wall of the manganese copper plate to ensure that the welding gaps and edge areas are covered, forming a completely sealed layer. Then, the copper plates on both sides of the distributor are electroplated.

[0013] Furthermore, the wrapping layer uses high-temperature resistant insulating tape to fully cover the surface of the manganese copper plate and the welding transition area with the copper, with the wrapping layer covering a width 1-2mm beyond the manganese copper area.

[0014] Furthermore, in step b), when silver plating the shunt, a cyanide silver plating solution is used, with a current density of 0.5-1.5 A / dm³. 2 The temperature is 20-30℃, the electroplating time is 20-40 minutes, and an 8-15μm silver layer is formed.

[0015] Furthermore, in step b), when nickel plating the shunt, a nickel sulfamate plating solution is used, with a current density of 2-4 A / dm³. 2 The temperature is 50-60℃, and the electroplating time is 30-60 minutes to form a 10-20μm nickel layer.

[0016] Furthermore, in step b), the manganese copper plate and the copper plates on both sides of the shunt are directly electroplated so that a coating is formed on the surface of both the copper plate and the manganese copper plate.

[0017] Perform directional grinding along the surface of the manganese copper plate to remove all the coating on the surface of the manganese copper plate, while retaining the coating in the copper area. The grinding depth should be controlled to 1.1-1.2 times the coating thickness to avoid damaging the manganese copper plate.

[0018] This shunt electroplating method effectively solves the problem of plating contamination on the manganese copper plate during the shunt electroplating process through two innovative techniques, while ensuring the quality of the silver or nickel plating on the outer side of the copper plate. Differential plating control between manganese copper and copper is achieved through masking or precise polishing, ensuring the electrical performance of the shunt. With strong process compatibility, this shunt electroplating method balances production efficiency and product quality, making it suitable for large-scale industrial production.

[0019] When using a coating layer to shield the surface of the manganese copper plate, direct contact between the electroplating solution and the manganese copper plate is avoided, ensuring thorough protection. This method can form a uniform silver or nickel plating layer on the outer side of the copper plate, improving conductivity and corrosion resistance.

[0020] When using a solution of overall electroplating followed by grinding of the manganese copper plate surface, no additional wrapping process is required, simplifying the process flow. This method is suitable for post-plating treatment of complex shunt structures. By precisely controlling the plating removal process, the integrity and quality of the copper plate plating can be ensured. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] The terms “vertical,” “horizontal,” “left,” “right,” and similar expressions used in this document are for illustrative purposes only and do not represent the only possible implementation.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] Example 1

[0025] The electroplating method for this shunt includes the following steps:

[0026] a) The main body of the shunt is welded from a manganese copper plate and two copper plates on both sides. The welding surfaces between the manganese copper plate and the copper plates on both sides of the shunt are made flat and seamless.

[0027] The welded distributor is then subjected to ultrasonic cleaning (alkaline cleaning agent, temperature 50-60℃, time 5-10 minutes), acid pickling activation (10% sulfuric acid solution, room temperature soaking for 30 seconds), and deionized water rinsing.

[0028] b) First, a wrapping layer is applied to the outer side of the manganese copper plate of the shunt. The wrapping layer is made of high-temperature resistant insulating tape (such as polyimide tape, polytetrafluoroethylene tape, or peelable insulating coating, such as acrylic resin coating). The wrapping layer is tightly attached to the entire outer wall of the manganese copper plate. The width of the wrapping layer extends 1-2 mm beyond the manganese copper area to ensure that the weld gaps and edge areas are covered. The thickness of the wrapping layer is 0.1 mm to 0.3 mm to avoid affecting the penetration of the electroplating solution into the copper plate and to form a completely sealed layer. Then, electroplating is performed on the copper plates on both sides of the shunt.

[0029] Prepare a cyanide silver plating solution with a silver ion concentration of 3-5 g / L and a pH value of 10-12. When silver plating the shunt, the current density should be 0.5-1.5 A / dm³. 2 The temperature is 20-30℃, the electroplating time is 20-40 minutes, and an 8-15μm silver layer is formed.

[0030] c) Clean the surface residue of the distributor, perform hot water cleaning, drying and anti-discoloration treatment on the distributor, and complete the electroplating process of the distributor.

[0031] Example 2

[0032] The only difference between this embodiment and Embodiment 1 is that:

[0033] In step b), the shunt is nickel-plated using a nickel sulfamate plating solution with a nickel ion concentration of 80-100 g / L, a pH of 3.5-4.5, and a current density of 2-4 A / dm³. 2 The temperature is 50-60℃, and the electroplating time is 30-60 minutes to form a 10-20μm nickel layer.

[0034] Example 3

[0035] The electroplating method for this shunt includes the following steps:

[0036] a) The main body of the shunt is welded from a manganese copper plate and two copper plates on both sides. The welding surfaces between the manganese copper plate and the copper plates on both sides of the shunt are made flat and seamless.

[0037] The welded distributor is then subjected to ultrasonic cleaning (alkaline cleaning agent, temperature 50-60℃, time 5-10 minutes), acid pickling activation (10% sulfuric acid solution, room temperature soaking for 30 seconds), and deionized water rinsing.

[0038] b) Electroplating is performed directly on the manganese copper plate and the copper plates on both sides of the shunt, so that a coating is formed on the surface of both the copper plate and the manganese copper plate.

[0039] Precision CNC grinding equipment is used to perform directional grinding along the surface of the manganese copper plate to remove all the coating on the surface of the manganese copper plate, while retaining the coating in the copper area. The grinding depth is controlled to be 1.1-1.2 times the coating thickness to avoid damaging the manganese copper plate.

[0040] c) Clean the surface residue of the distributor, perform hot water cleaning, drying and anti-discoloration treatment on the distributor, and complete the electroplating process of the distributor.

[0041] The above descriptions are merely three embodiments of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the principles of the present invention, and these should also be considered to fall within the scope of protection of the present invention.

Claims

1. A shunt electroplating method, comprising the following steps: a) Smooth and seamlessly weld the manganese copper plate body and the copper plates on both sides of the shunt. b) Prepare the electroplating solution and perform electroplating on the distributor; c) Clean the surface residue of the distributor, perform hot water cleaning, drying and anti-discoloration treatment on the distributor, and complete the electroplating process of the distributor.

2. The electroplating method for shunts according to claim 1, characterized in that: In step b), a wrapping layer is first applied to the outer side of the manganese copper plate of the distributor. The wrapping layer is then tightly attached to the entire outer wall of the manganese copper plate to ensure that the weld gaps and edge areas are covered, forming a completely sealed layer. Then, the copper plates on both sides of the distributor are electroplated.

3. The electroplating method for shunts according to claim 2, characterized in that: The wrapping layer uses high-temperature resistant insulating tape to fully cover the surface of the manganese copper plate and the welding transition area with the copper plate. The width of the wrapping layer extends 1-2 mm beyond the manganese copper area.

4. The electroplating method for a shunt according to claim 1, characterized in that: In step b), when silver plating the shunt, a cyanide silver plating solution is used, with a current density of 0.5-1.5 A / dm³. 2 The temperature is 20-30℃, the electroplating time is 20-40 minutes, and an 8-15μm silver layer is formed.

5. The electroplating method for a shunt according to claim 1, characterized in that: In step b), when nickel plating the shunt, a nickel sulfamate plating solution is used, with a current density of 2-4 A / dm³. 2 The temperature is 50-60℃, and the electroplating time is 30-60 minutes to form a 10-20μm nickel layer.

6. The electroplating method for a shunt according to claim 1, characterized in that: In step b), the manganese copper plate and the copper plates on both sides of the shunt are electroplated directly to form a coating on the surface of both the copper plate and the manganese copper plate. Perform directional grinding along the surface of the manganese copper plate to remove all the coating on the surface of the manganese copper plate, while retaining the coating in the copper area. The grinding depth should be controlled to 1.1-1.2 times the coating thickness to avoid damaging the manganese copper plate.