A method for removing foreign matter from the root of a rivet-type electrical contact

Abstract

The present invention specifically relates to a method for removing foreign matter from the base of a rivet-type electrical contact. The method involves immersing the rivet-type electrical contact in a cleaning solution containing the following components, or equivalent proportions thereof: 10g-15g of a corrosion inhibitor, 20ml-30ml of an inorganic acid, 30ml-50ml of acetone, 10ml-20ml of acetic acid, and 1000ml-2000ml of water. This specialized solution removes foreign matter from the base. The unique magnetic field distribution of magnetic polishing generates a strong and stable magnetic induction effect, which fully polishes the magnetic steel needle and the base of the rivet-type electrical contact from all angles and in all directions, effectively removing the foreign matter.

Description

Technical Field

[0001] The invention belongs to the field of rivet-type electric contact processing, and in particular relates to a method for removing foreign matter at the root of a rivet-type electric contact. Background Art

[0002] Rivet electrical contact materials are used in various relays, circuit breakers, contactors, and thermostats, and are an important factor affecting the working reliability of switch electrical contact systems.

[0003] The existing rivet electrical contact preparation process generally includes hammering, grinding, degreasing, annealing, pickling, polishing and other processes. During the grinding process, there will be dead corners at the root of the rivet-type electrical contact that cannot be ground, resulting in foreign matter being mixed in the root. After annealing and sintering, sintered foreign matter is formed, and the ordinary polishing process has poor removal effect.

[0004] Chinese invention patent application number 201810975028.5 discloses a method for removing surface defects of rivet-type electrical contacts based on magnetic polishing, wherein the polishing liquid includes an inorganic acid, an organic acid, and a corrosion inhibitor. The polishing liquid can remove oxides in black spots on the surface of the electrical contact, but there are still foreign matter that it cannot remove.

[0005] Therefore, studying how to optimize the method of removing foreign matter at the root of rivet-type electrical contacts is of great practical significance for improving the quality of rivet-type electrical contacts. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a method for removing foreign matter from the root of a rivet-type electrical contact. The foreign matter at the root is removed by soaking in a special solution, and then the unique magnetic line distribution of magnetic polishing is utilized to produce a strong and stable magnetic induction effect, so that the magnetic steel needle and the root of the rivet-type electrical contact are fully polished in all directions and at multiple angles, thereby achieving the effect of removing foreign matter.

[0007] The technical solution adopted by the present invention is as follows: a method for removing foreign matter at the root of a rivet-type electrical contact, wherein the rivet-type electrical contact is immersed in a cleaning solution, wherein the cleaning solution comprises the following components or is prepared in equal proportions: 10g~15g of corrosion inhibitor, 20ml~30ml of inorganic acid, 30ml~50ml of acetone, 10ml~20ml of acetic acid, and 1000ml~2000ml of water.

[0008] Preferably, the corrosion inhibitor is benzotriazole.

[0009] Preferably, the inorganic acid is sulfuric acid.

[0010] Preferably, the organic acid is acetic acid.

[0011] Preferably, the rivet-type electrical contact is immersed in the cleaning solution for 30-60 minutes.

[0012] Preferably, after soaking, magnetic polishing is used to clean the surface of the rivet-type electrical contact to remove foreign matter.

[0013] Preferably, the parameters of the magnetic polishing are: time 5-15 min, frequency 30-50 Hz.

[0014] The beneficial effects of the present invention are as follows: due to the existence of grinding dead angles, foreign matter will be mixed in the root of the rivet-type contact after grinding, and will form non-detachable foreign matter by sintering after annealing. The applicant innovatively discovered that the main component of the foreign matter is polyethylene, which mainly comes from various plastic substances. Once it is brought in and sintered at the root, it is difficult to remove it with ordinary polishing technology. Then, the applicant added acetone to the cleaning liquid and optimized its component content, so that it can effectively remove foreign matter in the root of the rivet-type electrical contact that cannot be removed by pickling. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0016] Figure 1 This is a schematic diagram of sintered foreign matter in a rivet-type electrical contact according to the present invention;

[0017] Figure 2 Schematic diagram of removing foreign matter from the rivet-type electrical contact after immersion according to the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0019] Example 1

[0020] The cleaning solution used in this embodiment has the following ratio (V / V): 12 g of benzotriazole, 25 ml of sulfuric acid, 35 ml of acetone, 15 ml of acetic acid, and 1500 ml of pure water.

[0021] When preparing, the reagents are mixed in the solvent in proportion. When using, completely immerse 2 kg of rivet-type electrical contacts in the above cleaning solution for 60 minutes. After using magnetic polishing to remove foreign matter through chemical reaction of the solution, proceed with the following steps:

[0022] (1) The parameters of the magnetic polishing machine are further set as follows: time 10 minutes, frequency 40 Hz;

[0023] (2) Use a magnetic polishing machine to polish the rivet electrical contacts, and then rinse and separate the rivet type electrical contacts after polishing;

[0024] (3) The cleaned rivet-type electrical contacts are dried and cooled to become finished products.

[0025] Example 2

[0026] The difference between this embodiment and embodiment 1 is that the cleaning solution used has the following ratio (V / V): 10 g of benzotriazole, 20 ml of sulfuric acid, 30 ml of acetone, 10 ml of acetic acid, and 1000 ml of pure water.

[0027] Comparative Example

[0028] The difference between this comparative example and Example 1 is that the cleaning solution used has the following ratio (V / V): 12 g of benzotriazole, 25 ml of sulfuric acid, 15 ml of acetic acid, and 1500 ml of pure water.

[0029] The test data are as follows:

[0030] 1. Figure 1 This is a schematic diagram of sintered foreign matter in a rivet-type electrical contact according to the present invention. Figure 2 (a) Figure 1 (a) Schematic diagram of foreign matter removal after the sample is soaked in the cleaning solution formulated in Example 1; Figure 2 (b) Figure 1 (b) Schematic diagram of foreign matter removal after the sample is soaked in the cleaning solution formulated in Example 2.

[0031] 2. Contact resistance immersion effect:

[0032]

[0033] As shown in the figure, the contact resistance of the product after immersion in acetone in Example 1 is stable, while the contact resistance of the product of the comparative example without immersion in acetone is relatively large. Compared with the comparative example, the improvement in Example 1 is effective.

[0034] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for removing foreign matter from the root of a rivet-type electrical contact, characterized in that: Soak the rivet-type electrical contact in a cleaning solution comprising the following components or their equivalent proportions: Benzotriazole 10g~15g, sulfuric acid 20ml~30ml, acetone 30ml~50ml, acetic acid 10ml~20ml, water 1000ml~2000ml; Soak the rivet-type electrical contacts in the cleaning solution for 30-60 minutes; After soaking, magnetic polishing is used to clean and remove foreign matter from the surface of the rivet-type electrical contact.

2. The method for removing foreign matter from the root of a rivet-type electrical contact according to claim 1, characterized in that: The parameters of the magnetic polishing are: time 5-15 min, frequency 30-50 Hz.

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