Appearance treatment process of thin film capacitor

Abstract

The invention discloses an appearance treatment process of a thin film capacitor. The appearance treatment process comprises the following procedures of preparation, assembly passivation, finished product passivation, cleaning, inspection, surface drying, unloading and cleaning. The time for each step is defined. The method is suitable for appearance treatment of the rail transit thin film capacitor with the stainless steel shell, the appearance of the thin film capacitor can be effectively made attractive, the corrosion resistance can be effectively improved, and the production efficiency of products is improved.

Description

Technical Field

[0001] The invention relates to the field of capacitor manufacturing, and in particular to an appearance processing process for a film capacitor. Background Art

[0002] High-voltage and high-power film capacitors are the core components of rail transit converters. The functions of this type of film capacitors are: to provide voltage support for rail transit converters, while suppressing harmonics on the DC side and buffering the energy exchange between the AC side and the DC side; the energy exchange process is relatively complex, and too large or too small capacitance will affect the control accuracy, and the fluctuation of DC voltage will also affect the size and cost of rail transit converters.

[0003] At present, film capacitors for rail transit include oil-immersed capacitors and dry-type capacitors. Among them, oil-immersed capacitors are composed of stainless steel case, case cover, insulator, guide rod, core and impregnated vegetable oil or silicone oil; dry capacitors are composed of stainless steel case, case cover, insulator, guide rod, core and cast resin. The weight of this type of capacitor is in the range of 10~40kg.

[0004] The case and cover of the film capacitor are made of stainless steel and need to be welded with special tools to make them sealed. In addition, there are many production processes for capacitors, and it is inevitable that the surface of the capacitor case will be bumped and scratched during the production process. Welds and scratches need to be treated for appearance. Usually, the appearance of this type of capacitor is sprayed with paint, so that the appearance of the capacitor becomes beautiful and the surface of the capacitor case becomes more resistant to corrosion. However, this treatment method does not meet the environmental protection policies of relevant government departments and export requirements. Therefore, it is necessary to have other appearance treatment methods to replace the painting process to ensure the appearance of the film capacitor and its corrosion resistance.

[0005] Among the methods for metal appearance treatment, passivation is also a commonly used process. Passivation, as a chemical surface treatment technology, forms a dense oxide film on the metal surface through a specific chemical reaction, thereby significantly improving the corrosion resistance of the metal. This oxide film can effectively isolate the metal from direct contact with the surrounding environment and prevent the corrosion of the metal matrix by corrosive media (such as oxygen, water, etc.). Passivation treatment is suitable for various types of stainless steel parts, plates and their equipment. The box shell of film capacitors for rail transit is mainly made of stainless steel, but the box cover is equipped with an oil filling hole or a pressure release valve. Conventional immersion passivation treatment is not applicable, so the appearance treatment of this type of capacitor can only be partially passivated. Since the weight of this type of capacitor is between 10 and 60 kg and the size is relatively large, the efficiency and operability of local passivation treatment also need to be considered. Summary of the invention

[0006] In order to solve the above problems, the present invention provides an appearance processing process for a thin film capacitor (hereinafter referred to as “capacitor”).

[0007] The technical solution adopted by the present invention is as follows.

[0008] The capacitor appearance processing method includes the following steps: (1) Preparation: Add clean water to the cleaning tank until the liquid level is 1 / 3 of the tank height, and add an appropriate amount of sodium bicarbonate to make it alkaline; (2) Component passivation: Place the cleaned box shell, box cover and metal parts on a clean platform, with the box shell upside down; stir the passivation paste evenly with a Chinese painting brush and set aside for use; use electrical tape to stick 10 mm around the box shell weld to ensure the passivation is beautiful; Apply the passivation paste evenly on the box shell, cover and metal parts welds, wait for 3 minutes, and wipe the passivation paste clean with cotton and linen cloth; for the welding parts of the oil filling hole, installation ladder and other parts, brush the welds vigorously with a hard brush and then wipe them clean with cotton and linen cloth; (3) Passivation of finished products: first protect the guide rod, insulator, pressure relief valve or oil filling hole with a protective cover, and stick them with electrical tape 10 mm around the weld of the box shell before passivation; stir the passivation paste evenly with a Chinese painting brush and set aside for use, apply the passivation paste evenly on the weld, wait for 3 minutes, and wipe the passivation paste clean with cotton and linen cloth; (4) Cleaning: Rinse the passivation area with plenty of clean water. The waste water must flow into the cleaning tank. Ensure that the passivation paste is cleaned and then blown dry with an air gun; (5) Inspection: The surface passivation of the box shell and cover should be clean and beautiful, without scratches and mechanical damage; (6) Drying the surface: Place the passivated capacitor components or finished products in a drying oven to heat and dry the surface. The heating temperature of the drying oven is 60°C and the placement time is 30 minutes. (7) Unloading: Load the capacitor components or finished products after surface drying onto a cart and put them into the parts warehouse or into the next process; (8) Cleaning: All used tools and waste water shall be recycled and neutralized with sodium bicarbonate alkaline solution until neutral before cleaning and discharge.

[0009] Among them, the deviation of the above time can be within ±5%, the deviation of size can be within ±10%, and the deviation of temperature can be within ±5%.

[0010] Furthermore, the operators wore masks and rubber gloves and protective clothing, and the exhaust fans worked normally.

[0011] Furthermore, the passivation paste is a passivation paste specially used for stainless steel.

[0012] Furthermore, if the surface of the capacitor assembly or the finished product is not passivated cleanly, a secondary operation is performed until the surface is passivated cleanly.

[0013] Furthermore, if there are stains such as oil on the cleaning parts, they can be passivated only after they are cleaned.

[0014] Furthermore, the water in the clean water tank must be neutral before it can be stored and discharged.

[0015] The beneficial effects of the present invention are: According to the structural characteristics of the stainless steel shell of the film capacitor for rail transit, the above method can effectively make the appearance of the film capacitor beautiful and increase the corrosion resistance, thereby improving the production efficiency of the product. DETAILED DESCRIPTION

[0016] The following specific examples further illustrate the present invention. This process includes the following steps: (1) Preparation: Add clean water to the cleaning tank until the liquid level is 1 / 3 of the tank height, and add an appropriate amount of sodium bicarbonate to make it alkaline; (2) Component passivation: Place the cleaned box shell, box cover and metal parts on a clean platform, with the box shell upside down; stir the passivation paste evenly with a Chinese painting brush and set aside for use; use electrical tape to stick 10 mm around the box shell weld to ensure the passivation is beautiful; Apply the passivation paste evenly on the box shell, cover and metal parts welds, wait for 3 minutes, and wipe the passivation paste clean with cotton and linen cloth; for the welding parts of the oil filling hole, mounting bracket and other parts, brush the welds vigorously with a hard brush and then wipe them clean with cotton and linen cloth; if the surface is not passivated cleanly, perform a secondary operation until the passivation is clean; (3) Passivation of finished products: first protect the guide rod, insulator, pressure relief valve or oil filling hole with a protective cover, and stick them with electrical tape 10mm around the box shell weld before passivation; stir the passivation paste evenly with a Chinese painting brush and set aside for use, apply the passivation paste evenly on the weld, wait for 3 minutes, and wipe the passivation paste clean with cotton and linen cloth; if the surface is not passivated cleanly, perform a secondary operation until the passivation is clean; (4) Cleaning: Rinse the passivation area with plenty of clean water. The waste water must flow into the cleaning tank. Ensure that the passivation paste is cleaned and then blown dry with an air gun; (5) Inspection: The surface passivation of the box shell and cover should be clean and beautiful, without scratches and mechanical damage; (6) Drying the surface: Place the passivated capacitor components or finished products in a drying oven to heat and dry the surface. The heating temperature of the drying oven is 60°C and the placement time is 30 minutes. (7) Unloading: Load the capacitor components or finished products after surface drying onto a cart and put them into the parts warehouse or into the next process; (8) Cleaning: All used tools and waste water shall be recycled and neutralized with sodium bicarbonate alkaline solution until neutral before cleaning and discharge.

[0017] Among them, the deviation of the above time can be within ±5%, the deviation of size can be within ±10%, and the deviation of temperature can be within ±5%.

[0018] Furthermore, the operators wore masks and rubber gloves and protective clothing, and the exhaust fans worked normally.

[0019] Furthermore, the passivation paste is a passivation paste specially used for stainless steel.

[0020] Furthermore, if there are stains such as oil on the cleaning parts, they can be passivated only after they are cleaned.

[0021] Furthermore, the water in the clean water tank must be neutral before it can be stored and discharged.

[0022] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A process for processing the appearance of a film capacitor, the process comprising the following steps: (1) Preparation: Add clean water to the cleaning tank until the liquid level is 1 / 3 of the tank height, and add an appropriate amount of sodium bicarbonate to make it alkaline; (2) Component passivation: Place the cleaned box shell, box cover and metal parts on a clean platform, with the box shell upside down; stir the passivation paste evenly with a Chinese painting brush and set aside for use; use electrical tape to stick 10 mm around the box shell weld to ensure the passivation is beautiful; Apply the passivation paste evenly on the box shell, cover and metal parts welds, wait for 3 minutes, and wipe the passivation paste clean with cotton and linen cloth; for the welding parts of the oil filling hole, mounting bracket and other parts, brush the welds vigorously with a hard brush and then wipe them clean with cotton and linen cloth; if the surface is not passivated cleanly, perform a secondary operation until the passivation is clean; (3) Passivation of finished products: first protect the guide rod, insulator, pressure relief valve or oil filling hole with a protective cover, and stick them with electrical tape 10mm around the box shell weld before passivation; stir the passivation paste evenly with a Chinese painting brush and set aside for use, apply the passivation paste evenly on the weld, wait for 3 minutes, and wipe the passivation paste clean with cotton and linen cloth; if the surface is not passivated cleanly, perform a secondary operation until the passivation is clean; (4) Cleaning: Rinse the passivation area with plenty of clean water. The waste water must flow into the cleaning tank. Ensure that the passivation paste is cleaned and then blown dry with an air gun; (5) Inspection: The surface passivation of the box shell and cover should be clean and beautiful, without scratches and mechanical damage; (6) Drying the surface: Place the passivated capacitor components or finished products in a drying oven to heat and dry the surface. The heating temperature of the drying oven is 60°C and the placement time is 30 minutes. (7) Unloading: Load the capacitor components or finished products after surface drying onto a cart and put them into the parts warehouse or into the next process; (8) Cleaning: All utilities and wastewater used should be recycled and neutralized with sodium bicarbonate alkaline solution until neutral before cleaning and discharge; in, The deviation of the above time can be within ±5%, the deviation of size can be within ±10%, and the deviation of temperature can be within ±5%.