Removing method of three-proof coating of aerospace PCB (printed circuit board), remover and remover preparation

Abstract

The invention provides a removing method of a three-proof coating of an aerospace PCB (printed circuit board) and preparation of a remover. According to the removing method and remover preparation, the operation is simple and fast, the removing efficiency is high, the damage is small, and the economic efficiency is good. The remover comprises components in parts by weight as follows: 30 parts of methylene dichloride, 20-30 parts of butanone, 0-20 parts of cyclohexanone and 50-60 parts of 120# gasoline. The removing method comprises steps as follows: step 1, three-proof coatings of a circuit board and a welding spot at a repair and refit part are coated with the remover according to a claim 3 by an anti-static banister brush, and are left to stand for 20-30 s; step 2, the coated positions are repeatedly wiped by non-woven fabric dipped with absolute ethanol until the coatings are cleaned up completely; step 3, after the coatings are cleaned up completely, the whole circuit board is placed in a drying oven and dried at the temperature of 50 DEG C plus or minus 5 DEG C for 2h, and a residual remover on the surface is evaporated; step 4, the circuit board is naturally cooled to the room temperature and is subjected to a verification test.

Description

technical field [0001] The invention belongs to the field of repairing and refitting aerospace circuit boards, and in particular relates to a method for removing a three-proof coating for aerospace printed circuit boards and preparation of a remover. Background technique [0002] Aerospace electronic and electrical products require moisture-proof, salt-spray and mildew-proof treatment due to their use requirements, so three-proof coatings are required on the surface of their circuit boards. However, when the printed circuit board is soldered, repaired or modified, the surface needs to be treated to remove the coating. [0003] At present, there are various coating removal methods, mainly including: combustion method, mechanical method, chemical solvent method and laser method, but the methods for removing conformal coatings on the surface of printed circuit boards and pads used in aerospace electronic products are relatively backward. , mainly because the materials used in ...

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Problems solved by technology

[0003] At present, there are various coating removal methods, mainly including: combustion method, mechanical method, chemical solvent method and laser method, but the method of removing the three-proof coating on the surface of printed circuit boards and pads used in aerospace electronic products is relatively backward. , mainly because the materials used in aerospace models have strict requirements, and the existing removers cannot be used to ensure the quality of aerospace products

Combustion is a traditional coating removal method, but it can cause great damage to the substrate and cannot be used in the electronics field; manual or mechanical methods to remove the coating are labor-intensive, low in efficiency, and easily cause damage to the printed circuit board itself The chemical solvent method often uses the acetone dissolution method to remove the three-proof coating on the surface of the printed circuit board and the tin-lead alloy pad. Although the acetone reagent can be purchased at any time, the acetone itself is extremely volatile and easy to flow, and the soaking time when removing the paint Long, during the specific operation, it is necessary to repeatedly add drops in the removal area, and then add drops after volatilization until the coating is completely removed. At the same time, it is easy to flow to other areas and damage the combination of the coating and components on the printed circuit board. In addition, the long-term coating cannot be completely removed, and additional tools are required to remove it, which is low in work efficiency and labor-intensive; for laser removal of coating, it is limited by equipment, layout of components on the printed circuit board, etc. Highly restrictive and thus limited in application

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