Solutions to common problems with copper tape

1. Solution to discoloration of copper tape

(1) Control the concentration of acid solution during pickling. In the case of washing off the oxide layer on the surface of the annealed copper strip, a high acid concentration does not make any sense. On the contrary, if the concentration is too high, the residual acid attached to the surface of the copper strip is not easy to be washed off, and the pollution of the cleaning water is accelerated, resulting in an excessively high concentration of residual acid in the cleaning water, which makes the copper strip after cleaning more prone to discoloration. Therefore, when determining the concentration of the pickling solution, the following principles should be followed: on the premise that the oxide layer on the surface of the copper strip can be cleaned, the concentration should be reduced as much as possible.

(2) Control the conductivity of pure water. Control the conductivity of pure water, that is, control the content of harmful substances such as chloride ions in pure water. Generally, it is safer to control the conductivity below 50μS/cm.

(3) Control the conductivity of hot cleaning water and passivating agent. The increase of the conductivity of hot cleaning water and passivator mainly comes from the residual acid brought in by the running copper belt. Therefore, under the condition of ensuring the quality of pure water for cleaning, controlling the conductivity, that is, controlling the amount of residual acid. According to many experiments, it is safe to control the electrical conductivity of hot cleaning water and passivation agent to be below 200 μS/cm, respectively.

(4) Ensure that the copper tape is dry. Partial sealing is carried out at the coiling outlet of the air cushion furnace, and dehumidifiers and air conditioners are used in the partial sealing device to control the humidity and temperature during coiling of copper strips within a certain range

(5) Passivation with passivating agent. Most copper processing plants now use benzotriazole or BTA (molecular formula: C6H5N3) as a passivating agent. Practice has proved that it is a convenient, economical and practical passivator. When the copper tape passes through the BTA solution, the oxide film on the surface undergoes a complex reaction with BTA to form a dense complex, which plays the role of protecting the copper substrate.

2. The solution of copper strip shear indentation

To prevent the indentation of the shearing edge, it is mainly necessary to select a reasonable difference between the outer diameter of the circular knife and the rubber peeling ring according to the thickness and hardness of the strip; the hardness of the rubber peeling ring meets the requirements of the strip to be cut; When the width of the strip is small, the thickness of the circular knife should be reasonably selected and the width of the rubber peeling ring should be increased.