The copper bar has a surface layer to reduce the "contact resistance", any two conductors are connected, in addition to the respective resistance of the conductors, there will be a "contact resistance" on the contact surface, "contact resistance" is related to the finish of the contact surface, contact area and the material itself. Tinning the contact surface is to make full use of the softness of tin - to increase the contact area under appropriate pressure, while not easy to rust and be corroded.
At least one anode plate and cathode plate are arranged in the tank body, and the anode plate is connected with the positive electrode of the power supply. The cathode plate is connected with the copper bar through a number of spadders, and the copper bar is placed locally or as a whole in the plating bath. A layer of tin coating is plated on the surface of the copper bar to prevent oxidation. In the process of electroplating, the copper bar suspended by the spadder and the power connection contact point is fixed, and the current density around the electrical connection contact point is smaller as it is farther away from the fixed electrical contact point, resulting in uneven coating on the surface of the copper bar and uneven surface. Moreover, the contact point of the copper bar electrical connection increases with the power time. The higher the temperature of the contact point, the lower the current density on the surface, which will lead to the decrease of electroplating efficiency. In this process, the plating tank is in the open state, and when electroplating copper, the plating solution in the tank is volatilized by heat, and the acid mist exhaust gas generated by electroplating cannot be sealed, collected and processed, and the exhaust gas cannot be sealed, and the acid mist permeates the space, and the working environment is poor, seriously affecting the environment, and the acid fog is harmful to health.
