The copper printed circuit uses a copper foil as a surface and is attached to a plastic plate as a support; the circuit wiring pattern is printed on the copper plate by means of photography; the excess portion is removed by etching to leave a circuit connected to each other. Then, the connection between the printed circuit board and the external portion is punched, and the terminal of the discrete component or other portion is inserted and soldered to the port, so that a complete circuit is assembled. If immersion plating is used, the welding of all joints can be done in one operation. Thus, for those applications that require fine placement of circuits, such as radios, televisions, computers, etc., the use of printed circuits can save a lot of wiring and fixed loop labor; thus, it is widely used and requires a large amount of copper foil to be consumed. In addition, various copper-based brazing materials with low cost, low melting point and good fluidity are required in the connection of the circuit.