There are two kinds of flat coils usually used in transformers, one is pure copper coil and the other is aluminum coil. The traditional process between welding and external terminals adopts brazing, but adding additive brazing and welding will increase the cross-sectional area due to the addition of additives. , resulting in excessive electricity and heat. In the process of use, because the ultrasonic metal welding technology is superior to the brazing welding process, there is no flux and the welding current is very small, almost O. Therefore, in recent years, the flat coils of copper and aluminum transformers have adopted ultrasonic waves. Technical welding.

Ultrasonic welding of flat coils is similar to friction welding, but there are differences, ultrasonic welding time is very short and the temperature is lower than recrystallization; it is also different from pressure welding because the applied static pressure is much less than pressure welding. It is generally believed that in the initial stage of the ultrasonic welding process, the tangential vibration of the oxide on the metal surface is a process of repeated micro-welding and destruction of the protruding parts of the rough surface, which increases the contact area, increases the temperature of the welding area, and in the weldment plastic deformation occurs at the interface. In this way, under the action of contact pressure, they approach the distance of atomic gravity, that is, to form solder joints. If the welding time is too long, or the ultrasonic amplitude is too large, the welding strength will be reduced or even damaged.

Compared with the round welding wire, the flat coil after ultrasonic welding has the characteristics of small magnetic leakage, light weight, low resistance, high efficiency and low noise under the same volume.

However, due to the limitations of ultrasonic power and power stability, such as general metal welding machines welding thicker inductor coils, it is relatively hard. Due to the selection of generator lines, 1mm thickness is the welding limit, and the traditional lines in Taiwan and the United States are very different. , The difference in voltage will also affect the thickness of the ultrasonic welding flat coil. Under normal circumstances, when the sound is dark, the ultrasonic force tends to be stable and the welding force is gentle.

Metal welding of transformer flat wires is usually carried out on the surface of the welding location. The base surface is designed with a grid pattern. The purpose of the mesh design is to prevent the flat wires from slipping and to transfer as much energy as possible to the welding location. Pattern designs generally have square, diamond, and strip patterns. The mesh size and depth are determined according to the specific requirements of the welding material.