Copper wire connection technology is widely used in power electronics, new energy vehicles, electrical appliances, medical, aerospace and other fields. The main connection methods are crimping, brazing and ultrasonic welding.
Crimping Technology: It’s carried out at room temperature, and the plastic deformation of the wire is formed by the crimping equipment to form a mechanical connection. The crimped wires are not completely in contact, and there is a high contact resistance at each connection interface, and in the process of long-term contact operation, the contact resistance will gradually increase, resulting in the increase of joint heating and power loss, which affects the safety of the circuit.
Brazing includes flame brazing, resistance brazing, etc. Compared with crimping technology, brazing requires solder, solvents, etc., and consumes more energy during the welding process, which may produce common metallurgical defects, such as slag inclusion, porosity, segregation, etc.
Ultrasonic welding uses ultrasonic high-frequency vibration to generate energy, and plastically deforms the contact interface and undergoes metallurgical reaction under the action of pressure, which is a solid-phase bonding technology. There is no smoke and dust in the welding process, no need to add flux, and the welding energy is only 2% of brazing, which is an energy-saving, environmentally friendly, green and efficient welding method. Ultrasonic welding of copper wires is suitable for occasions requiring high tensile strength and low contact resistance due to its small welding energy, fast speed, high strength and low joint resistance.
Principle of Ultrasonic Metal Welding
Ultrasonic welding technology is a technology that changes the physical state of the welded parts by applying high-frequency vibration in the horizontal direction to the contact surface.
Its working principle is to emit oscillating current through the ultrasonic generator, convert it into mechanical vibration through the transducer device, and further amplify the mechanical vibration through the horn. Under a certain welding pressure, high-frequency vibration friction between welding parts is achieved. , so that the temperature between the welded parts is rapidly increased through frictional heating, resulting in plastic deformation, forming a strong welded joint to achieve solid-phase connection.
Ultrasonic metal welding cycle is short, and the welding process contains at least three stages: local point connection → vibration breaks up oxides and contaminants to form surface connection → plastic deformation occurs under the action of ultrasonic softening and frictional heat to form a stable bond. The strength of the joint is affected by multiple parameters such as welding amplitude, time and pressure.
