We all know that plastic ultrasonic welding technology appeared early in the United States. In recent decades, with a large number of plastics and composite materials, the rapid development of industrial production and daily life, the emergence of the electronics industry and the emergence of new high-power sensors, ultrasonic plastic welding. The machine has high efficiency, good welding quality, easy automation, suitable for large-scale production and other advantages and excellent applications, and has become a common plastic welding method. Let us understand the four stages of ultrasonic welding.

The first stage: the welding head is in contact with the part, pressure and start-up vibration. The frictional heat melts into the guide, and the melt flows into the bonding surface. As the distance between the two parts decreases, the welding displacement (reducing the distance between the two parts due to the melt flow). The initial weld offset increases rapidly, and then slows down as the melting criterion unfolds and slows down when contacting the surface. In the solid state friction phase, heating is due to frictional energy between the two surfaces and internal friction. Friction welding can allow the polymer material to be heated to its melting point. Heating depends on frequency, amplitude and pressure.

Phase 2: The increase in melting speed leads to an increase in welding displacement and contact with the surface of the legs. At this stage, a thin molten layer is formed, and the thickness of the molten layer increases due to continuous heating. The heat at this stage is generated through viscosity dissipation.

The third stage: the thickness of the solution layer in the weld remains unchanged, and is accompanied by a constant temperature distribution.

Stage 4: After setting the time or specific energy, power level or distance, disconnect the power supply, the ultrasonic vibration stops, and start to enter the fourth stage. Keep pressure on the joint surface of the extruded part of the melt to extrude. When the weld is cooled and solidified, a large displacement is reached, and molecular diffusion occurs.