Handheld welding machine ultrasonic technique is put ultrasonic sonochemistry machine forward by Jones et al. 1956. In the 1960 s, the United States, Switzerland, Germany, Japan, Britain and other countries began to study this kind of welding technology, and began to put into practical application. In recent decades, with the plastic and composite materials in the rapid development of industrial production and daily life, and new type high power sensors in the electronics industry, the advantages of plastic ultrasonic welding in the welding speed has been widely used. Good welding quality and high degree of automation, the scale of production. It has become a commonly used plastic welding method.
The basic principle of ultrasonic welding is the use of ultrasonic ultrasonic cutting machine frequency (10 to 70 KHZ frequency, amplitude of 1 ~ 250 mm) applied to plastic parts in mechanical vibration. Therefore, it can produce local heating under pressure (heating is due to the surface and the combination of molecular friction) and melting welding joint formed by contact with parts, pressure and consolidation. Began to shake. Friction calorific value can make the guide rib melt, melt into the joint. With the decrease of the distance between the two parts, welding displacement (the distance between the two parts because of melt flow and reduce) began to increase.
At first, and then welding displacement increase rapidly, as the fusion energy conductor diffusion and slow down the surface contact parts. In solid friction part, heating is by the friction between two surfaces to internal friction, and parts. Frictional heating temperature to the melting point of polymer materials. Heat generation depends on the frequency, amplitude and pressure. Two phase increase lead to the melting rate of welding the increase of the displacement and the increase of the two parts surface contact. At this stage, the formation of a thin layer of melted layer, and due to the continuous heating, melting layer thickness increases. This stage of the heat is generated by the viscous dissipation.
In the third stage, the thickness of solution ultrasonic dispersion machine layer remains the same, and with constant temperature distribution, the stable melting.
In the fourth stage, after a certain time or a certain level of energy, power or distance, cut off the power and ultrasonic vibration to stop, start into the fourth stage. Keep the pressure, make some additional melt extrusion from the interface. When weld cooling solidification, displacement and molecular diffusion occur between.