The difference between ultrasonic metal welding and plastic welding
The ultrasonic metal welding process (whether aluminum or other metals) is fundamentally different from welding plastics in how the ultrasonic energy (or vibrations) is delivered to the weld, and in how the actual weld is created.
First, ultrasonic metal welding delivers vibrations to the zone via transverse vibrations that are parallel to the weld surfaces. Ultrasonic plastic welding delivers vibrations to the zone via longitudinal vibrations that are normal (i.e., at right angles) to the weld surfaces.
Second, ultrasonic metal welding creates the weld via a frictional action of the surfaces that creates a solid-state bond without any melting of the material. Ultrasonic plastic welding is based on melting and fusion of the material (in a sense, like many metal welding processes, such as arc, resistance or laser), but at much, much lower temperatures than experienced in metal fusion processes.
There are two slightly different ways of delivering the ultrasonic vibrations to the weld zone: "lateral drive" and "wedge-reed." While each has selected special advantages, they both end up getting the vibrations to the weld zone in a transverse vibration action.
With this fundamental distinction between ultrasonic metal and plastic welding in mind, then one has ultrasonic welding of all metals done in the same way. Weld in all cases are very fast-- on the order of 0.2 to 0.5 seconds.
