According to one embodiment, an ultrasonic bonding method for bonding a plurality of bonding members together by applying pressure and an ultrasonic wave includes a pressing step of applying pressure to one bonding member and another bonding member so as to press against each other, an application step of applying an ultrasonic wave to the one bonding member, a detection step of detecting a vibration state of another bonding member during the application step, and a step of determining a state of bonding between the bonding members based on the vibration state acquired in the detection step.

A vibration welding system and method having an operating vibration frequency of 260 Hz or higher. A pressing action between two workpieces is effected by directly controlling, with a control system and a sensor, the relative positions of the workpieces during some or all of the weld cycle, or by controlling the speed between the workpieces during some phase of the weld cycle and controlling the force between the workpieces during other phases. An external control device can be coupled to a control system, to produce an input signal to adjust the speed of relative motion between the workpieces, the force therebetween, or both speed and force based on the input signal. A positive force can be initially applied between the workpieces, and the weld is started by initiating lateral vibrations while the relative position between the workpieces in the pressing direction is maintained, a control variable is monitored, and the second workpiece is moved relative to the first only after the monitored variable satisfies a condition.

The present invention concerns a method of detecting the making or breaking of contact of a sonotrode (4) which is caused to vibrate with a frequency f and a vibration amplitude A.sub.0 with a counterpart element (5). To provide a method with which contact-making or breaking of a sonotrode with a counterpart element can be particularly quickly and inexpensively detected it is proposed according to the invention that the method has the following steps: a) recording a time configuration of the vibration amplitude A.sub.0 (1) during a first measurement time interval T, and b) determining from the time configuration of the vibration amplitude A.sub.0 (1) whether making or breaking of contact occurred within the measurement time interval T.

According to one embodiment, an ultrasonic bonding method for bonding a plurality of bonding members together by applying pressure and an ultrasonic wave includes a pressing step of applying pressure to one bonding member and another bonding member so as to press against each other, an application step of applying an ultrasonic wave to the one bonding member, a detection step of detecting a vibration state of another bonding member during the application step, and a step of determining a state of bonding between the bonding members based on the vibration state acquired in the detection step.