Method for ultrasonic spot welding and ultrasonic spot welding device

摘要

The invention relates to a method for ultrasonic spot welding in which at least two thermoplastic components to be joined are brought into contact in the region of a joining zone and between the contact surfaces of a sonotrode (20) of a vibration system (60) and an anvil (30) of an ultrasonic welding device (10 ), wherein by means of the sonotrode (20) a welding force is exerted on the components (40, 50) and the sonotrode (20) oscillates with ultrasonic vibrations (U) of a predetermined amplitude (A). According to the invention, a power consumption (P) of the oscillating system (60) is determined, a time derivative (dP / dt) of the power consumption (P) at predetermined time intervals (dt) is determined, and the amplitude (A) of the sonotrode oscillation is dependent on the value of the time derivative ( dP / dt) of power consumption (P). Furthermore, an ultrasonic spot welding device is specified.