Apparatus and a method for bonding webs of non-woven plastic material

An apparatus having a first treatment module and a second treatment module positionable in proximity to the first treatment module, wherein at least one of the first treatment module and the second treatment module includes a joining device for treating one or more workpieces, the apparatus comprising a controller arranged to:

• receive an ultrasonic amplitude signal representative of real-time ultrasonic vibration of at least one of the first treatment module and the second treatment module during a treatment cycle;
• segment the ultrasonic amplitude signal into a plurality of amplitude segments for the treatment cycle;
• monitor an amplitude value of each of the plurality of amplitude segments during the treatment cycle;
• operate a closed-loop control algorithm to predict a plurality of amplitude adjustment values, each of the plurality of amplitude adjustment values corresponding to a respective one of a plurality of amplitude segments in a subsequent treatment cycle;
• and apply each amplitude adjustment value to the corresponding respective one of the plurality of amplitude segments in the subsequent treatment cycle to reduce ultrasonic amplitude sag and amplitude overshoot and adapt to an ultrasonic load during the subsequent treatment cycle, wherein said treatment cycle comprises treating a single workpiece in a plurality of workpieces, and the treating comprises a bonding operation, a welding operation, a soldering operation, a fusing operation, or a cutting operation.