Dedicated optical instruments for ultrasonic welder inspection and control

Two different optical instruments for real-time vibration measurements, inspection and control of ultrasonic welders were designed, realized and characterized: a self-mixing laser interferometer and an optical triangulator, both studied for achieving high bandwidth and very good resolution within a short dynamic range. The implemented instruments can solve the problem of measurement and control of ultrasonic welders that until now has no low-cost solutions available on the market. The performance of the two developed instruments was compared in order to assess which is the most appropriate for this specific application. Finally, results of the real-time characterization of an ultrasonic welder are given and discussed.