Laser soldering of piezoelectric actuator with minimal thermal impact

Mechanical and electrical connecting of piezoelectric actuator is often done using conductive glue. Its advantage is not to heat the piezoelectric actuator during connection. But there are many disadvantages to gluing; the main one is curing time. Welding is another alternative, but when done in an oven, the temperature needed for this operation might destroy the heat sensitive actuator. The method described in this paper is laser soldering of piezoelectric actuator. The piezo actuator is mechanically and electrically connected to an alumina substrate by the use of tin solder heated by the mean of a laser diode. The advantage of the laser diode is its ability to selectively heat needed areas. Moreover, it is possible to control the energy brought to the system during the soldering process, thus reducing thermal impact on the piezoelectric actuator. Finally, the temperature can be monitored during the soldering process, allowing to control if the piezoelectric actuator was exposed to high temperature.