Laser Welding of NiTi Shape Memory Wires and Printed Circuit Boards with High Repetition Nanosecond Lasers

The integration of shape memory wires into actuator systems remains a formidable challenge, necessitating both mechanical and electrical anchoring to effectively induce and control the shape memory effect (SME). A promising approach involves directly connecting wires with printed circuit boards (PCBs), offering numerous benefits. This method eliminates the need for additional materials such as crimps or clamp connections, as well as extra steps for electrical connections. Consequently, engineering new actuator systems becomes more straightforward, as key integration obstacles are effectively addressed through the assembly. Traditionally, soldering has been the go-to technique for bonding components to PCBs. However, soldering NiTi presents challenges due to the poor wettability of its natural passivation layer, requiring the use of aggressive fluxes. Furthermore, soldered connections exhibit limited resistance to mechanical loads. To overcome these limitations and establish a more robust connection that ensures both mechanical and electrical integrity for actuators, micro laser welding proves to be a superior alternative. The control of heat input through laser radiation is of paramount importance for achieving this objective. Nanosecond laser welding with high repetition rates offers here a highly promising solution, due to the short interaction time of each pulse. In this study, the mechanical and functional properties of the compound are characterized