Laser Structuring Expands the Design Space for Shape Memory Alloy Actuators

Low-cost, low-power laser processing (patent pending- Khanjur) offers a scalable approach for microstructuring shape memory alloy (SMA) sheet, strip, and thin-film materials for advanced actuation applications. In this work, we demonstrate a laser cutting process capable of achieving feature sizes on the order of the SMA thickness—enabling precision structuring of sub-100 µm films up to hundreds of microns thick. This method allows for fabrication of auxetic, metamaterial, and serpentine geometries that extend the effective recoverable strain of SMAs from their intrinsic 4–8% to macroscale strains of 10–100s %, while maintaining low local strain (< 2%) within the material. Furthermore, these 2D structures allow the SMA materials to adapt to complex 3D curvatures.

One 2D auxetic geometry was successfully actuated for 2.5 million cycles at 10% macro strain, demonstrating the potential of geometric amplification to dramatically improve functional fatigue life without employing electropolishing. Compared with conventional machining or photochemical etching, this laser-based process minimizes thermal and mechanical damage to the SMA, preserving transformation behavior and surface quality critical for actuation performance.

Overall, this scalable laser structuring platform expands the design space for next-generation SMA components for actuators, interconnects, morphing structures, and stretchable electronics. It provides a rapid, low-cost manufacturing route to lightweight and miniaturized devices that leverage metamaterial geometries to achieve large, reversible deformations with exceptional durability and reliability.

Keywords—shape memory alloy, NiTi, microactuator, laser processing