Development of ETM microgrippers using Topology Optimization

This article presents the development process of an microgripper for the manipulation of microelements such as particles of organic and inorganic materials. The device was deigned to manipulate microparticles between 130-140 micrometers in diameter using the thermal expansion due to the Joule effect. The microgripper geometry was optimized through a Topology Optimization Method, which applies a continuum topology optimization with spatial filtering technique. The optimized topology was modeled using Finite Element Method in order to verify the behavior of the designed geometry. The structure was fabricated using simple, low-cost process based on a flip-chip technology. The structure was fabricated using electroplated nickel, in order to increase the displacement of the tip of the microgripper. Finally, the electrothermomechanical microgripper was tested and the total displacement of the structure measured using optical microscopy. A total displacement of 20 microns can be safely achieved without permanent deformation of the structure.